Resonant power supplies with high efficiency circuit. Resonant transformer and some of its applications. Heating from Andreev on a resonant choke with an Ш-shaped core from a transformer and DRL lamps

The principle is a device with an efficiency above 100%, you will say that this is a fake and everything is not real, but this is not true. The device was assembled using domestic parts. The design of the transformer has one feature: the transformer is W-shaped with a gap in the middle, but in the gap there is a neodymium magnet that sets the initial impulse to the coil feedback. The pickup coils can be wound in any direction, but at the same time, pinpoint precision is required in their winding; they must have the same inductance. If this is not observed, then there will be no resonance; a voltmeter connected in parallel to the battery will inform you about this. Special Applications I didn’t find it in this design, but you can connect a light source in the form of incandescent lamps.

Technical characteristics at resonance:
Efficiency is above 100%
Reverse current is 163-167 milliamps (I don’t know how this happens, but the battery is charging)
Current consumption is 141 milliamps (it turns out that 20 milliamps is free energy and goes to charge the battery)

Red wire coil L1
Green wire coil L2
The black wire is the pickup coil

Settings

From my own experience, I was convinced that coil L1, wound with the same wire, is more easily tuned to resonance with L2, creating more current than is consumed. As I understand it, ferromagnetic resonance is created, which powers the load and charges the battery with a high current. To adjust the resonance, there must be two identical coils or one; when the device is turned on, they move under the load of an incandescent lamp (in my case, a 12 Volt 5 Watt lamp). To set up, connect a voltmeter in parallel to the battery and start moving the coil(s). At resonance, the voltage on the battery should begin to increase. Having reached a certain threshold, the battery will stop charging and discharging. You need to install a large heatsink on the transistor. In the case of two coils, everything is more complicated, since you need to wind them so that the inductances are practically the same; with different loads, the location of the right and left coils will change. If these tuning rules are not followed, then resonance may not occur, but we will get a simple boost converter with high efficiency. My coil parameters are 1:3, that is, L1 8 turns, L2 24 turns, both with the same wire cross-section. L1 dangles on top of L2. Removable coils, no matter what kind of wire, but I have 1.5mm.

Photo

The finished device is in a non-resonant state (coils connected in series)

Test of self-powering from a removable coil through a diode. (Result: failure, runs for 14 seconds with decay)

The state of resonance on one coil without self-powering through a diode. The experiment was successful, with the battery connected, the converter worked for 37 hours 40 minutes, without losing voltage on the battery. At the beginning of the experiment, the battery voltage was 7.15 volts, by the end it was 7.60 volts. This experience has proven that the converter is capable of delivering efficiency above 100%. For the load I used a 12 Volt 5 Watt incandescent lamp. I refused to try to use other devices, since the magnetic field around the device is very strong and creates interference within a radius of one and a half meters, the radio stops working within a radius of 10 meters.

List of radioelements

Usage: development of high frequency pulse sources nutrition. The essence of the invention: the power source holds a key transistor voltage converter 1, made in the form of a half-bridge circuit on transistors 4.5 and capacitors 6.7, and a frequency control unit 25, made in the form of a series-connected node 26 for converting voltage into resistance and node 27 for converting resistance into frequency The output circuit of converter 1 includes a resonant circuit made of inductor 8 and capacitors 9, 10. Stabilization of changes in the operating frequency of converter 1 depending on changes in the output voltage. The formation of a special form of the base current of transistors 4, 5 using block 25 and chains made on elements 15-22 reduces losses both when the current is turned on and when transistors 4, 5 are turned off. f-ly, 3 ill.

The invention relates to electrical engineering and can be used in the development of high-quality switching power supplies. Famous pulse stabilizer voltage, containing a push-pull half-bridge voltage converter, input connected to input pins, and the output is through a rectifier and a filter with output leads, a pulse-width modulator, the outputs of which are connected to the control inputs of a push-pull half-bridge voltage converter, a square wave generator, a sawtooth voltage former, a reference voltage source and two transistors (1). The known device solves the technical problem of increasing efficiency by using it for comparison in a pulse-width modulator alternating voltages : rectangular reference and sawtooth, proportional to the input voltage. Obtaining such voltages and comparing them requires less energy expenditure. And using the reference voltage source current to simultaneously control the transistors of a push-pull half-bridge voltage converter, along with the use of passive PWM, further increases efficiency. PWM power supplies are prevalent nowadays. However, they are characterized by too high losses, since they belong to so-called hard switching circuits. With hard switching, the switched-on transistor switch turns off at the moment when current flows through it, and the switched-off transistor switch turns on when there is voltage across it, and therefore, the more often this switch is turned on and off, the greater the losses. In this case, the switching time of the transistor (duration of switching on or off) should be as short as possible. Thus, the disadvantage of the known device is high losses, i.e. low efficiency. Ideally, in order for losses to be minimal, the transistor switch should turn off when the current through it is zero (zero current switching) and turn on when the voltage across it is zero (zero voltage switching). Currently, the best solution for high-frequency switching power supplies is the use of resonant circuits. Unlike power supplies with PWM, resonant circuits “soften” the switching mode and thus help reduce switching losses. As a result, resonant power supplies provide higher efficiency at the same operating frequency. A known resonant power supply containing a key transistor voltage converter, input connections with input terminals and made in the form of a half-bridge circuit, in the output circuit of which a resonant circuit is included, consisting of a series circuit connected in parallel on the inductor and the first capacitor and a second capacitor, and parallel to the first capacitor the primary winding of the output transformer is turned on, the secondary winding of which is connected to the output terminals through a rectifier and filter, and the frequency control unit, the outputs of which are connected to the control inputs of the key transistor voltage converter, the power terminals of the transistors of which are shunted by blocking diodes (2). The known power source is an analogue that is closest to the proposed invention in terms of the totality of essential features. However, the known power source also has significant switching losses, due to the fact that the frequency control unit produces rectangular oscillations and, therefore, the control current of the converter transistor also has a rectangular shape. The technical objective of this invention is to reduce losses when switching transistors of a key transistor voltage converter and reduce the power consumed by the frequency control unit. The technical result that can be obtained by using the invention is to increase the efficiency of the resonant power supply. The stated technical problem is achieved by the fact that in a resonant power supply containing a key transistor, a voltage converter, input connections with output terminals and made in the form of a half-bridge circuit, in the output circuit of which a resonant circuit is included, consisting of a series circuit connected in parallel on the inductor and the first capacitor and a second capacitor, and in parallel with the first capacitor is connected the primary winding of the output transformer, the secondary winding of which is connected to the output terminals through a rectifier and filter, and a frequency control unit, the outputs of which are connected to the control inputs of the key transistor voltage converter, the power terminals of the transistors of which are shunted by blocking diodes, the block frequency control is made in the form of two base resistors and a diode connected in series and on an additional capacitor connected between common point resistors and a free output of the diode, while the control inputs of the transistors are connected through the corresponding base current generation chains to the corresponding control inputs of the key transistor voltage converter, and the resistance-to-frequency conversion unit is made in the form of a paraphase multivibrator on four logical inverters, the third and fourth capacitors, on an additional transistor and three resistors, and the logical inverters are connected in pairs in series, respectively, the first with the second and the third with the fourth, the third capacitor is connected between the output of the first and the input of the third logical inverters, and the fourth capacitor is connected between the output of the third and the output of the first logical inverters, the first resistor connected in parallel to the output of the voltage-to-resistance converter unit, through the second and third resistors connected to the outputs of the first and third logical inverters, respectively, the outputs of the second and fourth logical inverters are connected to the primary winding of an additional transformer, the two secondary windings of which are used as outputs of the resistance conversion unit to frequency and outputs of the frequency control unit, the input of which is the input of the voltage-to-resistance conversion unit connected to the output terminals. In addition, the voltage-to-resistance conversion unit is made of an additional transistor, the output of which is used as the output of the voltage-to-resistance conversion unit, a variable resistor used as the input of the voltage-to-resistance conversion unit, and a fourth resistor connected between the input and output of the voltage-to-resistance conversion unit. resistance, and the adjusting terminal of the variable resistor is connected to the base of the additional transistor. Logic inverters can be made using 2I-NOT elements. To ensure starting of the voltage converter, an additional transformer is equipped with a starting winding included in output circuit key transistor voltage converter in series with the resonant circuit. The invention is illustrated by drawings, where in FIGS. 1 shows a diagram of a resonant power supply; Fig. 2 form of the base current of the transistors of the key transistor voltage converter, in Fig. 3 its adjustment characteristic. The resonant power supply (Fig. 1) contains a key transistor voltage converter 1, connected by an input to the output terminals 2, 3 and made in the form of a half-bridge circuit on transistors 4, 5 and capacitors 6, 7, in the output circuit of which a resonant circuit is included, consisting of connected in parallel to the series circuit on the inductor 8 and the first capacitor 9 and the second capacitor 10, the output transformer 11, the primary winding which is connected in parallel to the capacitor 9, and the secondary winding through the rectifier 12 and filter 13 is connected to the output of the key transistor voltage converter connected to the output terminals, to which the load 14 is connected, base current generation chains made in the form of series-connected base resistors 15 and 16, 17, 18 and diodes 19 and 20, and on additional capacitors 21 and 22 connected between the common point of resistors 15, 16 and 17, 18 and free terminals of diodes 19 and 20, respectively, blocking diodes 23 and 24, shunting power terminals of transistors 4 and 5, frequency control unit 25, made in the form of series-connected nodes for converting voltage into resistance 26 and a node for converting resistance into frequency 27. Node 27 converting resistance to frequency contains a paraphase multivibrator on four logical inverters 28, 29, 30, 31, a third capacitor 32, a fourth capacitor 33, an additional transformer 34 and three resistors 35, 36, 37, and the logical inverters are connected in pairs in series, 28 with 29 and 30 with 31, the third capacitor 32 is connected between the output of the logical inverter 28 and the input of the logical inverter 30, the fourth capacitor 33 is connected between the output of the logical inverter 30 and the input of the logical inverter 28, the first resistor 35 is connected in parallel with the output of the voltage-to-resistance conversion node 26, through the second resistor 36 and third resistor 37 connected to the inputs, respectively, of logical inverter 28 and logical inverter 30, the outputs of logical inverter 29 and logical inverter 31 are connected to the primary winding 38 of an additional transformer 34, the secondary windings 39 and 40 of which are used as outputs of node 27 converting resistance to frequency and outputs of frequency control unit 25. Logic inverters 28, 29, 30, 31 can be made, for example, on 2I-NOT elements. As the input of the frequency control unit 25, the input of the voltage-to-resistance conversion unit 26 is used, made on an additional transistor 41, the output of which is used as the output of the voltage-to-resistance conversion unit 26, on a variable resistor 42, used as the input of the voltage-to-resistance conversion unit 26 , and the fourth resistor 43, connected between the input and output of the voltage-to-resistance conversion unit 26, and the adjusting terminal of the variable resistor 42 is connected to the base of the additional transistor 41. The input of the frequency control unit 25 is connected to the load 14. To ensure the start of the key transistor voltage converter, 1 additional transformer 34 is equipped with a starting winding 44, connected to the output circuit of the key transistor converter 1 in series with the resonant circuit. The paraphase multivibrator is powered from a separate power source and from a reference voltage source (elements 45, 46) by applying voltage to it from the output of the rectifier 12 of the key transistor voltage converter 1 through a capacitive filter 47. Resistors 48, 49, 50, 51 set the required operating mode transistors 4 and 5. The resonant power supply works as follows. When the power source is turned on, the key transistor voltage converter 1 is excited due to the positive feedback of the starting winding 44 of the additional transformer 34 and begins to generate low-frequency pulses. A voltage appears on the secondary winding of the output transformer 11, which through the rectifier 12 powers the microcircuit on the logical inverters 28.31 of the paraphase multivibrator. The multivibrator begins to generate high-frequency pulses that enter through transformer 34 on the base current generation chain of transistors 4 and 5. Thanks to the base current formation of transistors 4 and 5 of converter 1 using frequency control unit 25 and base current generation chains (elements 15.22), a reduction in losses is achieved transistors 4 and 5 when they are switched. At moment t 1 (Fig. 2), transistor 4 is turned on (turned on at zero voltage). With such a sharp jump in the base current, losses when the transistor is turned on are reduced. The transistor is turned on and saturated for time t 1 t 2 . In this case, the base current decreases linearly to a value of i b min. at which the transistor is still saturated. With a value of i b, the absorption time t of the transistor when it is turned off will be minimal, which leads to a decrease in losses when the transistor is turned off. During time t 2 t 3 when the base current takes negative values, turn-off time of the transistor due to an additional decrease in t races. decreases, thereby reducing heat losses when the transistor is turned off. Thus, due to the formation of the base current of transistors 4 and 5 of a special shape (Fig. 2), losses are reduced both when turning on and off the transistors of the converter 1. When transistor 4 is turned on, the current in the inductor 8 begins to gradually increase. This current equal to the sum current in the primary winding of transformer 11 and charging current capacitor 9. When the voltage on capacitor 9 and the primary winding of transformer 11 is equal to the input voltage, the voltage drop across inductor 8 will become zero, after which the energy stored in inductor 8 begins to charge capacitor 9. After a time interval, which is set by its own resonant frequency circuit, the current in inductor 8 and, consequently, in transistor 4 will become zero. Then the current through the inductor 8 will change direction and the capacitor 9 begins to discharge, maintaining the flow of current through the diode 23. In this case, the transistor 4 turns off (switching at zero current). The resonant half-cycle of charging capacitor 10 begins after transistor 4 is turned off and ends before transistor 5 is turned on. When both transistors are turned off, energy is transferred from inductor 8 to capacitor 10. As capacitor 10 charges, the voltage on transistor 4 increases and on transistor 5 decreases. When the voltage on transistor 5 drops to zero, it is turned on without loss, while diode 24 ensures that the energy remaining in inductor 8 is returned back to the input of the resonant power source. The next half-cycle is identical to the first and begins when transistor 5 turns off. Now the voltage on transistor 5 will increase, and the voltage on transistor 4 will decrease, and when it drops to zero, transistor 4 turns on without loss. As in other resonant power supplies, a change in the operating frequency of converter 1 leads to a change in the output voltage, and the operating frequency of converter 1 is higher than its resonant frequency, and operating point transformation is located on the right slope of the resonance curve of the circuit (Fig. 3) on its straight section. Stabilization of the output voltage is carried out by supplying a negative feedback voltage from the load 14 to the frequency control block 25 and generating control pulses in this block for transistors 4 and 5 of the converter 17. In the frequency control block 25, the voltage is converted into resistance using node 26, and then converting resistance into frequency using node 27. Frequency modulation occurs by changing the resistance of resistor 35, shunted by transistor 41. Resistor 35 and capacitors 32, 33 and resistors 36, 37 perform the function of timing elements of a paraphase multivibrator. When the output voltage decreases from the value U 0 to U 2 due to an increase in the load current, the frequency of the paraphase multivibrator decreases from the value f 1 to the value f 3 (Fig. 3), while output voltage converter 1 increases to the value U 1 and the decrease in the source output voltage is compensated. Thus, the output voltage of the resonant power supply will remain unchanged. Similarly, the output voltage is stabilized by reducing the load current. On the resonant (adjustment) characteristic (Fig. 3), the operating point of the conversion shifts along the line f 1, f 2, f 3: the greater the current in the load, the closer the operating point to the frequency and vice versa, the lower the current in the load, the closer the operating point to frequency f 2 . With very large load points or short circuits in the load, the conversion operating point shifts to the left beyond resonant frequency f p , reducing the voltage to almost zero (point f 4, Fig. 3). In this case, protection against short circuits of the power source is carried out without the use of any additional elements. The proposed design of the frequency control unit, in particular its resistance-to-frequency conversion unit, is very economical, because characterized by low power consumption. Thus, this invention makes it possible to increase the efficiency of a resonant power supply.

CLAIM

The principle of realizing secondary power through the use of additional devices that provide energy to circuits has been used for quite a long time in most electrical appliances. These devices are power supplies. They serve to convert voltage to required level. PSUs can be either built-in or separate elements. There are two principles for converting electricity. The first is based on the use of analog transformers, and the second is based on the use of switching power supplies. The difference between these principles is quite big, but, unfortunately, not everyone understands it. In this article we will figure out how a switching power supply works and how it differs so much from an analog one. Let's get started. Go!

Transformer power supplies were the first to appear. Their operating principle is that they change the voltage structure using a power transformer, which is connected to a 220 V network. There, the amplitude of the sinusoidal harmonic is reduced, which is sent further to the rectifier device. Then the voltage is smoothed by a parallel connected capacitor, which is selected according to the permissible power. Voltage regulation at the output terminals is ensured by changing the position of trimming resistors.

Now let's move on to pulse power supplies. They appeared a little later, however, they immediately gained considerable popularity due to a number of positive features, namely:

• Availability of packaging;
• Reliability;
• Possibility to expand the operating range for output voltages.

All devices that incorporate the principle switching power supply, are practically no different from each other.

The elements of a pulse power supply are:

• Linear power supply;
• Standby power supply;
• Generator (ZPI, control);
• Key transistor;
• Optocoupler;
• Control circuits.

To select a power supply with a specific set of parameters, use the ChipHunt website.

Let's finally figure out how a switching power supply works. It uses the principles of interaction between the elements of the inverter circuit and it is thanks to this that a stabilized voltage is achieved.

First, the rectifier receives a normal voltage of 220 V, then the amplitude is smoothed using capacitive filter capacitors. After this, the passing sinusoids are rectified by the output diode bridge. Then the sinusoids are converted into high-frequency pulses. The conversion can be performed either with galvanic separation of the power supply network from the output circuits, or without such isolation.

If the power supply is galvanically isolated, then the high-frequency signals are sent to a transformer, which performs galvanic isolation. To increase the efficiency of the transformer, the frequency is increased.

The operation of a pulse power supply is based on the interaction of three chains:

• PWM controller (controls pulse width modulation conversion);
• A cascade of power switches (consists of transistors that are switched on according to one of three circuits: bridge, half-bridge, with a midpoint);
• Pulse transformer (has primary and secondary windings, which are mounted around the magnetic core).

If the power supply is without decoupling, then the high-frequency isolation transformer is not used, and the signal is fed directly to the low-pass filter.

Comparing impulse blocks power supply with analog, you can see the obvious advantages of the former. UPSs have less weight, while their efficiency is significantly higher. They have a wider supply voltage range and built-in protection. The cost of such power supplies is usually lower.

Disadvantages include the presence of high-frequency interference and power limitations (both at high and low loads).

You can check the UPS using a regular incandescent lamp. Please note that you should not connect the lamp into the gap of the remote transistor, since the primary winding is not designed to pass direct current, so under no circumstances should it be allowed to pass.

If the lamp lights up, then the power supply is working normally, but if it doesn’t light up, then the power supply is not working. A short flash indicates that the UPS is locked immediately after startup. A very bright glow indicates a lack of stabilization of the output voltage.

Now you will know what the operating principle of switching and conventional analog power supplies is based on. Each of them has its own structural and operating features that should be understood. You can also check the performance of the UPS using a regular incandescent lamp. Write in the comments whether this article was useful to you and ask any questions you have about the topic discussed.

The essence of the invention: in a resonant power supply containing a rectifier unit, phase capacitors connected on the AC side, and an inductance connected to the output of the rectifier unit, the phase capacitors are connected in series with the corresponding inputs of the rectifier unit. 3 ill.

The invention relates to electrical engineering, in particular to devices for powering an arc discharge. Currently, a significant number of designs of power sources for welding and plasma arcs have been developed, differing from each other both in circuit design and operating principle. To power an arc discharge, sources with steeply falling or vertical characteristics (current sources) are most often used. In terms of circuit solutions, sources with saturation chokes, sources on controlled devices and parametric sources have become predominantly widespread (A. V. Donskoy, V. S. Klubnikin. Electroplasma processes and installations in mechanical engineering. L. Mechanical Engineering, 1979, 164 pp.). Arc installations with saturation chokes have become widespread due to their simplicity and reliability in operation. The external characteristic is formed by demagnetizing the saturation chokes. Arc electrical installations on controlled devices most often represent power sources on controlled thyristor valves. The operating current of such sources is determined by the valve firing angle, which leads to the need to install smoothing chokes in the DC circuit. The disadvantages of power supplies based on semiconductor valves controlled by the opening angle include inertia due to the synchronous operation of the controlled valves with the supply voltage, a decrease in the power factor, significant ripple and the impact on the supply network, especially at low loads. With deep regulation, these shortcomings can lead to disruption technological process and unstable arc combustion (A.V. Donskoy, V.S. Klubnikin. Electroplasma processes and installations in mechanical engineering. L. Mechanical Engineering, 1979, 168 pp.). Parametric arc discharge power supplies are built on passive inductive-capacitive elements. As studies have shown, the introduction of reactive elements into the circuit, while slightly reducing the efficiency of the installation, provides good current stabilization, a high power factor and a weak influence of the power source on the shape of the supply network voltage. The type of sources under consideration can be widely used in electric arc installations (B. E. Paton et al. Plasma processes in metallurgy and technology of inorganic materials. M. Nauka, 1973, 244 pp.). The main disadvantages of such installations include the complexity of regulation, which can be carried out in three ways: a smooth change in the supply voltage, designed for full throughput power, which is acceptable only for low-power installations; synchronous change in the inductance and capacitance of reactive elements, which is technically difficult to implement, and the imbalance of inductive and capacitive reactances sharply worsens the stabilizing properties of the circuit; changing the transformation ratio of the power transformer, for example, by changing the number of turns (A. V. Donskoy, V. S. Klubnikin, Electroplasma processes and installations in mechanical engineering. L. Mechanical Engineering, 1979, 170 pp.). A direct current source is known that contains a transformer having a primary winding and at least one secondary winding, the primary winding being connected to an alternating current source, a system of capacitors connected in parallel to the secondary winding. The capacitive reactance of the capacitor system is equal to the inductive reactance of the secondary winding. This creates a resonant inductive-capacitive circuit. A special device converts the output signal coming from the circuit into a constant one (US patent N 4580029, class B 23K 9/00). Figure 1 shows a schematic diagram of a known power source. The source, connected to the supply network through a transformer T, contains a secondary winding L 2, a system of capacitors C, a rectifier B, a choke L, a load R. The formation of a falling I-V characteristic of a known device is carried out by shunting a system of capacitors With a changing value of the load resistance and at R 0 the capacitance of the circuit absent, the resonance condition is violated, the total resistance of the circuit increases and limits the amount of current short circuit. An increase in load resistance leads to an increase in the recharge current of the capacitors and a corresponding increase in voltage. A necessary condition The performance of a known device is the equality of the inductive and capacitive resistances of the oscillating circuit. However, it is known that if the inductive and capacitive resistances are equal, the current in the circuit is determined only by the total active resistance of the circuit and can reach significant values. In particular, this should be expressed in an increased value of the no-load current. The next feature of the known device is the reduced efficiency of the power supply, since parallel to the current removed from the rectifier device, there is a recharging current of the capacitor system C and corresponding energy losses. Inductance L is obviously intended to smooth out ripples, because for the three-phase circuit of the known device, inductance L 1 is not provided. The purpose of the present invention is to simplify the circuit and improve operating efficiency. This goal is achieved by the fact that in a resonant power supply containing a rectifier unit, phase capacitors connected on the AC side, and an inductance connected to the input of the rectifier unit, the phase capacitors are connected in series with the corresponding inputs of the rectifier unit. The proposed power source (for the single-phase power supply option) is shown in Fig. 2 and contains a capacitor C, a rectifier block B, an inductance L, a load R (arc gap). The operation of the proposed device is based on the interaction of the voltage across the capacitive reactance of the capacitor C and the voltage across the inductance L, switched on for direct current, carried out by means of a switching element B, which converts alternating current into direct current. When the arc gap is short-circuited, the maximum current value is established in the circuit. In this case, the inductance connected via direct current is a smoothing choke. The ripple of the rectified current is insignificant; the inductor resistance is determined mainly by the active resistance of the winding. Thus, the voltage drop across the inductor is insignificant, and the main voltage drop occurs across capacitor C, the resistance of which determines the short circuit current. When an arc gap is formed, the active resistance of the circuit increases sharply, reducing the inductor current. Since the amount of ripple on the inductor is inversely dependent on the ratio /L/R, where is the cyclic frequency, L inductance, R load resistance (I. I. Belopolsky. Power supplies for radio devices. M. Energy, 1971, 92 pp.), then an increase in resistance leads to an increase in pulsation, i.e., the variable component in the voltage applied to the inductor. A decrease in current with an increase in the arc gap leads to a decrease in the voltage on the capacitor, since U c X c I, where U c is the voltage across the capacitance, X c is the capacitance reactance, I is the current through the capacitor. Due to the fact that the voltages across the inductance and capacitance are out of phase, the overall reactance of the circuit drops. Thus, an increase in resistance with an increase in the arc gap leads to a decrease in reactance and an increase in voltage across the latter. In fig. Figure 3 shows timing diagrams of the operation of the power source, where i R is the load current curve, i 1, i 2 are the rectifier current curves, U R the load voltage, U L the inductance voltage, U c the capacitor voltage, and capacitor current curves. For a three-phase supply network, the operating principle is similar. Distinctive feature The source of the proposed circuit solution is the ability to operate without a transformer, while the device converts a rigid current-voltage characteristic of the circuit into a steeply falling one without the danger of a short circuit and limits the power consumption depending on the conditions of the discharge. In the proposed circuit there is no oscillatory circuit for the alternating current supply, and the current flowing through the block of capacitors C corresponds to the operating current of the power source. As shown practical research of the proposed device, the voltage across the arc gap as its length increases and the electrical power changes several times due to the redistribution of voltages on the reactive elements of the power source. The studies were carried out in the current range from 5 to 100 A, no-load voltage 220 V. The operation of the source is characterized by high stability of arc discharge, the achieved efficiency is over 80% If it is necessary to change the operating voltage, it is permissible to use, in contrast to the known device, a transformer without leakage, which increases efficiency operation of the power source.

Claim

Resonant power supply with steep slope external characteristic, containing a rectifying unit, phase capacitors connected on the AC side, and an inductance connected to the output of the rectifying unit, characterized in that the phase capacitors are connected in series with the corresponding inputs of the rectifying unit.

MICOR technology. New generation of power supplies based on resonance phenomenon

Method using pulse width modulation(PWM), is the answer to the search for an almost perfect stabilized power supply. It is known that in a pulsed source the switch is either on or off and control is carried out with zero power dissipation, in contrast to a linear stabilizer, where stabilization occurs due to power dissipation in the pass element. In real-world applications, PWM provides a reasonable approach to lossless switching due to lower switching frequency, such as in the range of 20-40 kHz. If you look at the situation from the other side, you can tell why this frequency range has been popular for so long.

Since the early days of PWM stabilization, designers have tried to move toward higher frequencies because they can reduce the size, weight, and cost of the magnetic core and filter capacitors.

High switching frequencies also provide other benefits. By using higher frequencies, one can expect a reduction in radio interference and electromagnetic noise; fewer problems with shielding, decoupling, insulation and limitation in the circuit. You can also expect faster response, as well as lower output impedance and ripple.

The main obstacle to the use of higher frequencies was the practical difficulty of creating fast and sufficiently powerful switches. Due to the fact that it is impossible to achieve instantaneous switching on and off of the switch, there is voltage on it during switching and at the same time current flows through it. In other words, trapezoidal rather than square oscillations characterize the switching process. This in turn results in switching losses that cancel out the theoretically high efficiency of an ideal switch that turns on instantly, has zero on-resistance, and turns off instantly. In Fig. 1 compares PWM and switching mode in the resonant mode, which will be discussed in more detail.

From the above, it is obvious that an ideal switch should not have any voltage drop while it is on. All these considerations suggest that high efficiency was an elusive goal, especially at high switching frequencies, until progress was made in the creation of switching semiconductor devices.

It should also be pointed out that at the same time progress was needed in the creation of other devices, such as diodes, transformers and capacitors.

We must pay tribute to workers in all areas of technology: the switching frequency when using PWM was increased to 500 kHz. However, at higher frequencies, say 150 kHz, it is better to consider a different method. So, we come to the resonant mode of operation of the power source.

A stabilized power supply using resonant mode is truly a big leap forward in technology development. Although it must be said that the use of resonant phenomena in inverters, converters and power supplies precedes the era of semiconductors. It turned out that when using resonance phenomena it was often possible to obtain good results.

For example, in the first televisions, the necessary high voltages for the picture tube were obtained using a radio frequency power source.

It was a vacuum tube sine wave generator operating at a frequency of 150 to 300 kHz, in which an increase in alternating voltage was achieved in a resonant radio frequency transformer. As such, similar circuits are still used to generate voltages of at least several hundred thousand volts for a variety of industrial and research purposes. Higher voltages are often achieved through the combined use of resonant operation and a diode voltage multiplier.

It has long been known that the resonant output circuits of the inverter stabilize the operation of electric motors and welding equipment. Typically, a coil with high inductance was connected to the break in the wire leading from the DC voltage source to the inverter. In this case, the inverter behaves in relation to the load as a current source, which makes it easier to comply with the condition of the existence of resonant phenomena. In this case, it is more correct to call existing thyristor inverters quasi-resonant: the oscillatory circuit is periodically subjected to shock excitation, but there are no continuous oscillations. Between excitation pulses, the oscillatory circuit releases the stored energy to the load.

From the above it is clear that the widespread use of the resonant operating mode began after the creation of specialized control ICs. These ICs freed designers from the problems with failures that inevitably accompany the desire to use resonant mode at frequencies of several hundred kilohertz or several megahertz, where small component sizes can provide significant reductions in size, weight and cost.

In 2010, our specialists created a number of welding machines for manual arc welding using a resonance operating system: Handy-190, Handy-200, X-350 Storm (Fig. 2).

Currently, machines for semi-automatic and automatic welding are designed based on this technology (Fig. 3).

Such equipment has a number of technological advantages:

• almost “ideal” external current-voltage characteristic of the power source, a more elastic and soft arc due to the resonant control structure;
• reliable ignition and comfortable welding for all types of electrodes;
• significantly higher efficiency (lower power consumption);
• the possibility of more precise control of droplet transfer due to the instantaneous (1.5 MHz) response of the control circuit to external disturbances (arcs), and as a result - a significant reduction in spatter, stable burning of the welding arc in all spatial positions.

Rice. 1. Oscillograms showing the difference between PWM (left) and resonant mode (right). With PWM, switching losses occur due to the simultaneous flow of current through the switch and the presence of voltage across it.

Note that this situation does not exist in resonant operating mode, which uses frequency modulation (FM) to stabilize the voltage.

Rice. 2. Handy-190 Micor

Rice. 3. Basic circuit of a resonant converter