Pulse power supply with multiple protection functions

Abstract

The utility model discloses a pulse power supply with multiple protection functions, which comprises a rectification inverter circuit and a chopper circuit, the rectification inverter circuit inputs power frequency alternating current and outputs controllable direct current, and the chopper circuit inputs controllable direct current and outputs pulse current; the inverter control circuit controls and outputs a pulse width driving signal to the rectification inverter circuit according to the voltage control signal; the multi-protection circuit comprises at least two protection circuits, the output end of each protection circuit is connected with a forward diode and then outputs the voltage control signal, and the duty ratio of the pulse width driving signal is controlled to be zero according to the voltage control signal. The beneficial effects are that multiple protection can be carried out on the pulse power supply, and the multiple protection does not interfere with each other.

Description

Technical Field

[0001] The utility model relates to the technical field of pulse power supplies, in particular to a pulse power supply with multiple protection functions. Background Art

[0002] High-frequency pulse power supply is suitable for electroplating gold, silver, nickel, tin, and alloys, and can significantly improve the functionality of the coating. It includes a rectifier and inverter circuit that converts industrial frequency AC power into DC power, and a chopper circuit that converts DC power into pulse power. By controlling the duty cycle of the pulse width drive signal sent to the rectifier and inverter circuit, the current and voltage of the DC power can be controlled.

[0003] In the rectifier inverter circuit, when phase loss, overcurrent or high temperature occurs, the inverter needs to be stopped to protect the circuit;

[0004] The disadvantages of the existing technology are: the high-frequency pulse power supply does not provide multiple protections for the circuit, and cannot ensure that the multiple protections do not interfere with each other. Utility Model Content

[0005] In view of at least one defect of the prior art, the purpose of the present invention is to provide a pulse power supply with multiple protection functions, which can provide multiple protections for the pulse power supply without interfering with each other.

[0006] In order to achieve the above object, the utility model adopts the following technical solution: a pulse power supply with multiple protection functions, including a rectifier inverter circuit and a chopper circuit, the rectifier inverter circuit inputs industrial frequency AC power and outputs controllable DC power, the chopper circuit inputs controllable DC power and outputs pulse power;

[0007] The inverter control circuit also includes an inverter control circuit, which inputs a voltage control signal and outputs a pulse width drive signal to the rectifier inverter circuit, controls the duty cycle of the pulse width drive signal according to the voltage control signal, and further controls the voltage and current of the controllable direct current;

[0008] The key lies in: it also includes multiple protection circuits, the multiple protection circuits include at least two protection circuits, the output end of each protection circuit is connected to a forward diode, and the voltage control signal is output, and the duty cycle of the pulse width drive signal is controlled to be zero according to the voltage control signal.

[0009] When any protection circuit detects phase loss, overcurrent or high temperature, the rectifier inverter circuit receives a pulse width drive signal with a zero duty cycle, and then stops inversion to protect the circuit; a forward diode is connected to the output end of each protection circuit to ensure that multiple protection circuits do not interfere with each other, while still being able to output voltage control signals normally.

[0010] Furthermore, the multiple protection circuits include a temperature protection circuit;

[0011] The temperature protection circuit is provided with a temperature control switch, which is arranged on the radiator in the rectifier inverter circuit; or when the pulse power supply is used for electroplating, the temperature control switch is arranged on the electrolytic cell;

[0012] The +12V power supply terminal is connected to the cathode of the Zener diode D801, the anode of the Zener diode D801 is connected to the cathode of the Zener diode D802, the anode of the Zener diode D802 is grounded, the common terminal of the Zener diodes D801 and D802 is connected to the reverse terminal of the op amp U12B, and the Zener diode D801 is connected in parallel with the resistor R801;

[0013] The temperature control switch is connected to the reverse end of the operational amplifier U12B;

[0014] The +12V power supply terminal is connected to the front end of resistor R802, the back end of resistor R802 is connected in series with a reverse voltage zener diode D803 and then grounded, and the common end of resistor R802 and voltage zener diode D803 is connected to the same direction terminal of op amp U12B;

[0015] The output end of the operational amplifier U12B is connected to the anode of the diode D804, and the cathode of the diode D804 outputs the voltage control signal;

[0016] The reverse end of the operational amplifier U12B is connected in series with a capacitor C801 and then grounded. The same end of the operational amplifier U12B is connected in series with a capacitor C802 and then grounded. A parallel capacitor C803 is connected between the output end and the reverse end of the operational amplifier U12B.

[0017] The output end of the operational amplifier U12B is connected to the positive electrode of the light emitting diode ED4, and the negative electrode of the light emitting diode ED4 is connected in series with a resistor R803 and then grounded.

[0018] The voltage input to the same-direction end of the op amp U12B is the voltage regulation value of the voltage-regulating diode D803. When the temperature control switch does not output a signal, the voltage input to the reverse end of the op amp U12B is higher than that to the same-direction end, and the op amp U12B outputs a low level, which does not affect the voltage-controlled signal. When overtemperature causes the temperature control switch to output a low level, the voltage input to the reverse end of the op amp U12B is lower than that to the same-direction end, and the op amp U12B outputs a high level. The voltage-controlled signal is high, and after passing through the inverter control circuit, a pulse width drive signal with a duty cycle of zero is output, stopping the inversion process in the rectifier inverter circuit. The same-direction end and the reverse end of the op amp U12B are respectively connected in series with capacitors and then grounded, which can filter the signal input to the op amp U12B and ensure the stability of the input signal. The light-emitting diode ED4 can indicate the overtemperature state.

[0019] Furthermore, the rectifier-inverter circuit includes a power frequency rectifier circuit, a first filter circuit, a high frequency inverter circuit, a high frequency rectifier circuit, and a second filter circuit connected in sequence;

[0020] The power frequency rectifier circuit is used to: rectify the input three-phase AC power;

[0021] The first filter circuit is used to filter out the three-phase ripple generated after rectification by the power frequency rectification circuit.

[0022] The high-frequency inverter circuit is used to: invert the direct current output by the first filter circuit into high-frequency alternating current according to the pulse width drive signal, and perform voltage boosting or voltage reduction;

[0023] High-frequency rectifier circuit is used to: rectify high-frequency AC power into DC power;

[0024] The second filter circuit is used to filter out the high-frequency ripple generated after rectification by the high-frequency rectification circuit and output the controllable direct current.

[0025] Furthermore, the multiple protection circuits include a phase loss protection circuit;

[0026] The phase loss protection circuit includes an A-phase sampling circuit provided on phase A of the three-phase alternating current, and a B-phase sampling circuit provided on phase B of the three-phase alternating current, and the circuit structures of the A-phase sampling circuit and the B-phase sampling circuit are the same;

[0027] The signal output terminal of the A-phase sampling circuit is connected to the positive input terminal of the optocoupler U80, and the negative input terminal of the optocoupler U80 is grounded;

[0028] The signal output terminal of the B-phase sampling circuit is connected to the positive input terminal of the optocoupler U81, and the negative input terminal of the optocoupler U81 is grounded;

[0029] The +12V power supply end is connected to the front end of resistor R805, the back end of resistor R805 is connected to the positive output end of optocoupler U80, the negative output end of optocoupler U80 is connected to the positive output end of optocoupler U81, the negative output end of optocoupler U81 is connected to the front end of resistor R812, and the back end of resistor R812 is grounded;

[0030] A switch U17 is connected in parallel between the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81. When the switch U17 is turned on, the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81 are directly short-circuited.

[0031] The common end of the optocoupler U81 and the resistor R812 is connected to the inverting end of the operational amplifier U12C, the L5V power supply end is connected to the front end of the resistor R806, the rear end of the resistor R806 is connected to the front end of the resistor R804, the rear end of the resistor R804 is grounded, the common end of the resistor R806 and the resistor R804 is connected to the non-inverting end of the operational amplifier U12C, the output end of the operational amplifier U12C is connected to the positive electrode of the diode D805, and the negative electrode of the diode D805 outputs the voltage-controlled signal;

[0032] The reverse-direction end series capacitor C804 of the operational amplifier U12C is connected to ground, the same-direction end series capacitor C805 of the operational amplifier U12C is connected to ground, and the same-direction end series capacitor C806 of the operational amplifier U12C is connected to ground;

[0033] The output end of the operational amplifier U12C is connected to the positive electrode of the light emitting diode ED5, and the negative electrode of the light emitting diode ED5 is connected in series with a resistor R807 and then grounded.

[0034] The same-direction input terminal of the operational amplifier U12C is a fixed voltage obtained by dividing the voltage between the resistor R806 and the resistor R804 in series;

[0035] When the three-phase AC power is missing a phase, at least one of the optocoupler U80 and the optocoupler U81 is not conducting, the reverse end of the operational amplifier U12C is grounded after passing through the resistor R812, the reverse end of the operational amplifier U12C inputs a low level, the voltage at the same direction end of the operational amplifier U12C is higher than the voltage at the reverse end, the operational amplifier U12C outputs a high level, the voltage control signal is high, and the duty cycle of the pulse width drive signal is zero, the rectifier inverter circuit is prohibited from inverting, and phase loss protection is achieved;

[0036] When the three-phase AC power is normal, the optocoupler U80 and the optocoupler U81 are turned on at the same time, and the voltage input to the reverse terminal of the operational amplifier U12C is the voltage divided by the resistors R805 and R812 in series. At this time, the voltage at the reverse terminal of the operational amplifier U12C is greater than the voltage at the same direction terminal, and the operational amplifier U12C outputs a low level, which does not affect the voltage control signal or the duty cycle of the pulse width drive signal.

[0037] The switching switch U17 can realize the shielding phase loss protection function. When the switching switch is disconnected, the phase loss protection circuit performs protection control according to the actual collected three-phase AC signal. When the switching switch is turned on, the back end of the resistor R815 and the front end of the resistor R812 are directly short-circuited, and the reverse terminal voltage of the operational amplifier U12C is greater than the same direction terminal voltage. The operational amplifier U12C outputs a low level, which does not affect the voltage control signal or the duty cycle of the pulse width drive signal.

[0038] The light emitting diode ED5 can indicate the phase loss state.

[0039] Furthermore, the multiple protection circuit includes an overcurrent protection circuit; an overcurrent sampling resistor R815 is provided in the high-frequency inverter circuit;

[0040] The overcurrent protection circuit includes an overcurrent flip circuit composed of a diode D806, a diode D807, a diode D808, and a diode D809, wherein the cathode of the diode D806 is connected to the cathode of the diode D807, the anode of the diode D806 is connected to the cathode of the diode D808, the anode of the diode D807 is connected to the cathode of the diode D809, and the anode of the diode D808 and the anode of the diode D809 are grounded;

[0041] The front end of the overcurrent sampling resistor R815 is connected to the common end of the diode 806 and the diode 808, and the rear end of the overcurrent sampling resistor R815 is connected to the common end of the diode 807 and the diode 809;

[0042] The common end of diode 806 and diode 807 is connected to the front end of resistor R811, and the rear end of resistor R811 is connected to the same direction terminal of operational amplifier U12D; a resistor R808 is connected in parallel between the common end of diode 806 and diode 807 and the common end of diode 807 and diode 809;

[0043] The +12V power supply terminal is connected to the front end of resistor R809, the back end of resistor R809 is connected in series with a reverse voltage zener diode D811 and then grounded, the voltage zener diode D811 is connected in parallel with the two fixed ends of the adjustable resistor VR12, and the sliding end of the adjustable resistor VR12 is connected to the reverse terminal of the operational amplifier U12D;

[0044] The output end of the operational amplifier U12D is connected to the anode of the diode D810, and the cathode of the diode D810 outputs the voltage control signal;

[0045] The output end of the operational amplifier U12D is connected to the positive electrode of the light emitting diode ED6, and the negative electrode of the light emitting diode ED6 is connected in series with a resistor R810 and then grounded;

[0046] The same-direction end of the operational amplifier U12D is connected in series with a capacitor C807 and then grounded. The reverse-direction end of the operational amplifier U12B is connected in series with a capacitor C808 and then grounded. A parallel capacitor C809 is connected between the output end and the reverse end of the operational amplifier U12B.

[0047] The full-bridge circuit composed of diodes D806, D807, D808, and D809 ensures that the voltage at both ends of the overcurrent sampling resistor R815, whether it is a forward voltage or a reverse voltage, is ultimately output to the same-direction end of the operational amplifier U12D at a positive value; the reverse-direction end voltage of the operational amplifier U12D is controlled by an adjustable resistor VR12. When the current of the overcurrent sampling resistor R815 is greater than the overcurrent threshold, the voltage at the same-direction end of the operational amplifier U12D is greater than the reverse-direction end, and the operational amplifier U12D outputs a high level. The voltage-controlled signal is high, and thus the duty cycle of the pulse width drive signal is zero, prohibiting the rectifier inverter circuit from inverting, thereby achieving overcurrent protection.

[0048] When the current of the overcurrent sampling resistor R815 is less than the overcurrent threshold, the voltage at the same-direction terminal of the operational amplifier U12D is less than that at the reverse terminal, and the operational amplifier U12D outputs a low level, which has no effect on the voltage-controlled signal and the duty cycle of the pulse width drive signal.

[0049] The overcurrent threshold is adjusted by the adjustable resistor VR12;

[0050] The light emitting diode ED6 can indicate an overcurrent condition.

[0051] Furthermore, the inverter control circuit includes a pulse width modulation circuit and a pulse width drive circuit;

[0052] After the pulse width modulation circuit inputs the voltage control signal, it outputs a pulse width control signal; after the inverter drive circuit inputs the pulse width control signal, it outputs a pulse width drive signal;

[0053] The pulse width modulation circuit is used to: control the duty cycle of the pulse width control signal according to the voltage control signal;

[0054] The pulse width drive circuit is used to: isolate and improve the driving capability of the pulse width drive signal.

[0055] Since the switching tubes in the rectifier and inverter circuits have high power and are fragile devices, directly using a pulse width modulation circuit for control will firstly result in insufficient driving capability and secondly easily damage the pulse width modulation circuit and other circuits connected to the pulse width modulation circuit. However, using a pulse width drive circuit can achieve isolation and improve the driving capability of the pulse width drive signal.

[0056] Furthermore, the pulse width modulation circuit includes a pulse width modulation chip U4, and the model of the pulse width modulation chip U4 is SW494;

[0057] The +V1 terminal of the pulse width modulation chip U4 is connected to a resistor R302 in series and then to ground. The +V2 terminal of the pulse width modulation chip U4 is connected to a resistor R301 in series and then to ground. The -V1 terminal and -V2 terminal of the pulse width modulation chip U4 are connected to a resistor R303 in series and then to ground. The voltage control signal is input to the +V1 terminal or the +V2 terminal of the pulse width modulation chip U4.

[0058] The E1 and E2 terminals of the pulse width modulation chip U4 output two sets of pulse width control signals with complementary dead zones;

[0059] Short-circuit the first and third pins of terminal group JP7 to ground the E1 and E2 terminals of the pulse width modulation chip U4, forcing the duty cycle to zero.

[0060] By using a complementary pulse width control signal with a dead zone, current conflicts and short circuits caused by the conduction and switching of the switch tubes in the rectifier inverter circuit can be avoided.

[0061] Furthermore, the -V1 and -V2 terminals of the pulse width modulation chip U4 are connected in series with capacitors C304 and then grounded; the +V1 terminal of the pulse width modulation chip U4 is connected in series with capacitors C303 and then grounded; the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C301 and then grounded; and the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C302 and then grounded.

[0062] The voltage control signal input from the +V1 terminal of the pulse width modulation chip U4 is filtered through capacitor C303, and the voltage control signal input from the +V2 terminal of the pulse width modulation chip U4 is filtered and prevented from sudden changes through capacitors C301 and C302.

[0063] Furthermore, the pulse width driving circuit includes an optocoupler isolation chip U1;

[0064] The E1 terminal of the pulse width modulation chip U4 is connected to the front end of the resistor R103, the rear end of the resistor R103 is connected to the positive input terminal of the optocoupler isolation chip U1, and the negative input terminal of the optocoupler isolation chip U1 is grounded;

[0065] The output end of the optocoupler isolation chip U1 is connected to the base of the NPN transistor Q1 and the PNP transistor Q2, the +20V power supply end is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is connected to the emitter of the transistor Q2, and the collector of the transistor Q2 is grounded; the common end of the transistor Q1 and the transistor Q2 outputs the pulse width drive signal.

[0066] The isolation function is achieved through the optocoupler isolation chip of the pulse width drive circuit, and the driving capability of the pulse width drive signal is enhanced through the push-pull output circuit composed of NPN type transistors and PNP type transistors.

[0067] Furthermore, the +20V power supply terminal is connected to the front end of the resistor R101, the rear end of the resistor R101 is connected in series with a reverse voltage zener diode D101 and then grounded, and the common end of the resistor R101 and the voltage zener diode D101 is connected to the second pin of the terminal group JP1;

[0068] The common end of the transistor Q1 and the transistor Q2 is connected to the front end of the resistor R107, the rear end of the resistor R107 is connected to the front end of the resistor R108, and the rear end of the resistor R108 is connected to the second pin of the terminal group JP1; the common end of the resistor R107 and the resistor R108 is connected to the first pin of the terminal group JP1;

[0069] A bidirectional voltage regulator diode DW1 is connected in series between the first and second pins of the terminal group JP1;

[0070] When the transistor Q1 is turned on, a positive voltage is applied between the first pin and the second pin of the terminal group JP1; when the transistor Q2 is turned on, a negative voltage is applied between the first pin and the second pin of the terminal group JP1;

[0071] The first pin and the second pin of the terminal group JP1 output a group of pulse width driving signals.

[0072] When the transistor Q2 is turned on, a negative voltage is present between the first and second pins of the terminal group JP1, realizing the reverse shutdown function of the pulse width drive signal. The reverse shutdown voltage value of the pulse width drive signal is the regulated voltage value of the Zener diode D101, and the forward conduction voltage value of the pulse width drive signal is the regulated voltage value of the bidirectional Zener diode DW1.

[0073] Furthermore, the collector series capacitor C101 of the transistor Q1 is connected to the collector of the transistor Q2; the collector series capacitor C102 of the transistor Q1 is connected to the collector of the transistor Q2; the reverse voltage zener diode D101 is connected in parallel with the capacitor C103; and the reverse voltage zener diode D101 is connected in parallel with the capacitor C104.

[0074] The capacitors C103 and C104 can filter the signal output from the first pin of the terminal group JP1 and smooth the startup impact; the capacitors C103 and C104 can filter the signal output from the second pin of the terminal group JP1 and smooth the startup impact.

[0075] Significant effect: The utility model provides a pulse power supply with multiple protection functions, which can provide multiple protections for the pulse power supply, and the multiple protections do not interfere with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a module structure diagram of the utility model;

[0077] Figure 2 This is the schematic diagram of the rectifier inverter circuit;

[0078] Figure 3 This is the schematic diagram of the pulse width modulation circuit;

[0079] Figure 4 This is the schematic diagram of the pulse width drive circuit;

[0080] Figure 5 This is the schematic diagram of the temperature protection circuit;

[0081] Figure 6 This is the schematic diagram of the phase loss protection circuit;

[0082] Figure 7 This is the schematic diagram of the overcurrent protection circuit. DETAILED DESCRIPTION

[0083] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0084] like Figure 1 As shown, a pulse power supply with multiple protection functions includes a rectifier inverter circuit and a chopper circuit. The rectifier inverter circuit inputs industrial frequency AC power and outputs controllable DC power. The chopper circuit inputs controllable DC power and outputs pulse power.

[0085] The inverter control circuit also includes an inverter control circuit, which inputs a voltage control signal and outputs a pulse width drive signal to the rectifier inverter circuit, controls the duty cycle of the pulse width drive signal according to the voltage control signal, and further controls the voltage and current of the controllable direct current;

[0086] It also includes multiple protection circuits, which include a temperature protection circuit, a phase loss protection circuit and a current limiting protection circuit. After the output end of each protection circuit is connected to a forward diode, the voltage-controlled signal is output, and the duty cycle of the pulse width drive signal is controlled to be zero according to the voltage-controlled signal.

[0087] It also includes a low-power power supply, which uses existing mature technology to provide +20V power supply end, +12V power supply end, -12V power supply end, and L5V power supply end to power the inverter control circuit and multiple protection circuits.

[0088] The rectifier and inverter circuit includes an industrial frequency rectifier circuit, a first filter circuit, a high frequency inverter circuit, a high frequency rectifier circuit, and a second filter circuit connected in sequence;

[0089] The power frequency rectifier circuit is used to: rectify the input three-phase AC power;

[0090] The first filter circuit is used to filter out the three-phase ripple generated after rectification by the power frequency rectification circuit.

[0091] The high-frequency inverter circuit is used to: invert the direct current output by the first filter circuit into high-frequency alternating current according to the pulse width drive signal, and perform voltage boosting or voltage reduction;

[0092] High-frequency rectifier circuit is used to: rectify high-frequency AC power into DC power;

[0093] The second filter circuit is used to filter out the high-frequency ripple generated after rectification by the high-frequency rectification circuit and output the controllable direct current.

[0094] like Figure 2 As shown, the power frequency rectifier circuit is a three-phase full-bridge rectifier circuit composed of diode D91, diode D92, diode D93, diode D94, diode D5 and diode D6. The power frequency rectifier circuit inputs three-phase AC power and outputs DC power with three-phase ripple.

[0095] The first filter circuit is composed of an inductor L11, a capacitor C11 and a capacitor C12, and filters the DC power with three-phase ripple;

[0096] The high-frequency inverter circuit is composed of switching tubes IGBT1, IGBT2, IGBT3, IGBT4, an overcurrent sampling resistor R815, and a transformer T1. The inverter circuit composed of switching tubes IGBT1, IGBT2, IGBT3, and IGBT4 inverts the DC power output by the first filter circuit into high-frequency AC power, which is then stepped up or down by transformer T1. The overcurrent sampling resistor R815 can perform current sampling on the inverted high-frequency AC power.

[0097] The high-frequency rectifier circuit mainly includes diode D96 and diode D97. The two ends of the secondary side of transformer T1 are connected to the positive electrodes of diode D96 and diode D97 respectively. The negative electrodes of diode D96 and diode D97 serve as the positive output terminal of the high-frequency rectifier circuit. The center tap of the secondary side of transformer T1 serves as the negative output terminal of the high-frequency rectifier circuit. The high-frequency rectifier circuit rectifies the high-frequency AC power that has been stepped up or down by transformer T1 into DC power with high-frequency ripple.

[0098] The second filter circuit mainly includes an inductor L12, which filters out high-frequency ripples so that the controllable DC power it outputs has no ripples.

[0099] By inputting a set of pulse width drive signals to the gates of IGBT1 and IGBT4, or inputting another set of pulse width drive signals to the gates of IGBT2 and IGBT3, the controllable DC power output by the second filter circuit can be controlled. The two sets of pulse width drive signals are complementary and have dead zones. When the duty cycle of the pulse width drive signal is zero, the high-frequency inverter circuit stops inverting, and the voltage and current of the controllable DC power output are zero.

[0100] The pulse width drive signal is output by the inverter control circuit, and the duty cycle of the pulse width drive signal is controlled by the voltage control signal input to the inverter control circuit;

[0101] like Figure 1 As shown, the inverter control circuit includes a pulse width modulation circuit and a pulse width drive circuit;

[0102] After the pulse width modulation circuit inputs the voltage control signal, it outputs a pulse width control signal; after the inverter drive circuit inputs the pulse width control signal, it outputs a pulse width drive signal;

[0103] The pulse width modulation circuit is used to: control the duty cycle of the pulse width control signal according to the voltage control signal;

[0104] The pulse width drive circuit is used to: isolate and improve the driving capability of the pulse width drive signal.

[0105] Since the switching tubes in the rectifier and inverter circuits have high power and are fragile devices, when the pulse width modulation circuit is directly used for control, firstly, the driving capability is insufficient, and secondly, the pulse width modulation circuit and other circuits connected to the pulse width modulation circuit are easily damaged. However, the pulse width drive circuit not only achieves isolation, but also improves the driving capability of the pulse width drive signal.

[0106] like Figure 3 As shown, the pulse width modulation circuit includes a pulse width modulation chip U4, and the model of the pulse width modulation chip U4 is SW494;

[0107] The +V1 terminal of the pulse width modulation chip U4 is connected to a resistor R302 in series and then to ground. The +V2 terminal of the pulse width modulation chip U4 is connected to a resistor R301 in series and then to ground. The -V1 terminal and -V2 terminal of the pulse width modulation chip U4 are connected to a resistor R303 in series and then to ground. The voltage control signal is input to the +V1 terminal or the +V2 terminal of the pulse width modulation chip U4.

[0108] The E1 and E2 terminals of the pulse width modulation chip U4 output two sets of pulse width control signals with complementary dead zones;

[0109] The RT end of the pulse width modulation chip U4 is connected to the front end of the resistor R305, the rear end of the resistor R305 is connected to the front end of the resistor R306, and the rear end of the resistor R306 is grounded; the CT end of the pulse width modulation chip U4 is connected in series with the capacitor C306 and then grounded, the VREF end of the pulse width modulation chip U4 is connected to the front end of the resistor R330, the rear end of the resistor R330 is connected to the front end of the resistor R304, and the rear end of the resistor R304 is grounded, and the common end of the resistor R330 and the resistor R304 is connected to the DTC end of the pulse width modulation chip U4; the VREF end and the 0C end of the pulse width modulation chip U4 are connected to the L5V power supply end;

[0110] By adjusting the capacitance or resistance of capacitor C306, resistor R305 and resistor R306, the frequency of the pulse width control signal is adjusted; by adjusting the resistance of resistor R330 and resistor R304, the dead time of the pulse width control signal output from the E1 terminal and the E2 terminal of the pulse width modulation chip U4 is adjusted;

[0111] By adjusting the voltage control signal input to the +V1 terminal or the +V2 terminal of the pulse width modulation chip U4, the duty cycle of the pulse width control signal output from the E1 terminal and the E2 terminal of the pulse width modulation chip U4 is adjusted;

[0112] By using a complementary pulse width control signal with a dead zone, current conflicts and short circuits caused by the conduction and switching of the switch tubes in the rectifier inverter circuit can be avoided.

[0113] The E1 terminal of the pulse width modulation chip U4 is connected to the anode of the diode D301, the E2 terminal of the pulse width modulation chip U4 is connected to the anode of the diode D302, the cathode of the diode D301 is connected to the cathode of the diode D302, the common terminal of the diode D301 and the diode D302 is connected in series with a resistor R313 and then grounded, the common terminal of the diode D301 and the diode D302 is connected to the first pin of the terminal group JP7, and the third pin of the terminal group JP7 is grounded;

[0114] Short-circuit the first and third pins of terminal group JP7 to ground the E1 and E2 terminals of the pulse width modulation chip U4, forcing the duty cycle to zero.

[0115] The -V1 and -V2 terminals of the pulse width modulation chip U4 are connected in series with capacitors C304 and then grounded; the +V1 terminal of the pulse width modulation chip U4 is connected in series with capacitors C303 and then grounded; the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C301 and then grounded; the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C302 and then grounded.

[0116] The voltage control signal input from the +V1 terminal of the pulse width modulation chip U4 is filtered through the capacitor C303, and the voltage control signal input from the +V2 terminal of the pulse width modulation chip U4 is filtered through the capacitors C301 and C302.

[0117] like Figure 4 As shown, the pulse width driving circuit includes two groups of isolated driving circuits with the same structure. Taking the first group of isolated driving circuits as an example:

[0118] The E1 terminal of the pulse width modulation chip U4 is connected to the front end of the resistor R103, the rear end of the resistor R103 is connected to the positive input terminal of the optocoupler isolation chip U1, and the negative input terminal of the optocoupler isolation chip U1 is grounded;

[0119] The output end of the optocoupler isolation chip U1 is connected to the base of the NPN transistor Q1 and the PNP transistor Q2, the +20V power supply end is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is connected to the emitter of the transistor Q2, and the collector of the transistor Q2 is grounded; the common end of the transistor Q1 and the transistor Q2 outputs the pulse width drive signal;

[0120] The isolation function is achieved through the optocoupler isolation chip of the pulse width drive circuit, and the driving capability of the pulse width drive signal is enhanced through the push-pull output circuit composed of NPN type transistors and PNP type transistors.

[0121] The +20V power supply terminal is connected to the front end of the resistor R101, the rear end of the resistor R101 is connected in series with a reverse voltage zener diode D101 and then grounded, and the common end of the resistor R101 and the voltage zener diode D101 is connected to the second pin of the terminal group JP1;

[0122] The common end of the transistor Q1 and the transistor Q2 is connected to the front end of the resistor R107, the rear end of the resistor R107 is connected to the front end of the resistor R108, and the rear end of the resistor R108 is connected to the second pin of the terminal group JP1; the common end of the resistor R107 and the resistor R108 is connected to the first pin of the terminal group JP1;

[0123] A bidirectional voltage regulator diode DW1 is connected in series between the first and second pins of the terminal group JP1;

[0124] When the transistor Q1 is turned on, a positive voltage is applied between the first pin and the second pin of the terminal group JP1; when the transistor Q2 is turned on, a negative voltage is applied between the first pin and the second pin of the terminal group JP1;

[0125] The first pin and the second pin of the terminal group JP1 output a group of pulse width driving signals.

[0126] When the transistor Q2 is turned on, a negative voltage is present between the first and second pins of the terminal group JP1, realizing the reverse shutdown function of the pulse width drive signal. The reverse shutdown voltage value of the pulse width drive signal is the regulated voltage value of the Zener diode D101, and the forward conduction voltage value of the pulse width drive signal is the regulated voltage value of the bidirectional Zener diode DW1.

[0127] The collector series capacitor C101 of the transistor Q1 is connected to the collector of the transistor Q2; the collector series capacitor C102 of the transistor Q1 is connected to the collector of the transistor Q2; the reverse voltage zener diode D101 is connected in parallel with the capacitor C103; the reverse voltage zener diode D101 is connected in parallel with the capacitor C104.

[0128] The capacitors C103 and C104 can filter the signal output from the first pin of the terminal group JP1 and smooth the startup impact; the capacitors C103 and C104 can filter the signal output from the second pin of the terminal group JP1 and smooth the startup impact.

[0129] like Figure 5 As shown, the temperature protection circuit is provided with a temperature control switch, which is provided on the radiator in the rectifier inverter circuit; or when the pulse power supply is used for electroplating, the temperature control switch is provided on the electrolytic cell;

[0130] The +12V power supply terminal is connected to the cathode of the Zener diode D801, the anode of the Zener diode D801 is connected to the cathode of the Zener diode D802, the anode of the Zener diode D802 is grounded, the common terminal of the Zener diodes D801 and D802 is connected to the reverse terminal of the op amp U12B, and the Zener diode D801 is connected in parallel with the resistor R801;

[0131] The temperature control switch is connected to the reverse terminal of the operational amplifier U12B;

[0132] The +12V power supply terminal is connected to the front end of resistor R802, the back end of resistor R802 is connected in series with a reverse voltage zener diode D803 and then grounded, and the common end of resistor R802 and voltage zener diode D803 is connected to the same direction terminal of op amp U12B;

[0133] The output end of the operational amplifier U12B is connected to the anode of the diode D804, and the cathode of the diode D804 outputs the voltage control signal;

[0134] The reverse end of the operational amplifier U12B is connected in series with a capacitor C801 and then grounded. The same end of the operational amplifier U12B is connected in series with a capacitor C802 and then grounded. A parallel capacitor C803 is connected between the output end and the reverse end of the operational amplifier U12B.

[0135] The output end of the operational amplifier U12B is connected to the positive electrode of the light emitting diode ED4, and the negative electrode of the light emitting diode ED4 is connected in series with a resistor R803 and then grounded.

[0136] The voltage input to the same-direction end of the op amp U12B is the voltage regulation value of the voltage-regulating diode D803. When the temperature control switch does not output a signal, the voltage input to the reverse end of the op amp U12B is higher than that to the same-direction end, and the op amp U12B outputs a low level, which does not affect the voltage-controlled signal. When overtemperature causes the temperature control switch to output a low level, the voltage input to the reverse end of the op amp U12B is lower than that to the same-direction end, and the op amp U12B outputs a high level. The voltage-controlled signal is high, and after passing through the inverter control circuit, a pulse width drive signal with a duty cycle of zero is output, stopping the inversion process in the rectifier inverter circuit. The same-direction end and the reverse end of the op amp U12B are respectively connected in series with capacitors and then grounded, which can filter the signal input to the op amp U12B and ensure the stability of the input signal. The light-emitting diode ED4 can indicate the overtemperature state.

[0137] like Figure 6 As shown, the phase loss protection circuit includes an A-phase sampling circuit provided on phase A of the three-phase AC power, and a B-phase sampling circuit provided on phase B of the three-phase AC power, and the circuit structures of the A-phase sampling circuit and the B-phase sampling circuit are the same;

[0138] The signal output terminal of the A-phase sampling circuit is connected to the positive input terminal of the optocoupler U80, and the negative input terminal of the optocoupler U80 is grounded;

[0139] The signal output terminal of the B-phase sampling circuit is connected to the positive input terminal of the optocoupler U81, and the negative input terminal of the optocoupler U81 is grounded;

[0140] The +12V power supply end is connected to the front end of resistor R805, the back end of resistor R805 is connected to the positive output end of optocoupler U80, the negative output end of optocoupler U80 is connected to the positive output end of optocoupler U81, the negative output end of optocoupler U81 is connected to the front end of resistor R812, and the back end of resistor R812 is grounded;

[0141] A switch U17 is connected in parallel between the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81. When the switch U17 is turned on, the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81 are directly short-circuited.

[0142] The common end of the optocoupler U81 and the resistor R812 is connected to the inverting end of the operational amplifier U12C, the L5V power supply end is connected to the front end of the resistor R806, the rear end of the resistor R806 is connected to the front end of the resistor R804, the rear end of the resistor R804 is grounded, the common end of the resistor R806 and the resistor R804 is connected to the non-inverting end of the operational amplifier U12C, the output end of the operational amplifier U12C is connected to the positive electrode of the diode D805, and the negative electrode of the diode D805 outputs the voltage-controlled signal;

[0143] The reverse-direction end series capacitor C804 of the operational amplifier U12C is connected to ground, the same-direction end series capacitor C805 of the operational amplifier U12C is connected to ground, and the same-direction end series capacitor C806 of the operational amplifier U12C is connected to ground;

[0144] The output end of the operational amplifier U12C is connected to the positive electrode of the light emitting diode ED5, and the negative electrode of the light emitting diode ED5 is connected in series with a resistor R807 and then grounded.

[0145] The same-direction input terminal of the operational amplifier U12C is a fixed voltage obtained by dividing the voltage between the resistor R806 and the resistor R804 in series;

[0146] When the three-phase AC power is missing a phase, at least one of the optocoupler U80 and the optocoupler U81 is not conducting, the reverse end of the operational amplifier U12C is grounded after passing through the resistor R812, the reverse end of the operational amplifier U12C inputs a low level, the voltage at the same direction end of the operational amplifier U12C is higher than the voltage at the reverse end, the operational amplifier U12C outputs a high level, the voltage control signal is high, and the duty cycle of the pulse width drive signal is zero, the rectifier inverter circuit is prohibited from inverting, and phase loss protection is achieved;

[0147] When the three-phase AC power is normal, the optocoupler U80 and the optocoupler U81 are turned on at the same time, and the voltage input to the reverse terminal of the operational amplifier U12C is the voltage divided by the resistors R805 and R812 in series. At this time, the voltage at the reverse terminal of the operational amplifier U12C is greater than the voltage at the same direction terminal, and the operational amplifier U12C outputs a low level, which does not affect the voltage control signal or the duty cycle of the pulse width drive signal.

[0148] The switching switch U17 can realize the shielding phase loss protection function. When the switching switch is disconnected, the phase loss protection circuit performs protection control according to the actual collected three-phase AC signal. When the switching switch is turned on, the back end of the resistor R815 and the front end of the resistor R812 are directly short-circuited, and the reverse terminal voltage of the operational amplifier U12C is greater than the same direction terminal voltage. The operational amplifier U12C outputs a low level, which does not affect the voltage control signal or the duty cycle of the pulse width drive signal.

[0149] The light emitting diode ED5 can indicate the phase loss state.

[0150] like Figure 1 He Ru Figure 7 As shown, an overcurrent sampling resistor R815 is provided in the high-frequency inverter circuit; the overcurrent protection circuit collects the voltage signal at both ends of the overcurrent sampling resistor R815;

[0151] The overcurrent protection circuit includes an overcurrent flip circuit composed of a diode D806, a diode D807, a diode D808, and a diode D809, wherein the cathode of the diode D806 is connected to the cathode of the diode D807, the anode of the diode D806 is connected to the cathode of the diode D808, the anode of the diode D807 is connected to the cathode of the diode D809, and the anode of the diode D808 and the anode of the diode D809 are grounded;

[0152] The front end of the overcurrent sampling resistor R815 is connected to the common end of the diode 806 and the diode 808, and the rear end of the overcurrent sampling resistor R815 is connected to the common end of the diode 807 and the diode 809;

[0153] The common end of diode 806 and diode 807 is connected to the front end of resistor R811, and the rear end of resistor R811 is connected to the same direction terminal of operational amplifier U12D; a resistor R808 is connected in parallel between the common end of diode 806 and diode 807 and the common end of diode 807 and diode 809;

[0154] The +12V power supply terminal is connected to the front end of resistor R809, the back end of resistor R809 is connected in series with a reverse voltage zener diode D811 and then grounded, the voltage zener diode D811 is connected in parallel with the two fixed ends of the adjustable resistor VR12, and the sliding end of the adjustable resistor VR12 is connected to the reverse terminal of the operational amplifier U12D;

[0155] The output end of the operational amplifier U12D is connected to the anode of the diode D810, and the cathode of the diode D810 outputs the voltage control signal;

[0156] The output end of the operational amplifier U12D is connected to the positive electrode of the light emitting diode ED6, and the negative electrode of the light emitting diode ED6 is connected in series with a resistor R810 and then grounded;

[0157] The same-direction end of the operational amplifier U12D is connected in series with a capacitor C807 and then grounded. The reverse-direction end of the operational amplifier U12B is connected in series with a capacitor C808 and then grounded. A parallel capacitor C809 is connected between the output end and the reverse end of the operational amplifier U12B.

[0158] The full-bridge circuit composed of diodes D806, D807, D808, and D809 ensures that the voltage at both ends of the overcurrent sampling resistor R815, whether it is a forward voltage or a reverse voltage, is ultimately output to the same-direction end of the operational amplifier U12D at a positive value; the reverse-direction end voltage of the operational amplifier U12D is controlled by an adjustable resistor VR12. When the current of the overcurrent sampling resistor R815 is greater than the overcurrent threshold, the voltage at the same-direction end of the operational amplifier U12D is greater than the reverse-direction end, and the operational amplifier U12D outputs a high level. The voltage-controlled signal is high, and thus the duty cycle of the pulse width drive signal is zero, prohibiting the rectifier inverter circuit from inverting, thereby achieving overcurrent protection.

[0159] When the current of the overcurrent sampling resistor R815 is less than the overcurrent threshold, the voltage at the same-direction terminal of the operational amplifier U12D is less than that at the reverse terminal, and the operational amplifier U12D outputs a low level, which has no effect on the voltage-controlled signal and the duty cycle of the pulse width drive signal.

[0160] The overcurrent threshold is adjusted by the adjustable resistor VR12;

[0161] The light emitting diode ED6 can indicate an overcurrent condition.

[0162] like Figure 5 、 Figure 6 and Figure 7 As shown, the output ends of the temperature protection circuit, the phase loss protection circuit and the current limiting protection circuit are connected to the anodes of the diodes D804, D805 and D810 respectively, and the cathodes of the diodes D804, D805 and D810 output voltage control signals to the Figure 3 The pulse width modulation circuit in; Figure 3 The E1 and E2 terminals of the pulse width modulation circuit output two sets of complementary pulse width control signals with dead zones to Figure 4 Pulse width drive circuit in; Select Figure 4 The first and second pins of the middle group JP1 drive Figure 2 IGBT1 and IGBT4, Figure 2 The current on the primary side of the transformer flows in the forward direction, or select Figure 4 The third and fourth pins of the mid-range group JP1 drive Figure 2 IGBT2 and IGBT3, Figure 2 The current on the primary side of the transformer flows in the reverse direction.

[0163] Finally, it should be noted that the above examples are only specific implementation examples of the present invention. Of course, those skilled in the art can make changes and modifications to the present invention. If these modifications and modifications fall within the scope of the claims of the present invention and their equivalent technologies, they should be considered to be within the scope of protection of the present invention.

Claims

1. A pulse power supply with multiple protection functions, including a rectifier inverter circuit and a chopper circuit. The rectifier inverter circuit inputs industrial frequency AC power and outputs controllable DC power, while the chopper circuit inputs controllable DC power and outputs pulse power. The inverter control circuit also includes an inverter control circuit, which inputs a voltage control signal and outputs a pulse width drive signal to the rectifier inverter circuit, controls the duty cycle of the pulse width drive signal according to the voltage control signal, and further controls the voltage and current of the controllable direct current; Its characteristics are: It also includes multiple protection circuits, which include at least two protection circuits. After the output end of each protection circuit is connected to a forward diode, the voltage-controlled signal is output, and the duty cycle of the pulse width drive signal is controlled to be zero according to the voltage-controlled signal.

2. The pulse power supply with multiple protection functions according to claim 1, characterized in that: The multiple protection circuits include a temperature protection circuit; The temperature protection circuit is provided with a temperature control switch, which is arranged on the radiator in the rectifier inverter circuit; or when the pulse power supply is used for electroplating, the temperature control switch is arranged on the electrolytic cell; The +12V power supply terminal is connected to the cathode of the Zener diode D801, the anode of the Zener diode D801 is connected to the cathode of the Zener diode D802, the anode of the Zener diode D802 is grounded, the common terminal of the Zener diodes D801 and D802 is connected to the reverse terminal of the op amp U12B, and the Zener diode D801 is connected in parallel with the resistor R801; The temperature control switch is connected to the reverse terminal of the operational amplifier U12B; The +12V power supply terminal is connected to the front end of resistor R802, the back end of resistor R802 is connected in series with a reverse voltage zener diode D803 and then grounded, and the common end of resistor R802 and voltage zener diode D803 is connected to the same direction terminal of op amp U12B; The output end of the operational amplifier U12B is connected to the anode of the diode D804, and the cathode of the diode D804 outputs the voltage control signal; The reverse end of the operational amplifier U12B is connected in series with a capacitor C801 and then grounded. The same end of the operational amplifier U12B is connected in series with a capacitor C802 and then grounded. A parallel capacitor C803 is connected between the output end and the reverse end of the operational amplifier U12B. The output end of the operational amplifier U12B is connected to the positive electrode of the light emitting diode ED4, and the negative electrode of the light emitting diode ED4 is connected in series with a resistor R803 and then grounded.

3. The pulse power supply with multiple protection functions according to claim 1, characterized in that: The rectifier and inverter circuit includes an industrial frequency rectifier circuit, a first filter circuit, a high frequency inverter circuit, a high frequency rectifier circuit, and a second filter circuit connected in sequence; The power frequency rectifier circuit is used to: rectify the input three-phase AC power; The first filter circuit is used to filter out the three-phase ripple generated after rectification by the power frequency rectification circuit; The high-frequency inverter circuit is used to: invert the direct current output by the first filter circuit into high-frequency alternating current according to the pulse width drive signal, and perform voltage boosting or voltage reduction; High-frequency rectifier circuit is used to: rectify high-frequency AC power into DC power; The second filter circuit is used to filter out the high-frequency ripple generated after rectification by the high-frequency rectification circuit and output the controllable direct current.

4. The pulse power supply with multiple protection functions according to claim 3, characterized in that: The multiple protection circuits include a phase loss protection circuit; The phase loss protection circuit includes an A-phase sampling circuit provided on phase A of the three-phase alternating current, and a B-phase sampling circuit provided on phase B of the three-phase alternating current, and the circuit structures of the A-phase sampling circuit and the B-phase sampling circuit are the same; The signal output terminal of the A-phase sampling circuit is connected to the positive input terminal of the optocoupler U80, and the negative input terminal of the optocoupler U80 is grounded; The signal output terminal of the B-phase sampling circuit is connected to the positive input terminal of the optocoupler U81, and the negative input terminal of the optocoupler U81 is grounded; The +12V power supply end is connected to the front end of resistor R805, the back end of resistor R805 is connected to the positive output end of optocoupler U80, the negative output end of optocoupler U80 is connected to the positive output end of optocoupler U81, the negative output end of optocoupler U81 is connected to the front end of resistor R812, and the back end of resistor R812 is grounded; A switch U17 is connected in parallel between the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81. When the switch U17 is turned on, the positive output terminal of the optocoupler U80 and the negative output terminal of the optocoupler U81 are directly short-circuited. The common end of the optocoupler U81 and the resistor R812 is connected to the inverting end of the operational amplifier U12C, the L5V power supply end is connected to the front end of the resistor R806, the rear end of the resistor R806 is connected to the front end of the resistor R804, the rear end of the resistor R804 is grounded, the common end of the resistor R806 and the resistor R804 is connected to the non-inverting end of the operational amplifier U12C, the output end of the operational amplifier U12C is connected to the positive electrode of the diode D805, and the negative electrode of the diode D805 outputs the voltage-controlled signal; The reverse-direction end series capacitor C804 of the operational amplifier U12C is connected to ground, the same-direction end series capacitor C805 of the operational amplifier U12C is connected to ground, and the same-direction end series capacitor C806 of the operational amplifier U12C is connected to ground; The output end of the operational amplifier U12C is connected to the positive electrode of the light emitting diode ED5, and the negative electrode of the light emitting diode ED5 is connected in series with a resistor R807 and then grounded.

5. The pulse power supply with multiple protection functions according to claim 3, characterized in that: The multiple protection circuit includes an overcurrent protection circuit; an overcurrent sampling resistor R815 is provided in the high-frequency inverter circuit; The overcurrent protection circuit includes an overcurrent flip circuit composed of a diode D806, a diode D807, a diode D808, and a diode D809, wherein the cathode of the diode D806 is connected to the cathode of the diode D807, the anode of the diode D806 is connected to the cathode of the diode D808, the anode of the diode D807 is connected to the cathode of the diode D809, and the anode of the diode D808 and the anode of the diode D809 are grounded; The front end of the overcurrent sampling resistor R815 is connected to the common end of the diode 806 and the diode 808, and the rear end of the overcurrent sampling resistor R815 is connected to the common end of the diode 807 and the diode 809; The common end of diode 806 and diode 807 is connected to the front end of resistor R811, and the rear end of resistor R811 is connected to the same direction terminal of operational amplifier U12D; a resistor R808 is connected in parallel between the common end of diode 806 and diode 807 and the common end of diode 807 and diode 809; The +12V power supply terminal is connected to the front end of resistor R809, the back end of resistor R809 is connected in series with a reverse voltage zener diode D811 and then grounded, the voltage zener diode D811 is connected in parallel with the two fixed ends of the adjustable resistor VR12, and the sliding end of the adjustable resistor VR12 is connected to the reverse terminal of the operational amplifier U12D; The output end of the operational amplifier U12D is connected to the anode of the diode D810, and the cathode of the diode D810 outputs the voltage control signal; The output end of the operational amplifier U12D is connected to the positive electrode of the light emitting diode ED6, and the negative electrode of the light emitting diode ED6 is connected in series with a resistor R810 and then grounded; The same-direction end of the operational amplifier U12D is connected in series with a capacitor C807 and then grounded. The reverse-direction end of the operational amplifier U12B is connected in series with a capacitor C808 and then grounded. A parallel capacitor C809 is connected between the output end and the reverse end of the operational amplifier U12B.

6. The pulse power supply with multiple protection functions according to claim 2, 4 or 5, characterized in that: The inverter control circuit includes a pulse width modulation circuit and a pulse width drive circuit; After the pulse width modulation circuit inputs the voltage control signal, it outputs a pulse width control signal; after the inverter drive circuit inputs the pulse width control signal, it outputs a pulse width drive signal; The pulse width modulation circuit is used to: control the duty cycle of the pulse width control signal according to the voltage control signal; The pulse width drive circuit is used to: isolate and improve the driving capability of the pulse width drive signal.

7. The pulse power supply with multiple protection functions according to claim 6, characterized in that: The pulse width modulation circuit includes a pulse width modulation chip U4, and the model of the pulse width modulation chip U4 is SW494; The +V1 terminal of the pulse width modulation chip U4 is connected to a resistor R302 in series and then to ground. The +V2 terminal of the pulse width modulation chip U4 is connected to a resistor R301 in series and then to ground. The -V1 terminal and -V2 terminal of the pulse width modulation chip U4 are connected to a resistor R303 in series and then to ground. The voltage control signal is input to the +V1 terminal or the +V2 terminal of the pulse width modulation chip U4. The E1 and E2 terminals of the pulse width modulation chip U4 output two sets of pulse width control signals with complementary dead zones; The E1 terminal of the pulse width modulation chip U4 is connected to the anode of the diode D301, the E2 terminal of the pulse width modulation chip U4 is connected to the anode of the diode D302, the cathode of the diode D301 is connected to the cathode of the diode D302, the common terminal of the diode D301 and the diode D302 is connected in series with a resistor R313 and then grounded, the common terminal of the diode D301 and the diode D302 is connected to the first pin of the terminal group JP7, and the third pin of the terminal group JP7 is grounded; Short the first and third pins of terminal block JP7 to ground the E1 and E2 terminals of the pulse width modulation chip U4, forcing the duty cycle to zero. The -V1 and -V2 terminals of the pulse width modulation chip U4 are connected in series with capacitors C304 and then grounded; the +V1 terminal of the pulse width modulation chip U4 is connected in series with capacitors C303 and then grounded; the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C301 and then grounded; the +V2 terminal of the pulse width modulation chip U4 is connected in series with capacitors C302 and then grounded.

8. The pulse power supply with multiple protection functions according to claim 6, characterized in that: The pulse width driving circuit includes an optical coupling isolation chip U1; The E1 terminal of the pulse width modulation chip U4 is connected to the front end of the resistor R103, the rear end of the resistor R103 is connected to the positive input terminal of the optocoupler isolation chip U1, and the negative input terminal of the optocoupler isolation chip U1 is grounded; The output end of the optocoupler isolation chip U1 is connected to the base of the NPN transistor Q1 and the PNP transistor Q2, the +20V power supply end is connected to the collector of the transistor Q1, the emitter of the transistor Q1 is connected to the emitter of the transistor Q2, and the collector of the transistor Q2 is grounded; the common end of the transistor Q1 and the transistor Q2 outputs the pulse width drive signal.

9. The pulse power supply with multiple protection functions according to claim 8, characterized in that: The +20V power supply terminal is connected to the front end of the resistor R101, the rear end of the resistor R101 is connected in series with a reverse voltage zener diode D101 and then grounded, and the common end of the resistor R101 and the voltage zener diode D101 is connected to the second pin of the terminal group JP1; The common end of the transistor Q1 and the transistor Q2 is connected to the front end of the resistor R107, the rear end of the resistor R107 is connected to the front end of the resistor R108, and the rear end of the resistor R108 is connected to the second pin of the terminal group JP1; the common end of the resistor R107 and the resistor R108 is connected to the first pin of the terminal group JP1; A bidirectional voltage regulator diode DW1 is connected in series between the first and second pins of the terminal group JP1; When the transistor Q1 is turned on, a positive voltage is applied between the first pin and the second pin of the terminal group JP1; when the transistor Q2 is turned on, a negative voltage is applied between the first pin and the second pin of the terminal group JP1; The first pin and the second pin of the terminal group JP1 output a group of pulse width driving signals.

10. The pulse power supply with multiple protection functions according to claim 9, characterized in that: The collector series capacitor C101 of the transistor Q1 is connected to the collector of the transistor Q2; the collector series capacitor C102 of the transistor Q1 is connected to the collector of the transistor Q2; the reverse voltage zener diode D101 is connected in parallel with the capacitor C103; the reverse voltage zener diode D101 is connected in parallel with the capacitor C104.

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