IGBT driving power supply positive and negative voltage switch type voltage stabilizing circuit

Abstract

The application discloses an IGBT driving power supply positive and negative voltage switch type voltage stabilizing circuit, which comprises an isolation power supply unit, positive and negative voltage output ends, a common ground end, positive and negative voltage storage capacitors, positive and negative voltage power supply load resistors, a bidirectional electric energy transfer unit and a PWM control unit. The bidirectional electric energy transfer unit comprises a first switch, a second switch, a first diode, a second diode and a storage inductor, one end of the storage inductor is connected with the common ground end, and the other end is connected with corresponding ends of the switches and the diodes. The PWM control unit samples positive and negative voltage output voltages, outputs two-way PWM signals to control the on-off of the switches, and transfers electric energy from a voltage high side to a voltage low side by means of energy storage and release of the storage inductor. The IGBT driving power supply positive and negative voltage switch type voltage stabilizing circuit of the technical scheme reduces power consumption and temperature rise, realizes bidirectional electric energy transfer and positive and negative double-way synchronous voltage stabilization, and improves voltage stability, load adaptability and operation reliability of the IGBT driving power supply.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a positive and negative voltage switching regulator circuit for IGBT drive power supply. Background Technology

[0002] With the rapid development of industrial automation, new energy vehicles, rail transportation and other fields, the stability of the driving power supply of the Insulated Gate Bipolar Transistor (IGBT) as a core power device directly determines the safe and reliable operation of the entire equipment.

[0003] IGBT driver power supplies need to provide both positive turn-on voltage and negative turn-off voltage simultaneously. Traditional IGBT driver power supplies mostly use linear regulation schemes, achieving negative voltage regulation through Zener diodes and current-limiting resistors. This approach has several technical drawbacks: linear regulation is an energy-consuming method, with excess electrical energy directly converted into heat, resulting in severe circuit overheating and low energy efficiency; it can only achieve single-channel negative voltage regulation, lacking positive voltage output regulation capability, making the output voltage prone to deviation from the rated value when the input voltage fluctuates or the load changes; the circuit has poor resistance to pulse loads, and voltage instability is prone to occur during high-frequency IGBT switching, posing a risk of device damage and equipment malfunction. Therefore, existing IGBT driver power supply regulation schemes cannot meet the application requirements of high efficiency, stability, and high reliability. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a positive and negative voltage switching regulator circuit for IGBT drive power supplies. The aim is to reduce power consumption and heat loss while achieving synchronous voltage regulation control of both positive and negative voltages for IGBT drive, thereby improving the stability and reliability of the drive power supply.

[0005] The embodiments of this application disclose the following technical solutions: The first aspect of this application provides an IGBT drive power supply positive and negative voltage switching regulator circuit, including an isolated power supply unit, a positive voltage output terminal, a negative voltage output terminal, a common ground terminal, a positive voltage energy storage capacitor, a negative voltage energy storage capacitor, a positive power supply load resistor, a negative power supply load resistor, a bidirectional power transfer unit, and a PWM control unit. The positive voltage energy storage capacitor is connected between the positive voltage output terminal and the common ground terminal, and the negative voltage energy storage capacitor is connected between the common ground terminal and the negative voltage output terminal; The positive power supply load resistor is connected between the positive voltage output terminal and the common ground terminal, and the negative power supply load resistor is connected between the common ground terminal and the negative voltage output terminal. The bidirectional power transfer unit includes a first switch, a second switch, a first diode, a second diode, and an energy storage inductor; the first end of the energy storage inductor is connected to a common ground terminal, and the second end of the energy storage inductor is connected to the first end of the first switch, the anode of the first diode, the first end of the second switch, and the cathode of the second diode; the second end of the first switch and the cathode of the first diode are both connected to the positive voltage output terminal; the second end of the second switch and the anode of the second diode are both connected to the negative voltage output terminal. The sampling terminal of the PWM control unit is connected to the positive voltage output terminal and the negative voltage output terminal respectively. The first signal output terminal of the PWM control unit is connected to the control terminal of the first switch, and the second signal output terminal is connected to the control terminal of the second switch. The PWM control unit collects the real-time voltage of the positive voltage output terminal and the negative voltage output terminal, and outputs two PWM signals to control the on / off state of the first switch and the second switch respectively. Through the energy storage and release of the energy storage inductor, the electrical energy on the high voltage side is transferred to the low voltage side.

[0006] In an optional implementation, the rated output voltage of the positive voltage output terminal is +15V, and the rated output voltage of the negative voltage output terminal is -10V.

[0007] In an optional implementation, the isolated power supply unit outputs a rated DC voltage of 25V, the positive terminal of the isolated power supply unit is connected to the positive voltage output terminal, and the negative terminal of the isolated power supply unit is connected to the negative voltage output terminal.

[0008] In optional implementations, the isolated power supply unit is a flyback switching power supply circuit, a push-pull switching power supply circuit, a forward switching power supply circuit, a half-bridge switching power supply circuit, or a full-bridge switching power supply circuit.

[0009] In an optional implementation, the PWM control unit performs independent closed-loop feedback control on the voltages of the positive voltage output terminal and the negative voltage output terminal, respectively, and controls the on-time of the corresponding switch by adjusting the duty cycle of the corresponding PWM signal.

[0010] In an optional implementation, when the positive voltage output terminal voltage is higher than the rated value, the PWM control unit outputs a first PWM signal to control the first switch to periodically turn on and off; when the first switch is on, the electrical energy at the positive voltage output terminal flows into the energy storage inductor through the first switch to complete energy storage; when the first switch is off, the energy storage inductor releases energy to the negative voltage output terminal through the second diode, transferring excess electrical energy at the positive voltage output terminal to the negative voltage output terminal, thereby stabilizing the voltage at the positive voltage output terminal.

[0011] In an optional implementation, when the voltage at the negative voltage output terminal is lower than the rated value, the PWM control unit outputs a first PWM signal to control the first switch to periodically turn on and off; when the first switch is on, the electrical energy at the positive voltage output terminal flows into the energy storage inductor through the first switch to complete energy storage; when the first switch is off, the energy storage inductor releases energy to the negative voltage output terminal through the second diode to replenish the electrical energy gap at the negative voltage output terminal and stabilize the voltage at the negative voltage output terminal.

[0012] In an optional implementation, when the positive voltage output terminal voltage is lower than the rated value, the PWM control unit outputs a second PWM signal to control the second switch to periodically turn on and off; when the second switch is on, the electrical energy of the negative voltage output terminal flows into the energy storage inductor through the second switch to complete energy storage; when the second switch is off, the energy storage inductor releases energy to the positive voltage output terminal through the first diode to replenish the electrical energy gap of the positive voltage output terminal and stabilize the positive voltage output terminal voltage.

[0013] In an optional implementation, when the voltage at the negative voltage output terminal is higher than the rated value, the PWM control unit outputs a second PWM signal to control the second switch to periodically turn on and off; when the second switch is on, the electrical energy at the negative voltage output terminal flows into the energy storage inductor through the second switch to complete energy storage; when the second switch is off, the energy storage inductor releases energy to the positive voltage output terminal through the first diode, transferring excess electrical energy at the negative voltage output terminal to the positive voltage output terminal, thereby stabilizing the voltage at the negative voltage output terminal.

[0014] In an optional implementation, the two PWM signals output by the PWM control unit are interlocked signals.

[0015] Compared with the prior art, this application has the following beneficial effects: This application discloses an IGBT driver power supply positive and negative voltage switching regulator circuit, including an isolated power supply unit, a positive voltage output terminal, a negative voltage output terminal, a common ground terminal, a positive voltage energy storage capacitor, a negative voltage energy storage capacitor, a positive power supply load resistor, a negative power supply load resistor, a bidirectional power transfer unit, and a PWM control unit. The positive voltage energy storage capacitor is connected between the positive voltage output terminal and the common ground terminal, and the negative voltage energy storage capacitor is connected between the common ground terminal and the negative voltage output terminal. The positive power supply load resistor is connected between the positive voltage output terminal and the common ground terminal, and the negative power supply load resistor is connected between the common ground terminal and the negative voltage output terminal. The bidirectional power transfer unit includes a first switch, a second switch, a first diode, a second diode, and an energy storage inductor. The first terminal of the energy storage inductor is connected to the common ground terminal, and the second terminal of the energy storage inductor is connected to the common ground terminal. The first terminal of the first switch, the anode of the first diode, the first terminal of the second switch, and the cathode of the second diode are described. The second terminal of the first switch and the cathode of the first diode are both connected to the positive voltage output terminal. The second terminal of the second switch and the anode of the second diode are both connected to the negative voltage output terminal. The sampling terminal of the PWM control unit is connected to the positive voltage output terminal and the negative voltage output terminal respectively. The first signal output terminal of the PWM control unit is connected to the control terminal of the first switch, and the second signal output terminal is connected to the control terminal of the second switch. The PWM control unit collects the real-time voltage of the positive voltage output terminal and the negative voltage output terminal, and outputs two PWM signals to control the on / off state of the first switch and the second switch respectively. Through the energy storage and release of the energy storage inductor, the electrical energy on the high voltage side is transferred to the low voltage side. As can be seen, the IGBT driver power supply positive and negative voltage switching regulator circuit provided in this application acquires the positive and negative output voltages in real time through the PWM control unit. Combined with the on / off control of the first and second switches to regulate the charging and discharging of the energy storage inductor, it replaces the energy-consuming structure of the traditional Zener diode and resistor, eliminating the heat generated by energy dissipation at the source and effectively reducing circuit power consumption and temperature rise. Through the unidirectional current conduction of the first and second diodes, the energy storage inductor achieves directional energy release between the positive and negative power supplies, completing bidirectional energy transfer regulation. Relying on the energy storage and filtering effects of the positive and negative energy storage capacitors, combined with precise PWM closed-loop control, it ensures that the positive and negative output voltages of the IGBT driver remain stable within the rated range, achieving synchronous voltage regulation of both positive and negative channels, significantly improving the voltage stability, load adaptability, and operational reliability of the IGBT driver power supply. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This application provides a schematic diagram of the structure of an IGBT drive power supply positive and negative voltage switching regulator circuit. Figure 2 A schematic diagram of a flyback switching power supply circuit structure provided in an embodiment of this application; Figure 3 A schematic diagram of the current loop during the first switch conduction stage under a positive voltage high operating condition, provided for an embodiment of this application; Figure 4 A schematic diagram of the current loop during the energy release stage of an energy storage inductor under low negative voltage conditions, provided for an embodiment of this application; Figure 5 A schematic diagram of the current loop during the conduction stage of the second switch under a low positive voltage condition, provided for an embodiment of this application; Figure 6 This is a schematic diagram of the current loop during the energy release stage of an energy storage inductor under a negative voltage high operating condition, provided as an embodiment of this application. Detailed Implementation

[0018] As described earlier, most current IGBT driver power supplies employ linear voltage regulation schemes, using Zener diodes and current-limiting resistors to achieve negative voltage regulation. This approach has several technical drawbacks: linear regulation is an energy-consuming method, directly converting excess electrical energy into heat, resulting in severe circuit overheating and low energy efficiency; it can only achieve single-channel negative voltage regulation, lacking positive voltage output adjustment capability, making the output voltage prone to deviation from rated values ​​when the input voltage fluctuates or the load changes; and the circuit has poor resistance to pulse loads, making it susceptible to voltage instability during IGBT high-frequency switching, posing a risk of device damage and equipment malfunction. Therefore, existing IGBT driver power supply voltage regulation schemes cannot meet the application requirements of high efficiency, stability, and high reliability.

[0019] To address the aforementioned problems, the inventors have developed a positive and negative voltage switching regulator circuit for IGBT drive power supplies.

[0020] The IGBT driver power supply positive and negative voltage switching regulator circuit includes an isolated power supply unit, a positive voltage output terminal, a negative voltage output terminal, a common ground terminal, a positive voltage energy storage capacitor, a negative voltage energy storage capacitor, a positive power supply load resistor, a negative power supply load resistor, a bidirectional power transfer unit, and a PWM control unit. The positive voltage energy storage capacitor is connected between the positive voltage output terminal and the common ground terminal, and the negative voltage energy storage capacitor is connected between the common ground terminal and the negative voltage output terminal. The positive power supply load resistor is connected between the positive voltage output terminal and the common ground terminal, and the negative power supply load resistor is connected between the common ground terminal and the negative voltage output terminal. The bidirectional power transfer unit includes a first switch, a second switch, a first diode, a second diode, and an energy storage inductor. The first terminal of the energy storage inductor is connected to the common ground terminal, and the second terminal of the energy storage inductor is connected to the first switch. The first terminal of the switch, the anode of the first diode, the first terminal of the second switch, and the cathode of the second diode are connected to the positive voltage output terminal; the second terminal of the second switch and the anode of the second diode are connected to the negative voltage output terminal; the sampling terminal of the PWM control unit is connected to the positive voltage output terminal and the negative voltage output terminal respectively; the first signal output terminal of the PWM control unit is connected to the control terminal of the first switch, and the second signal output terminal is connected to the control terminal of the second switch; the PWM control unit collects the real-time voltage of the positive voltage output terminal and the negative voltage output terminal, and outputs two PWM signals to control the on / off state of the first switch and the second switch respectively, and transfers the electrical energy on the high voltage side to the low voltage side through the energy storage and release of the energy storage inductor.

[0021] The IGBT driver power supply positive and negative voltage switching regulator circuit provided in this application acquires the positive and negative output voltages in real time through a PWM control unit. Combined with the on / off control of the first and second switches to regulate the charging and discharging of the energy storage inductor, it replaces the energy-consuming structure of traditional Zener diodes and resistors, eliminating the heat generated by energy dissipation at the source and effectively reducing circuit power consumption and temperature rise. Through the unidirectional current conduction of the first and second diodes, the energy storage inductor achieves directional energy release between the positive and negative power supplies, completing bidirectional energy transfer regulation. Relying on the energy storage and filtering effects of the positive and negative energy storage capacitors, combined with precise PWM closed-loop control, it ensures that the positive and negative output voltages of the IGBT driver remain stable within the rated range, achieving synchronous voltage regulation of both positive and negative channels, significantly improving the voltage stability, load adaptability, and operational reliability of the IGBT driver power supply.

[0022] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0023] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] See Figure 1 This figure is a schematic diagram of the structure of an IGBT drive power supply positive and negative voltage switching regulator circuit provided in an embodiment of this application. Figure 1 As shown, the IGBT drive power supply positive and negative voltage switching regulator circuit includes an isolated power supply unit 101, a positive voltage output terminal VCC2, a negative voltage output terminal VEE2, a common ground terminal GND2, a positive voltage energy storage capacitor C1, a negative voltage energy storage capacitor C2, a positive power supply load resistor R1, a negative power supply load resistor R2, a bidirectional power transfer unit 102, and a PWM control unit 103.

[0025] In this embodiment, the isolated power supply unit 101 is used to provide an electrically isolated DC main power supply to power the subsequent voltage regulator circuit and the IGBT drive load. The positive output terminal is connected to the positive voltage output terminal VCC2, and the negative output terminal is connected to the negative voltage output terminal VEE2.

[0026] Positive voltage energy storage capacitor C1 is connected between the positive voltage output terminal VCC2 and the common ground terminal GND2. It is used to store energy and filter the positive power supply, smooth the pulse current when the IGBT is driven to turn on, and maintain the stability of the positive voltage output. Negative voltage energy storage capacitor C2 is connected between the common ground terminal GND2 and the negative voltage output terminal VEE2. It is used to store energy and filter the negative power supply, smooth the pulse current when the IGBT is driven to turn off, and maintain the stability of the negative voltage output.

[0027] The positive power supply load resistor R1 is connected between the positive output terminal VCC2 and the common ground terminal GND2. R1 serves as the equivalent resistance of the IGBT drive turn-on load, simulating the pulse current load characteristics when the IGBT is turned on. The negative power supply load resistor R2 is connected between the common ground terminal GND2 and the negative output terminal VEE2. R2 serves as the equivalent resistance of the IGBT drive turn-off load, simulating the pulse current load characteristics when the IGBT is turned off. During the IGBT's high-frequency switching process, the turn-on and turn-off actions correspondingly change the equivalent load size of R1 and R2, causing output voltage fluctuations. The voltage regulation circuit in this application can adjust in real time to address load fluctuations and maintain stable output voltage.

[0028] The positive voltage output terminal VCC2 provides positive turn-on power to the IGBT driver circuit, with a rated output voltage of +15V. The common ground terminal GND2 serves as the reference ground for both the IGBT driver circuit and the voltage regulator circuit. The negative voltage output terminal VEE2 provides negative turn-off power to the IGBT driver circuit, with a rated output voltage of -8V to -10V, preferably -10V in this embodiment.

[0029] The bidirectional power transfer unit 102 includes a first switch K1, a second switch K2, a first diode D1, a second diode D2, and an energy storage inductor L. The first end of the energy storage inductor L is connected to the common ground terminal GND2, and the second end of the energy storage inductor L is connected to the first end of the first switch K1, the anode of the first diode D1, the first end of the second switch K2, and the cathode of the second diode D2. The second end of the first switch K1 and the cathode of the first diode D1 are both connected to the positive voltage output terminal VCC2. The second end of the second switch K2 and the anode of the second diode D2 are both connected to the negative voltage output terminal VEE2.

[0030] In this embodiment, the first switch K1 is a controllable switch for controlling the energy storage of the positive power supply side inductor, used to provide a charging circuit from the positive voltage output terminal VCC2 to the common ground terminal GND2 for the energy storage inductor L when it is turned on. The second switch K2 is a controllable switch for controlling the energy storage of the negative power supply side inductor, used to provide a charging circuit from the common ground terminal GND2 to the negative voltage output terminal VEE2 for the energy storage inductor L when it is turned on.

[0031] The first diode D1 is a positive power supply side inductor discharge diode, used to provide an energy release path for the energy storage inductor L to the positive voltage output terminal VCC2 when the second switch K2 is turned off. Its unidirectional conduction characteristic prevents current backflow. The second diode D2 is a negative power supply side inductor discharge diode, used to provide an energy release path for the energy storage inductor L to the negative voltage output terminal VEE2 when the first switch K1 is turned off. Its unidirectional conduction characteristic prevents current backflow.

[0032] The energy storage inductor L is the core energy storage element for bidirectional energy transfer. It is used to store electrical energy when the switch is on and release electrical energy when the switch is off, thus realizing bidirectional energy transfer between the positive and negative output terminals.

[0033] The sampling terminals I1 and I2 of the PWM control unit 103 are connected to the positive voltage output terminal VCC2 and the negative voltage output terminal VEE2, respectively. The first signal output terminal O1 of the PWM control unit 103 is connected to the control terminal of the first switch K1, and the second signal output terminal O2 is connected to the control terminal of the second switch K2.

[0034] In this embodiment, the PWM control unit 103 collects the real-time voltages of the positive voltage output terminal VCC2 and the negative voltage output terminal VEE2, compares the real-time voltages with the preset rated voltages, and outputs two PWM signals to control the on / off state of the first switch K1 and the second switch K2. Through the energy storage and release of the energy storage inductor L, the electrical energy on the high voltage side is transferred to the low voltage side, thereby realizing the regulated output of the positive voltage output terminal VCC2 and the negative voltage output terminal VEE2.

[0035] In this embodiment, the PWM control unit 103 can be a dedicated PWM control chip, which integrates a sampling circuit, an error amplifier, a comparator, a PWM generator, and a drive circuit. It can realize two independent closed-loop feedback control. By adjusting the duty cycle of the corresponding PWM signal, the conduction time of the corresponding switch is controlled, thereby adjusting the energy storage and release time of the energy storage inductor L, and realizing precise adjustment of the output voltage.

[0036] In one alternative implementation, the rated output voltage of the positive voltage output terminal VCC2 is +15V, and the rated output voltage of the negative voltage output terminal VEE2 is -10V.

[0037] In one alternative implementation, the isolation power supply unit 101 is a flyback switching power supply circuit, a push-pull switching power supply circuit, a forward switching power supply circuit, a half-bridge switching power supply circuit, or a full-bridge switching power supply circuit. The specific type is not limited here. It can be flexibly selected according to the power level, input voltage range, and isolation requirements of the IGBT drive power supply. All of them can achieve electrically isolated DC total power output and are compatible with the positive and negative voltage switching regulator circuit of the IGBT drive power supply provided in the embodiments of this application.

[0038] In one example implementation, the isolation power supply unit 101 is a flyback switching power supply circuit with a rated DC output voltage of 25V, which can achieve electrical isolation between the input side and the output side and meet the isolation withstand voltage requirements of the IGBT drive circuit.

[0039] See Figure 2 , Figure 2 A schematic diagram of a flyback switching power supply circuit structure provided in an embodiment of this application is shown below. Figure 2As shown, the flyback switching power supply circuit includes a transformer T0, a power switch Q0, a rectifier diode D0, and an output filter capacitor C0. The primary winding of transformer T0 is connected to the input DC power supply and the power switch Q0, while the secondary winding is connected to the rectifier diode D0 and the output filter capacitor C0. The power switch Q0 receives an external PWM drive signal to control the energy transfer on the primary side of transformer T0. The AC voltage induced in the secondary winding is rectified by the rectifier diode D0 and filtered by the output filter capacitor C0, outputting a 25V isolated DC voltage to power the subsequent voltage regulator circuit.

[0040] In one alternative implementation, the PWM control unit 103 performs independent closed-loop feedback control on the voltages of the positive output terminal VCC2 and the negative output terminal VEE2, respectively, and controls the on-time of the corresponding switch by adjusting the duty cycle of the corresponding PWM signal.

[0041] Specifically, when the voltage at the positive output terminal VCC2 deviates from the rated value, the PWM control unit 103 adjusts the duty cycle of the first PWM signal to change the on-time of the first switch K1; when the voltage at the negative output terminal VEE2 deviates from the rated value, the PWM control unit 103 adjusts the duty cycle of the second PWM signal to change the on-time of the second switch K2; when the IGBT switch action causes a change in the equivalent resistance of the positive power supply load resistor R1 and the negative power supply load resistor R2, resulting in output voltage fluctuations, the PWM control unit 103 can quickly respond and adjust to achieve independent adjustment of the two output voltages without interference.

[0042] The working principle of the IGBT drive power supply positive and negative voltage switching regulator circuit provided in this application embodiment will be described in detail below, taking into account specific voltage conditions: In one optional implementation, when the voltage at the positive output terminal VCC2 is higher than the rated value, the PWM control unit 103 outputs a first PWM signal to control the first switch K1 to periodically turn on and off. When the first switch K1 is on, the electrical energy at the positive output terminal VCC2 flows into the energy storage inductor L through the first switch K1 to complete energy storage. When the first switch K1 is off, the energy storage inductor L releases energy to the negative output terminal VEE2 through the second diode D2, transferring the excess electrical energy at the positive output terminal VCC2 to the negative output terminal VEE2, thereby stabilizing the voltage at the positive output terminal VCC2.

[0043] In this embodiment, this operating condition typically occurs during the IGBT turn-off phase. The equivalent load of the positive power supply load resistor R1 decreases, and the load current at the positive voltage output terminal VCC2 decreases, causing the voltage rise to exceed the rated range. After the PWM control unit 103 acquires the voltage deviation through the sampling terminal, it adjusts the duty cycle of the first PWM signal to match the current voltage deviation and precisely controls the conduction time of the first switch K1 to achieve quantitative transfer of excess electrical energy.

[0044] See Figure 3 , Figure 3 This is a schematic diagram of the current loop during the first switch conduction stage under a positive voltage high operating condition, provided as an embodiment of this application. Figure 3 As shown, when the first switch K1 is turned on, the first PWM signal output by the PWM control unit 103 is at a high level, and the second switch K2 remains off. Current flows out from the positive voltage output terminal VCC2, through the turned-on first switch K1, into the second terminal of the energy storage inductor L, passes through the energy storage inductor L, flows out from its first terminal, returns to the common ground terminal GND2, and finally flows back to the lower end of the positive voltage energy storage capacitor C1, forming a complete charging circuit. The excess electrical energy at the positive voltage output terminal VCC2 is converted into magnetic field energy and stored in the energy storage inductor L. When the first switch K1 is turned off, the energy storage inductor L forms an energy release circuit through the second diode D2, releasing the stored electrical energy to the negative voltage output terminal VEE2, completing the transfer of excess electrical energy on the positive voltage side, and causing the voltage at the positive voltage output terminal VCC2 to drop back to the rated value.

[0045] In one optional implementation, when the voltage at the negative voltage output terminal VEE2 is lower than the rated value, the PWM control unit 103 outputs a first PWM signal to control the first switch K1 to periodically turn on and off; when the first switch K1 is on, the electrical energy at the positive voltage output terminal VCC2 flows into the energy storage inductor L through the first switch K1 to complete energy storage; when the first switch K1 is off, the energy storage inductor L releases energy to the negative voltage output terminal VEE2 through the second diode D2 to replenish the electrical energy gap at the negative voltage output terminal VEE2 and stabilize the voltage at the negative voltage output terminal VEE2.

[0046] In this embodiment, this operating condition typically occurs during the IGBT turn-on phase. The equivalent load of the negative power supply load resistor R2 increases, and the load current at the negative voltage output terminal VEE2 rises, causing the voltage drop to exceed the rated range. After the PWM control unit 103 acquires the voltage deviation through the sampling terminal, it controls the conduction time of the first switch K1 by adjusting the duty cycle of the first PWM signal to match the power gap on the negative voltage side and achieve quantitative power replenishment.

[0047] See Figure 4 , Figure 4 This is a schematic diagram of the current loop during the energy release stage of an energy storage inductor under low negative voltage conditions, provided as an embodiment of this application. Figure 4As shown, when the first switch K1 is turned off, based on the characteristic that the inductor current cannot change abruptly, the energy storage inductor L maintains the current direction during the conduction phase. The potential of its second terminal is pulled down to a level lower than that of the negative voltage output terminal VEE2, causing the second diode D2 to meet the forward conduction condition. Current flows out from the negative voltage output terminal VEE2, flows into the second terminal of the energy storage inductor L through the conducting second diode D2, flows out from its first terminal after passing through the energy storage inductor L, returns to the common ground terminal GND2, and then flows back to the negative voltage output terminal VEE2 through the negative voltage energy storage capacitor C2, forming a complete energy release circuit. The electrical energy stored in the energy storage inductor L replenishes the negative voltage output terminal VEE2, causing the voltage of the negative voltage output terminal VEE2 to rise back to its rated value.

[0048] In one optional implementation, when the voltage at the positive output terminal VCC2 is lower than the rated value, the PWM control unit 103 outputs a second PWM signal to control the second switch K2 to periodically turn on and off. When the second switch K2 is on, the electrical energy at the negative output terminal VEE2 flows into the energy storage inductor L through the second switch K2 to complete energy storage. When the second switch K2 is off, the energy storage inductor L releases energy to the positive output terminal VCC2 through the first diode D1 to replenish the electrical energy gap at the positive output terminal VCC2 and stabilize the voltage at the positive output terminal VCC2.

[0049] In this embodiment, this operating condition typically occurs during the IGBT turn-on phase. The equivalent load of the positive power supply load resistor R1 increases, and the load current at the positive voltage output terminal VCC2 rises, causing the voltage drop to exceed the rated range. After the PWM control unit 103 acquires the voltage deviation through the sampling terminal, it controls the conduction time of the second switch K2 by adjusting the duty cycle of the second PWM signal to match the power gap on the positive voltage side and achieve quantitative power replenishment.

[0050] See Figure 5 , Figure 5 This is a schematic diagram of the current loop during the conduction stage of the second switch under a low positive voltage condition, provided as an embodiment of this application. Figure 5 As shown, when the second switch K2 is turned on, the second PWM signal output by the PWM control unit 103 is at a high level, and the first switch K1 remains off. Current flows out from the common ground terminal GND2, into the first terminal of the energy storage inductor L, passes through the energy storage inductor L, flows out from its second terminal, flows through the turned-on second switch K2 into the negative voltage output terminal VEE2, and finally flows back to the lower end of the negative voltage energy storage capacitor C2, forming a complete charging circuit. The electrical energy on the negative voltage side is converted into magnetic field energy and stored in the energy storage inductor L. When the second switch K2 is turned off, the energy storage inductor L forms an energy release circuit through the first diode D1, releasing the stored electrical energy to the positive voltage output terminal VCC2, replenishing the energy gap on the positive voltage side, and causing the voltage at the positive voltage output terminal VCC2 to rise back to its rated value.

[0051] In one optional implementation, when the voltage at the negative voltage output terminal VEE2 is higher than the rated value, the PWM control unit 103 outputs a second PWM signal to control the second switch K2 to periodically turn on and off. When the second switch K2 is on, the electrical energy at the negative voltage output terminal VEE2 flows into the energy storage inductor L through the second switch K2 to complete energy storage. When the second switch K2 is off, the energy storage inductor L releases energy to the positive voltage output terminal VCC2 through the first diode D1, transferring the excess electrical energy at the negative voltage output terminal VEE2 to the positive voltage output terminal VCC2, thereby stabilizing the voltage at the negative voltage output terminal VEE2.

[0052] In this embodiment, this operating condition typically occurs during the IGBT turn-off phase. The equivalent load of the negative power supply load resistor R2 decreases, and the load current at the negative voltage output terminal VEE2 decreases, causing the voltage rise to exceed the rated range. After the PWM control unit 103 acquires the voltage deviation through the sampling terminal, it adjusts the duty cycle of the second PWM signal to match the current voltage deviation and precisely controls the conduction time of the second switch K2 to achieve quantitative transfer of excess electrical energy.

[0053] See Figure 6 , Figure 6 This is a schematic diagram of the current loop during the energy release stage of an energy storage inductor under a negative voltage high operating condition, provided as an embodiment of this application. Figure 6 As shown, when the second switch K2 is turned off, based on the characteristic that the inductor current cannot change abruptly, the energy storage inductor L maintains the current direction during the conduction phase. The potential of its second terminal is pulled up to a level higher than that of the positive voltage output terminal VCC2, causing the first diode D1 to meet the forward conduction condition. Current flows out from the second terminal of the energy storage inductor L, flows through the conducting first diode D1 into the positive voltage output terminal VCC2, flows back to the common ground terminal GND2 through the positive voltage energy storage capacitor C1, and then flows into the first terminal of the energy storage inductor L, forming a complete energy release circuit. The excess energy of the negative voltage output terminal VEE2 is transferred to the positive voltage output terminal VCC2, causing the voltage of the negative voltage output terminal VEE2 to drop back to its rated value.

[0054] In one alternative implementation, to prevent the positive voltage output terminal VCC2 and the negative voltage output terminal VEE2 from being short-circuited and damaging the circuit devices due to the simultaneous conduction of the first switch K1 and the second switch K2, the two PWM signals output by the PWM control unit 103 are interlocked signals.

[0055] In this embodiment, the interlocking signal means that only one of the two PWM signals is allowed to output a high level at any given time, while the other is forced to remain at a low level. This eliminates the shoot-through risk of the first switch K1 and the second switch K2 being turned on simultaneously from the control logic perspective. Furthermore, a dead time is set between the two interlocked PWM signals to accommodate the turn-on and turn-off delays of the switching devices, further avoiding instantaneous shoot-through during switching and meeting the high-frequency operating requirements of the IGBT drive power supply.

[0056] In one example implementation, the interlock signal can be implemented through the hardware interlock circuit built into the PWM control chip, or through software logic programming of the PWM control unit. Without adding additional hardware components, the circuit's operational safety and long-term reliability can be improved, meeting the high reliability requirements of IGBT drive power supplies in industrial, new energy vehicle, and rail transit scenarios.

[0057] The IGBT driver power supply positive and negative voltage switching regulator circuit provided in this application acquires the positive and negative output voltages in real time through a PWM control unit. Combined with the on / off control of the first and second switches to regulate the charging and discharging of the energy storage inductor, it replaces the energy-consuming structure of traditional Zener diodes and resistors, eliminating the heat generated by energy dissipation at the source and effectively reducing circuit power consumption and temperature rise. Through the unidirectional current conduction of the first and second diodes, the energy storage inductor achieves directional energy release between the positive and negative power supplies, completing bidirectional energy transfer regulation. Relying on the energy storage and filtering effects of the positive and negative energy storage capacitors, combined with precise PWM closed-loop control, it ensures that the positive and negative output voltages of the IGBT driver remain stable within the rated range, achieving synchronous voltage regulation of both positive and negative channels, significantly improving the voltage stability, load adaptability, and operational reliability of the IGBT driver power supply.

[0058] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0059] The above description is merely one specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A positive and negative voltage switching regulator circuit for IGBT drive power supply, characterized in that, It includes an isolated power supply unit, a positive voltage output terminal, a negative voltage output terminal, a common ground terminal, a positive voltage energy storage capacitor, a negative voltage energy storage capacitor, a positive power supply load resistor, a negative power supply load resistor, a bidirectional power transfer unit, and a PWM control unit; The positive voltage energy storage capacitor is connected between the positive voltage output terminal and the common ground terminal, and the negative voltage energy storage capacitor is connected between the common ground terminal and the negative voltage output terminal; The positive power supply load resistor is connected between the positive voltage output terminal and the common ground terminal, and the negative power supply load resistor is connected between the common ground terminal and the negative voltage output terminal. The bidirectional power transfer unit includes a first switch, a second switch, a first diode, a second diode, and an energy storage inductor; the first end of the energy storage inductor is connected to a common ground terminal, and the second end of the energy storage inductor is connected to the first end of the first switch, the anode of the first diode, the first end of the second switch, and the cathode of the second diode; the second end of the first switch and the cathode of the first diode are both connected to the positive voltage output terminal; the second end of the second switch and the anode of the second diode are both connected to the negative voltage output terminal. The sampling terminal of the PWM control unit is connected to the positive voltage output terminal and the negative voltage output terminal respectively. The first signal output terminal of the PWM control unit is connected to the control terminal of the first switch, and the second signal output terminal is connected to the control terminal of the second switch. The PWM control unit collects the real-time voltage of the positive voltage output terminal and the negative voltage output terminal, and outputs two PWM signals to control the on / off state of the first switch and the second switch respectively. Through the energy storage and release of the energy storage inductor, the electrical energy on the high voltage side is transferred to the low voltage side.

2. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, The rated output voltage of the positive voltage output terminal is +15V, and the rated output voltage of the negative voltage output terminal is -10V.

3. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, The isolated power supply unit outputs a rated DC voltage of 25V. The positive terminal of the isolated power supply unit is connected to the positive voltage output terminal, and the negative terminal of the isolated power supply unit is connected to the negative voltage output terminal.

4. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, The isolated power supply unit is a flyback switching power supply circuit, a push-pull switching power supply circuit, a forward switching power supply circuit, a half-bridge switching power supply circuit, or a full-bridge switching power supply circuit.

5. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, The PWM control unit performs independent closed-loop feedback control on the voltages of the positive voltage output terminal and the negative voltage output terminal, respectively, and controls the on-time of the corresponding switch by adjusting the duty cycle of the corresponding PWM signal.

6. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, When the positive voltage output terminal voltage is higher than the rated value, the PWM control unit outputs a first PWM signal to control the first switch to periodically turn on and off; when the first switch is on, the electrical energy of the positive voltage output terminal flows into the energy storage inductor through the first switch to complete energy storage; when the first switch is off, the energy storage inductor releases energy to the negative voltage output terminal through the second diode, transferring the excess electrical energy of the positive voltage output terminal to the negative voltage output terminal, thereby stabilizing the voltage of the positive voltage output terminal.

7. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, When the voltage at the negative voltage output terminal is lower than the rated value, the PWM control unit outputs a first PWM signal to control the first switch to periodically turn on and off. When the first switch is on, the electrical energy at the positive voltage output terminal flows into the energy storage inductor through the first switch to complete energy storage. When the first switch is off, the energy storage inductor releases energy to the negative voltage output terminal through the second diode to replenish the electrical energy gap at the negative voltage output terminal and stabilize the voltage at the negative voltage output terminal.

8. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, When the positive voltage output terminal voltage is lower than the rated value, the PWM control unit outputs a second PWM signal to control the second switch to periodically turn on and off; when the second switch is on, the electrical energy of the negative voltage output terminal flows into the energy storage inductor through the second switch to complete energy storage; when the second switch is off, the energy storage inductor releases energy to the positive voltage output terminal through the first diode to replenish the electrical energy gap of the positive voltage output terminal and stabilize the positive voltage output terminal voltage.

9. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, When the voltage at the negative voltage output terminal is higher than the rated value, the PWM control unit outputs a second PWM signal to control the second switch to periodically turn on and off. When the second switch is on, the electrical energy at the negative voltage output terminal flows into the energy storage inductor through the second switch to complete energy storage. When the second switch is off, the energy storage inductor releases energy to the positive voltage output terminal through the first diode, transferring excess electrical energy from the negative voltage output terminal to the positive voltage output terminal and stabilizing the voltage at the negative voltage output terminal.

10. The IGBT drive power supply positive and negative voltage switching regulator circuit according to claim 1, characterized in that, The two PWM signals output by the PWM control unit are interlocked signals.

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