阅读说明：本技术 采用变压器隔离带负偏置任意占空比的电源驱动装置 (Power supply driving device adopting negative bias of transformer isolation belt with any duty ratio ) 是由 韩锋 姚继忠 龚华刚 潘佩 韩卫峰 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种采用变压器隔离带负偏置任意占空比的电源驱动装置,包括设有初级绕组和次级绕组的变压器,初级绕组两端之间连接有变压器驱动电路,次级绕组的两端并联有正偏压电路、整流电路和负偏压电路,正偏压电路、整流电路和负偏压电路分别电连接至射极跟随电路,射极跟随电路的输出端连接至IGBT功率器件；由控制电路产生单向PWM或PFM控制脉冲,通过变压器驱动电路、正偏压电路、整流电路、负偏压电路等分立器件的配合,变为合适任意占空比、带负偏压、无延时和无占空比丢失的IGBT驱动脉冲,消除了目前使用的普通变压器驱动和光耦驱动的技术缺陷,使IGBT功率器件的驱动中,不需要额外的正、负驱动电源,无光电耦合器、无集成电路,电路简单可靠。(The invention discloses a power supply driving device adopting a transformer isolation belt to negatively bias any duty ratio, which comprises a transformer provided with a primary winding and a secondary winding, wherein a transformer driving circuit is connected between two ends of the primary winding; the control circuit generates unidirectional PWM or PFM control pulse, and the unidirectional PWM or PFM control pulse is changed into IGBT drive pulse with proper duty ratio, negative bias, no time delay and no duty ratio loss through the cooperation of the transformer drive circuit, the positive bias circuit, the rectification circuit, the negative bias circuit and other discrete devices, thereby eliminating the technical defects of the common transformer drive and the optocoupler drive used at present, and ensuring that no additional positive and negative drive power supply is needed in the drive of the IGBT power device, no optocoupler and no integrated circuit exist, and the circuit is simple and reliable.)

1. Adopt negative bias power drive arrangement of arbitrary duty cycle of transformer median, including the transformer, the transformer is equipped with primary winding and secondary winding, its characterized in that: the power supply comprises a primary winding, a secondary winding, a transformer driving circuit, a positive bias circuit, a rectifying circuit and a negative bias circuit, wherein the transformer driving circuit is connected between two ends of the primary winding, the positive bias circuit, the rectifying circuit and the negative bias circuit are connected in parallel at two ends of the secondary winding, the positive bias circuit, the rectifying circuit and the negative bias circuit are respectively and electrically connected to an emitter follower circuit, and the output end of the emitter follower circuit is connected to an IGBT power device.

2. The power driving apparatus using negative bias of the transformer isolation strip with any duty cycle as claimed in claim 1, wherein: the transformer driving circuit comprises a triode Q1, a triode Q2, a resistor R1 and a capacitor C1, wherein the input end of the resistor R1 is connected to a control power supply, the output end of the resistor R1 is respectively connected to the base electrode of the triode Q1 and the base electrode of the triode Q2, the collector electrode of the triode Q1 is connected to an auxiliary power supply, the emitter electrode of the triode Q1 and the emitter electrode of the triode Q2 are respectively connected to the input end of the capacitor C1, the collector electrode of the triode Q2 is grounded, and the primary winding is connected between the output end of the capacitor C1 and the collector electrode of the triode Q2.

3. The power driving apparatus using negative bias of the transformer isolation strip with any duty cycle as claimed in claim 2, wherein: the triode Q1 is an NPN switch type triode, the triode Q2 is a PNP switch type triode, the auxiliary power supply is 12V, and the transformation ratio of the primary winding to the secondary winding is 1: 2.

4. The power driving apparatus using negative bias of the transformer isolation strip with any duty cycle as claimed in claim 1, wherein: the forward bias circuit comprises a diode D1 and a capacitor C3 connected in series across the secondary winding, the cathode of the diode D1 is connected to the input terminal of the capacitor C3, and the cathode of the diode D1 is also connected to the emitter follower circuit.

5. The power driving apparatus using negative bias arbitrary duty cycle of transformer isolation strip as claimed in claim 4, wherein: the rectification circuit comprises a capacitor C2, a diode D2 and a voltage stabilizing diode DZ1 which are connected in series at two ends of the secondary winding, wherein the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the voltage stabilizing diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises a voltage stabilizing diode DZ2, a diode D3 and a capacitor C4 which are connected in series at two ends of the secondary winding, wherein the cathode of the voltage stabilizing diode DZ2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

6. The power driving apparatus using negative bias arbitrary duty cycle of transformer isolation strip as claimed in claim 4, wherein: the rectification circuit comprises a capacitor C2, a diode D2 and a resistor R8 which are connected in series across the secondary winding, wherein the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the resistor R8, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises a resistor R7, a diode D3 and a capacitor C4 which are connected in series across the secondary winding, wherein the resistor R7 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

7. The power driving apparatus using negative bias arbitrary duty cycle of transformer isolation strip as claimed in claim 4, wherein: the rectification circuit comprises a capacitor C2, a diode D2 and a voltage stabilizing diode DZ1 which are connected in series at two ends of the secondary winding, wherein the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the voltage stabilizing diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises an independent winding which is arranged in series with the secondary winding, a diode D3 and a capacitor C4 are connected in series with two ends of the independent winding, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

8. The power driving apparatus using negative bias of transformer isolation band with arbitrary duty cycle as claimed in claim 5, 6 or 7, wherein: the emitter follower circuit comprises a transistor Q3, a transistor Q4 and a resistor R4, wherein the base of the transistor Q3 is respectively connected to the cathode of the diode D2, the capacitor C4 and the base of the transistor Q4, the collector of the transistor Q3 is connected to the cathode of the diode D1, and the emitter of the transistor Q3 is connected to the IGBT power device through the resistor R4; the base of the transistor Q4 is connected to the cathode of the diode D2 and the capacitor C4, the collector of the transistor Q4 is connected to the anode of the diode D3, the emitter of the transistor Q4 is connected to the IGBT power device through the resistor R4, and a voltage bias circuit and a bidirectional voltage limiting circuit are connected in parallel between the IGBT power device and the resistor R4.

9. The power driving apparatus using negative bias arbitrary duty cycle of transformer isolation strip as claimed in claim 8, wherein: the triode Q3 is an NPN switch type triode, the triode Q4 is a PNP switch type triode, a current-limiting resistor R2 is further connected between the collector of the triode Q3 and the diode D1 or between the emitter of the triode Q3 and the emitter of the triode Q4, and a current-limiting resistor R3 is further connected between the base of the triode Q4 and the capacitor C4.

10. The power driving apparatus using negative bias arbitrary duty cycle of transformer isolation strip as claimed in claim 8, wherein: the voltage bias circuit is provided as a bias resistor R5 connected between the IGBT power device and the base of the transistor Q4;

the bidirectional voltage limiting circuit is a voltage stabilizing diode DZ3 and a voltage stabilizing diode DZ4 which are connected in series between the IGBT power device and the base electrode of the triode Q4, and the anode of the voltage stabilizing diode DZ3 is electrically connected with the anode of the voltage stabilizing diode DZ 4.

Technical Field

The invention relates to the technical field of IGBT driving, in particular to a power driving device adopting a negative bias of a transformer isolation belt and having any duty ratio.

Background

An IGBT (insulated gate bipolar transistor) is a composite fully-controlled voltage-driven power semiconductor device consisting of BJTs (bipolar junction transistors) and MOS (insulated gate field effect transistors), has the advantages of both high input impedance of the MOSFET and low conduction voltage drop of GTR, and is very suitable for being applied to the fields of current transformation systems with direct-current voltage of 600V or more, such as alternating-current motors, frequency converters, switching power supplies, lighting circuits, traction transmission and the like.

The IGBT device has the greatest differences in its driving apparatus compared to the MOFET, based on its own characteristics: the C, E pole of the IGBT to which the forward gate voltage is applied is turned on, but the gate voltage is turned off not only below the turn-on threshold Vgth but also negatively biased. Therefore, the IGBT can be turned off as soon as possible and can be kept turned off, the influence of the Miller effect is reduced, and the mis-conduction cannot occur. The IGBT device is mostly applied to the high-voltage field, and circuits for generating driving pulse signals are all low-voltage analog devices and digital devices, so that the electrical isolation between the IGBT power device and the control unit is very necessary.

At present, the common practice is to use a special driving thick film circuit module, a control circuit generates a low-voltage driving pulse signal, and an auxiliary power supply provides a special isolated positive and negative power supply. The device that undertakes electrical isolation work among the internal circuit of drive thick film module generally adopts high pressure, high-speed optoelectronic coupler, transmits drive pulse to the power end by control end by optoelectronic coupler, adds IGBT's grid through pulse shaping circuit, drive arrangement again, and its defect that exists mainly has:

1. the signal transmission of the photoelectric coupler has large delay, so that the driving pulse is delayed, the duty ratio is lost, and the power control is influenced;

2. the withstand voltage of the photoelectric coupler is not high, and the insulation effect is influenced;

3. the photoelectric coupler is greatly influenced by the temperature of the temperature environment, and the reliability of the equipment is influenced.

Another common method is to directly drive the IGBT gate by using a driving transformer, which has certain defects, such as large distortion of driving pulse signals, easily causing loss of duty ratio of pulses, and affecting efficiency and control accuracy of the power supply power part; difficult to apply when the duty cycle is greater than 50%; a persistent negative bias or the like is not effectively applied when the pulse is OFF.

Disclosure of Invention

The invention aims to solve the technical problem of providing a power supply driving device which has high reliability, does not need to specially set a positive power supply and a negative power supply, has low drive pulse distortion, is suitable for pulses with any duty ratio, and can continuously apply negative bias during turn-off and adopts a transformer isolation belt to negatively bias any duty ratio.

In order to solve the technical problems, the technical scheme of the invention is as follows: the power supply driving device adopts a transformer isolation belt to negatively bias any duty ratio and comprises a transformer, wherein the transformer is provided with a primary winding and a secondary winding, a transformer driving circuit is connected between two ends of the primary winding, a positive bias circuit, a rectifying circuit and a negative bias circuit are connected in parallel with two ends of the secondary winding, the positive bias circuit, the rectifying circuit and the negative bias circuit are respectively and electrically connected to an emitter follower circuit, and the output end of the emitter follower circuit is connected to an IGBT power device.

Preferably, the transformer driving circuit includes a transistor Q1, a transistor Q2, a resistor R1, and a capacitor C1, an input terminal of the resistor R1 is connected to a control power supply, output terminals of the resistor R1 are respectively connected to a base of the transistor Q1 and a base of the transistor Q2, a collector of the transistor Q1 is connected to an auxiliary power supply, an emitter of the transistor Q1 and an emitter of the transistor Q2 are respectively connected to an input terminal of the capacitor C1, a collector of the transistor Q2 is grounded, and the primary winding is connected between an output terminal of the capacitor C1 and the collector of the transistor Q2.

As a preferred technical solution, the transistor Q1 is an NPN switching transistor, the transistor Q2 is a PNP switching transistor, the auxiliary power supply is 12V, and the ratio of the primary winding to the secondary winding is 1: 2.

As a preferred technical solution, the forward bias circuit includes a diode D1 and a capacitor C3 connected in series across the secondary winding, a cathode of the diode D1 is connected to an input end of the capacitor C3, and a cathode of the diode D1 is further connected to the emitter follower circuit.

As a preferred technical solution, the rectifier circuit includes a capacitor C2, a diode D2 and a zener diode DZ1 connected in series across the secondary winding, the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the zener diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises a voltage stabilizing diode DZ2, a diode D3 and a capacitor C4 which are connected in series at two ends of the secondary winding, wherein the cathode of the voltage stabilizing diode DZ2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

As a preferred technical solution, the rectifier circuit includes a capacitor C2, a diode D2 and a resistor R8 connected in series across the secondary winding, the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the resistor R8, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises a resistor R7, a diode D3 and a capacitor C4 which are connected in series across the secondary winding, wherein the resistor R7 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

As a preferred technical solution, the rectifier circuit includes a capacitor C2, a diode D2 and a zener diode DZ1 connected in series across the secondary winding, the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the zener diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit;

the negative bias circuit comprises an independent winding which is arranged in series with the secondary winding, a diode D3 and a capacitor C4 are connected in series with two ends of the independent winding, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit.

As a preferred technical solution, the emitter follower circuit includes a transistor Q3, a transistor Q4, and a resistor R4, wherein a base of the transistor Q3 is connected to a cathode of the diode D2, the capacitor C4, and a base of the transistor Q4, respectively, a collector of the transistor Q3 is connected to a cathode of the diode D1, and an emitter of the transistor Q3 is connected to the IGBT power device through the resistor R4; the base of the transistor Q4 is connected to the cathode of the diode D2 and the capacitor C4, the collector of the transistor Q4 is connected to the anode of the diode D3, the emitter of the transistor Q4 is connected to the IGBT power device through the resistor R4, and a voltage bias circuit and a bidirectional voltage limiting circuit are connected in parallel between the IGBT power device and the resistor R4.

Preferably, the transistor Q3 is an NPN switching transistor, the transistor Q4 is a PNP switching transistor, a current-limiting resistor R2 is further connected between a collector of the transistor Q3 and the diode D1 or between an emitter of the transistor Q3 and an emitter of the transistor Q4, and a current-limiting resistor R3 is further connected between a base of the transistor Q4 and the capacitor C4.

As an improvement to the above technical solution, the voltage bias circuit is configured as a bias resistor R5 connected between the IGBT power device and the base of the transistor Q4;

the bidirectional voltage limiting circuit is a voltage stabilizing diode DZ3 and a voltage stabilizing diode DZ4 which are connected in series between the IGBT power device and the base electrode of the triode Q4, and the anode of the voltage stabilizing diode DZ3 is electrically connected with the anode of the voltage stabilizing diode DZ 4.

The power supply driving device adopting the technical scheme and adopting the negative bias of the transformer isolation belt with any duty ratio comprises a transformer, wherein the transformer is provided with a primary winding and a secondary winding, a transformer driving circuit is connected between two ends of the primary winding, a positive bias circuit, a rectifying circuit and a negative bias circuit are connected in parallel with two ends of the secondary winding, the positive bias circuit, the rectifying circuit and the negative bias circuit are respectively and electrically connected to an emitter follower circuit, and the output end of the emitter follower circuit is connected to an IGBT power device; the invention has the following beneficial effects: the control circuit (analog or digital) generates unidirectional PWM or PFM control pulse, and the pulse is changed into IGBT drive pulse with any duty ratio, negative bias, no time delay and no duty ratio loss through the cooperation of the transformer drive circuit, the positive bias circuit, the rectification circuit, the negative bias circuit and other discrete devices, thereby fundamentally eliminating the technical defects of the common transformer drive and the optocoupler drive used at present, ensuring that no additional positive and negative drive power supply, no optocoupler and no integrated circuit are needed in the whole drive work of the IGBT power device, and the circuit is simple and reliable.

Drawings

The drawings are only for purposes of illustrating and explaining the present invention and are not to be construed as limiting the scope of the present invention. Wherein:

FIG. 1 is a schematic circuit diagram of a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a circuit of the embodiment of the invention after adjusting the positions of a current-limiting resistor R2 and a transistor Q3;

FIG. 3 is a schematic circuit diagram of a second embodiment of the present invention, in which a MOSFET power device is used instead of an IGBT power device;

FIG. 4 is a schematic circuit diagram of a second embodiment of the present invention, in which a MOS transistor is used instead of a triode;

FIG. 5 is a circuit schematic of a third embodiment of the present invention;

FIG. 6 is a circuit schematic diagram of another bias circuit according to a fourth embodiment of the present invention;

FIG. 7 is an input waveform diagram of an embodiment of the present invention;

FIG. 8 is a waveform diagram of an output of an embodiment of the present invention;

FIG. 9 is a waveform diagram of an output after duty cycle adjustment according to an embodiment of the present invention;

Detailed Description

The invention is further illustrated below with reference to the figures and examples. In the following detailed description, certain exemplary embodiments of the present invention are described by way of illustration only. Needless to say, a person skilled in the art realizes that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Accordingly, the drawings and description are illustrative in nature and not intended to limit the scope of the claims.

The first embodiment is as follows:

as shown in fig. 1, the power driving apparatus using a transformer isolation band to negatively bias a power supply with any duty ratio includes a transformer T1, the transformer T1 is provided with a primary winding and a secondary winding, a transformer driving circuit is connected between two ends of the primary winding, a positive bias circuit, a rectifying circuit and a negative bias circuit are connected in parallel to two ends of the secondary winding, the positive bias circuit, the rectifying circuit and the negative bias circuit are respectively and electrically connected to an emitter follower circuit, an output end of the emitter follower circuit is connected to an IGBT power device, and by cooperation of the above circuits, the present embodiment uses the transformer T1 as a boundary, a control side is formed on the left side, and a power side is formed on the right side.

As shown in fig. 1, the transformer driving circuit includes a transistor Q1, a transistor Q2, a resistor R1, and a capacitor C1, wherein an input terminal of the resistor R1 is connected to a control power supply, output terminals of the resistor R1 are respectively connected to a base of the transistor Q1 and a base of the transistor Q2, a collector of the transistor Q1 is connected to an auxiliary power supply, an emitter of the transistor Q1 and an emitter of the transistor Q2 are respectively connected to an input terminal of the capacitor C1, a collector of the transistor Q2 is grounded, and the primary winding is connected between an output terminal of the capacitor C1 and the collector of the transistor Q2. The triode Q1 is an NPN switch type triode, the triode Q2 is a PNP switch type triode, the auxiliary power supply is 12V, the transformation ratio of the primary winding to the secondary winding is 1:2, and the magnetic core of the transformer T1 may be a ferrite magnetic core or an amorphous or ultra-microcrystalline magnetic core.

In the transformer driving circuit, the transistor Q1, the transistor Q2 and the resistor R1 form an emitter follower, the resistor R1 is a base resistor of two transistors and can limit the base current of each transistor, the transistor Q1 and the transistor Q2 form a driving current signal from the signal source V1 of the control power supply and amplify and output the driving current signal in a push-pull type working mode, the collector of the transistor Q2 is connected with a control ground, the capacitor C1 is a dc blocking capacitor, a dc current is isolated between the transformer T1 and the emitter follower formed by the transistor Q1, the transistor Q2 and the resistor R1, and only an ac pulse current can flow into the primary winding of the transformer T1; the same name of the two windings of the transformer T1 is connected with the control ground.

In this embodiment, after the pulse signal is transmitted from the primary side to the secondary side of the transformer T1, the pulse signal is divided into three paths at the non-dotted terminal of the secondary winding, that is, the pulse signal is transmitted by the positive bias circuit, the rectifier circuit and the negative bias circuit, respectively, and the dotted terminal thereof is connected to the power ground. Specifically, the forward bias circuit includes a diode D1 and a capacitor C3 connected in series across the secondary winding, the cathode of the diode D1 is connected to the input terminal of the capacitor C3, and the cathode of the diode D1 is also connected to the emitter follower circuit. In the circuit, current is rectified from the cathode to the anode of the diode D1, filtered and stored by the capacitor C3 to establish a forward bias direct current voltage, and the forward bias direct current voltage is supplied to the emitter follower circuit.

The rectification circuit comprises a capacitor C2, a diode D2 and a voltage stabilizing diode DZ1 which are connected in series at two ends of the secondary winding, wherein the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the voltage stabilizing diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit. In the circuit, the capacitor C2 is transmitted to the emitter follower circuit after blocking, and the Zener diode DZ1 generates a negative bias signal and determines the amplitude of the negative bias.

The negative bias circuit comprises a voltage stabilizing diode DZ2, a diode D3 and a capacitor C4 which are connected in series at two ends of the secondary winding and cooperate to generate a negative power supply. Specifically, the cathode of the zener diode DZ2 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit. This circuit is opposite to the positive bias circuit, and the zener diode DZ1 and the zener diode DZ2 determine the magnitude of the negative bias of the driving pulse. For example, when the voltage of the auxiliary power supply is 12V, the transformation ratio of the transformer T1 can be set to 1:2, so that the gate forward bias voltage of the IGBT power device reaches a magnitude of 13-19.5V, which is well known to those skilled in the art and will not be described in detail herein.

The emitter follower circuit of the present embodiment includes a transistor Q3, a transistor Q4, and a resistor R4, wherein a base of the transistor Q3 is connected to a cathode of the diode D2, the capacitor C4, and a base of the transistor Q4, respectively, the transistor Q3 and the transistor Q4 constitute an emitter follower, a collector of the transistor Q3 is connected to a cathode of the diode D1, and an emitter of the transistor Q3 is connected to the IGBT power device through the resistor R4; the base of the transistor Q4 is connected to the cathode of the diode D2 and the capacitor C4, the collector of the transistor Q4 is connected to the anode of the diode D3, the emitter of the transistor Q4 is connected to the IGBT power device through the resistor R4, and a voltage bias circuit and a bidirectional voltage limiting circuit are connected in parallel between the IGBT power device and the resistor R4.

The triode Q3 is an NPN switching type triode, the triode Q4 is a PNP switching type triode, a current-limiting resistor R2 (shown in fig. 1) is further connected between the collector of the triode Q3 and the diode D1, or a current-limiting resistor R2 (shown in fig. 2) is further connected between the emitter of the triode Q3 and the emitter of the triode Q4, and a current-limiting resistor R3 is further connected between the base of the triode Q4 and the capacitor C4. The current limiting resistor R2 is a current limiting resistor with positive bias voltage, and limits the driving current of a grid G pole of the IGBT power device so as to reduce the rising speed of pulses and reduce dv/dt of the IGBT collector voltage; the current limiting resistor R3 and the resistor R4 are resistors of a grid G pole of the IGBT power device and limit oscillation of a driving signal on the grid.

The voltage bias circuit is provided as a bias resistor R5 connected between the IGBT power device and the base of the triode Q4, can provide bias voltage for a field effect transistor, and can play a role in discharging voltage to protect a grid G-emitter E (or a source S) of the IGBT power device. The bidirectional voltage limiting circuit is a voltage stabilizing diode DZ3 and a voltage stabilizing diode DZ4 which are connected in series between the IGBT power device and the base electrode of the triode Q4, and the anode of the voltage stabilizing diode DZ3 is electrically connected with the anode of the voltage stabilizing diode DZ 4. The zener diode DZ3 and the zener diode DZ4 cooperate to prevent the amplitude of the driving pulse from exceeding ± 20V.

Example two:

in this embodiment, the IGBT power device in the first embodiment may be replaced by a MOSFET power device, as shown in fig. 3, or the transistor Q1 and the transistor Q3 may be replaced by an N-channel MOS transistor M2 and an MOS transistor M4, respectively, and the transistor Q2 and the transistor Q4 may be replaced by an N-channel MOS transistor M3 and an MOS transistor M5, respectively, as shown in fig. 4. Both of the above-mentioned improved circuits can achieve the whole functions of the present embodiment, but because the small MOS transistor has a low withstand voltage, it is assembled without being affected by static electricity.

Example three:

as shown in fig. 5, the rectifier circuit includes a capacitor C2, a diode D2 and a resistor R8 connected in series across the secondary winding, the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the resistor R8, and the cathode of the diode D2 is also connected to the emitter follower circuit; the negative bias circuit comprises a resistor R7, a diode D3 and a capacitor C4 which are connected in series across the secondary winding, wherein the resistor R7 is connected to the cathode of the diode D3, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit. The difference from the first embodiment is that the resistor R8 is used to replace the zener diode DZ1, and the resistor R7 is used to replace the zener diode DZ2, and the two can be replaced separately or simultaneously, and after replacement, the circuit function of the first embodiment can be realized.

Example four:

as shown in fig. 6, the rectifier circuit includes a capacitor C2, a diode D2 and a zener diode DZ1 connected in series across the secondary winding, the cathode of the diode D2 is connected to the capacitor C2, the anode of the diode D2 is connected to the anode of the zener diode DZ1, and the cathode of the diode D2 is also connected to the emitter follower circuit; the negative bias circuit comprises an independent winding which is arranged in series with the secondary winding, a diode D3 and a capacitor C4 are connected in series with two ends of the independent winding, the anode of the diode D3 is connected to the capacitor C4, and the capacitor C4 is connected to the emitter follower circuit. The fourth embodiment can also realize the circuit function of the first embodiment, but the complexity of the circuit is increased, the cost is relatively increased, and the overall cost is still greatly reduced compared with the prior art.

The invention finally realizes an isolation driving circuit of the power electronic switch device, overcomes the defects of common photoelectric coupling isolation driving and other transformer isolation driving schemes, can improve the reliability and power conversion efficiency of the power electronic device and the stability of power switch control, does not use an integrated circuit, and is completely composed of discrete devices.

As shown in fig. 7, 8 and 9, the input waveform diagram is regular square wave pulses, the amplitude generated by the digital control circuit or the analog control circuit is 12V, and the dc continuous pulses have arbitrary unlimited frequency (limited only by the characteristics of the transformer T1) and unlimited duty ratio; the output waveform diagram is a pulse with negative bias voltage, and the pulse can be directly connected to a grid-emitter (G-E) or a grid-source (G-S) of the IGBT power device or the MOSFET power device to control the ON-OFF (ON-OFF) of the IGBT power device or the MOSFET power device.

As can be seen from fig. 8 and 9, the step change moments of the two waveforms are basically identical, and there is no obvious time delay, which indicates that there is no duty ratio loss problem in the output waveform of the driving circuit, and further, the power switching device and the control signal are turned on and off synchronously, so that the device can operate at a large duty ratio, and the power conversion intermediate voltage does not need to be increased due to the duty ratio loss problem, thereby reducing the power loss of the power conversion apparatus.

The positive bias section of the output waveform corresponds to the ON-period of the IGBT power device, and the negative bias section corresponds to the OFF-period of the IGBT power device. The oscillating pulse with the negative bias superimposed corresponds to the effect of the sudden change in the collector (C-pole) or source (S) -voltage of the switching device (IGBT or MOSFET) on the gate (S-pole). When this effect increases beyond its turn-on threshold Vgth, the power device will be turned on erroneously and thus damaged. The negative bias is added to enable the influence to be far away from Vgth, the reliable work of a power device is guaranteed, the width of a pulse is changed within the range of 0-99%, the output waveform of the power device can follow the change of an input signal, the duty ratio loss phenomenon cannot occur, the positive bias is always kept, and the power device is suitable for different power circuit topologies. The invention is suitable for driving an IGBT power device or an MOSFET power device switch device, is particularly suitable for a high-power IGBT module, has higher reliability and lower cost, and has driving pulse more suitable for the IGBT than the common transformer driving scheme, so that the power electronic device adopting the invention has more reliable performance and higher overall efficiency.

The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.