阅读说明：本技术 一种宽禁带功率器件的多梯级驱动控制方法 (Multi-step driving control method of wide bandgap power device ) 是由 董振邦 曹萌萌 邱冬 赖勇 史文萍 于 2020-12-07 设计创作，主要内容包括：本发明一种宽禁带功率器件的多梯级驱动控制方法涉及的是控制方法,尤其是一种优化宽禁带功率器件开关性能的多梯级驱动控制方法。包括应用于器件开通过程的开通方法和应用于器件关断过程的关断方法。实现该方法的多梯级驱动电压控制系统,包含MCU微处理器、多梯级电平器和功率放大器；MCU微处理器用于产生梯级驱动电压的触发脉冲信号,多梯级电平器用于预设多梯级驱动电压,功率放大器对被触发的梯级驱动电压进行功率放大。本发明能够实现器件开关速度的可调节,降低器件保护的设计难度,提升器件工作安全区的利用；有效降低器件开关过程中,电压电流尖峰,减轻电压电流的振荡现象,提高器件利用的安全性能,进而提升了高压大容量电力电子装置的安全性。(The invention discloses a multi-step driving control method of a wide bandgap power device, relates to a control method, and particularly relates to a multi-step driving control method for optimizing the switching performance of the wide bandgap power device. Including turn-on methods applied to device turn-on processes and turn-off methods applied to device turn-off processes. The multi-step driving voltage control system for realizing the method comprises an MCU microprocessor, a multi-step level device and a power amplifier; the MCU microprocessor is used for generating a trigger pulse signal of the step driving voltage, the multi-step level device is used for presetting the multi-step driving voltage, and the power amplifier is used for carrying out power amplification on the triggered step driving voltage. The invention can realize the adjustment of the switching speed of the device, reduce the design difficulty of the device protection and improve the utilization of the working safety area of the device; effectively reduce the device switching in-process, the voltage current peak alleviates voltage current's oscillation phenomenon, improves the security performance that the device utilized, and then has promoted high voltage large capacity power electronic device's security.)

1. A multi-step drive control method of a wide-bandgap power device is characterized in that a multi-step drive voltage control system for realizing the multi-step drive control method comprises an MCU microprocessor, a multi-step level device and a power amplifier; the MCU microprocessor is used for generating a trigger pulse signal of the step driving voltage, the multi-step level device is used for presetting the multi-step driving voltage, and the power amplifier is used for carrying out power amplification on the triggered step driving voltage.

2. The multi-step driving control method of the wide bandgap power device as claimed in claim 1, wherein the method comprises an on method applied to a device on process and an off method applied to a device off process.

3. The multi-step driving control method of the wide bandgap power device according to claim 2, wherein the switching-on method comprises the following steps:

s1-1, grading the step voltage of the multi-step drive control system for n times in the multi-step level device, and grading the step voltage V_n∈(V_th,V_gon) Wherein n is a positive integer, V_thIs the threshold voltage of the device, V_gonIs the forward driving voltage of the device, and realizes the drain current i in the process of turning on the device_dThe rate of change di/dt and its oscillation;

s1-2, in the process of turning on the device, the holding time of the step voltage is set by a control program in the microprocessor, and the pulse trigger signal of the next step voltage is delayed to obtain the holding time;

s1-3, drain current i in step S1-1_dRate of change di/dt, drain current peak value I_pAnd current oscillation adjustment time t_sonMeasuring, comparing with a corresponding value in conventional driving, selecting a better value, and determining the value of n and the amplitude of the step driving voltage, wherein n is a positive integer; the corresponding values represent conventional drain current slew rates, peak values and current oscillation adjustment times.

4. The multi-step driving control method of wide bandgap power device as claimed in claim 3, wherein in step S1-1, the first step driving voltage V of the multi-step level shifter in the multi-step driving voltage control system is set₁The first step drive voltage V₁Is greater than the threshold voltage V of the device_th。

5. The multi-step driving control method of the wide bandgap power device as claimed in claim 3, wherein in step S1-2, the step voltage holding time is set in the control program according to the following formula (1):

wherein τ ═ R_g*C_iss，R_gIs the drive resistance of the device, C_issIs the input capacitance of the device, V_nIs the drive voltage of the nth step, T_nIs a stepped drive voltage V_nMaintenance time of V_noIs the initial gate-source voltage, V, of the device at the nth step voltage_nnThe terminal gate-source voltage of the device at the nth step voltage is shown, and n is a positive integer.

6. The multi-step driving control method of the wide bandgap power device according to claim 2, wherein the turn-off method comprises the following steps:

s2-1, grading the step voltage of the multi-step drive control system for m times in the multi-step level device, and obtaining the step voltage V_m∈(V_goff,V_miller) Wherein m is a positive integer, V_millerIs the Miller plateau voltage, V_goffFor negative driving voltage, the drain-source electrode voltage V in the turn-off process is realized_dsRegulation control of the rate of change dv/dt and its oscillation;

s2-2, in the process of turning off the device, the holding time of the step voltage is set by a control program in the microprocessor, and the pulse trigger signal of the next step voltage is delayed to obtain the holding time;

s2-3, drain-source voltage V in step S2-1_dsRate of change dv/dt, peak value V_pAnd voltage oscillation regulation time t_soffMeasuring, comparing with a corresponding value in conventional driving, selecting a better value, and determining the value of m and the amplitude of the step driving voltage; the corresponding values represent conventional drain-source voltage rate of change, peak value, and voltage oscillation adjustment time.

7. The multi-step driving control method of wide bandgap power device as claimed in claim 6, wherein in step S2-1, the mth step driving voltage V of the multi-step level shifter in the multi-step driving voltage control system is set_mMth step drive voltage V_mShould be less than the Miller plateau voltage V of the device_miller。

8. The multi-step driving control method of the wide bandgap power device as claimed in claim 6, wherein in step S2-2, the step voltage holding time is set in the control program according to the following formula (2):

in the formula, V_mIs the driving voltage of the mth step, T_mIs a stepped drive voltage V_mMaintenance time of V_moIs the initial gate-source voltage, V, of the device at the mth step voltage_mmThe voltage is the terminal grid source voltage of the device at the mth step voltage, and m is a positive integer.

Technical Field

The invention discloses a multi-step driving control method of a wide bandgap power device, relates to a control method, and particularly relates to a multi-step driving control method for optimizing the switching performance of the wide bandgap power device.

Background

Wide bandgap power semiconductor devices have come into use when it is increasingly difficult for silicon-based devices to break through their physical limitations. As a novel third-generation power semiconductor device, the semiconductor device has the advantages of high power, high voltage, high temperature, low switching loss and the like. Along with the development of extra-high voltage, large capacity, long distance and intelligence, the demand for high-performance power electronic devices is more and more urgent. When the wide bandgap power device is applied to a high-voltage large-capacity power electronic device of a power system, the cascade number of power modules can be reduced, the topological structure of the system is optimized, the occupied space of the power electronic device is reduced, the compact structural design is realized, and the utilization efficiency of equipment is improved.

However, due to the characteristic of high switching speed, the wide bandgap power device may generate voltage and current spikes and serious oscillations during the switching process, which may affect the effective utilization of the device and the safety and stability of the power equipment. The main problem lies in that the current driving mode of the wide bandgap power device still refers to the driving mode of the traditional silicon-based device, adopts direct pulse type triggering, does not consider the switching characteristics of a novel device, and carries out the driving design conforming to the device itself.

Disclosure of Invention

The invention aims to provide a multi-step driving control method of a wide bandgap power device aiming at the defects, which is a multi-step driving control method which is combined with the switching characteristic of the wide bandgap device and switched in from a driving mode and accords with a novel device; in the switching process of the wide-bandgap power device, multi-step driving control is performed, so that the switching speed of the device, namely the change of di/dt and dv/dt, is changed, and the performance of the device is improved.

The multi-step driving voltage control system for realizing the multi-step driving control method of the wide bandgap power device comprises an MCU (micro control unit), a multi-step level device and a power amplifier. The operation logic relation of the system is that a microprocessor sends out trigger pulses to trigger and control the step voltage in the multi-step level device, then the triggered step voltage is sent to a power amplifier, and the step voltage is subjected to power amplification to obtain the grid driving voltage of a power device.

The multi-step driving voltage control system is reversely designed from a power device end to an upstream control end thereof, firstly, the step number of step driving voltage is determined according to the switching characteristic of a used SiCMOS (wide bandgap power device) device, and then a multi-step level device is designed; and then, according to the set multi-step driving voltage amplitude, correspondingly designing a level power supply in the multi-step level device. The duration of the step voltage in the multi-step level device does not need to be designed separately in the multi-step level device, and can be obtained by the time delay of the microprocessor to the next trigger pulse signal. The microprocessor sends out trigger pulse to trigger and control the level in the multi-step level device, which requires programming the trigger pulse signal and giving the timing sequence of the pulse signal.

A multi-step driving control method of a wide bandgap power device comprises an on method applied to a device on process and an off method applied to a device off process.

The opening method comprises the following steps:

s1-1, in the multi-step level device, performing n on step voltage of the multi-step drive control systemSub-classification, stepped voltage V after classification_n∈(V_th,V_gon) Wherein n is a positive integer, V_thIs the threshold voltage of the device, V_gonIs the forward driving voltage of the device, and realizes the drain current i in the process of turning on the device_dThe rate of change di/dt and its oscillation;

s1-2, in the process of turning on the device, the holding time of the step voltage is set by a control program in the microprocessor, and the pulse trigger signal of the next step voltage is delayed to obtain the holding time;

s1-3, drain current i in step S1-1_dRate of change di/dt, drain current peak value I_pAnd current oscillation adjustment time t_sonAnd measuring, comparing with a corresponding value in conventional driving, selecting a better value, and determining the value of n and the amplitude of the step driving voltage, wherein n is a positive integer. The corresponding values represent conventional drain current slew rates, peak values and current oscillation adjustment times.

In step S1-1, a first step driving voltage V of a multi-step level in a multi-step driving voltage control system is set₁The first step drive voltage V₁Should have a voltage value greater than the threshold voltage V of the device_th。

In step S1-2, the step voltage holding time is set in the control program according to the following equation (1):

wherein τ ═ R_g*C_iss，R_gIs the drive resistance of the device, C_issIs the input capacitance of the device, V_nIs the drive voltage of the nth step, T_nIs a stepped drive voltage V_nMaintenance time of V_noIs the initial gate-source voltage, V, of the device at the nth step voltage_nnThe terminal gate-source voltage of the device at the nth step voltage is shown, and n is a positive integer.

The turn-off method comprises the following steps:

s2-1, grading the step voltage of the multi-step drive control system for m times in the multi-step level device, and obtaining the step voltage V_m∈(V_goff,V_miller) Wherein m is a positive integer, V_millerIs the Miller plateau voltage, V_goffFor negative driving voltage, the drain-source electrode voltage V in the turn-off process is realized_dsRegulation control of the rate of change dv/dt and its oscillation;

s2-2, in the process of turning off the device, the holding time of the step voltage is set by a control program in the microprocessor, and the pulse trigger signal of the next step voltage is delayed to obtain the holding time;

s2-3, drain-source voltage V in step S2-1_dsRate of change dv/dt, peak value V_pAnd voltage oscillation regulation time t_soffAnd measuring, comparing with a corresponding value in the conventional driving, selecting a better value, and determining the value of m and the amplitude of the step driving voltage. The corresponding values represent conventional drain-source voltage rate of change, peak value, and voltage oscillation adjustment time.

In step S2-1, the mth step drive voltage V of the multi-step level in the multi-step drive voltage control system is set_mMth step drive voltage V_mShould be less than the Miller plateau voltage V of the device_miller。

In step S2-2, the step voltage holding time is set in the control program according to the formula (2).

In the formula, V_mIs the driving voltage of the mth step, T_mIs a stepped drive voltage V_mMaintenance time of V_moIs the initial gate-source voltage, V, of the device at the mth step voltage_mmThe voltage is the terminal grid source voltage of the device at the mth step voltage, and m is a positive integer.

The technical scheme of the invention has the following advantages:

1. the invention can combine the characteristic that a wide bandgap power device has a high-speed switching process, takes drive control as an entry point, carries out drive control design conforming to the self switching characteristic of the device, realizes the adjustment of the switching speed of the device, reduces the design difficulty of device protection, and improves the utilization of the working safety zone of the device.

2. According to the invention, by adopting a multi-step driving control method in the switching-on and switching-off processes of the wide bandgap power device, the voltage and current peaks in the switching-on and switching-off processes of the device can be effectively reduced, the oscillation phenomenon of the voltage and current is reduced, the safety performance of the device utilization is improved, and the safety of the high-voltage large-capacity power electronic device is further improved.

Drawings

The invention will be further explained with reference to the drawings, in which:

FIG. 1 is a diagram of an embodiment of a multi-step driving voltage control system implementing the control method of the present invention;

FIG. 2 is a functional diagram of the control method of the present invention;

FIG. 3 is a schematic diagram comparing the control method of the present invention with a conventional drive switch process;

fig. 4 is a waveform diagram comparing voltage and current during two-step driving and conventional driving switching.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings 1 to 4 and specific embodiments.

The multi-step driving voltage control system for realizing the multi-step driving control method of the wide bandgap power device comprises an MCU (micro control unit), a multi-step level device and a power amplifier. Setting a control program in a microprocessor to generate a pulse signal for triggering step voltage; the multi-step level is transmitted to a multi-step level device, and the multi-step level device is preset with multi-step driving voltage, so that the step driving voltage can be correctly selected when a trigger pulse signal is received; and the power amplifier is used for carrying out power amplification on the triggered cascade driving voltage to obtain the grid driving voltage of the power device.

An MCU (microprocessor) as in fig. 1 provides a pulsed signal of the drive voltage. V₁、V₂、V₃…V_n(V₁、V₂、V₃…V_m) Is the voltage amplitude, T, of each step of the multi-step driving voltage₁、T₂、T₃…T_n(T₁、T₂、T₃…T_m) Is the holding time of the voltage amplitude of each step of the multi-step driving voltage. The SiCMOS transistor is a typical wide bandgap power device and is also a first generation power semiconductor device applied to high-voltage large-capacity power electronic devices at present.

FIG. 2 is a schematic diagram of the operation of the multi-step drive of the control method of the present invention, wherein U is_gIs the gate voltage of the device, V_gonIs a forward driving voltage, V_goffIs a negative drive voltage. The number of steps, the voltage amplitude of each step and the holding time thereof in the figure can be set according to the switching characteristics and the actual using conditions of the device.

Fig. 3 is a schematic diagram comparing the multi-step driving of the control method of the present invention with the conventional driving switch process. I in FIG. 3(a)_dFor device drain current, I₀Is the load current; v in FIG. 3(b)_dsFor drain-source voltage of the device, U_dcIs the dc bus voltage. It can be seen from the schematic diagram that the multi-step driving control method can effectively reduce the problems of voltage and current spikes and the like in the switching process of the device and improve the use performance of the device.

In fig. 4, the voltage and current waveforms of the device in the conventional driving and the voltage and current waveforms of the device in the two-step driving of the present invention are shown, respectively. It can be seen from the comparison of voltage and current waveforms that the switching performance of the device can be effectively improved by adopting the step driving control method.

The specific embodiment is as follows:

the switching process of the power device is essentially the charging and discharging process of different interelectrode capacitors, and the change of the voltage difference between two ends of the capacitor is a key factor influencing the charging and discharging speed of the capacitor.

The following description of the two-step driving voltage control embodiment is made by taking a CAS300M17BM2 type SiCMOSFET half-bridge module device as an example. During the switching process of the device, the driving voltage of the device is designed in two steps. The trigger signal is sent by MCU (microprocessor) to select and trigger the voltage in two-step level device. The voltage contains two elements, its voltage amplitude and the duration of the voltage.

The step voltage is larger than the threshold voltage V of the device during the turn-on process_th(2.5V) and less than the forward drive voltage V_gon(20V), the step voltage is preset to 10V. After accounting, the step voltage is held for 200ns in the microprocessor.

During turn-off, the step voltage is less than the Miller plateau voltage V of the device_miller(8V) and is greater than the forward drive voltage V_goff(-5V), the step voltage is preset to 0V. After accounting, the same hold time program for the step voltage is set to 200ns in the microprocessor.

TABLE 1 two-step drive vs. conventional drive Start-Up Process parameter comparison

	di/dt(kA/us)	Ip/A	tson/ns
				Conventional drive	4.98	270	2520
Two step drive	1.78	220	1404

TABLE 2 two-step drive vs. conventional drive shut-off Process parameter comparison

	dv/dt(kA/us)	Vp/A	tsoff/ns
				Conventional drive	15.23	1060	3880
Two step drive	7.61	950	2464

Tables 1 and 2 are the results of comparing the parameters of the switching process using the two-step drive with the conventional drive, respectively. In Table 1I_pFor drain current i during the turn-on of SiCMOS MOSFET_dSharp peak value of, t_sonIs the adjustment time of the drain current oscillation; in Table 2V_pFor drain-source electrode voltage V in the process of opening SiMOSFET_dsSharp peak value of, t_soffThe adjustment time for the drain-source voltage oscillation. From Table 1, it can be seen that di/dt is reduced by 64.3%, the current peak is reduced by 18.52%, and the regulation time of the current oscillation is reduced by 44.3%; it can be seen from Table 2 that dv/dt is reduced by 50%, the voltage peak is reduced by 10.4%, and the voltage oscillation settling time is reduced by 36.5%.

It can be seen from the comparison results in tables 1 and 2 and the voltage-current comparison waveform in fig. 4 that the multi-step driving control method can effectively control the switching speed of the wide bandgap power device, reduce the protection design requirements of the device, and improve the safety use performance of the device.