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CN-122017331-A - Multi-parameter detection circuit for conducting voltage drop and peak detection

CN122017331ACN 122017331 ACN122017331 ACN 122017331ACN-122017331-A

Abstract

The invention discloses a conduction voltage drop and peak value detection multi-parameter detection circuit which comprises a conduction voltage drop test circuit and a peak value voltage detection circuit which are arranged at two ends of a tested power device in parallel, wherein the conduction voltage drop test circuit is used for respectively collecting forward conduction voltage drop and reverse conduction voltage drop of the power device in a conduction and follow current state of the power device, the peak value voltage detection circuit is used for capturing transient peak voltage between the collector and the emitter of the power device in the turn-off process of the power device, and the output ends of the conduction voltage drop test circuit and the peak value voltage detection circuit are connected into an analog-to-digital converter after being isolated so as to realize simultaneous detection of multiple parameters of the same power device. The circuit can realize high-precision and strong-robustness measurement of forward and reverse on-voltage and transient spike voltage in a complex switching environment.

Inventors

  • CHEN GUOFU
  • HU JINGYANG
  • LUO HAOZE
  • LI WUHUA
  • HE XIANGNING

Assignees

  • 浙江大学

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. 1. The multi-parameter detection circuit for detecting the conduction voltage drop and the peak value is applied to a three-level ANPC converter and is characterized by comprising a conduction voltage drop test circuit and a peak voltage detection circuit which are arranged at two ends of a tested power device in parallel; The conduction voltage drop test circuit is used for respectively collecting the positive conduction voltage drop and the reverse conduction voltage drop of the power device in the conduction and follow current states of the power device, and comprises a negative pressure overshoot suppression and input protection unit, a control unit and a control unit, wherein the negative pressure overshoot suppression and input protection unit is used for suppressing the interference of negative voltage overshoots caused by parasitic parameters of a power loop on measurement; the peak voltage detection circuit is used for capturing transient spike voltage between the emitter and the collector in the turn-off process of the power device, and comprises a self-adaptive charge-discharge control unit for automatically controlling capturing and discharging of the transient spike voltage according to the change of voltage at two ends of the power device; The output ends of the conduction voltage drop test circuit and the peak voltage detection circuit are connected into the analog-to-digital converter after being isolated, so that the simultaneous detection of multiple parameters of the same power device is realized.
  2. 2. The conduction voltage drop and peak detection multiparameter detection circuit of claim 1, wherein the conduction voltage drop test circuit comprises: The constant current source unit is used for providing stable tiny excitation current for the tested power device; The double diode clamping unit is connected between the constant current source unit and the power device and used for blocking high voltage when the device is turned off and maintaining a measuring path when the device is turned on and freewheels; the signal processing unit is used for carrying out scaling and level lifting on the collected conduction voltage drop signal; and the negative voltage overshoot suppression and input protection unit is arranged between the double diode clamping unit and the signal processing unit and is used for filtering negative voltage overshoots caused by parasitic inductance and current change rate.
  3. 3. The circuit of claim 2 wherein the constant current source unit is a transistor Q 1 , a transistor Q 2 , a transistor Q 3 , The bipolar mirror constant current source structure comprises a triode Q 4 and a resistor R 10 , wherein the base electrode of the triode Q 1 is connected with the base electrode of the triode Q 2 and is connected with the collector electrode of the triode Q 2 , the base electrode of the triode Q 3 is connected with the base electrode of the triode Q 4 and is connected with the collector electrode of the triode Q 4 , the emitting electrode of the triode Q 1 and the emitting electrode of the triode Q 2 are connected with a power supply end together, the collector electrode of the triode Q 1 and the emitting electrode of the triode Q 3 are connected, the collecting electrode of the triode Q 2 and the emitting electrode of the triode Q 4 are connected, the collecting electrode of the triode Q 4 and one end of the resistor R 10 are connected, the other end of the resistor R 10 is grounded, and the collecting electrode of the triode Q 3 and the input end of the double-diode clamping unit are connected.
  4. 4. The circuit of claim 2, wherein the dual diode clamp unit comprises a diode D 1 , a diode D 2 , a diode D 4 , and a zener diode D 3 , wherein an anode of the diode D 2 is connected to an output terminal of the constant current source unit, a cathode of the diode D 2 is connected to an anode of the diode D 1 , a cathode of the zener diode D 3 , and a negative pressure overshoot suppression and input protection unit, a cathode of the diode D 1 is connected to a collector of the power device under test, an anode of the zener diode D 3 is connected to an anode of the diode D 4 , and a cathode of the diode D 4 is grounded.
  5. 5. The circuit of claim 2, wherein the negative pressure overshoot suppression and input protection unit is a first-order RC low-pass filter network, and comprises a resistor R 3 , a resistor R 4 , a capacitor C 3 and a capacitor C 4 , wherein the resistor R 3 is connected in series between the output end of the constant current source unit and the input end of the signal processing unit, the resistor R 4 is connected in series between the output end of the dual diode clamp unit and the input end of the signal processing unit, one end of the capacitor C 3 is connected between the resistor R 3 and the signal processing unit, the other end of the capacitor C 3 is grounded, one end of the capacitor C 4 is connected between the resistor R 4 and the signal processing unit, and the other end of the capacitor C 4 is grounded.
  6. 6. The circuit of claim 2, wherein the signal processing unit comprises a resistor R 5 , a resistor R 6 , a resistor R 7 , a resistor R 8 , Resistor R 9 , The voltage source V s1 and the operational amplifier U 1 , the inverting input end of the operational amplifier U 1 is connected with a resistor R 5 and one end of a resistor R 7 , the other end of the resistor R 5 is connected with a negative pressure overshoot suppression and input protection unit, the other end of the resistor R 7 is connected with the output end of the operational amplifier U 1 , the non-inverting input end of the operational amplifier U 1 is connected with a resistor R 6 , One end of a resistor R 8 and one end of a resistor R 9 are connected, the other end of the resistor R 6 and negative pressure overshoot suppression are connected with an input protection unit, the other end of the resistor R 8 is connected with the positive electrode of a voltage source V s1 , and the negative electrode of the voltage source V s1 and the other end of the resistor R 9 are grounded.
  7. 7. The on-voltage drop and peak detection multiparameter detection circuit of claim 1, wherein the peak voltage detection circuit comprises: the high-bandwidth voltage dividing unit is used for dividing the voltage at two ends of the tested power device and compensating the voltage at high frequency; the peak value holding unit is connected with the output end of the high-bandwidth voltage dividing unit and is used for capturing and holding the peak voltage of the divided signal; The self-adaptive charge and discharge control unit is connected with the output end of the high-bandwidth voltage division unit and the discharge control end of the peak holding unit and is used for automatically controlling the peak holding unit to enter a peak capturing state when the voltage rises according to the voltage change of the divided signals and discharging the held peak voltage when the voltage drops.
  8. 8. The circuit for detecting multiple parameters of on-voltage drop and peak value according to claim 7, wherein the high-bandwidth voltage dividing unit comprises a resistor R 1 , a resistor R 2 , a capacitor C 1 and a capacitor C 2 , the resistor R 1 and the capacitor C 1 are connected in parallel to form a high-voltage arm, the input end of the high-voltage arm is connected to the collector of the measured power device, the resistor R 2 and the capacitor C 2 are connected in parallel to form a low-voltage arm, the output end of the low-voltage arm is connected to the emitter of the measured power device and the adaptive charge-discharge control unit and is grounded, the high-voltage arm and the low-voltage arm are connected in series, and the connection points of the high-voltage arm and the low-voltage arm are also connected to the peak value holding unit and the adaptive charge-discharge control unit respectively.
  9. 9. The circuit of claim 7, wherein the peak hold unit comprises a diode D 5 , a diode D 6 , a resistor R 11 , a capacitor C 5 , An operational amplifier U 2 and an operational amplifier U 3 , wherein the non-inverting input end of the operational amplifier U 2 is connected with a high-bandwidth voltage dividing unit, the inverting input end of the operational amplifier U 2 is connected with the anode of a diode D 5 and one end of a resistor R 11 , the output end of the operational amplifier U 2 is connected with the cathode of a diode D 5 and the anode of a diode D 6 , the inverting input end of the operational amplifier U 3 is connected with the output end of the operational amplifier U 3 and the other end of a resistor R 11 , the non-inverting input end of the operational amplifier U 3 is connected with one end of a capacitor C 5 , The cathode of the diode D6 and the adaptive charge-discharge control unit are connected, and the other end of the capacitor C 5 is grounded.
  10. 10. The circuit of claim 9, wherein the adaptive charge/discharge control unit comprises a resistor R 12 , a resistor R 13 , a MOS transistor S 1 , a voltage source V S2 , The MOS transistor comprises an operational amplifier U 4 and a driving chip, wherein the inverting input end of the operational amplifier U 4 is connected with a high-bandwidth voltage dividing unit, the non-inverting input end of the operational amplifier U 4 is connected with a resistor R 12 and one end of a resistor R 13 , the other end of the resistor R 12 is connected with the positive electrode of a voltage source V S2 , the negative electrode of the voltage source V S2 is connected with the high-bandwidth voltage dividing unit and the emitter of a tested power device and is grounded, the output end of the operational amplifier U 4 is connected with the other end of the resistor R 13 and the input end of the driving chip, the output end of the driving chip is connected with the grid electrode of a MOS transistor S 1 , the drain electrode of the MOS transistor S 1 is connected with the non-inverting input end of the operational amplifier U 3 , and the source electrode of the MOS transistor S 1 is connected with the ground end of a capacitor C 5 .

Description

Multi-parameter detection circuit for conducting voltage drop and peak detection Technical Field The invention relates to the technical field of power electronics, in particular to a conduction voltage drop and peak value detection multi-parameter detection circuit. Background The three-level ANPC (Active Neutral Point Clamped) circuit can reduce the voltage stress of a switching device and the switching loss, and is widely applied to high-voltage high-power electric propulsion, rail transit, wind power generation, electric automobile driving and other systems. However, under these severe operating environments, core power devices (such as IGBTs or SiC MOSFETs) are subject to aging, affecting system reliability. Therefore, on-line status monitoring of the power device is of great importance. The positive and negative on-voltage and the off-peak voltage are used as key electrical parameters of the power device, have important state representation significance, but in the practical application of the three-level ANPC circuit, the on-line extraction of the three-level ANPC circuit still faces remarkable technical challenges. The three-level ANPC topology has a greater number of devices and more complex current commutation paths than a conventional two-level structure, and the power loop topology typically exhibits greater parasitic inductance and distribution parameters. Under the high-frequency switching condition, when the power device is subjected to on-off commutation, the loop parasitic inductance and the current change rate (di/dt) act together to generate obvious voltage overshoot at two ends of the device, and particularly, a larger negative pressure overshoot is easy to form at the emitter or source side of the tested device at the moment of opposite-side bridge arm commutation. Such negative voltage overshoot not only increases the electrical stress of the device body, but also is directly coupled to the on-voltage drop detection circuit. Because the on-voltage drop test circuit generally adopts a high-precision operational amplifier to amplify a tiny voltage difference, when negative voltage exceeding a power supply range appears at the input end of the on-voltage drop test circuit, the input end of the operational amplifier can exceed a nominal common mode range and even enter an abnormal working range, so that measurement errors and response delay are caused, and the reliability and the service life of a device can be influenced in severe cases. In addition, in the aspect of transient spike voltage detection, the prior art generally adopts an active control mode to realize peak hold or charge-discharge control, namely, a logic control unit or a digital signal processor actively controls the charge-discharge process of the sampling capacitor according to a switch state. Although the scheme can realize peak capture, the scheme has the defects that an additional control circuit and a driving unit are required to be added, the system structure is complex, the cost is high, a control strategy is required to be closely matched with a carrier frequency and a switching time sequence, when a modulation frequency or a working mode is changed, a control logic is required to be synchronously adjusted, and under high-frequency and complex working conditions, the control delay or misjudgment can cause peak loss or repeated sampling, so that the measurement accuracy and the system stability are affected. Disclosure of Invention The invention aims to provide a multi-parameter detection circuit for conducting voltage drop and peak detection. The circuit can realize high-precision and strong-robustness measurement of forward and reverse on-voltage and transient spike voltage in a complex switching environment. The technical scheme of the invention is that the conduction voltage drop and peak value detection multi-parameter detection circuit is applied to a three-level ANPC converter and comprises a conduction voltage drop test circuit and a peak value voltage detection circuit which are arranged at two ends of a tested power device in parallel; The conduction voltage drop test circuit is used for respectively collecting the positive conduction voltage drop and the reverse conduction voltage drop of the power device in the conduction and follow current states of the power device, and comprises a negative pressure overshoot suppression and input protection unit, a control unit and a control unit, wherein the negative pressure overshoot suppression and input protection unit is used for suppressing the interference of negative voltage overshoots caused by parasitic parameters of a power loop on measurement; the peak voltage detection circuit is used for capturing transient spike voltage between the emitter and the collector in the turn-off process of the power device, and comprises a self-adaptive charge-discharge control unit for automatically controlling capturing and discharging of the transient spike voltage accord