A circuit for measuring the on-state voltage and decoupling of inverter-level devices

Abstract

The present invention discloses an inverter-level device on-state voltage decoupling measurement circuit, which relates to the field of semiconductor device measurement. The measurement circuit includes a decoupling module and an output module. The output module is adaptively connected to the inverter through the decoupling module to form a decoupling measurement circuit after the adaptive connection. The decoupling module includes a bridge selection unit and a decoupling unit. When measuring the on-state voltage drop of the device in the inverter, the target measurement bridge in the inverter is selected by the bridge selection unit, and the working mode of the inverter is configured according to the selected target measurement bridge. The target device in the target measurement bridge in the current working mode is adaptively connected to the output module through the decoupling unit, so as to obtain the on-state voltage drop of the target device in the current working mode by using the output module, and the target device is a target power device or a target diode. The present invention solves the problem that the inverter-level on-state voltage drop measurement circuit cannot decouple and measure the on-state voltage drop of a single device in the inverter.

Description

Technical Field

[0001] The invention relates to the field of semiconductor device on-state voltage drop measurement, in particular to an inverter-level device on-state voltage drop coupling measurement circuit. Background Art

[0002] The wide application of single-phase inverters in photovoltaic power generation, uninterruptible power supply, new energy vehicles, aerospace and other fields has attracted much attention to its reliability issues. Power semiconductor devices have the highest failure rate in inverters, so it is of great practical significance to implement online status monitoring of inverter power semiconductor devices. The on-state voltage drop, such as the drain-source voltage Vds of MOSFET devices and the forward voltage drop VF of diodes, is currently the most concerned indicator reflecting the health status of power semiconductor devices and is widely used in the life prediction of power semiconductors.

[0003] The on-state voltage drop measurement circuit can be divided into device-level measurement circuit and inverter-level measurement circuit. The inverter-level measurement circuit is different from the traditional device-level measurement circuit. It is designed to detect multiple tubes of the inverter at the same time by directly connecting to the output of the inverter, reducing the complexity and cost of the measurement. In the paper titled "ASimplified On-State Voltage Measurement Circuit for Power Semiconductor Devices", an inverter-level measurement circuit that does not require power supply is proposed, which can ensure sufficient measurement accuracy and dynamic response speed, but the combined on-state voltage drop of the power tube and the anti-parallel diode is measured.

[0004] The document with publication number CN117169675A discloses an inverter-level wide temperature range power device conduction voltage drop online monitoring circuit, which can maintain high accuracy and fast response speed in a wide temperature range, but the measured value is also the combined conduction voltage drop of the power tube and the anti-parallel diode.

[0005] From the above description, it can be seen that although the existing inverter-level on-state voltage drop measurement circuit has high accuracy and response speed, what is measured is mostly the combined voltage drop of the power tube and the anti-parallel diode. Although monitoring the total value of the on-state voltage drop has practical significance for the health status assessment of the inverter, it is impossible to specifically locate a certain device during fault detection, which is not conducive to fault detection and maintenance of the inverter. Summary of the invention

[0006] In view of the above problems and technical requirements, the inventors have proposed a decoupling measurement circuit for the on-state voltage of an inverter-level device, comprising a decoupling module and an output module. The output module is adaptively connected to the inverter through the decoupling module to form a decoupling measurement circuit after the adaptive connection, wherein:

[0007] The decoupling module includes a bridge selection unit for selecting a target measurement bridge, and a decoupling unit for controlling a connection state between the target measurement bridge and the output module;

[0008] When measuring the conduction voltage drop of the device in the inverter, the target measurement bridge in the inverter is selected by the bridge selection unit, the working mode of the inverter is configured according to the selected target measurement bridge, and the target device in the target measurement bridge in the current working mode is adapted and connected to the output module by the decoupling unit, so as to obtain the conduction voltage drop of the target device in the current working mode by using the output module, wherein,

[0009] The target device is a target power device or a target diode.

[0010] A further technical solution is that the decoupling unit includes a power device S1, a power device S2, and a diode D connected in reverse parallel to the power device S1. S1 , and a diode D connected in reverse parallel to the power device S2 S2 ;

[0011] When measuring the conduction voltage drop of the devices in the inverter, configure the power devices S1, S2, and diode D in the decoupling unit according to the conduction state of the devices in the inverter. S1 And diode D S2 The conduction state.

[0012] A further technical solution is that the working mode of the inverter includes a first measurement mode and a second measurement mode;

[0013] When the inverter is in the first measurement mode, it includes a power device in a conducting state and a diode forming a loop with the power device;

[0014] When the inverter is in the second measurement mode, it includes two power devices in a conducting state forming a loop or two diodes forming a loop.

[0015] A further technical solution is that the inverter comprises a unipolar SPWM single-phase inverter, comprising a first bridge arm and a second bridge arm, wherein:

[0016] The first bridge arm includes a power device Q1, a power device Q2, and a diode D connected in reverse parallel to the power device Q1. 11 and a diode D connected in reverse parallel to the power device Q2. 12 ;

[0017] The second electrode of the power device Q1 is connected to the input capacitor C dc The first electrode of the power device Q2 is connected to the input capacitor C dc The other end of the capacitor C dcOne end is connected to the input voltage source V DC The positive terminal is connected to the input voltage source V DC The negative connection of

[0018] The first electrode of the power device Q1 is connected to the second electrode of the power device Q2 to form a first bridge arm connection point a, and the first bridge arm connection point a is connected to the bridge selection unit;

[0019] The second bridge arm includes a power device Q3, a power device Q4, and a diode D connected in reverse parallel to the power device Q3. 13 and a diode D connected in reverse parallel to the power device Q4. 14 ;

[0020] The second electrode of the power device Q3 is connected to the second electrode of the power device Q1 and the second electrode of the power device S1, and the first electrode of the power device Q4 is connected to the first electrode of the power device Q2 and the first electrode of the power device S2;

[0021] The first electrode of the power device Q3 is connected to the second electrode of the power device Q4 to form a second bridge arm connection point b, and the second bridge arm connection point b is connected to the bridge selection unit.

[0022] A further technical solution is that when the target measurement bridge is the first bridge arm, the inverter is modulated to be in the first measurement mode;

[0023] When the target measurement bridge is the second bridge arm, the inverter is modulated to be in the first measurement mode and / or the second measurement mode.

[0024] A further technical solution is that the conduction states of the power devices S1 and S2 in the decoupling unit are configured according to the conduction states of the devices in the inverter, including:

[0025] The conduction state of the power device S1 in the decoupling unit is the same as the conduction state of the power device Q3 in the inverter, and the conduction state of the power device S2 in the decoupling unit is the same as the conduction state of the power device Q4 in the inverter.

[0026] A further technical solution is that the bridge selection unit includes a first switch subunit and a second switch subunit, wherein:

[0027] One end of the first switch subunit is connected to the first bridge arm connection point a, and one end of the second switch subunit is connected to the second bridge arm connection point b;

[0028] The other end of the first switch subunit is connected to the other end of the second switch subunit and the output module to form a connection point d;

[0029] When the first bridge arm of the inverter is selected as the target measurement bridge, the first bridge arm connection point a is connected to the output module through the first switch subunit;

[0030] When the second bridge arm of the inverter is selected as the target measurement bridge, the second bridge arm connection point b is connected to the output module through the second switch subunit.

[0031] A further technical solution is that the output module includes an output clamping unit and a current limiting unit, wherein:

[0032] The output clamping unit includes a positive clamping circuit and a negative clamping circuit;

[0033] The positive clamp circuit includes a voltage source V CC1 and diode D 21 , the voltage source V CC1 The positive terminal of the diode D 21 The cathode connection of the voltage source V CC1 The negative pole is grounded;

[0034] The negative clamp circuit includes a voltage source V CC2 and diode D 22 , the voltage source V CC2 The positive terminal of the diode D 22 The cathode connection of the voltage source V CC2 The cathode of the diode D 21 The anode and current limiting unit are connected to the diode D 22 The anode of the CC1 The negative pole of and connection point d are connected.

[0035] A further technical solution is that the current limiting unit includes a resistor R1, one end of the resistor R1 is connected to a voltage source V CC2 The other end of the resistor R1 is connected to the first electrode of the power device S1 to form a connection point c;

[0036] -V CC2 <V cd <0 or 0 <V cd <V CC1 When the on-state voltage drop measurement circuit uses the output clamp unit to obtain the on-state voltage drop of the target power device or target diode in the target measurement bridge circuit, where V cd is the voltage between the connection point c and the connection point d.

[0037] Its further technical solution is that when V cd >V CC1 When the positive clamping circuit outputs the positive clamping voltage, the positive clamping voltage is expressed as V CC1 +V D21, V D21 For the diode D 21 The conduction voltage drop;

[0038] When V cd <-V CC2 When the negative clamping circuit outputs a negative clamping voltage, the negative clamping voltage is expressed as -(V CC2 +V D22 ), V D22 For the diode D 22 The conduction voltage drop.

[0039] The beneficial technical effects of the present invention are:

[0040] The inverter-level device decoupling measurement circuit provided by the present invention is a measurement path formed by the output module through the decoupling module and the inverter adaption connection. When measuring the conduction voltage drop of the device in the inverter, the target measurement bridge in the inverter is selected by the bridge selection unit, the working mode of the inverter is configured according to the selected target measurement bridge, and the target power device or target diode in the target measurement bridge in the current working mode is adapted and connected to the output module through the decoupling unit. The present invention can separately decouple and measure the conduction voltage drop of each power device and each diode in the inverter, and can measure and locate the specific faulty device online when detecting inverter faults, providing reliable support for the health status assessment and fault detection of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a circuit principle diagram of an embodiment provided by the present invention.

[0042] Figure 2-Figure 9 1 is a schematic diagram of a decoupling measurement circuit corresponding to a unipolar SPWM single-phase inverter in mode (a) to mode (h) when the first bridge arm is used as the target measurement bridge circuit in an embodiment of the present invention, wherein:

[0043] Figure 2 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (a) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0044] Figure 3 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (b) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0045] Figure 4 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (c) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0046] Figure 5It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (d) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0047] Figure 6 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (e) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0048] Figure 7 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (f) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0049] Figure 8 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (g) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0050] Fig. 9 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (h) when the first bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0051] Figure 10-Figure 17 1 is a schematic diagram of a decoupling measurement circuit corresponding to a unipolar SPWM single-phase inverter in mode (a) to mode (h) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention, wherein:

[0052] Fig.10 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (a) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0053] Fig.11 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (b) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0054] Fig.12 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (c) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0055] Fig.13 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (d) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0056] Fig.14 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (e) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0057] Fig.15 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (f) when the second bridge arm is used as the target bridge circuit in an embodiment of the present invention.

[0058] Fig.16 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (g) when the second bridge arm is used as the target to measure the bridge circuit in an embodiment of the present invention.

[0059] Fig.17 It is a schematic diagram of a decoupling measurement circuit of a unipolar SPWM single-phase inverter in mode (h) when the second bridge arm is used as the target to measure the bridge circuit in an embodiment of the present invention.

[0060] Reference numerals: 100 - inverter, 200 - decoupling module, 300 - output module. DETAILED DESCRIPTION

[0061] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0062] The present invention provides an inverter-level device on-state voltage decoupling measurement circuit, comprising a decoupling module 200 and an output module 300, wherein the output module 300 is adaptively connected to the inverter 100 through the decoupling module 200 to form a decoupling measurement circuit after the adaptive connection, wherein:

[0063] The decoupling module 200 includes a bridge selection unit for selecting a target measurement bridge, and a decoupling unit for controlling the connection state between the target measurement bridge and the output module;

[0064] When measuring the on-state voltage drop of devices in the inverter, the target measurement bridge in the inverter 100 is selected through the bridge selection unit, the working mode of the inverter 100 is configured according to the selected target measurement bridge, and the target device in the target measurement bridge in the current working mode is adapted and connected to the output module 300 through the decoupling unit, so as to obtain the on-state voltage drop of the target device in the current working mode using the output module 300, wherein the target device is a target power device or a target diode.

[0065] Specifically, the inverter 100 is usually used to convert a DC input into an AC output, and its circuit topology generally includes a plurality of power devices and diodes. The measurement of the conduction voltage drop of the devices in the inverter described in the present invention is to measure the conduction voltage drop of the power devices and diodes during the operation of the inverter 100. The operation process of the inverter 100 can be divided into a plurality of operation modes according to the conduction conditions of the devices in the inverter 100. When the conduction voltage drop of the devices in the inverter 100 is measured, the operation mode of the inverter 100 is configured according to the selected target measurement bridge circuit. The operation mode of the inverter 100 corresponding to the target measurement bridge circuit can refer to the following description. The above-mentioned selection of the target measurement bridge circuit in the inverter 100 by the bridge circuit selection unit specifically refers to connecting the target measurement bridge circuit of the inverter 100 to the output module 300 by the bridge circuit selection unit. The specific connection form can also refer to the following description.

[0066] According to the conduction status of the devices in the inverter 100, the inverter 100 includes multiple working modes. In order to achieve the separate measurement of the conduction voltage drop of the power device and the conduction voltage drop of the diode, in a working mode of the inverter 100 corresponding to the target measurement bridge, only one power device or one diode in the target measurement bridge is used as the measurement object. In any working mode, the power device used as the measurement object in the target measurement bridge is the target power device, and the diode used as the measurement object in the target measurement bridge is the target diode. The connection state of the target measurement bridge and the output module 300 is controlled by the decoupling unit, which specifically refers to connecting the output module 300 in parallel with the two ends of the target device in the current working mode through the decoupling unit, so as to obtain the conduction voltage drop of the target device in the current working mode by using the output module 300. The specific manner in which the power device output module 300 is adaptively connected with the inverter 100 through the decoupling module 200 to form a decoupling measurement circuit can refer to the following description.

[0067] The present invention can separately decouple and measure the conduction voltage drop of each power device and each diode in the inverter 100. When the inverter 100 detects a fault, it can measure online and locate the specific faulty device, providing reliable support for the health status assessment and fault detection of the inverter 100.

[0068] Furthermore, the decoupling unit includes a power device S1, a power device S2, and a diode D connected in reverse parallel to the power device S1. S1 and a diode D connected in reverse parallel to the power device S2 S2 ;

[0069] When measuring the conduction voltage drop of the devices in the inverter 100, the power devices S1, S2, and diode D in the decoupling unit are configured according to the conduction state of the power devices in the inverter 100. S1 And diode D S2 The conduction state.

[0070] Specifically, by configuring the power device S1, the power device S2, and the diode D in the decoupling unit S1 And diode D S2 The conduction state of the target measurement bridge changes the connection relationship between the target measurement bridge and the output module 300, and the power device S1, the power device S2, the diode D S1 And diode D S2 The conduction state of the device needs to be adjusted according to the conduction state of the device in the inverter 100, so that the output module 300 is connected in parallel to the two ends of the target power device or the target diode in the current working mode, and the power device S1, the power device S2, and the diode D S1 And diode D S2 The specific method of the conduction state can refer to the following description.

[0071] Furthermore, the inverter 100 comprises a unipolar SPWM (Sinusoidal Pulse Width Modulation) single-phase inverter, comprising a first bridge arm and a second bridge arm, wherein:

[0072] The first bridge arm includes a power device Q1, a power device Q2, and a diode D connected in reverse parallel to the power device Q1. 11 and a diode D connected in reverse parallel to the power device Q2. 12 ;

[0073] The second electrode of the power device Q1 is connected to the input capacitor C dc The first electrode of the power device Q2 is connected to the input capacitor C dc The other end of the capacitor C dc One end is connected to the input voltage source V DC The positive terminal is connected to the input voltage source V DC The negative connection of

[0074] The first electrode of the power device Q1 is connected to the second electrode of the power device Q2 to form a first bridge arm connection point a, and the first bridge arm connection point a is connected to the bridge selection unit;

[0075] The second bridge arm includes a power device Q3, a power device Q4, and a diode D connected in reverse parallel to the power device Q3. 13 and a diode D connected in reverse parallel to the power device Q4. 14 ;

[0076] The second electrode of the power device Q3 is connected to the second electrode of the power device Q1 and the second electrode of the power device S1, and the first electrode of the power device Q4 is connected to the first electrode of the power device Q2 and the first electrode of the power device S2;

[0077] The first electrode of the power device Q3 is connected to the second electrode of the power device Q4 to form a second bridge arm connection point b, and the second bridge arm connection point b is connected to the bridge selection unit.

[0078] Optionally, the power device Q1, power device Q2, power device Q3, power device Q4, power device S1 and power device S2 are MOSFET devices or IGBT devices. For MOSFET devices, the first electrode is the source and the second electrode is the drain; for IGBT devices, the first electrode is the collector and the second electrode is the emitter.

[0079] Figure 1 An embodiment in which the above-mentioned power devices are all MOSFET devices is shown. Generally, the single-phase inverter is also connected with a freewheeling filter unit for freewheeling and filtering between the first bridge arm connection point a and the second bridge arm connection point b. The freewheeling filter unit includes a resistor R0 and an inductor L0. The first bridge arm connection point a is connected to one end of the inductor L0, and the other end of the inductor L0 is connected to the second bridge arm connection point b through the resistor R0.

[0080] Specifically, the unipolar SPWM single-phase inverter has eight operating modes in one cycle of the modulation wave, of which four operating modes correspond to the first measurement mode and the other four operating modes correspond to the second measurement mode. When the unipolar SPWM single-phase inverter is in the first measurement mode, it includes a power device in a conducting state and a diode forming a loop with the power device. When the unipolar SPWM single-phase inverter is in the second measurement mode, it includes two power devices in a conducting state or two diodes forming a loop. The voltage waveform output by the single-phase inverter under unipolar SPWM modulation includes the inverter input voltage ±V DC and a voltage near the zero level, wherein when the unipolar SPWM single-phase inverter is in the second measurement mode, the output voltage of the unipolar SPWM single-phase inverter is equal to the input voltage ±V DC When the unipolar SPWM single-phase inverter is in the first measurement mode, the unipolar SPWM single-phase inverter is in a freewheeling state and outputs a voltage near the zero level. The output voltage is equal to the sum of the conduction voltage drops of the turned-on power device and a diode forming a loop with the power device in this first measurement mode. The working principle of the unipolar SPWM single-phase inverter is consistent with the prior art.

[0081] The above configuration of the working mode of the inverter 100 according to the selected target measurement bridge circuit specifically refers to: when the target measurement bridge circuit is the first bridge arm, the inverter 100 is modulated to be in the first measurement mode;

[0082] When the target measurement bridge is the second bridge arm, the inverter 100 is modulated to be in the first measurement mode and / or the second measurement mode.

[0083] Specifically, it can be seen from the above description that the unipolar SPWM single-phase inverter 100 includes 4 first measurement modes and 4 second measurement modes in each modulation wave cycle, and the first bridge arm and the second bridge arm each include two power devices and two diodes. When the target measurement bridge is the first bridge arm, the unipolar SPWM single-phase inverter 100 needs to be modulated in the first measurement mode to measure the conduction voltage drop of the device in the first bridge arm, and the first measurement mode corresponds to the target power device or target diode in the first bridge arm. Therefore, in one cycle of the modulation wave, the conduction voltage drop of each device in the first bridge arm can be measured separately.

[0084] When the target measurement bridge is the second bridge arm, the unipolar SPWM single-phase inverter 100 is modulated in the first measurement mode and / or the second measurement mode to measure the conduction voltage drop of the device in the second bridge arm, and the four first measurement modes correspond one-to-one to the four devices to be measured in the second bridge arm, and the four second measurement modes also correspond one-to-one to the four devices to be measured in the second bridge arm. In summary, by switching the target measurement bridge through the bridge selection unit, the conduction voltage drop of each device in the unipolar SPWM single-phase inverter 100 can be measured separately within two modulation wave cycles. When the first bridge arm or the second bridge arm is the target measurement bridge, the corresponding target power device or target diode in each measurement mode can refer to the following description.

[0085] When measuring the on-state voltage drop of the device in the unipolar SPWM single-phase inverter 100, the first bridge arm and the second bridge arm are used as target measurement bridge circuits in turn. Figure 2-Figure 9 The figure shows the circuit flow conditions corresponding to each working mode of the unipolar SPWM single-phase inverter when the first bridge arm is used as the target bridge circuit; Figure 10-17 The figure shows the circuit flow of the unipolar SPWM single-phase inverter in each working mode when the second bridge arm is used as the target bridge circuit. Figure 3 and Fig.11 The mode shown (b), Figure 4 and Fig.12 The mode shown (c), Figure 7 and Fig.15 The mode (f) shown and Figure 8 and Fig.16 The mode (g) shown is the first measured mode; Figure 2 and Fig.10The modes shown (a), Figure 5 and Fig.13 The mode (d) shown, Figure 6 and Fig.14 The mode (e) shown and Fig. 9 and Fig.17 The mode (h) shown is the second measured mode.

[0086] Combine the following Figure 2-Figure 9 The conduction conditions of the devices in the first bridge arm and the second bridge arm in each working mode of the unipolar SPWM single-phase inverter are described as follows:

[0087] like Figure 2 As shown, in mode (a), the power device Q1 and the power device Q4 are turned on and form a path.

[0088] like Figure 3 As shown, in mode (b), the power device Q1 and the diode D 13 Conduct and form a path.

[0089] like Figure 4 As shown, in mode (c), the diode D 12 It is connected to the power device Q4 and forms a path.

[0090] like Figure 5 As shown, in mode (d), the diode D 12 With diode D 13 Conduct and form a path.

[0091] like Figure 6 As shown, in mode (e), the power device Q2 and the power device Q3 are turned on and form a path.

[0092] like Figure 7 As shown, in mode (f), the power device Q2 and the diode D 14 Conduct and form a path.

[0093] like Figure 8 As shown, in mode (g), the diode D 11 It is connected to the power device Q3 and forms a path.

[0094] like Fig. 9 As shown, in mode (h), the diode D 11 With diode D 14 Conduct and form a path.

[0095] Further, configuring the conduction states of the power devices S1 and S2 in the decoupling unit according to the conduction states of the devices in the inverter 100 includes:

[0096] The conduction state of the power device S1 in the decoupling unit is the same as the conduction state of the power device Q3 in the inverter 100 , and the conduction state of the power device S2 in the decoupling unit is the same as the conduction state of the power device Q4 in the inverter 100 .

[0097] The diode D in the decoupling unit is configured according to the conduction state of the device in the inverter 100. S1 And diode D S2 The conduction states include:

[0098] Decoupling unit internal diode D S1 The conduction state of the diode D in the inverter 100 13 The conduction state of the decoupling unit is the same as that of the diode D S2 The conduction state of the diode D in the inverter 100 14 The conduction state is the same.

[0099] The conduction state of the power device S1 in the decoupling unit is the same as the conduction state of the power device Q3 in the inverter 100 , and the conduction state of the power device S2 in the decoupling unit is the same as the conduction state of the power device Q4 in the inverter 100 .

[0100] Specifically, in order to make the conduction state of the power device S1 the same as the conduction state of the power device Q3, and the conduction state of the power device S2 the same as the conduction state of the power device Q4, in this embodiment, when the inverter is subjected to unipolar SPWM modulation, the drive signal is simultaneously connected to the MOSFET device S1 and the MOSFET device S2, so that the drive signal of the MOSFET device S1 is synchronized with the first bridge arm power device Q3, and the drive signal of the MOSFET device S2 is synchronized with the second bridge arm power device Q4, and the drive signal frequency under unipolar modulation is the industrial frequency. Diode D S1 And diode D S2 The configuration method of the conduction state can be the same as the prior art.

[0101] Furthermore, the bridge selection unit includes a first switch sub-unit and a second switch sub-unit, wherein one end of the first switch sub-unit is connected to the first bridge arm connection point a, one end of the second switch sub-unit is connected to the second bridge arm connection point b, and the other end of the first switch sub-unit is connected to the other end of the second switch sub-unit and the output module 300 to form a connection point d.

[0102] Specifically, when the first bridge arm of the inverter 100 is selected as the target measurement bridge, the first bridge arm connection point a is connected to the output module through the first switch subunit; when the second bridge arm of the inverter 100 is selected as the target measurement bridge, the second bridge arm connection point b is connected to the output module through the second switch subunit. The first switch subunit and the second switch subunit can be active switches, relays or power devices. In this embodiment, the first switch subunit is switch SW1, and the second switch subunit is switch SW2. Figure 2-Figure 9 As shown, when the first bridge arm of the inverter 100 is selected as the target measurement bridge, the switch SW1 is closed and the switch SW2 is opened; Figure 10-Figure 17 As shown, when the second bridge arm of the inverter 100 is selected as the target measurement bridge, the switch SW1 is opened and the switch SW2 is closed.

[0103] Furthermore, the output module 300 includes an output clamping unit and a current limiting unit, wherein:

[0104] The output clamping unit includes a positive clamping circuit and a negative clamping circuit.

[0105] Specifically, the positive clamp circuit includes a voltage source V CC1 and diode D 21 , the voltage source V CC1 The positive terminal of the diode D 21 The cathode connection of the voltage source V CC1 The negative pole is grounded;

[0106] The negative clamp circuit includes a voltage source V CC2 and diode D 22 , the voltage source V CC2 The positive terminal of the diode D 22 The cathode connection of the voltage source V CC2 The cathode of the diode D 21 The anode and current limiting unit are connected and serve as an output terminal v of the measurement circuit out , the diode D 22 The anode of the CC1 The negative pole of the measuring circuit is connected to the connection point d and serves as another output terminal v of the measuring circuit. gnd Use a voltage measurement tool to measure the output terminal v out and output terminal v gnd The voltage between the two is used to measure the output voltage of the circuit. The output voltage of the circuit is measured using V out To express.

[0107] Furthermore, the current limiting unit includes a resistor R1, one end of which is connected to a voltage source V CC2The other end of the resistor R1 is connected to the first electrode of the power device S1 to form a connection point c.

[0108] Specifically, resistor R1 is used to bear the input voltage source V DC The high voltage and the power consumption of the measuring circuit are limited. Therefore, the resistance value of resistor R1 needs to be based on the power consumption P of the measuring circuit. D To select, it can be specifically expressed as: R1 = V DC 2 / 2P D .

[0109] The working principle of the output clamp unit is: when -V CC2 <V cd <0 or 0 <V cd <V CC1 When V cd is the voltage between connection point c and connection point d, and the diode D in the output clamp unit 21 、Diode D 22 The output clamp module 300 does not clamp the output voltage. At this time, due to the diode D 21 、Diode D 22 Both are not conducting, diode D 21 and diode D 22 Equivalent to a large parasitic parallel resistor R sh , parasitic parallel resistance R sh The resistance value is much larger than the overall resistance of the decoupling module 200 and the resistor R1. The voltage division of the decoupling module 200 and the resistor R1 in the measurement circuit is very small and has almost no effect on the measurement of the conduction voltage drop. Therefore, the output voltage V out It is approximately equal to the conduction voltage drop of the target power device or the target diode in the target measurement bridge circuit in the unipolar SPWM single-phase inverter 100 in the current working mode.

[0110] When V cd >V CC1 When the diode D 21 Conducting, diode D 22 When the output clamp module is turned off, only the positive clamp circuit is turned on. The output voltage V out It is clamped by the positive clamp circuit and outputs a positive clamp voltage through the positive clamp circuit. The positive clamp voltage is expressed as V CC1 +V D21 , V D21 For the diode D 21 The conduction voltage drop.

[0111] When V cd <-V CC2 When the diode D 22 Conducting, diode D21 When the output clamp module is turned off, only the negative clamp circuit is turned on. The output voltage V out It is clamped by the negative clamp circuit, and the negative clamp circuit outputs a negative clamp voltage, which is expressed as -(V CC2 +V D22 ), V D22 For the diode D 22 The conduction voltage drop.

[0112] Optionally, the voltage source V CC1 can be connected with the voltage source V CC2 The output voltage is the same, both are output clamp voltage source V CC The output voltage, V CC1 =V CC2 =V CC .

[0113] In one embodiment of the present invention, the voltage source V CC1 With the voltage source V CC2 The output voltage is clamped by the voltage source V CC The output voltage is combined with Figure 2-Figure 17 The specific working process and working principle of the decoupling measurement circuit in one embodiment of the present invention are described in detail:

[0114] The switch SW1 is closed and the switch SW2 is opened to select the first bridge arm of the unipolar SPWM single-phase inverter as the target measurement bridge. When the first bridge arm is the target measurement bridge, the flow of the decoupling measurement circuit corresponding to each mode of the unipolar SPWM single-phase inverter is as follows: Figure 2-Figure 9 For the convenience of description, the inverter 100 hereinafter refers to a unipolar SPWM single-phase inverter.

[0115] Figure 2 When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (a). Mode (a) is the second measurement mode. In mode (a), the power device Q1 and the power device Q4 in the inverter 100 are turned on and form a path, and the power device S2 and the power device Q4 are turned on at the same time. At this time, V cd <-V CC , output voltage V out Clamped by the negative clamp circuit, V out =-V CC -V D22 .

[0116] Figure 3When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (b). Mode (b) is the first measurement mode. In mode (b), the power device Q1 and the diode D 13 The diode D S1 On, at this time, 0 <V cd <V CC , the output clamp unit is for the output voltage V out Without clamping, the MOSFET device Q1 in the first bridge arm is the target power device, V out =V dson1 , V dson1 is the channel conduction voltage of MOSFET device Q1.

[0117] Figure 4 When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (c). Mode (c) is the first measurement mode. In mode (c), the power device Q4 and the diode D 12 The power device S2 and the power device Q4 are turned on at the same time. <V cd <V CC , the output clamp unit 1 element for the output voltage V out Without clamping, the diode D in the first bridge arm 12 is the target diode, V out =V F2 , V F2 For diode D 12 The on-state voltage.

[0118] Figure 5 The decoupling measurement circuit is the circuit conduction condition of the inverter 100 in mode (d) when the first bridge arm is used as the target bridge circuit. Mode (d) is the second measurement mode. In mode (d), the diode D in the inverter 100 12 With diode D 13 The diode D S1 At this time, V cd <-V CC , output voltage V out Clamped by the negative clamp circuit, V out =-V CC -V D22 .

[0119] Figure 6When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is used to measure the circuit conduction of the inverter 100 in mode (e). Mode (e) is the second measurement mode. In mode (e), the power device Q2 and the power device Q3 in the inverter 100 are turned on and form a path, and the power device S1 and the power device Q3 are turned on at the same time. At this time, V cd >V CC , output voltage V out Clamped by the positive clamp circuit, V out =V CC +V D21 .

[0120] Figure 7 When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 under the mode (f). Mode (f) is the first measurement mode. In mode (f), the power device Q2 and the diode D 14 The diode D S2 On, at this time, -V CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the MOSFET device Q2 in the first bridge arm is the target power device, V out =-V dson2 , V dson2 is the channel conduction voltage of MOSFET device Q2.

[0121] Figure 8 When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 under the mode (g). Mode (g) is the first measurement mode. In mode (g), the power device Q3 and the diode D 11 The power device S1 and the power device Q3 are turned on at the same time. At this time, -V CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the diode D in the first bridge arm 11 is the target diode, V out =-V F1 , V F1 For diode D 11 The on-state voltage.

[0122] Fig. 9 When the first bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (h). Mode (h) is the second measurement mode. In mode (h), the diode D 11 With diode D 14The diode D S2 At this time, V cd >V CC , output voltage V out Clamped by the positive clamp circuit, V out =V CC +V D21 .

[0123] After completing the individual measurement of the conduction voltage drop of each device in the first bridge arm, the switch SW1 is opened and the switch SW2 is closed to select the second bridge arm of the unipolar SPWM single-phase inverter as the target measurement bridge. When the second bridge arm is the target measurement bridge, the flow of the decoupling measurement circuit corresponding to each mode of the unipolar SPWM single-phase inverter is as follows: Figure 10-Figure 17 As shown,

[0124] Fig.10 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is used to measure the circuit conduction of the inverter 100 in mode (a). Mode (a) is the second measurement mode. In mode (a), the power device Q1 and the power device Q4 in the inverter 100 are turned on and form a path, and the power device S2 and the power device Q4 are turned on at the same time. At this time, -V CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the MOSFET device Q4 in the second bridge arm is the target power device, V out =-V dson4 , V dson4 is the channel conduction voltage of MOSFET device Q4.

[0125] Fig.11 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (b). Mode (b) is the first measurement mode. In mode (b), the power device Q1 and the diode D in the inverter 100 are connected to each other. 13 The diode D S1 On, at this time, -V CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the diode D in the second bridge arm 13 is the target diode, V out =-V F3 , V F3 For diode D 13 The on-state voltage.

[0126] Fig.12When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (c). Mode (c) is the first measurement mode. In mode (c), the power device Q4 and the diode D 12 The power device S2 and the power device Q4 are turned on at the same time. CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the MOSFET device Q4 in the second bridge arm is the target power device, V out =-V dson4 , V dson4 is the channel conduction voltage of MOSFET device Q4.

[0127] Fig.13 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 in mode (d). Mode (d) is the second measurement mode. In mode (d), the diode D 12 With diode D 13 The diode D S1 On, at this time, -V CC <V cd <0, the output clamp unit is sensitive to the output voltage V out Without clamping, the diode D in the second bridge arm 13 is the target diode, V out =-V F3 , V F3 For diode D 13 The on-state voltage.

[0128] Fig.14 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is measured in the inverter 100 mode (e) circuit conduction condition. Mode (e) is the second measurement mode. In mode (e), the power device Q2 and the power device Q3 in the inverter 100 are turned on and form a path, and the power device S1 and the power device Q3 are turned on at the same time. At this time, 0 <V cd <V CC , the output clamp unit is for the output voltage V out Unclamped, the MOSFET device Q3 in the second bridge arm is the target power device, V out =V dson3 , V dson3 is the channel conduction voltage of MOSFET device Q3.

[0129] Fig.15When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 under the mode (f). Mode (f) is the first measurement mode. In mode (f), the power device Q2 and the diode D 14 The diode D S2 On, at this time, 0 <V cd <V CC , the output clamp unit is for the output voltage V out Without clamping, the diode D in the second bridge arm 14 is the target diode, V out =V F4 , V F4 For diode D 14 The on-state voltage.

[0130] Fig.16 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 under the mode (g). Mode (g) is the first measurement mode. In mode (g), the power device Q3 and the diode D 11 The power device S1 and the power device Q3 are turned on at the same time. <V cd <V CC ,,Output clamp unit to output voltage V out Without clamping, MOSFET device Q3 is the target power device, V out =V dson3 , V dson3 is the channel conduction voltage of MOSFET device Q3.

[0131] Fig.17 When the second bridge arm is used as the target bridge circuit, the decoupling measurement circuit is in the circuit conduction state of the inverter 100 under the mode (h). Mode (h) is the second measurement mode. In mode (h), the diode D 11 With diode D 14 The diode D S2 On, at this time, 0 <V cd <V CC , the output clamp unit is for the output voltage V out Without clamping, the diode D in the second bridge arm 14 is the target diode, V out =V F4 , V F4 For diode D 14 The on-state voltage.

[0132] Table 1 shows the specific working process of the above decoupling measurement circuit when the target measurement bridge is the first bridge arm and the second bridge arm, and the output voltage V corresponding to the decoupling measurement circuit under each working mode of the inverter 100 out .

[0133] Table 1 Output voltage V corresponding to the decoupling measurement circuit in each working mode of the inverter out

[0134]

[0135] In summary, the present invention can measure the on-state voltage drop of a power device or a diode separately under different working modes of the unipolar SPWM single-phase inverter 100, realize the decoupled positioning measurement of the on-state voltage drop of the inverter 100, simplify the measurement steps, and use the measured data to perform reliability evaluation on a single device in the inverter 100.

[0136] It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the above description refer to directions in the drawings of the present application specification, and the words "front" and "back", "inner" and "outer" refer to directions toward or away from a specific component, respectively. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0137] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. An inverter-level device on-state voltage decoupling measurement circuit, characterized in that: It includes a decoupling module and an output module, wherein the output module is adaptively connected to the inverter through the decoupling module to form a decoupling measurement circuit after the adaptive connection, wherein: The decoupling module includes a bridge selection unit for selecting a target measurement bridge, and a decoupling unit for controlling a connection state between the target measurement bridge and the output module; When measuring the conduction voltage drop of the device in the inverter, the target measurement bridge in the inverter is selected by the bridge selection unit, the working mode of the inverter is configured according to the selected target measurement bridge, and the target device in the target measurement bridge in the current working mode is adapted and connected to the output module by the decoupling unit, so as to obtain the conduction voltage drop of the target device in the current working mode by using the output module, wherein, The target device is a target power device or a target diode; The decoupling unit includes a power device S1, a power device S2, and a diode D connected in reverse parallel to the power device S1. S1 and a diode D connected in reverse parallel to the power device S2 S2 ; When measuring the conduction voltage drop of the devices in the inverter, configure the power devices S1, S2, and diode D in the decoupling unit according to the conduction state of the devices in the inverter. S1 And diode D S2 The conduction state.

2. The inverter-level device on-state voltage decoupling measurement circuit according to claim 1, characterized in that: The working mode of the inverter includes a first measurement mode and a second measurement mode; When the inverter is in the first measurement mode, it includes a power device in a conducting state and a diode forming a loop with the power device; When the inverter is in the second measurement mode, it includes two power devices in a conducting state forming a loop or two diodes forming a loop.

3. The inverter-level device on-state voltage decoupling measurement circuit according to claim 2, characterized in that: The inverter comprises a unipolar SPWM single-phase inverter, and the unipolar SPWM single-phase inverter comprises a first bridge arm and a second bridge arm, wherein: The first bridge arm includes a power device Q1, a power device Q2, and a diode D connected in reverse parallel to the power device Q1. 11 and a diode D connected in reverse parallel to the power device Q2. 12 ; The second electrode of the power device Q1 is connected to the input capacitor C dc The first electrode of the power device Q2 is connected to the input capacitor C dc The other end of the capacitor C dc One end is connected to the input voltage source V DC The positive terminal is connected to the input voltage source V DC The negative connection of The first electrode of the power device Q1 is connected to the second electrode of the power device Q2 to form a first bridge arm connection point a, and the first bridge arm connection point a is connected to the bridge selection unit; The second bridge arm includes a power device Q3, a power device Q4, and a diode D connected in reverse parallel to the power device Q3. 13 and a diode D connected in reverse parallel to the power device Q4. 14 ; The second electrode of the power device Q3 is connected to the second electrode of the power device Q1 and the second electrode of the power device S1, and the first electrode of the power device Q4 is connected to the first electrode of the power device Q2 and the first electrode of the power device S2; The first electrode of the power device Q3 is connected to the second electrode of the power device Q4 to form a second bridge arm connection point b, and the second bridge arm connection point b is connected to the bridge selection unit.

4. The inverter-level device on-state voltage decoupling measurement circuit according to claim 3, characterized in that: When the target measurement bridge is the first bridge arm, the inverter is modulated to be in the first measurement mode; When the target measurement bridge is the second bridge arm, the inverter is modulated to be in the first measurement mode and / or the second measurement mode.

5. The inverter-level device on-state voltage decoupling measurement circuit according to claim 2, characterized in that: Configuring the conduction states of the power devices S1 and S2 in the decoupling unit according to the conduction states of the devices in the inverter includes: The conduction state of the power device S1 in the decoupling unit is the same as the conduction state of the power device Q3 in the inverter, and the conduction state of the power device S2 in the decoupling unit is the same as the conduction state of the power device Q4 in the inverter.

6. The inverter-level device on-state voltage decoupling measurement circuit according to claim 2, characterized in that: The bridge selection unit includes a first switch subunit and a second switch subunit, wherein: One end of the first switch subunit is connected to the first bridge arm connection point a, and one end of the second switch subunit is connected to the second bridge arm connection point b; The other end of the first switch subunit is connected to the other end of the second switch subunit and the output module to form a connection point d; When the first bridge arm of the inverter is selected as the target measurement bridge, the first bridge arm connection point a is connected to the output module through the first switch subunit; When the second bridge arm of the inverter is selected as the target measurement bridge, the second bridge arm connection point b is connected to the output module through the second switch subunit.

7. The inverter-level device on-state voltage decoupling measurement circuit according to claim 6, characterized in that: The output module includes an output clamp unit and a current limiting unit, wherein: The output clamping unit includes a positive clamping circuit and a negative clamping circuit; The positive clamp circuit includes a voltage source V CC1 and diode D 21 , the voltage source V CC1 The positive terminal of the diode D 21 The cathode connection of the voltage source V CC1 The negative pole is grounded; The negative clamp circuit includes a voltage source V CC2 and diode D 22 , the voltage source V CC2 The positive terminal of the diode D 22 The cathode connection of the voltage source V CC2 The cathode of the diode D 21 The anode and current limiting unit are connected to the diode D 22 The anode of the CC1 The negative pole of and connection point d are connected.

8. The inverter-level device on-state voltage decoupling measurement circuit according to claim 7, characterized in that: The current limiting unit includes a resistor R1, one end of which is connected to a voltage source V CC2 The other end of the resistor R1 is connected to the first electrode of the power device S1 to form a connection point c; -V CC2 <V cd <0 or 0 <V cd <V CC1 When the on-state voltage drop measurement circuit uses the output clamp unit to obtain the on-state voltage drop of the target power device or target diode in the target measurement bridge circuit, where V cd is the voltage between the connection point c and the connection point d.

9. The inverter-level device on-state voltage decoupling measurement circuit according to claim 6, characterized in that: When V cd >V CC1 When the positive clamping circuit outputs the positive clamping voltage, the positive clamping voltage is expressed as V CC1 +V D21 , V D21 For the diode D 21 The conduction voltage drop; When V cd <-V CC2 When the negative clamping circuit outputs a negative clamping voltage, the negative clamping voltage is expressed as -(V CC2 +V D22 ), V D22 For the diode D 22 The conduction voltage drop.

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