Power semiconductor device series voltage-sharing circuit and power electronic converter

Abstract

The invention relates to a power semiconductor device series voltage-sharing circuit and a power electronic converter, and the power semiconductor device series voltage-sharing circuit comprises a power semiconductor device series circuit which comprises a plurality of power semiconductor devices connected in series; the voltage-sharing circuit comprises a plurality of voltage-sharing units, and each voltage-sharing unit is connected with each power semiconductor device in parallel and is used for balancing the voltage at the two ends of each power semiconductor device; and the voltage clamping circuit is connected with the power semiconductor device series circuit in parallel, the voltage clamping circuit comprises a plurality of voltage clamping units which are connected in parallel, and the plurality of voltage clamping units which are connected in parallel are used for balancing the voltage at the two ends of each power semiconductor device when the power semiconductor device is in a turn-off transient state. According to the power semiconductor device series connection voltage-sharing circuit, the problem of unbalanced voltage division in the series connection process of the power semiconductor devices can be effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular, to a series voltage equalizing circuit for power semiconductor devices and a power electronic converter. Background Art

[0002] With the development of modern power electronics technology, in application scenarios such as high-voltage inverters and high-voltage direct current transmission systems, the demand for high-voltage applications is increasing continuously. However, due to the influence of process and performance on a single power semiconductor device, its application and development are restricted. Therefore, the series connection of power semiconductor devices is an important way to solve and realize high-voltage and large-capacity power electronic converters at present. However, the individual performance differences of power semiconductor devices and the stray parameter differences of the matching circuits will both cause uneven series voltage division. If not controlled, it may lead to the damage of power semiconductor devices.

[0003] In the prior art, a voltage equalizing circuit composed of parallel resistors and capacitors or parallel resistors on each power semiconductor device can be used for voltage equalization to achieve the series voltage equalization of power semiconductor devices. However, the voltage equalizing effect in the prior art is not ideal. Summary of the Invention

[0004] Based on this, it is necessary to provide a series voltage equalizing circuit for power semiconductor devices and a power electronic converter that can effectively improve the problem of uneven voltage division during the series connection of power semiconductor devices.

[0005] In a first aspect, an embodiment of the present application provides a series voltage equalizing circuit for power semiconductor devices, including: a power semiconductor device series circuit, which includes a plurality of serially connected power semiconductor devices; a voltage equalizing circuit, which includes a plurality of voltage equalizing units, and each voltage equalizing unit is connected in parallel with each power semiconductor device and is used for equalizing the voltages across each power semiconductor device; a voltage clamping circuit, which is connected in parallel with the power semiconductor device series circuit, and the voltage clamping circuit includes a plurality of parallel voltage clamping units, and the plurality of parallel voltage clamping units are used for equalizing the voltages across each power semiconductor device during the turn-off transient of the power semiconductor device.

[0006] In one of the embodiments, the voltage clamping unit is in a high impedance state when the voltage across the voltage clamping unit does not exceed a preset operating voltage; and the voltage clamping unit is in a low impedance state when the voltage across the voltage clamping unit exceeds the preset operating voltage.

[0007] In one of the embodiments, the plurality of parallel voltage clamping units include: a passive clamping unit, and / or, an active clamping unit.

[0008] In one embodiment, the active clamping unit includes a snubber diode, a gate resistor, a dissipative resistor, and a thyristor; the anode of the snubber diode is connected to the first end of the gate resistor and the gate of the thyristor, the cathode of the snubber diode is connected to the first end of the dissipative resistor to form a first output port, the second end of the dissipative resistor is connected to the anode of the thyristor, and the cathode of the thyristor is connected to the second end of the gate resistor to form a second output port; when the voltage across the active clamping unit exceeds the operating voltage of the snubber diode, the snubber diode is reverse broken down and generates a current injected into the gate of the thyristor, making the active clamping unit in a low impedance state.

[0009] In one embodiment, if multiple parallel voltage clamping units include active clamping units and passive clamping units, the first output ports of each active clamping unit are connected to each other and are also connected to the first end of the series circuit of the power semiconductor devices and the first ends of each passive clamping unit, and the second output ports of each active clamping unit are connected to each other and are also connected to the second end of the series circuit of the power semiconductor devices and the second ends of each passive clamping unit.

[0010] In one embodiment, the operating voltages of at least two voltage clamping units among multiple parallel voltage clamping units are the same, or the operating voltages of at least two voltage clamping units among multiple parallel voltage clamping units are different.

[0011] In one embodiment, each voltage equalizing unit includes a dynamic voltage equalizing unit and a static voltage equalizing unit, and the dynamic voltage equalizing unit is connected in parallel with the static voltage equalizing unit; the dynamic voltage equalizing unit is used to slow down the change rate of the voltage across the power semiconductor device during the turn-on transient and turn-off transient of the power semiconductor device to balance the dynamic voltages across each power semiconductor device; the static voltage equalizing unit is used to balance the leakage current of the power semiconductor device when the power semiconductor device is blocked to balance the static voltages across each power semiconductor device.

[0012] In one embodiment, the dynamic voltage equalizing unit includes a capacitor and a first resistor, and the capacitor is connected in series with the first resistor; the static voltage equalizing unit includes a second resistor, and the resistance value of the second resistor is less than the equivalent impedance when the power semiconductor device is blocked.

[0013] In one embodiment, in the series circuit of power semiconductor devices, each power semiconductor device is reversely connected in parallel with a diode, which is used to block and control the forward current and forward voltage.

[0014] In a second aspect, the present application provides a power electronic converter, which includes the power semiconductor device series voltage equalizing circuit described in any one of the above first aspects.

[0015] The above-mentioned power semiconductor device series voltage equalization circuit includes a power semiconductor device series circuit, a voltage equalization circuit, and a voltage clamping circuit. The power semiconductor device series circuit includes multiple serially connected power semiconductor devices. The voltage equalization circuit includes multiple voltage equalization units, and each voltage equalization unit is connected in parallel with each power semiconductor device and is used to balance the voltages across each power semiconductor device. The voltage clamping circuit is connected in parallel with the power semiconductor device series circuit. The voltage clamping circuit includes multiple parallel-connected voltage clamping units, and the multiple parallel-connected voltage clamping units are used to balance the voltages across each power semiconductor device during the turn-off transient of the power semiconductor device. In this way, the static voltage imbalance and dynamic voltage imbalance problems during the series connection of power semiconductor devices are improved through the voltage equalization circuit. At the same time, by connecting multiple voltage clamping units in parallel, the voltages across the power semiconductor device can be clamped during the turn-off transient of the power semiconductor device, which can improve the voltage clamping effect of the voltage clamping circuit and further improve the problem of uneven voltage division during the series connection process of power semiconductor devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1 Schematic diagram of the power semiconductor device series voltage equalization circuit provided for one embodiment;

[0018] Figure 2 Active clamping unit structure provided for one embodiment;

[0019] Figure 3 Schematic diagram of the voltage clamping circuit when two active clamping units are connected in parallel provided for one embodiment;

[0020] Figure 4 Schematic diagram of the voltage clamping circuit when one active clamping unit and one passive clamping unit are connected in parallel provided for one embodiment;

[0021] Figure 5 Voltage equalization unit structure provided for one embodiment;

[0022] Figure 6 Schematic diagram of the power semiconductor device series voltage equalization circuit provided for another embodiment;

[0023] Figure 7 Schematic diagram of the power semiconductor device series voltage equalization circuit provided for another embodiment;

[0024] Figure 8Schematic diagram of the series voltage equalization circuit for a power semiconductor device provided for another embodiment.

[0025] Description of reference numerals:

[0026] 10. Series voltage equalization circuit for power semiconductor devices; 100. Series circuit of power semiconductor devices; 110. Power semiconductor device; 111. Diode; 200. Voltage equalization circuit; 210. Voltage equalization unit; 211. Dynamic voltage equalization unit; 212. Static voltage equalization unit; 213. Capacitor; 214. First resistor; 215. Second resistor; 300. Voltage clamping circuit; 310. Voltage clamping unit; 311. Passive clamping unit; 312. Active clamping unit; 313. Snubber diode; 314. Gate resistor; 315. Dissipative resistor; 316. Thyristor; 300'. Branch voltage clamping circuit. Detailed implementation manners

[0027] To facilitate the understanding of the present application, the present application will be described more comprehensively below with reference to the relevant drawings. Embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present application belongs. The terms used in the description of the present application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0029] It can be understood that the terms "first", "second", etc. used in the present application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from another element. For example, without departing from the scope of the present application, the first resistor can be called the second resistor, and similarly, the second resistor can be called the first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0030] It can be understood that "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if there is an electrical signal or data transmission between the connected circuits, modules, units, etc.

[0031] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "At least part of an element" means part or all of the element.

[0032] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprises / comprising" or "has / have" etc. specify the presence of the stated features, integers, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0033] With the development of modern power electronics technology, in application scenarios such as high-voltage inverters and high-voltage direct current transmission systems, the demand for high-voltage applications is increasing continuously. However, due to the influence of process and performance on a single power semiconductor device, its application and development are restricted. Therefore, the series connection of power semiconductor devices is an important way to solve and realize high-voltage and large-capacity power electronic converters at present. However, the individual performance differences of power semiconductor devices and the stray parameter differences of the matching circuits will both cause uneven series voltage sharing. If not controlled, it may lead to the damage of power semiconductor devices.

[0034] In the prior art, an equalizing circuit composed of a parallel resistor and capacitor or a resistor is connected in parallel to each power semiconductor device to achieve series voltage equalization of power semiconductor devices. However, the voltage equalization effect in the prior art is not ideal.

[0035] In view of this, the embodiments of the present application provide a power semiconductor device series voltage equalizing circuit that can effectively improve the problem of uneven voltage sharing during the series connection of power semiconductor devices.

[0036] In an exemplary embodiment, as Figure 1 shown, a power semiconductor device series voltage equalizing circuit 10 is provided. The power semiconductor device series voltage equalizing circuit 10 includes a power semiconductor device series circuit 100, an equalizing circuit 200 and a voltage clamping circuit 300. The power semiconductor device series circuit 100 includes a plurality of serially connected power semiconductor devices 110; the equalizing circuit 200 includes a plurality of equalizing units 210, and each equalizing unit 210 is connected in parallel with each power semiconductor device 110 for equalizing the voltages across each power semiconductor device 110; the voltage clamping circuit 300 is connected in parallel with the power semiconductor device series circuit 100, and the voltage clamping circuit 300 includes a plurality of parallel-connected voltage clamping units 310. The plurality of parallel-connected voltage clamping units 310 are used for equalizing the voltages across each power semiconductor device 110 at the moment when the power semiconductor device 110 turns off transiently.

[0037] Optionally, the power semiconductor device 110 may be a high-power electronic device for electric energy conversion and circuit control, which is a bridge between weak current control and strong current operation. It is mainly used for functions such as frequency conversion, voltage conversion, current conversion, power amplification, and power management. The power semiconductor device 110 may include thyristors, insulated gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), or integrated gate-commutated thyristors (IGCTs), etc.

[0038] Optionally, the series circuit 100 of power semiconductor devices may be two or more power semiconductor devices 110 electrically connected in sequence in the same circuit to improve the overall voltage and power capacity. The individual power semiconductor devices 110 connected in series can distribute the voltage and improve the voltage withstand capacity of the overall circuit. In the embodiments of the present application, the number, type, model, etc. of the power semiconductor devices 110 are not limited in any way and can be specifically selected according to the actual situation. For example, when n power semiconductor devices 110 are connected in series, the first power semiconductor device is the level with the highest potential in the series circuit 100 of power semiconductor devices, and the nth power semiconductor device is the level with the lowest potential in the series circuit 100 of power semiconductor devices.

[0039] Optionally, due to the individual performance differences of the power semiconductor devices 110 and the stray parameter differences of the matching circuits, the voltage division of the series circuit 110 of power semiconductor devices will be unbalanced. When the power semiconductor device 110 is in the on or off state, the voltage of the power semiconductor device 110 remains stable, but there is static voltage imbalance. For example, taking the power semiconductor device as a MOSFET, the static non-uniformity is mainly caused by the inconsistent leakage current parameters between MOSFETs; when the power semiconductor device 110 is in the on transient or off transient state, the voltage of the power semiconductor device 110 changes rapidly, and there is dynamic voltage imbalance. Therefore, voltage equalizing units need to be connected in parallel across each power semiconductor device 110 to balance the voltages across each power semiconductor device 110.

[0040] Optionally, the voltage equalizing unit may be a static voltage equalizing unit and / or a dynamic voltage equalizing unit, and the embodiments of the present application do not limit this.

[0041] Optionally, when the power semiconductor device 110 is in the turn-off transient state, the inductor current in the branch where the power semiconductor device 110 is located is interrupted, causing the voltage across the power semiconductor device 110 to rise rapidly, exacerbating the phenomenon of voltage imbalance between the power semiconductor devices 110. At the same time, the power semiconductor device 110 has a risk of overvoltage breakdown failure. Therefore, a voltage clamping circuit 300 needs to be connected in parallel across the series circuit 100 of power semiconductor devices. The equivalent impedance of the voltage clamping circuit 300 decreases as the voltage across the power semiconductor device 110 increases, and can limit the further rise of the voltage across the power semiconductor device 110 during the turn-off transient state of the power semiconductor device 110, enabling other power semiconductor devices in the series branch to bear the voltage, so that the voltages across the two ends of each device approach, and the voltages across the two ends of each power semiconductor device 110 are balanced.

[0042] Optionally, the voltage clamping circuit 300 can be implemented by connecting multiple voltage clamping units 310 in parallel. In this way, the voltage clamping circuit 300 can have multi-stage impedance adjustment and redundancy backup capabilities, improving the voltage clamping effect of the voltage clamping circuit and further alleviating the problem of uneven voltage division during the series connection of power semiconductor devices.

[0043] The above-mentioned series voltage equalization circuit for power semiconductor devices includes a series circuit of power semiconductor devices, a voltage equalization circuit, and a voltage clamping circuit. The series circuit of power semiconductor devices includes multiple serially connected power semiconductor devices. The voltage equalization circuit includes multiple voltage equalization units, and each voltage equalization unit is connected in parallel with each power semiconductor device to balance the voltages across the two ends of each power semiconductor device. The voltage clamping circuit is connected in parallel with the series circuit of power semiconductor devices. The voltage clamping circuit includes multiple parallel-connected voltage clamping units. The multiple parallel-connected voltage clamping units are used to balance the voltages across the two ends of each power semiconductor device during the turn-off transient state of the power semiconductor device. In this way, the static voltage imbalance and dynamic voltage imbalance problems during the series connection of power semiconductor devices are improved through the voltage equalization circuit. At the same time, by connecting multiple voltage clamping units in parallel, the voltage across the two ends of the power semiconductor device can be clamped during the turn-off transient state of the power semiconductor device, improving the voltage clamping effect of the voltage clamping circuit and further alleviating the problem of uneven voltage division during the series connection of power semiconductor devices.

[0044] In an exemplary embodiment, the voltage clamping unit 310 is in a high-impedance state when the voltage across the voltage clamping unit 310 does not exceed the preset operating voltage, and is in a low-impedance state when the voltage across the voltage clamping unit 310 exceeds the preset operating voltage.

[0045] Optionally, when the power semiconductor device 110 is in the turn-off transient state, the voltage across the power semiconductor device 110 rises rapidly, causing the voltage across the voltage clamping unit 310 to exceed the preset operating voltage. At this time, the voltage clamping unit 310 is in a low-impedance state and can absorb energy to limit the further rise of the voltage across the power semiconductor device 110.

[0046] Optionally, the operating voltages of at least two of the multiple parallel-connected voltage clamping units are the same, or the operating voltages of at least two of the multiple parallel-connected voltage clamping units are different.

[0047] Optionally, when the voltage across the voltage clamping unit 310 exceeds the preset operating voltage, if the operating voltages of at least two voltage clamping units 310 are the same, at this time, these at least two voltage clamping units 310 are both in a low-impedance state, and the equivalent parallel impedance of the voltage clamping circuit 300 decreases. The same operating voltages of at least two voltage clamping units 310 achieve redundancy of the voltage clamping circuit 300, improving the energy absorption and voltage clamping effects. At the same time, the risk of overheating and explosion caused by only one voltage clamping unit 310 absorbing energy is avoided, which can improve the safety of the voltage clamping circuit.

[0048] Optionally, when the voltage across the voltage clamping unit 310 exceeds the preset operating voltage, if the operating voltages of at least two voltage clamping units 310 are different, at this time, the voltage clamping unit with a lower operating voltage is in a low-impedance state, and the voltage clamping unit with a higher operating voltage is in a high-impedance state. The voltage clamping unit in the low-impedance state absorbs energy to achieve voltage clamping. When the voltage clamping unit in the low-impedance state cannot complete voltage clamping, the voltage clamping unit with a higher operating voltage is in a low-impedance state to reduce the equivalent parallel impedance of the voltage clamping circuit, realizing the cascaded clamping of the voltage clamping circuit 300 and improving the energy absorption and voltage clamping effects.

[0049] In an exemplary embodiment, the multiple parallel-connected voltage clamping units 310 include: a passive clamping unit 311, and / or, an active clamping unit 312.

[0050] Optionally, the voltage clamping circuit 300 can be realized by paralleling multiple passive clamping units 311, or can be realized by paralleling multiple active clamping units 312, or can also be realized by paralleling multiple passive clamping units 311 and multiple active clamping units 312. The embodiments of the present application do not make any limitations on the types and models of the voltage clamping units.

[0051] Optionally, the passive clamping unit 311 can be a voltage-controlled variable resistor device. A voltage-controlled variable resistor device is a component whose resistance value changes with the control voltage. It can adjust its own resistance value according to the externally applied voltage, thereby affecting the distribution of current or voltage in the circuit.

[0052] Optionally, the passive clamping unit 311 can include a lightning arrester, a lightning protection tube, a Zener diode, a transient suppression diode, etc. Among them, a lightning arrester is a varistor, that is, the resistance value of the lightning arrester changes with the voltage across its two ends. A lightning protection tube is a gas discharge tube. When the voltage across its two ends breaks down the insulating gas, a short-circuit arc is formed, thereby releasing energy.

[0053] Optionally, as Figure 2 shown, the active clamping unit 312 includes a snubber diode 313, a gate resistor 314, a power-consuming resistor 315, and a thyristor 316. The anode of the snubber diode 313 is connected to the first end of the gate resistor 314 and the gate of the thyristor 316. The cathode of the snubber diode 313 is connected to the first end of the power-consuming resistor 315 to form a first output port. The second end of the power-consuming resistor 315 is connected to the anode of the thyristor 316. The cathode of the thyristor 316 is connected to the second end of the gate resistor 314 to form a second output port. When the voltage across the active clamping unit 312 exceeds the operating voltage of the snubber diode 313, the snubber diode 313 is reverse-biased and generates a current injected into the gate of the thyristor 316, making the active clamping unit 312 in a low-impedance state.

[0054] Optionally, when the voltage across the active clamping unit 312 does not exceed the operating voltage of the snubber diode 313, the gate of the thyristor 316 is connected to its own cathode through the gate resistor, and the thyristor 316 remains in the blocking state. The active clamping unit 312 is in a high-impedance state. When the voltage across the active clamping unit 312 exceeds the operating voltage of the snubber diode 313, the snubber diode 313 is reverse-biased and generates a current injected into the gate of the thyristor 316. The thyristor 316 conducts, and the power-consuming resistor 315 is connected in parallel between the first output port and the second output port of the active clamping unit 312. The equivalent parallel impedance of the two output ports changes from high to low, making the active clamping unit 312 in a low-impedance state.

[0055] Exemplarily, as Figure 3As shown, taking the case where the voltage clamping circuit 300 is formed by two active clamping units 312 in parallel, the first output ports of the two active clamping units 312 are connected to each other, and the second output ports are connected to each other; when the voltage across the active clamping unit 312 exceeds the operating voltage of the snubber diode 313, and when the operating voltages of the snubber diodes 313 in the two active clamping units 312 are the same, redundancy of the voltage clamping circuit 300 is achieved, enhancing the energy absorption and voltage clamping effects and avoiding the risk of overheating and explosion. When the operating voltages of the snubber diodes 313 in the two active clamping units 312 are different, the active clamping unit 312 where the snubber diode 313 with a lower operating voltage is located first enters a low-impedance state, and the active clamping unit where the snubber diode 313 with a higher operating voltage is located remains in a high-impedance state. The active clamping unit 312 in the low-impedance state performs energy absorption and voltage clamping. When the active clamping unit 312 in the low-impedance state cannot complete voltage clamping, the active clamping unit where the snubber diode 313 with a higher operating voltage is located then enters a low-impedance state, further reducing the parallel equivalent impedance, achieving cascaded clamping, and enhancing the energy absorption and voltage clamping effects.

[0056] Optionally, due to the fast dynamic response speed of the thyristor 316 in the active clamping unit 312, good consistency of each component, and simple component selection, the consistency of the operating voltage of the active clamping unit 312 can be ensured, further enhancing the full operating condition safety of the power semiconductor device.

[0057] Optionally, if multiple parallel voltage clamping units 310 include active clamping units 312 and passive clamping units 311, the first output ports of the active clamping units 312 are connected to each other and are connected to the first end of the power semiconductor device series circuit 100 and the first end of each passive clamping unit 311. The second output ports of the active clamping units 312 are connected to each other and are connected to the second end of the power semiconductor device series circuit 100 and the second end of each passive clamping unit 311. The embodiments of the present application do not limit the number and connection sequence of the voltage clamping units.

[0058] Exemplarily, such as Figure 4As shown, taking the voltage clamping circuit 300 with one active clamping unit 312 and one passive clamping unit 311 connected in parallel as an example, the passive clamping unit 311 can be a lightning arrester. The state of the passive clamping unit 311 is determined by the voltage across the passive clamping unit 311 and the operating voltage of the lightning arrester. When the voltage across the passive clamping unit 311 exceeds the operating voltage of the lightning arrester, the passive clamping unit 311 is in a low impedance state. When the voltage across the passive clamping unit 311 does not exceed the operating voltage of the lightning arrester, the passive clamping unit 311 is in a high impedance state. Similarly, the operating voltage of the lightning arrester and the operating voltage of the zener diode 313 can be the same or different. That is, when the operating voltages of the passive clamping unit 311 and the active clamping unit 312 are the same, redundancy of the voltage clamping circuit 300 is achieved, improving the energy absorption and voltage clamping effects and avoiding the risk of overheating and explosion. When the operating voltages of the passive clamping unit 311 and the active clamping unit 312 are different, stepped clamping of the voltage clamping circuit 300 is achieved, improving the energy absorption and voltage clamping effects.

[0059] In an exemplary embodiment, each voltage sharing unit 210 includes a dynamic voltage sharing unit 211 and a static voltage sharing unit 212, and the dynamic voltage sharing unit 211 is connected in parallel with the static voltage sharing unit 212. The dynamic voltage sharing unit 211 is configured to slow down the rate of change of the voltage across the power semiconductor device 110 during the turn-on transient and turn-off transient of the power semiconductor device 110, so as to equalize the dynamic voltages across the power semiconductor devices 110. The static voltage sharing unit 212 is configured to balance the leakage current of the power semiconductor device 110 when the power semiconductor device 110 is blocked, so as to equalize the static voltages across the power semiconductor devices 110.

[0060] Optionally, as Figure 5 shown, the dynamic voltage sharing unit 211 includes a capacitor 213 and a first resistor 214, and the capacitor 213 is connected in series with the first resistor 214. The static voltage sharing unit 212 includes a second resistor 215, and the resistance value of the second resistor 215 is less than the equivalent impedance when the power semiconductor device 110 is blocked.

[0061] Optionally, when the power semiconductor device 110 is in the turn-off transient, the voltage across the power semiconductor device 110 rises and charges the capacitor 213 through the first resistor 214. The dynamic voltage sharing unit 211 provides an additional current path, reducing the equivalent input impedance across the power semiconductor device 110 and the rate of rise of the voltage across it. When the power semiconductor device 110 is in the turn-on transient, the voltage across the power semiconductor device 110 drops and discharges the capacitor 213 through the first resistor 214. The dynamic voltage sharing unit 211 provides an additional current source, reducing the equivalent output impedance across the power semiconductor device 110 and the rate of drop of the voltage across it.

[0062] Optionally, the resistance value of the second resistor 215 of the static voltage equalizing unit 212 is much smaller than the equivalent impedance when the power semiconductor device 110 is blocked, and can balance the leakage current of the power semiconductor device 110 during blocking, thereby equalizing the static voltages of the power semiconductor devices 110.

[0063] Each of the above voltage equalizing units includes a dynamic voltage equalizing unit and a static voltage equalizing unit, and the dynamic voltage equalizing unit is connected in parallel with the static voltage equalizing unit; the dynamic voltage equalizing unit is used to slow down the change rate of the voltage across the power semiconductor device during the turn-on transient and turn-off transient of the power semiconductor device, so as to equalize the dynamic voltages across the power semiconductor devices; the static voltage equalizing unit is used to balance the leakage current of the power semiconductor device during blocking, so as to equalize the static voltages across the power semiconductor devices, which can improve the problem of uneven voltage division during the series connection of power semiconductor devices.

[0064] In an exemplary embodiment, as Figure 6 shown, in the power semiconductor device series circuit 100, each power semiconductor device 110 is reversely connected in parallel with a diode 111, which is used to block and control the forward current and forward voltage.

[0065] Exemplarily, Figure 6 in the case where the power semiconductor device 110 is an asymmetric IGCT device, the voltage clamping circuit 300 is realized by connecting two active clamping units in parallel.

[0066] Optionally, in the above embodiments, the power semiconductor device is all realized based on the power semiconductor device 110 reversely connected in parallel with the diode 111. The anode of the diode 111 is connected to the cathode of the power semiconductor device 110, and the cathode of the diode 111 is connected to the anode of the power semiconductor device 110, which can block and control the forward current and forward voltage. When there is a reverse current or reverse voltage in the power semiconductor device 110, the diode 111 conducts, and a loop is formed by the diode 111 and the power semiconductor device 110 to prevent the voltage equalizing circuit 200 and the voltage clamping circuit 300 from conducting.

[0067] In a possible implementation manner, as Figure 7As shown, taking the unipolar series circuit where the power semiconductor device series circuit 100 consists of 1 power semiconductor device as an example, the voltage clamping circuit 300 is realized by the parallel connection of an active clamping unit and 1 passive clamping unit. Each power semiconductor device 110 may not be anti-parallel connected with a diode, but a diode 111 is connected in parallel across the two ends of the first resistor 214 of the dynamic voltage sharing unit 211. The anode of the diode 111 is connected to the first end of the first resistor 214, and the cathode of the diode 111 is connected to both the second end of the first resistor 214 and the first end of the capacitor 213. And when the active clamping unit 312 is included in the power supply clamping circuit 300, the anode of the snubber diode 313 is connected to the anode of the diode 111, the cathode of the diode 111 is connected to both the first end of the gate resistor 314 and the gate of the thyristor 316, the cathode of the snubber diode 313 is connected to the first end of the energy-consuming resistor 315 to form a first output port, the second end of the energy-consuming resistor 315 is connected to the anode of the thyristor 316, and the cathode of the thyristor 316 is connected to the second end of the gate resistor 314 to form a second output port, preventing the voltage sharing circuit 200 and the voltage clamping circuit 300 from conducting.

[0068] In an exemplary embodiment, optionally, based on the above embodiment, the power semiconductor device series voltage sharing circuit may further include a plurality of branch voltage clamping circuits, and the branch voltage clamping circuits are respectively connected in parallel with each power semiconductor device, and the number of the branch voltage clamping circuits is the same as the number of the series-connected power semiconductor devices.

[0069] Optionally, the structure of the branch voltage clamping circuit is the same as the structure of the voltage clamping circuit in the above embodiment, and details are not described herein again in the embodiments of the present application.

[0070] Optionally, each power semiconductor device in the power semiconductor series circuit is connected in parallel with a branch voltage clamping circuit, and the branch voltage clamping circuit may include at least one voltage clamping unit. Similarly, the voltage clamping unit may be a passive clamping unit or an active clamping unit. When a plurality of voltage clamping units are included in the branch voltage clamping circuit, the voltage clamping units are connected in parallel with each other. The structures of the branch voltage clamping circuits connected in parallel with each power semiconductor device may be the same or different, which is set according to the situation, and details are not limited in the embodiments of the present application.

[0071] Exemplarily, such as Figure 8As shown, taking the series circuit 100 of power semiconductor devices in parallel with the voltage clamping circuit 300, each power semiconductor device 110 in parallel with the dynamic voltage sharing unit 211, the static voltage sharing unit 212 and the branch voltage clamping circuit 300' as an example, each branch voltage clamping circuit 300' is composed of a passive clamping unit 311. The passive clamping unit 311 can be a lightning arrester. The equivalent impedance of each branch voltage clamping circuit 300' decreases as the voltage across the power semiconductor device increases, and is used to limit the further rise of the voltage across the overvoltage power semiconductor device during the turn-off transient, forcing other power semiconductor devices in the series branch to bear the voltage, so that the voltages across each power semiconductor device approach. The voltage clamping circuit 300 can clamp the voltage across the power semiconductor device during the turn-off transient of the power semiconductor device by paralleling multiple voltage clamping units, which can improve the voltage clamping effect of the voltage clamping circuit and further improve the problem of uneven voltage division during the series connection of power semiconductor devices.

[0072] In an exemplary embodiment, the power electronic converter includes the series voltage sharing circuit of power semiconductor devices described in any of the above embodiments of the series voltage sharing circuit of power semiconductor devices.

[0073] In the description of this specification, the descriptions referring to the terms "some embodiments", "other embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0074] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0075] The above embodiments only represent several implementation manners of the present application, and their descriptions are relatively specific and detailed, but should not be construed as a limitation to the scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A power semiconductor device series voltage balancing circuit, characterized in that: include: A power semiconductor device series circuit, wherein the power semiconductor device series circuit comprises a plurality of power semiconductor devices connected in series; A voltage balancing circuit, wherein the voltage balancing circuit comprises a plurality of voltage balancing units, each of which is connected in parallel with each of the power semiconductor devices to balance the voltage across both ends of each of the power semiconductor devices; A voltage clamping circuit is connected in parallel with the power semiconductor device series circuit, and the voltage clamping circuit includes a plurality of parallel voltage clamping units, and the plurality of parallel voltage clamping units are used to balance the voltages across the power semiconductor devices when the power semiconductor devices are in a shutdown transient state.

2. The circuit according to claim 1, characterized in that The voltage clamping unit is used for being in a high impedance state when the voltage at both ends of the voltage clamping unit does not exceed a preset action voltage; When the voltage across the voltage clamping unit exceeds the preset action voltage, the voltage clamping unit is in a low impedance state.

3. The circuit according to claim 2, characterized in that The plurality of voltage clamping units connected in parallel include: a passive clamping unit and / or an active clamping unit.

4. The circuit according to claim 3, characterized in that The active clamping unit includes a turn-around diode, a gate resistor, an energy-consuming resistor and a thyristor; The anode of the breakover diode is connected to the first end of the gate resistor and the gate of the thyristor, the cathode of the breakover diode is connected to the first end of the energy dissipation resistor to form a first output port, the second end of the energy dissipation resistor is connected to the anode of the thyristor, and the cathode of the thyristor is connected to the second end of the gate resistor to form a second output port; When the voltage across the active clamping unit exceeds the action voltage of the breakover diode, the breakover diode is reversely broken down and generates a current injected into the gate of the thyristor, so that the active clamping unit is in a low impedance state.

5. The circuit according to claim 4, characterized in that If the multiple parallel voltage clamping units include active clamping units and passive clamping units, the first output ports of the active clamping units are connected to each other and are connected to the first end of the power semiconductor device series circuit and the first end of each passive clamping unit, and the second output ports of the active clamping units are connected to each other and are connected to the second end of the power semiconductor device series circuit and the second end of each passive clamping unit.

6. The circuit according to claim 3, characterized in that The operating voltages of at least two of the plurality of voltage clamping units connected in parallel are the same, or the operating voltages of at least two of the plurality of voltage clamping units connected in parallel are different.

7. The circuit according to claim 1, characterized in that Each of the pressure balancing units includes a dynamic pressure balancing unit and a static pressure balancing unit, and the dynamic pressure balancing unit is connected in parallel with the static pressure balancing unit; The dynamic voltage balancing unit is used to slow down the rate of change of the voltage across the power semiconductor device during the turn-on transient and turn-off transient of the power semiconductor device, so as to balance the dynamic voltage across the power semiconductor device; The static voltage balancing unit is used to balance the leakage current of the power semiconductor device when the power semiconductor device is blocked, so as to balance the static voltage across the two ends of each power semiconductor device.

8. The circuit according to claim 7, characterized in that The dynamic voltage balancing unit includes a capacitor and a first resistor, and the capacitor is connected in series with the first resistor; The static voltage balancing unit includes a second resistor, and the resistance of the second resistor is smaller than the equivalent impedance of the power semiconductor device when it is blocked.

9. The circuit according to claim 1, characterized in that In the power semiconductor device series circuit, each power semiconductor device is connected with a reverse-parallel diode to block and control the forward current and forward voltage.

10. A power electronic converter, characterized in that: The power electronic converter comprises a power semiconductor device series voltage balancing circuit as claimed in any one of claims 1 to 9.

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