Direct-current energy consumption device module protection method and circuit based on full-control device

Abstract

The invention provides a direct-current energy consumption device module protection method and circuit based on a full-control device, is suitable for the technical field of power electronics, and can effectively improve the reliability of a direct-current energy consumption device. According to the scheme, when the voltage at the two ends of any power module of the direct-current energy consumption device is larger than or equal to the threshold voltage of the power module, one or more technical means of software, an active protection circuit and a passive protection circuit can be adopted to quickly reduce the voltage at the two ends of the power module to be below the threshold voltage; therefore, the purposes of eliminating the overvoltage of the power module and protecting a full-control device are achieved.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, and specifically relates to a protection method and circuit for a DC power consumption device module based on fully controlled devices. Background Technology

[0002] Flexible DC transmission technology is a primary technical means to solve the grid connection problem for offshore wind power. However, when a fault occurs in the receiving-end AC grid, the wind farm energy that cannot be consumed in time will cause a rapid increase in DC voltage, threatening the safety of the converter valves and the entire system. Therefore, DC energy dissipation devices are needed to consume the energy that the system cannot transmit normally, thereby stabilizing the DC voltage and assisting the system in completing fault ride-through.

[0003] Controllable high-power semiconductor switching devices are an important component of DC power consumption device research. Currently, DC power consumption device schemes mainly use integrated gate-commutated thyristors (IGCT) and insulated gate bipolar transistors (IGBT) as controllable switching devices.

[0004] There are two main technical approaches to DC power dissipation devices: centralized resistor power dissipation devices and distributed resistor power dissipation devices. Centralized power dissipation devices concentrate the power dissipation resistors on both sides of the electrode space and, in practical applications, are located outside the valve chamber; these resistors meet natural cooling requirements. Distributed power dissipation devices distribute the power dissipation resistors within various modules between the electrodes; these resistors require water cooling.

[0005] Existing technologies for DC power dissipation devices mainly focus on the power module circuit topology and control methods. Current DC power dissipation devices typically use half-bridge modules composed of IGBT devices as power dissipation valve sub-modules. However, the flexible chopper-type DC power dissipation device involved in this invention uses a novel topology with IGCT devices in direct series connection. Its operating principle, overvoltage process, and protection strategy differ from existing solutions. Therefore, most existing module overvoltage protection schemes are not applicable to flexible chopper-type DC power dissipation devices. Overvoltage protection schemes based on bypass switches rely on the bypass switch of the overvoltage module, which is independent of the DC power dissipation device topology and can be applied to flexible chopper-type DC power dissipation devices. However, the bypass switch cannot be turned off for a short time after being turned on, which reduces the utilization rate of all controllable devices and the flexibility of DC power dissipation device control. Summary of the Invention

[0006] This invention proposes a protection method and circuit for DC power consumption device modules based on fully controlled devices, which can effectively solve various overvoltage problems that the power modules in DC power consumption devices may encounter, thereby effectively improving the reliability of DC power consumption devices.

[0007] To address the above problems, the present invention adopts the following technical solution:

[0008] In the first aspect, a protection method for a DC power consumption device module based on fully controlled devices is provided, which is applicable to the first power module in a DC power consumption device, wherein the first power module is any one of a plurality of power modules connected in series in the DC power consumption device.

[0009] The method includes:

[0010] The voltage across the first power module was detected to be greater than the threshold voltage.

[0011] The overvoltage protection strategy is activated, which reduces the voltage across the first power module to less than or equal to the threshold voltage.

[0012] Optionally, the first power module includes a fully controlled device, and the overvoltage protection strategy includes: actively controlling the first power module to discharge by sending a conduction signal to the fully controlled device, protectively conducting the fully controlled device, and reducing the module voltage below the threshold voltage.

[0013] Based on the DC power consumption device module protection method based on fully controlled devices provided in the first aspect, when the voltage across any power module of the DC power consumption device is greater than the threshold voltage of the power module, an overvoltage protection strategy is activated to actively suppress the voltage of the module and quickly reduce the voltage across any power module to below the threshold voltage, so as to stabilize the voltage across the power module and avoid damage to the fully controlled devices.

[0014] Unlike existing solutions that directly trigger the overvoltage module bypass switch, this DC power consumption device module protection method based on fully controlled devices can achieve recoverable overvoltage protection by triggering the fully controlled devices. That is, the module can return to the off state after the overvoltage disappears, which can effectively improve the utilization rate of the power module and improve the reliability and flexibility of the overvoltage protection of the DC power consumption device.

[0015] Secondly, an active protection circuit for a DC power consumption device module based on fully controlled devices is provided. This circuit is applicable to the nth power module in an N-series power module of a DC power consumption device. The nth power module includes fully controlled devices. The anode of the fully controlled devices is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus. The cathode of the fully controlled devices is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus. 1≤n≤N.

[0016] The active protection circuit includes: a first inductor, a second inductor, a first diode, a second diode, a third diode, a first switch, a second switch, a first capacitor, a second capacitor, and a comparator; wherein,

[0017] One end of the first inductor is electrically connected to one end of the second inductor and the cathode of the third diode;

[0018] The other end of the first inductor is electrically connected to the anode of the first diode and one end of the first switch, and the other end of the second inductor is electrically connected to the anode of the second diode and one end of the second switch.

[0019] The cathodes of the first diode and the second diode are electrically connected to the gate of the fully controlled device.

[0020] One end of the first capacitor and the second capacitor are electrically connected to the anode of the third diode and the other end of the first switch and the second switch, and the other end of the first capacitor and the second capacitor are electrically connected to the cathode of the fully controlled device.

[0021] The control terminals of the first and second switches are electrically connected to the output terminal of the comparator. The comparator also includes a first input terminal and a second input terminal. The first input terminal of the comparator is used to receive the DC voltage across the nth power module, and the second input terminal of the comparator is used to receive the threshold voltage of the nth power module.

[0022] When the DC voltage across the nth power module is greater than the threshold voltage of the nth power module, the comparator outputs a control signal, which is used to control the first switch and the second switch to open sequentially.

[0023] Optionally, the active protection circuit further includes: a third switch; wherein,

[0024] One end of the third switch is electrically connected to the cathode of the fully controlled device, and the other end of the third switch is electrically connected to one end of the first inductor and the second inductor, as well as the cathode of the third diode; wherein,

[0025] Before the nth power module is powered on, the first switch is turned on, and the second and third switches are turned off.

[0026] After the nth power module is powered on, the first switch is turned off, and the second and third switches are turned on.

[0027] Based on the active protection circuit of the DC power consumption device module based on the fully controlled device provided in the second aspect, when the voltage across any power module of the DC power consumption device is greater than the threshold voltage of the power module, the comparator outputs a control signal to control the first switch and the second switch to open sequentially. In this way, the first inductor and the first diode (or the second inductor and the second diode), the gate and cathode of the fully controlled device, the first capacitor and the second capacitor, and the third diode form a circuit to charge the first capacitor and the second capacitor, so as to consume the energy stored in the first inductor or the second inductor. During this process, the voltage across the first inductor or the second inductor can be applied between the gate and cathode of the fully controlled device through the first diode or the second diode, forcibly triggering the fully controlled device to conduct, thereby achieving the effect of reducing the voltage across the power module.

[0028] This active protection circuit for DC power consumption device modules based on fully controlled devices can achieve overvoltage protection of the power module in the event of a fault in the triggered fiber or trigger, which can effectively improve the reliability of overvoltage protection for DC power consumption devices.

[0029] Furthermore, the active protection circuit for the DC energy-consuming device module based on fully controlled devices can also be implemented in conjunction with the DC energy-consuming device module protection method based on fully controlled devices proposed in this invention, serving as a backup protection for the power module. If, for some reason, the fully controlled device Tm of a power module fails to conduct according to the valve control command, and the DC energy-consuming device module protection method based on fully controlled devices fails, the active protection circuit can still force the power module to conduct, thereby achieving overvoltage protection for the power module and further improving the reliability of overvoltage protection for the DC energy-consuming device.

[0030] Thirdly, a passive protection circuit for a DC power consumption device module based on fully controlled devices is provided, which is applicable to the nth power module in N series-connected power modules in a DC power consumption device. The nth power module includes fully controlled devices, the anode of which is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus, and the cathode of which is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus, where 1≤n≤N;

[0031] The passive protection circuit includes: a first resistor, a second resistor, a third capacitor, a fourth diode, a fifth diode, a Zener diode, and a Zener diode; among which,

[0032] One end of the first resistor is electrically connected to the anode of the fully controlled device, and the other end of the first resistor is electrically connected to the anode of the fourth diode.

[0033] The cathode of the fourth diode is electrically connected to the anode of the Zener diode, and the cathode of the Zener diode is electrically connected to one end of the second resistor, one end of the third capacitor, and the cathode of the Zener diode.

[0034] The other end of the second resistor and the other end of the third capacitor are electrically connected to the cathode of the fully controlled device.

[0035] The anode of the Zener diode is electrically connected to the anode of the fifth diode, and the cathode of the fifth diode is electrically connected to the gate of the fully controlled device.

[0036] Based on the passive protection circuit of the DC power consumption device module based on the fully controlled device provided in the third aspect, when the voltage across any power module of the DC power consumption device is greater than the threshold voltage of the power module, as the voltage across the power module gradually increases, the Zener diode will conduct due to the avalanche effect and charge the third capacitor. When the voltage of the third capacitor rises to a value greater than or equal to the stable voltage value of the Zener diode, the Zener diode conducts. The voltage of the third capacitor will be applied between the gate and cathode of the fully controlled device through the Zener diode and the fifth diode, forcibly triggering the fully controlled device to conduct, thereby achieving the effect of reducing the voltage across the power module.

[0037] This passive protection circuit for the DC power consumption device module based on fully controlled components can provide overvoltage protection for the power module in the event of a drive unit failure, effectively improving the reliability of overvoltage protection for DC power consumption devices.

[0038] Furthermore, the passive protection circuit for the DC power consumption device module based on fully controlled devices can also be implemented in conjunction with the protection method for the DC power consumption device module based on fully controlled devices or the active protection circuit for the DC power consumption device module based on fully controlled devices proposed in this invention, as a backup protection method for the power module. If one or both of these protection schemes are implemented, and the power module fails to trigger the conduction function, causing the fully controlled device Tm of the power module to fail to conduct in time, the passive protection circuit can still force the fully controlled device to conduct, thereby achieving overvoltage protection for the power module and further improving the reliability of overvoltage protection for the DC power consumption device.

[0039] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of the DC power consumption device provided in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the power module provided in an embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the working scenario of the power module when all controllable devices are turned on, provided in an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram of the working scenario of the power module when all controllable devices are turned off, provided in an embodiment of the present invention.

[0045] Figure 5 A schematic diagram of a power module power supply failure provided in an embodiment of the present invention;

[0046] Figure 6 A flowchart illustrating the DC power consumption device module protection method based on fully controlled devices provided in an embodiment of the present invention;

[0047] Figure 7 A schematic diagram of the active protection circuit for a DC power consumption device module based on fully controlled devices provided in an embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of the passive protection circuit for a DC power consumption device module based on fully controlled devices, provided in an embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] First, combine Figure 1 This illustrates that the DC energy dissipation device provided in the embodiments of the present invention can consume the electrical energy that has been generated by the DC power generation system but cannot be transmitted to the AC power grid in scenarios such as AC power grid failure, thereby achieving the purpose of protecting the DC power generation system.

[0051] For example, Figure 1 This is a schematic diagram of the structure of a DC power consumption device provided in an embodiment of the present invention.

[0052] like Figure 1 As shown, power modules SM-1, SM-2, ..., SM-N are connected in series with R1, R2, L1 and L2 to form the main circuit of the DC power consumption device.

[0053] The fully controllable device Tm (taking IGCT as an example in this article) can accurately control the power module to turn on or off, thereby controlling the main circuit current to turn on and off. By adjusting the duty cycle, the turn-on time and turn-off time of the power module can be controlled, achieving the purpose of flexible control.

[0054] R1 and R2 are called centralized DC power dissipation resistors. Their main function is to convert electrical energy into heat energy for dissipation, thereby suppressing the rise of DC bus voltage.

[0055] Reactors L1 and L2 use large inductors, and their main function is to suppress the rate of change of current (di / dt) during the turn-on and turn-off processes of the fully controlled device Tm.

[0056] The absorption resistor Rs and the buffer capacitor Cs form an absorption circuit to absorb the energy generated during the process of turning off the fully controlled device Tm, thereby limiting the voltage Um across the fully controlled device Tm.

[0057] like Figure 2 As shown, the power module mainly includes: static equalizing resistor Rd, fully controlled device Tm, buffer capacitor Cs, absorption resistor Rs, and online power supply and buffer capacitor Cs.

[0058] Anti-parallel diode Dr: A diode with a junction capacitance that is the same as or similar to that of the fully controlled device Tm. Before the fully controlled device Tm is subjected to reverse voltage, the anti-parallel diode Dr conducts, thereby protecting the fully controlled device Tm.

[0059] Static equalizing resistor Rd: Its main function is to equalize the voltage across each power module when the centralized energy consumption device is disconnected, so as to avoid overvoltage and undervoltage in the DC energy consumption device and ensure the normal operation of the DC energy consumption device.

[0060] The main function of the fully controlled device Tm is to control the current flowing through the power module. The fully controlled device Tm operates at a certain frequency. By controlling the on-time and off-time of the current flowing through the fully controlled device Tm, the effective value of the current can be effectively adjusted.

[0061] The buffer capacitor Cs, the absorption resistor Rs, and the anti-parallel diode Df form the damping branch of the centralized resistive energy dissipation device. Its main function is to dynamically equalize the voltage during the frequent switching on of the power modules, thereby stabilizing the voltage of each power module.

[0062] Power extraction branch: Its main function is to supply power to the high potential board DM (also known as the drive unit) of the power module. The energy buffered once can support the operation of a single power module for more than a few seconds.

[0063] Power source: It mainly obtains energy from the buffer capacitor Cs to provide power to the drive unit.

[0064] High-potential driver board DM: namely the driver unit, which controls the on and off of the fully controlled device Tm. It controls the on or off of the fully controlled device Tm by controlling the energy change between the gate and cathode of the fully controlled device Tm.

[0065] Combination Figure 1 ,like Figure 3 As shown, Udc is the equivalent DC bus voltage, Uk is the voltage of the current-limiting reactor Lk (k = 1 or 2), Un is the voltage of the energy-consuming resistor Rn (n = 1 or 2), Um is the voltage across the power module, and T... m It is a fully controlled device, such as an IGCT. When the control power module is turned on, current flows through the energy-consuming branch, and at this time, the current mainly flows through the fully controlled device Tm. For example... Figure 4 As shown, when the control power module is turned off, the current cannot directly drop to zero. During the transient shutdown process, the current flows through the buffer capacitor Cs to charge it, thereby absorbing electrical energy and limiting the voltage across the power module. However, in the energy consumption state or hot standby state, due to certain unforeseen faults, such as... Figure 5 Power supply failures F1 and F2 in the drive unit may cause overvoltage failures in the power module of the DC power consumption device.

[0066] To address the overvoltage problem (Tm) of fully controlled devices, this invention provides a power module protection method.

[0067] Figure 6 The present invention provides a method for protecting a DC power consumption device module based on fully controlled devices, which can be applied to the first power module in the DC power consumption device. The first power module is any one of a plurality of power modules connected in series in the DC power consumption device, such as any one of SM-1 to SM-N, where N is the number of power modules connected in series in the DC power consumption device.

[0068] Combination Figure 5 ,like Figure 6 As shown, the method includes:

[0069] S601, the voltage Um across the first power module is detected to be greater than the threshold voltage U. E That is, Um>U E .

[0070] S602, activate the overvoltage protection strategy.

[0071] The overvoltage protection strategy is used to reduce the voltage Um across the first power module to less than or equal to the threshold voltage U. E .

[0072] Optionally, the first power module includes a fully controlled device Tm, and the overvoltage protection strategy includes: actively controlling the first power module to discharge by sending a conduction signal to the fully controlled device, actively turning on the fully controlled device, suppressing the module voltage, and reducing the power module voltage below the threshold voltage.

[0073] When any power module experiences overvoltage, i.e., Um > U E When the overvoltage protection strategy is activated, the valve control device will actively send a conduction signal to the power module experiencing overvoltage, controlling all controllable devices within the power module to conduct and quickly reduce the voltage U across the power module. m Reduced to threshold voltage U E The following measures are taken to control the voltage across the power module and prevent damage to all control components.

[0074] Unlike existing solutions that directly trigger the overvoltage module bypass switch, this DC power consumption device module protection method based on fully controlled devices can achieve recoverable overvoltage protection by triggering the fully controlled devices. That is, the module can return to the off state after the overvoltage disappears, which can effectively improve the utilization rate of the power module and improve the reliability and flexibility of the overvoltage protection of the DC power consumption device.

[0075] If the triggering system inside the power module is working properly, but the triggering fiber or trigger of some power modules is faulty, the power module may not be able to trigger and conduct in time when an overvoltage fault occurs. This will result in excessively high voltage across the power module, which may cause the fully controlled device Tm in the power module to break down.

[0076] To address the overvoltage problem of the fully controlled device Tm when the trigger fiber or trigger of the power module fails, this invention provides an active protection circuit for the power module.

[0077] Figure 7 An active protection circuit for a DC power consumption device module based on a fully controlled device is provided in this embodiment of the invention. It is applicable to the nth power module in the N series-connected power modules of the above-mentioned DC power consumption device. The nth power module includes a fully controlled device Tm. The anode of the fully controlled device Tm is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus. The cathode of the fully controlled device Tm is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus. 1≤n≤N;

[0078] Combination Figure 5 ,like Figure 7 As shown, the active protection circuit includes: a first inductor L3, a second inductor L4, a first diode D1, a second diode D2, a third diode D3, a first switch Q1, a second switch Q2, a first capacitor C1, a second capacitor C2, and a comparator; wherein,

[0079] One end of the first inductor L3 is electrically connected to one end of the second inductor L4 and the cathode of the third diode D3;

[0080] The other end of the first inductor L3 is electrically connected to the anode of the first diode D1 and one end of the first switch Q1, and the other end of the second inductor L4 is electrically connected to the anode of the second diode D2 and one end of the second switch Q2.

[0081] The cathodes of the first diode D1 and the second diode D2 are electrically connected to the gate of the fully controlled device Tm.

[0082] One end of the first capacitor C1 and the second capacitor C2 are electrically connected to the anode of the third diode D3 and the other end of the first switch Q1 and the second switch Q2. The other end of the first capacitor C1 and the second capacitor C2 are electrically connected to the cathode of the fully controlled device Tm.

[0083] The control terminals of the first switch Q1 and the second switch Q2 are electrically connected to the output terminal of the comparator. The comparator also includes a first input terminal and a second input terminal. The first input terminal of the comparator is used to receive the DC voltage across the nth power module, and the second input terminal of the comparator is used to receive the threshold voltage U of the nth power module. E ;

[0084] Among them, when the DC voltage across the nth power module is greater than the threshold voltage U of the nth power module E When the comparator outputs a control signal, the control signal is used to control the first switch Q1 and the second switch Q2 to open sequentially.

[0085] Optionally, the active protection circuit further includes: a third switch Q3; wherein,

[0086] One end of the third switch Q3 is electrically connected to the cathode of the fully controlled device Tm, and the other end of the third switch Q3 is electrically connected to one end of the first inductor L3 and the second inductor L4, as well as the cathode of the third diode D3; wherein,

[0087] Before the nth power module is powered on, the first switch Q1 is turned on, and the second switch Q2 and the third switch Q3 are turned off.

[0088] After the nth power module is powered on, the first switch Q1 is turned off, and the second switch Q2 and the third switch Q3 are turned on.

[0089] Please continue to refer to this. Figure 7 When the drive unit DM is not powered on, the third switch Q3 is closed, and the first capacitor C1 and the second capacitor C2 are short-circuited. At this time, the gate-cathode of the fully controlled device Tm is short-circuited, and the fully controlled device Tm is in a protected state.

[0090] After the drive unit is powered on, the third switch Q3 is turned off, and the first switch Q1 and the second switch Q2 are turned on, so the power module works normally.

[0091] When an overvoltage is detected in the power module, such as due to a fault in the trigger fiber or trigger, the voltage Um across the power module (applied across the fully controlled device Tm) is input to the comparator and the threshold voltage U. E When comparing, when the power module voltage Um > U E When this happens, Q1 and Q2 are disconnected in sequence, forcibly triggering the conduction of the fully controlled device Tm, thereby achieving the purpose of reducing the voltage across the power module.

[0092] Based on the active protection circuit of this power module, when the voltage Um across any power module of the DC power consumption device is greater than the threshold voltage U of that power module... E When the comparator outputs a control signal, it controls the first switch Q1 and the second switch Q2 to open sequentially. In this way, the first inductor L3 and the first diode D1 (or the second inductor L4 and the second diode D2), the gate and cathode of the fully controlled device Tm, the first capacitor C1 and the second capacitor C2, and the third diode D3 form a circuit, which charges the first capacitor C1 and the second capacitor C2 to consume the energy stored in the first inductor L3 or the second inductor L4. During this process, the voltage across the first inductor L3 or the second inductor L4 can be applied between the gate and cathode of the fully controlled device Tm through the first diode D1 or the second diode D2, forcibly triggering the fully controlled device Tm to conduct, thereby achieving the purpose of reducing the voltage across the power module.

[0093] This active protection circuit for DC power consumption device modules based on fully controlled devices can achieve overvoltage protection of the power module in the event of a fault in the triggered fiber or trigger, which can effectively improve the reliability of overvoltage protection for DC power consumption devices.

[0094] Furthermore, the active protection circuit for the DC energy-consuming device module based on fully controlled devices can also be implemented in conjunction with the DC energy-consuming device module protection method based on fully controlled devices proposed in this invention, serving as a backup protection for the power module. If, for some reason, the fully controlled device Tm of a power module fails to conduct according to the valve control command, and the DC energy-consuming device module protection method based on fully controlled devices fails, the active protection circuit can still force the power module to conduct, thereby achieving overvoltage protection for the power module and further improving the reliability of overvoltage protection for the DC energy-consuming device.

[0095] When the power module drive unit DM fails, the power module cannot be triggered and turned on normally. If an overvoltage occurs in the power module at this time, without protective measures, the fully controlled device Tm in the power module will be damaged due to the overvoltage breakdown. Common causes of power module triggering and conduction failure in DC power consumption devices include: a fault in the drive unit DM itself, a fault in the power supply, or the drive unit DM lacking a triggering function.

[0096] To address the issue of overvoltage breakdown of the fully controlled device Tm when the power module trigger function fails, this invention provides a passive protection circuit.

[0097] Figure 8 This invention provides a passive protection circuit for a DC power consumption device module based on a fully controlled device. It is applicable to the nth power module in an N-series power module of a DC power consumption device. The nth power module includes a fully controlled device Tm. The anode of the fully controlled device Tm is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus. The cathode of the fully controlled device Tm is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus. 1≤n≤N.

[0098] Combination Figure 5 ,like Figure 8 As shown, the passive protection circuit includes: a first resistor R3, a second resistor R4, a third capacitor C3, a fourth diode D4, a fifth diode D5, a Zener diode TVS, and a Zener diode ZD; wherein,

[0099] One end of the first resistor R3 is connected to the anode of the fully controlled device Tm, and the other end of the first resistor R3 is connected to the anode of the fourth diode D4.

[0100] The cathode of the fourth diode D4 is electrically connected to the anode of the Zener diode ZD. The cathode of the Zener diode ZD is electrically connected to one end of the second resistor R4, one end of the third capacitor C3, and the cathode of the Zener diode TVS.

[0101] The other end of the second resistor R4 and the other end of the third capacitor C3 are electrically connected to the cathode of the fully controlled device Tm.

[0102] The anode of the Zener diode TVS is electrically connected to the anode of the fifth diode D5, and the cathode of the fifth diode D5 is electrically connected to the gate of the fully controlled device Tm.

[0103] Please continue to refer to this. Figure 8The passive protection circuit mainly utilizes the avalanche effect of the Zener diode (ZD). When the voltage Um across the fully controlled device Tm gradually increases, the anode-cathode voltage U of the Zener diode ZD exceeds Uz (Zener diode avalanche voltage), causing the Zener diode ZD to conduct and charge the third capacitor C3 in the protection branch. The voltage of the third capacitor C3 gradually increases. When the voltage of the third capacitor C3 rises to a value greater than the stable voltage of the Zener diode TVS, a path is formed between the third capacitor C3, the Zener diode TVS, the fifth diode D5, and the gate and cathode of the fully controlled device Tm. The third capacitor C3 injects current into the gate-cathode of the fully controlled device Tm, causing the anode-cathode of the fully controlled device Tm to conduct. The voltage Um across the power module decreases, thereby avoiding the risk of overvoltage in the fully controlled device Tm.

[0104] Based on the passive protection circuit of this power module, when the voltage Um across any power module of the DC power consumption device exceeds the threshold voltage U of that power module... E As the voltage Um across the power module gradually increases, the Zener diode ZD will conduct due to the avalanche effect and charge the third capacitor C3. When the voltage of the third capacitor C3 rises to a value greater than or equal to the stable voltage of the Zener diode TVS, the Zener diode TVS will conduct. The voltage of the third capacitor C3 will be applied between the gate and cathode of the fully controlled device Tm through the Zener diode TVS and the fifth diode D5, forcibly triggering the fully controlled device Tm to conduct, thereby achieving the purpose of reducing the voltage across the power module.

[0105] This passive protection circuit for the DC power consumption device module based on fully controlled components can provide overvoltage protection for the power module in the event of a drive unit failure, effectively improving the reliability of overvoltage protection for DC power consumption devices.

[0106] Furthermore, the passive protection circuit for the DC power consumption device module based on fully controlled devices can also be implemented in conjunction with the protection method for the DC power consumption device module based on fully controlled devices or the active protection circuit for the DC power consumption device module based on fully controlled devices proposed in this invention, as a backup protection method for the power module. If one or both of these protection schemes are implemented, and the power module fails to trigger the conduction function, causing the fully controlled device Tm of the power module to fail to conduct in time, the passive protection circuit can still force the fully controlled device to conduct, thereby achieving overvoltage protection for the power module and further improving the reliability of overvoltage protection for the DC power consumption device.

[0107] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A protection method for a DC power consumption device module based on fully controlled devices, characterized in that, The first power module is applicable to a DC power consumption device, wherein the first power module is any one of a plurality of power modules connected in series in the DC power consumption device; The method includes: The voltage across the first power module was detected to be greater than the threshold voltage. An overvoltage protection strategy is activated, which reduces the voltage across the first power module to less than or equal to the threshold voltage.

2. The DC power consumption device module protection method based on fully controlled devices according to claim 1, characterized in that, The first power module includes a fully controlled device, and the overvoltage protection strategy includes: actively controlling the first power module to discharge by sending a conduction signal to the fully controlled device.

3. An active protection circuit for a DC power consumption device module based on fully controlled components, characterized in that, The method is applicable to the nth power module in an N series-connected power module of a DC power consumption device. The nth power module includes a fully controlled device. The anode of the fully controlled device is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus. The cathode of the fully controlled device is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus. 1≤n≤N. The active protection circuit includes: a first inductor, a second inductor, a first diode, a second diode, a third diode, a first switch, a second switch, a first capacitor, a second capacitor, and a comparator; wherein, One end of the first inductor is electrically connected to one end of the second inductor and the cathode of the third diode; The other end of the first inductor is electrically connected to the anode of the first diode and one end of the first switch, and the other end of the second inductor is electrically connected to the anode of the second diode and one end of the second switch; The cathodes of the first diode and the second diode are electrically connected to the gate of the fully controlled device; One end of the first capacitor and the second capacitor are electrically connected to the anode of the third diode and the other end of the first switch and the second switch, and the other end of the first capacitor and the second capacitor are electrically connected to the cathode of the fully controlled device. The control terminals of the first switch and the second switch are electrically connected to the output terminal of the comparator. The comparator also includes a first input terminal and a second input terminal. The first input terminal of the comparator is used to receive the DC voltage across the nth power module, and the second input terminal of the comparator is used to receive the threshold voltage of the nth power module. When the DC voltage across the nth power module is greater than the threshold voltage of the nth power module, the comparator outputs a control signal, which is used to control the first switch and the second switch to open sequentially.

4. The active protection circuit for the DC power consumption device module based on fully controlled devices according to claim 3, characterized in that, The active protection circuit further includes: a third switch; wherein, One end of the third switch is electrically connected to the cathode of the fully controlled device, and the other end of the third switch is electrically connected to one end of the first inductor and the second inductor, as well as the cathode of the third diode; wherein, Before the nth power module is powered on, the first switch is turned on, and the second and third switches are turned off. After the nth power module is powered on, the first switch is turned off, and the second and third switches are turned on.

5. A passive protection circuit for a DC power consumption device module based on fully controlled components, characterized in that, The method is applicable to the nth power module in an N series-connected power module of a DC power consumption device. The nth power module includes a fully controlled device. The anode of the fully controlled device is electrically connected to the negative terminal of the (n-1)th power module or the positive terminal of the DC bus. The cathode of the fully controlled device is electrically connected to the positive terminal of the (n+1)th power module or the negative terminal of the DC bus. 1≤n≤N. The passive protection circuit includes: a first resistor, a second resistor, a third capacitor, a fourth diode, a fifth diode, a Zener diode, and a Zener diode; wherein, One end of the first resistor is electrically connected to the anode of the fully controlled device, and the other end of the first resistor is electrically connected to the anode of the fourth diode; The cathode of the fourth diode is electrically connected to the anode of the Zener diode, and the cathode of the Zener diode is electrically connected to one end of the second resistor, one end of the third capacitor, and the cathode of the Zener diode. The other end of the second resistor and the other end of the third capacitor are electrically connected to the cathode of the fully controlled device; The anode of the Zener diode is electrically connected to the anode of the fifth diode, and the cathode of the fifth diode is electrically connected to the gate of the fully controlled device.

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