A high-voltage-resistant electronic switch for energy storage and a control method thereof

Abstract

The application discloses a kind of high voltage-resistance electronic switches for energy storage and control method thereof, belong to new energy power system energy storage technical field, including multistage switching unit, the switching unit includes at least two levels, first stage switching unit at least includes one high voltage-resistance switching device, the voltage resistance of high voltage-resistance switching device is not less than the total voltage of the battery;Second stage switching unit at least includes two low voltage-resistance switching devices in series, and the voltage resistance of each low voltage-resistance switching device is not less than half of total voltage;First stage switching unit is connected in parallel with second stage switching unit;Control circuit is used to receive external control signal, and the conduction and shutdown of first stage switching unit and second stage switching unit are triggered according to external control signal.The application solves the problem of short service life and high cost of traditional energy storage high-voltage direct current switch;Solve the problem of complex heat dissipation when using IGBT as direct current electronic switch;Solve the problem of easy damage to circuit when using MOSFET in series as direct current electronic switch.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology for new energy power systems, and in particular to a high-voltage electronic switch for energy storage and its control method. Background Technology

[0002] In large-capacity energy storage, a battery series architecture is used, and a DC high-voltage switch is usually added to each string to control the connection and disconnection of that string.

[0003] The following disadvantages exist in the use of high voltage DC switches: (1) Traditional high voltage DC switches are mechanical devices with limited mechanical life. After closing and opening, there will be sparks at the contact points, or a separate gas arc extinguishing device needs to be configured, which is also very expensive; (2) Using IGBTs as electronic switches results in high power consumption during conduction, requiring a dedicated heat dissipation device, which is also very expensive and results in large energy loss; (3) Using MOS as electronic switches makes it difficult to achieve high withstand voltage; (4) If multi-stage MOS is used in series for voltage division, the MOS switches cannot truly achieve synchronous opening or closing at the moment of opening and closing due to the discrete nature of the devices. The MOS that is turned on or off last will be damaged by high voltage. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a high-voltage electronic switch for energy storage and its control method. This switch can replace traditional mechanical or electronic switches, reduce costs, improve system efficiency, and ensure circuit safety and reliability.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] In a first aspect, the present invention provides a high-voltage electronic switch for energy storage, wherein the primary side of the electronic switch is connected between a battery and a load / power source, comprising:

[0007] A multi-stage switching unit, wherein the multi-stage switching unit comprises at least two stages, wherein:

[0008] The first-stage switching unit includes at least one high-voltage switching device, wherein the voltage withstand capability of the high-voltage switching device is not lower than the total voltage of the battery;

[0009] The second-stage switching unit includes at least two low-voltage switching devices connected in series, and the withstand voltage of each low-voltage switching device is not less than half of the total voltage.

[0010] The first-stage switching unit and the second-stage switching unit are connected in parallel.

[0011] The control circuit is used to receive external control signals and trigger the first-stage switching unit and the second-stage switching unit to turn on and off according to the external control signals.

[0012] Furthermore, the switching device is a hybrid structure of IGBT and MOSFET, wherein the high-voltage stage uses IGBT and the low-voltage stage uses MOSFET.

[0013] Furthermore, the multi-stage switching unit comprises four stages, as follows:

[0014] The first-stage switching unit includes an IGBT with a withstand voltage equal to the total battery voltage.

[0015] The second-stage switching unit includes two IGBTs, each with a withstand voltage of 1 / 2 of the total battery voltage;

[0016] The third-stage switching unit includes four MOSFETs, each with a voltage rating of 1 / 4 of the total battery voltage;

[0017] The fourth-stage switching unit includes eight MOSFETs, each with a voltage rating of 1 / 8 of the total battery voltage.

[0018] Furthermore, the control circuit includes a voltage comparison module and a drive module. The voltage comparison module is triggered according to the voltage value of the external control signal, and the voltage comparison module sends the comparison result to the drive module to control the conduction or cutoff of the corresponding stage switching device.

[0019] Furthermore, the control circuit also includes a power isolation module for providing isolated power supply to the drive circuits of each level of switching devices.

[0020] Furthermore, the voltage comparison module includes a voltage comparator.

[0021] Furthermore, the external control signal is a ramp voltage signal ranging from 0V to 12V.

[0022] Furthermore, the rising edge of the ramp voltage signal is used to turn on the switching device step by step, and the falling edge of the ramp voltage signal is used to turn off the switching device step by step.

[0023] Secondly, the present invention also provides a control method for a high-voltage withstand electronic switch for energy storage, applied to the aforementioned high-voltage withstand electronic switch for energy storage, comprising the following steps:

[0024] Receive an external control signal, wherein the external control signal is a ramp voltage signal;

[0025] Based on the voltage change of the ramp voltage signal, the switching devices of multiple stages are sequentially triggered to turn on or off.

[0026] During conduction, the current gradually shifts from the high-voltage stage to the low-impedance stage;

[0027] During the turn-off process, the current gradually shifts from the low impedance stage to the high withstand voltage stage.

[0028] In summary, compared with the prior art, the beneficial effects of the above technical solution are:

[0029] (1) During the conduction process, the current gradually changes from the first-stage switching unit to the fourth-stage switching unit. The circuit makes full use of the high withstand voltage of the first-stage switching unit and the low impedance characteristics of the fourth-stage switching unit to achieve high withstand voltage and low impedance. That is, at the beginning of conduction, the first-stage switching unit bears the high voltage. When gradually transitioning to the fourth-stage switching unit, the first-stage switching unit has a short time and basically does not heat up. During the gradual transition to the fourth-stage switching unit, the voltage drop across the two ends is always very low. The sequence of opening and closing is inconsistent and will not cause the circuit to burn out.

[0030] (2) This invention solves the problems of short lifespan and high cost of traditional high voltage DC switches for energy storage; solves the problem of complex heat dissipation when using IGBTs as DC electronic switches; and solves the problem of easy circuit damage when using MOS series as DC electronic switches. Attached Figure Description

[0031] Figure 1 A simplified diagram showing the connection of a high-voltage electronic switch;

[0032] Figure 2 This is a diagram of the external interface of a high-voltage electronic switch.

[0033] Figure 3 This is the internal primary circuit diagram of a high-voltage electronic switch;

[0034] Figure 4 This is the control diagram of each switching element inside a high-voltage electronic switch, i.e., the drive control unit;

[0035] Figure 5 For external control signals;

[0036] Figure 6 This is a primary circuit diagram;

[0037] Figure 7 These are the drive control units for the corresponding first-level and second-level switching devices, with the upper part being the drive control unit for the first-level switching device and the lower part being the drive control unit for the second-level switching device.

[0038] Figure 8 It serves as the drive control unit for the third-level switching device;

[0039] Figure 9 This is the drive control unit for the corresponding fourth-level switching devices;

[0040] Figure 10This is the drive control unit for another part of the switching devices in the corresponding fourth stage.

[0041] Explanation of the reference numerals in the attached diagram: 1. Signal control line; 2. Auxiliary power supply line. Detailed Implementation

[0042] The principles and features of the present invention are described below with reference to all the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0043] This invention discloses a high-voltage electronic switch for energy storage and its control method.

[0044] In a first aspect, embodiments of the present invention disclose a high-voltage electronic switch for energy storage.

[0045] Reference Figures 1-10 This is a high-voltage electronic switch for energy storage. Its primary side is connected between the battery and the load / power source. The electronic switch also has a signal input port and an auxiliary power supply port. The power source includes various types such as PCS and DC-DC converters. Typically, the high-voltage electronic switch is connected between the PCS and the energy storage battery, acting as a high-voltage DC switch. Taking 12V as an example, when the external control signal changes from 0V to 12V, the electronic switch turns on; when it changes from 12V to 0V, the electronic switch turns off.

[0046] The electronic switch internally comprises multiple switching units, with at least two levels. The first-level switching unit includes at least one high-voltage switching device, whose withstand voltage is not less than the total voltage of the battery. The second-level switching unit includes at least two low-voltage switching devices connected in series, each with a withstand voltage not less than half the total voltage of the battery. The first-level and second-level switching units are connected in parallel. The electronic switch also includes peripheral circuitry, i.e., a control circuit, for receiving external control signals and triggering the first-level and second-level switching units to turn on and off based on the external control signals.

[0047] In this embodiment, the switching devices include IGBT (Insulated Gate Bipolar Transistor) and MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). IGBT is a high-voltage switching device, and MOSFET is a low-voltage switching device.

[0048] Specifically, the multi-level switching unit in this embodiment includes four-level switching units, namely:

[0049] The first-stage switching unit includes an IGBT with a withstand voltage equal to the total battery voltage.

[0050] The second-stage switching unit includes two IGBTs connected in series, and each IGBT has a withstand voltage of 1 / 2 of the total battery voltage.

[0051] The third-stage switching unit includes four MOSFETs connected in series, each with a withstand voltage of 1 / 4 of the total battery voltage;

[0052] The fourth-stage switching unit includes eight MOSFETs connected in series, with each MOSFET having a voltage rating of 1 / 8 of the total battery voltage.

[0053] The control circuit includes a voltage comparison module and a drive module. The voltage comparison module is triggered by the voltage value of the external control signal, and the voltage comparison module sends the comparison result to the drive module to control the on or off of the corresponding switching device.

[0054] The control circuit also includes a power isolation module, which provides isolated power to the drive circuits of each level of switching devices.

[0055] It should be noted that each IGBT or MOSFET contains a corresponding control circuit, such as... Figure 4 As shown, the voltage comparison module and Figure 2 The signal control lines of the medium and high voltage electronic switches are connected, and the power isolation module is connected to... Figure 2 The auxiliary power supply line of the medium and high voltage electronic switch is connected, and the drive module (drive circuit) is connected to the base of the corresponding IGBT or the gate of the corresponding MOSFET.

[0056] In this embodiment, the voltage comparison module includes a voltage comparator located within the internal circuit of each switching device. The comparison result of the voltage comparator is sent to the drive circuit to control the corresponding stage of the switching device to turn on or off. Each voltage comparator corresponds to a single-stage switching device and is used to trigger the corresponding stage to turn on or off based on the voltage value of the external control signal. The trigger threshold of the voltage comparator is set by voltage division based on the total voltage of the external control signal and the total number of stages.

[0057] The external control signal is a ramp voltage signal from 0V to 12V. The rising edge of the ramp voltage signal is used to turn on the switching device step by step, and the falling edge of the ramp voltage signal is used to turn off the switching device step by step.

[0058] During the conduction process, the current gradually changes from the first-stage switching unit to the fourth-stage switching unit. The circuit makes full use of the high withstand voltage of the first-stage switching unit and the low impedance of the fourth-stage switching unit to achieve high withstand voltage and low impedance. That is, at the beginning of conduction, the first-stage switching unit bears the high voltage. When gradually transitioning to the fourth-stage switching unit, the first-stage switching unit has a short time and basically does not heat up. During the gradual transition to the fourth stage, the voltage drop across the two ends is always very low. The sequence of turning on and off is not consistent, and it will not cause the circuit to burn out.

[0059] The above solution will be further illustrated with specific examples below:

[0060] like Figure 1 As shown, a high-voltage electronic switch connects the battery and the load.

[0061] like Figure 2 As shown, both sides of the high-voltage electronic switch are primary sides, connected to... Figure 1 It contains the battery and load, and also has a signal input port and an auxiliary power supply port.

[0062] like Figure 3 As shown, the high-voltage electronic switch is internally composed of multiple IGBTs and MOSFETs, such as... Figure 3 In the first stage, there is one IGBT, which bears the load. Figure 1 The first stage consists of the total voltage of the battery; the second stage consists of 2 IGBTs, each with a voltage rating of 1 / 2 of the total voltage; the third stage consists of 4 MOSFETs, each with a voltage rating of 1 / 4 of the total voltage; and the fourth stage consists of 8 MOSFETs, each with a voltage rating of 1 / 8 of the total voltage.

[0063] like Figure 4 As shown, each IGBT and MOSFET has an external circuit, namely a control circuit, which includes a power isolation module, a voltage comparison module, and a drive module.

[0064] like Figure 5 As shown, a typical external signal input port is applied to the peripheral circuitry of the IGBT and MOSFET to control the switching devices to turn on and off.

[0065] like Figure 6 The diagram shown is a primary circuit diagram, illustrating the entire high-voltage, high-current path from the positive terminal of the battery through the series-connected IGBTs and MOSFETs, to the load / PCS / DCDC.

[0066] Figures 7-10All of these are secondary circuits (control circuits, drive circuits), specifically used to receive external "0-12V ramp signals" (this embodiment only uses 12V as a typical voltage example, but other voltages are also possible), and through isolation, comparison, and driving processes, ultimately precisely control the gate / base of each IGBT or MOSFET. Specifically: Figure 7 This refers to the drive control unit for the corresponding first-stage and second-stage switching devices, with the upper part being the drive control unit for the first-stage switching device and the lower part being the drive control unit for the second-stage switching device. Figure 8 This is the drive control unit for the third-level switching device. Figure 9 and Figure 10 All of them are drive control units for fourth-level switching devices.

[0067] External control signals pass through the internal circuitry of each switching device and enter the voltage comparator. When the external control signal changes from 0V to 12V (taking 12V as an example), due to the slope of this signal (i.e., a ramp voltage signal), when the signal changes from 0V to 1*12V / 4 (where 12 represents the control signal, 1 represents the first stage, and 4 represents a total of 4 stages), the voltage comparator in the internal circuitry of the IGBT in the first-stage switching unit is triggered. The voltage comparator outputs the result to the driver module, and the IGBT in the first-stage switching unit turns on first, applying battery voltage to the load. Figure 3 The voltage drop across the IGBT in the first-stage switching unit becomes the IGBT's on-state voltage drop. At this time, the current flowing from the battery to the load is all superimposed on the IGBT.

[0068] As the external control signal continues to increase, from 1*12V / 4 to 2*12V / 4, it triggers the voltage comparator in the internal circuit of the IGBT in the second-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the two IGBTs in the second-stage switching unit are turned on. At this time, since the withstand voltage of the IGBT is half that of the IGBT in the first-stage switching unit, the sum of the on-state voltage drops of the two IGBTs will be lower than that of the IGBT in the first-stage switching unit. At this time, most of the current flowing from the current to the load is superimposed on the IGBT in the second-stage switching unit.

[0069] As the external control signal continues to increase, changing from 2*12V / 4 to 3*12V / 4, it triggers the voltage comparator in the internal circuit of the MOSFET of the third-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the four MOSFETs of the third-stage switching unit are turned on. At this time, since the withstand voltage of the MOSFET is half that of the IGBT of the second-stage switching unit, the sum of the on-state voltage drop of the four MOSFETs will be lower than that of the IGBT of the second-stage switching unit. At this time, most of the current flowing from the current to the load is superimposed on the MOSFET of the third-stage switching unit.

[0070] As the external control signal continues to increase, changing from 3*12V / 4 to 4*12V / 4, it triggers the voltage comparator in the internal circuit of the MOSFET of the third-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the four MOSFETs of the third-stage switching unit are turned on. At this time, since the withstand voltage of the MOSFET of the fourth-stage switching unit is half that of the MOSFET of the third-stage switching unit, the sum of the on-state voltage drops of the eight MOSFETs will be lower than that of the MOSFET of the third-stage switching unit. At this time, most of the current flowing from the current to the load is superimposed on the MOSFET of the fourth-stage switching unit.

[0071] When the external control signal decreases from 4*12V / 4 to 3*12V / 4, it triggers the voltage comparator in the internal circuit of the MOSFET of the fourth-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the eight MOSFETs of the fourth-stage switching unit are turned off. At this time, most of the current flowing through the eight MOSFETs becomes flowing through the four MOSFETs of the third-stage switching unit.

[0072] When the external control signal continues to decrease, from 3*12V / 4 to 2*12V / 4, it triggers the voltage comparator in the internal circuit of the MOSFET of the third-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the four MOSFETs of the third-stage switching unit are turned off. At this time, most of the current flowing through the four MOSFETs of the third-stage switching unit becomes the current flowing through the two IGBTs of the second-stage switching unit.

[0073] When the external control signal continues to decrease, from 2*12V / 4 to 1*12V / 4, it triggers the voltage comparator in the internal circuit of the IGBT of the second-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the two IGBTs of the second-stage switching unit are turned off. At this time, most of the current flowing through the two IGBTs of the second-stage switching unit becomes flowing through the IGBT of the first-stage switching unit.

[0074] When the external control signal continues to decrease, changing from 1*12V / 4 to 0V, it triggers the voltage comparator in the internal circuit of the IGBT of the first-stage switching unit. The comparison result of the voltage comparator is sent to the drive module, and the IGBT of the first-stage switching unit is turned off. At this time, the circuit is turned off.

[0075] Secondly, based on the same inventive concept, embodiments of the present invention also disclose a control method for a high-voltage electronic switch for energy storage, comprising the following steps:

[0076] Receive an external control signal, wherein the external control signal is a ramp voltage signal;

[0077] Based on the voltage change of the ramp voltage signal, the switching devices of multiple stages are sequentially triggered to turn on or off.

[0078] During conduction, the current gradually shifts from the high-voltage stage to the low-impedance stage;

[0079] During the turn-off process, the current gradually shifts from the low impedance stage to the high withstand voltage stage.

[0080] In practical applications, while a single power electronic device can withstand high voltage, it cannot withstand large currents for extended periods. Conversely, a low-voltage MOSFET, while unable to withstand high voltage, can withstand large currents for extended periods. By leveraging the advantages of both, and sequentially switching them on and off, a high-voltage electronic switch can be implemented. High-voltage electronic switches can significantly improve the stability and safety of energy storage systems. Through multi-stage switching design, the system can flexibly adjust the current path according to actual needs, thereby preventing a single device from being subjected to high voltage or large current for extended periods, effectively extending the overall circuit's lifespan.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-voltage withstand electronic switch for energy storage, characterized in that, The primary side of the electronic switch is connected between the battery and the load / power source, including: A multi-stage switching unit, wherein the multi-stage switching unit comprises at least two stages, wherein: The first-stage switching unit includes at least one high-voltage switching device, wherein the voltage withstand capability of the high-voltage switching device is not lower than the total voltage of the battery; The second-stage switching unit includes at least two low-voltage switching devices connected in series, and the withstand voltage of each low-voltage switching device is not less than half of the total voltage of the battery; The first-stage switching unit and the second-stage switching unit are connected in parallel. The switching device is a hybrid structure of IGBT and MOSFET, wherein the high-voltage stage uses IGBT and the low-voltage stage uses MOSFET; The multi-stage switching unit comprises four stages, as follows: The first-stage switching unit includes an IGBT with a withstand voltage equal to the total battery voltage. The second-stage switching unit includes two IGBTs, each with a withstand voltage of 1 / 2 of the total battery voltage; The third-stage switching unit includes four MOSFETs, each with a voltage rating of 1 / 4 of the total battery voltage; The fourth-stage switching unit includes eight MOSFETs, each with a voltage rating of 1 / 8 of the total battery voltage; The control circuit is used to receive external control signals and trigger the first-stage switching unit and the second-stage switching unit to turn on and off according to the external control signals.

2. The high-voltage withstand electronic switch for energy storage according to claim 1, characterized in that, The control circuit includes a voltage comparison module and a drive module. The voltage comparison module is triggered according to the voltage value of the external control signal. The voltage comparison module sends the comparison result to the drive module to control the on or off of the corresponding switching device.

3. A high-voltage withstand electronic switch for energy storage according to claim 2, characterized in that, The control circuit also includes a power isolation module for providing isolated power to the drive circuits of each level of switching devices.

4. A high-voltage withstand electronic switch for energy storage according to claim 3, characterized in that, The voltage comparison module includes a voltage comparator.

5. A high-voltage withstand electronic switch for energy storage according to claim 1, characterized in that, The external control signal is a ramp voltage signal ranging from 0V to 12V.

6. A high-voltage withstand electronic switch for energy storage according to claim 5, characterized in that, The rising edge of the ramp voltage signal is used to turn on the switching device step by step, and the falling edge of the ramp voltage signal is used to turn off the switching device step by step.

7. A control method for a high-voltage withstand electronic switch for energy storage, characterized in that, An application of a high-voltage withstand electronic switch for energy storage as described in any one of claims 1-6 includes the following steps: Receive an external control signal, wherein the external control signal is a ramp voltage signal; Based on the voltage change of the ramp voltage signal, the switching devices of multiple stages are sequentially triggered to turn on or off. During conduction, the current gradually shifts from the high-voltage stage to the low-impedance stage; During the turn-off process, the current gradually shifts from the low impedance stage to the high withstand voltage stage.

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