Insulation detection method, circuit, energy storage system and electrical equipment for energy storage converter

Abstract

The present application relates to the field of energy storage technology and provides an insulation detection method, circuit, energy storage system, and electrical equipment for an energy storage converter. The method includes: controlling a control interface of a controller to output a target level; obtaining a first test voltage of the positive bus and a second test voltage of the negative bus after a first preset time; obtaining a third test voltage of the positive bus and a fourth test voltage of the negative bus after a second preset time; determining whether the energy storage system has an insulation abnormality based on the first test voltage, the second test voltage, the third test voltage, and the fourth test voltage; wherein the first preset time is a preset voltage stabilization delay time, and the second preset time is the sum of the delay time of the first delay circuit and the preset voltage stabilization delay time. The method can at least reduce the use of pins of the PCS controller while ensuring stable impedance detection of the energy storage converter.

Description

Technical Field

[0001] The present application relates to the field of energy storage technology, and in particular to an insulation detection method, circuit, energy storage system and electrical equipment for an energy storage converter. Background Art

[0002] The power conversion system (PCS) controls the charging and discharging of batteries, converting AC to DC, and can directly power AC loads in the absence of a power grid. The PCS consists of a DC / AC bidirectional converter and a control unit. The PCS receives backend control commands via communication and controls the converter to charge or discharge the batteries based on the sign and magnitude of the power commands, thereby regulating the active and reactive power of the grid. The PCS also monitors battery status, such as insulation resistance, to ensure safe operation.

[0003] In related technologies, energy storage converters require numerous control and detection functions, which limits their pin usage. Therefore, how to conserve pins and achieve stable PCS detection is a pressing issue for energy storage converters. Summary of the Invention

[0004] Based on this, it is necessary to provide an insulation detection method, circuit, energy storage system and electrical equipment for an energy storage converter to address the above technical problems, which can at least ensure stable impedance detection of the energy storage converter while reducing the use of PCS controller pins.

[0005] In the first aspect, the present application provides an insulation detection circuit for an energy storage converter, the insulation detection circuit including a controller, a first delay circuit, an upper arm switching switch and a lower arm switching switch, the control interface of the controller being connected to the control end of the upper arm switching switch and the input end of the first delay circuit respectively, and the output end of the first delay circuit being connected to the control end of the lower arm switching switch.

[0006] In one embodiment, the insulation detection circuit further includes a first reverse circuit, the input end of the first reverse circuit is connected to the output end of the first delay circuit, and the output end of the first reverse circuit is connected to the control end of the upper arm switching switch.

[0007] In one embodiment, the insulation detection circuit also includes a second delay circuit and an anti-backflow circuit, the input end of the second delay circuit is connected to the output end of the second reverse circuit, the output end of the second delay circuit is connected to the control end of the lower bridge arm switching switch, one end of the anti-backflow circuit is connected to the output end of the first delay circuit, and the other end of the anti-backflow circuit is connected to the control end of the lower bridge arm switching switch; wherein, the delay time of the second delay circuit is greater than the first preset time, and the first preset time is a preset voltage stabilization delay time.

[0008] In the second aspect, the present application also provides an insulation detection method for an energy storage converter, which is applied to an insulation detection circuit of the energy storage converter. The insulation detection circuit includes a controller, a first delay circuit, an upper arm switching switch and a lower arm switching switch. The control interface of the controller is respectively connected to the control end of the upper arm switching switch and the input end of the first delay circuit, and the output end of the first delay circuit is connected to the control end of the lower arm switching switch. The method includes: controlling the control interface of the controller to output a target level; after a first preset time, obtaining a first test voltage of the positive bus and a second test voltage of the negative bus; after a second preset time, obtaining a third test voltage of the positive bus and a fourth test voltage of the negative bus; determining whether the energy storage converter has insulation abnormalities based on the first test voltage, the second test voltage, the third test voltage and the fourth test voltage; wherein the first preset time is a preset voltage stabilization delay time, and the second preset time is the sum of the delay time of the first delay circuit and the preset voltage stabilization delay time.

[0009] In one embodiment, the insulation detection circuit also includes a first reverse circuit, the input end of the first reverse circuit is connected to the output end of the first delay circuit, and the output end of the first reverse circuit is connected to the control end of the upper bridge arm switching switch; the insulation detection circuit also includes a second delay circuit and an anti-backflow circuit, the input end of the second delay circuit is connected to the output end of the second reverse circuit, the output end of the second delay circuit is connected to the control end of the lower bridge arm switching switch, one end of the anti-backflow circuit is connected to the output end of the first delay circuit, and the other end of the anti-backflow circuit is connected to the control end of the lower bridge arm switching switch; wherein the delay time of the second delay circuit is greater than the first preset time, and the first preset time is a preset voltage stabilization delay time; the method also includes: after the second preset time, obtaining the fifth test voltage of the positive bus and the sixth test voltage of the negative bus; and determining whether there is insulation abnormality in the energy storage converter based on the first test voltage, the second test voltage, the fifth test voltage, and the sixth test voltage.

[0010] In one embodiment, determining whether there is insulation abnormality in the energy storage converter according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage includes: obtaining a first standard equivalent resistance, a second standard equivalent resistance, a third standard equivalent resistance and a fourth standard equivalent resistance, the first standard equivalent resistance being the standard equivalent resistance of the upper bridge arm applied to the positive bus when the upper bridge arm switching switch is closed, the second standard equivalent resistance being the equivalent resistance of the lower bridge arm applied to the positive bus when the lower bridge arm switching switch is disconnected, and the third standard equivalent resistance being the equivalent resistance of the lower bridge arm applied to the positive bus when the lower bridge arm switching switch is closed. The equivalent resistance of the bridge arm applied to the positive bus, the fourth standard equivalent resistance is the equivalent resistance of the upper bridge arm applied to the positive bus when the upper bridge arm switching switch is disconnected; the first test equivalent resistance and the second test equivalent resistance are calculated according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth standard equivalent resistance; based on the first test equivalent resistance, the second test equivalent resistance, the pre-set first equivalent resistance threshold and the second equivalent resistance threshold, it is determined whether the energy storage converter has insulation abnormality.

[0011] In one embodiment, the method further includes: calculating a third test equivalent resistance and a fourth test equivalent resistance based on the first test voltage, the second test voltage, the fifth test voltage, the sixth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance, and the fourth standard equivalent resistance; and determining whether there is an insulation abnormality in the energy storage converter based on the third test equivalent resistance, the fourth test equivalent resistance, the pre-set first equivalent resistance threshold, and the second equivalent resistance threshold.

[0012] In one embodiment, calculating the third test equivalent resistance and the fourth test equivalent resistance based on the first test voltage, the second test voltage, the fifth test voltage, the sixth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth standard equivalent resistance includes: calculating the first intermediate calculation parameter based on the first test voltage and the second test voltage; calculating the second intermediate calculation parameter based on the fifth test voltage and the sixth test voltage; calculating the third test equivalent resistance and the fourth test equivalent resistance based on the first intermediate calculation parameter, the second intermediate calculation parameter, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth standard equivalent resistance.

[0013] In a third aspect, the present application also provides an energy storage system, including: a battery pack; a thermal management subsystem; a management subsystem; and an energy storage inverter, wherein the energy storage inverter includes the insulation detection circuit of the energy storage inverter of any of the above embodiments, and the controller in the energy storage inverter is used to execute the insulation detection method of the energy storage inverter of any of the above embodiments.

[0014] In a fourth aspect, the present application also provides an electrical device, including the energy storage system of any of the above embodiments.

[0015] The insulation detection method, circuit, energy storage system and electrical equipment of the above-mentioned energy storage converter add a delay circuit between the controller of the insulation detection circuit of the energy storage converter and the lower bridge arm switching switch, so that one interface of the controller can realize the separate control of the upper bridge arm switching switch and the lower bridge arm switching switch. At the same time, combined with the control method of the controller, the insulation condition of the energy storage system is detected by setting a first preset time and a second preset time corresponding to the delay time of the delay circuit, thereby ensuring the insulation detection of the energy storage system, reducing the use of the PCS controller interface, and avoiding the PCS controller reducing the control and detection of the energy storage system due to the lack of available interfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 1 is a flow chart of an insulation detection method for an energy storage converter according to an embodiment;

[0018] Figure 2 is an equivalent circuit diagram of insulation detection of an energy storage converter in one embodiment;

[0019] Figure 3 Schematic diagram of an insulation detection circuit for an energy storage converter in one embodiment Figure 1 ;

[0020] Figure 4 Schematic diagram of an insulation detection circuit for an energy storage converter in one embodiment Figure 2 .

[0021] Reference numerals and descriptions:

[0022] 101, controller; 102, first delay circuit; S1, upper arm switching switch; S2, lower arm switching switch; 301, first reverse circuit; 302, second delay circuit; 303, anti-backflow circuit; 1011, DSP chip; 1021, FPGA. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0024] Please refer to Figure 1 In an exemplary embodiment, an insulation detection method for an energy storage converter is provided. The method is applied to an insulation detection circuit of the energy storage converter.

[0025] For details, please refer to Figure 3 The insulation detection circuit includes a controller 101, a first delay circuit 102, an upper arm switching switch S1 and a lower arm switching switch S2.

[0026] The control interface of the controller 101 is connected to the control end of the upper arm switching switch S1 and the input end of the first delay circuit 102 respectively, and the output end of the first delay circuit 102 is connected to the control end of the lower arm switching switch S2.

[0027] Specifically, the insulation detection method of the energy storage converter includes:

[0028] Step S101 : Control the control interface of the controller 101 to output a target level.

[0029] Here, the output interface is a pin of the controller 101 , and the target level may be a high level.

[0030] Step S102: After a first preset time, obtain a first test voltage of the positive bus and a second test voltage of the negative bus.

[0031] Step S103: After the second preset time, obtain a third test voltage of the positive bus and a fourth test voltage of the negative bus.

[0032] Step S104: Determine whether there is insulation abnormality in the energy storage system based on the first test voltage, the second test voltage, the third test voltage, and the fourth test voltage.

[0033] In this way, the controller 101 only needs to use one control interface to output the target level, and can obtain the four test voltages required for insulation detection through the delay of the delay circuit, thereby determining whether there is insulation abnormality in the energy storage system.

[0034] The first preset time is a preset voltage stabilization delay time, and the second preset time is the sum of the delay time of the first delay circuit 102 and the preset voltage stabilization delay time.

[0035] Here, it should be noted that in the energy storage circuit, after the upper arm switch or the lower arm switch is controlled to operate, the voltage needs a certain amount of time to stabilize. At this time, the voltage detection of the positive bus and the negative bus is accurate. Therefore, it is necessary to ensure that the test voltage value can only be obtained after a certain delay after the upper arm switch or the lower arm switch is operated.

[0036] Similarly, after the control signal is delayed by the delay circuit and the lower arm switching switch S2 is controlled, it is also necessary to stabilize the positive bus and the negative bus for a certain period of time. Therefore, it is necessary to obtain the third test voltage of the positive bus and the fourth test voltage of the negative bus after the second preset time.

[0037] As an example, the controller 101 includes a DSP chip 1011 and an FPGA 1021. The DSP (Digital Signal Processor) is a programmable microprocessor designed specifically for digital signal processing. Its core function is to perform signal acquisition, filtering, compression, and recognition in real time through high-speed operations (such as multiplication and addition operations). The DSP (Digital Signal Processor) is a programmable microprocessor designed specifically for digital signal processing. Its core function is to perform signal acquisition, filtering, compression, and recognition in real time through high-speed operations (such as multiplication and addition operations). Therefore, in the energy storage system, the FPGA 1021 needs to perform more control tasks, and the use of pins is very limited.

[0038] See also Figure 4 In an optional embodiment, the insulation detection circuit further includes a first reverse circuit 301 .

[0039] The input end of the first reverse circuit 301 is connected to the output end of the first delay circuit 102 , and the output end of the first reverse circuit 301 is connected to the control end of the upper arm switching switch S1 .

[0040] Specifically, after adding the first reverse circuit 301 to the insulation detection circuit, the method further includes: obtaining a fifth test voltage of the positive bus and a sixth test voltage of the negative bus after a second preset time; and determining whether there is an insulation abnormality in the energy storage system based on the first test voltage, the second test voltage, the fifth test voltage, and the sixth test voltage.

[0041] Specifically, the method also includes: calculating a third test equivalent resistance and a fourth test equivalent resistance based on the first test voltage, the second test voltage, the fifth test voltage, the sixth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth equivalent resistance; and determining whether there is an insulation abnormality based on the third test equivalent resistance, the fourth test equivalent resistance, a pre-set first equivalent resistance threshold and a second equivalent resistance threshold.

[0042] Among them, the third test equivalent resistance and the fourth test equivalent resistance are calculated according to the first test voltage, the second test voltage, the fifth test voltage, the sixth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth equivalent resistance, including: calculating the first intermediate calculation parameter according to the first test voltage and the second test voltage; calculating the second intermediate calculation parameter according to the fifth test voltage and the sixth test voltage; calculating the third test equivalent resistance and the fourth test equivalent resistance according to the first intermediate calculation parameter, the second intermediate calculation parameter, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth equivalent resistance.

[0043] Here, it should be noted that there can be four possible combination states of the upper arm switching switch S1 and the lower arm switching switch S2 when detecting the positive busbar and the negative busbar of the energy storage battery, including: both the upper arm switching switch S1 and the lower arm switching switch S2 are disconnected, both the upper arm switching switch S1 and the lower arm switching switch S2 are closed, the upper arm switching switch S1 is closed and the lower arm switching switch S2 is disconnected, and the upper arm switching switch S1 is disconnected and the lower arm switching switch S2 is closed. By selecting any two of the above four possible combination states of the upper arm switching switch S1 and the lower arm switching switch S2, the energy storage system can be tested for insulation abnormalities.

[0044] However, the voltages of the positive bus and the negative bus detected in the two states of the upper arm switching switch S1 being closed and the lower arm switching switch S2 being disconnected, and the upper arm switching switch S1 being disconnected and the lower arm switching switch S2 being closed are the most accurate. Therefore, the present application proposes an insulation detection circuit with a first reverse circuit 301.

[0045] In this way, after the control signal is delayed by the first delay circuit 102, while the lower arm switching switch S2 is controlled to be closed, the upper arm switching switch S1 is controlled to be opened through the reverse circuit. This forms the detection of the positive bus and the negative bus in two states: the upper arm switching switch S1 is closed and the lower arm switching switch S2 is opened, and the upper arm switching switch S1 is opened and the lower arm switching switch S2 is closed.

[0046] For example, the first delay circuit 102 can be an RC delay circuit, which is based on the resistor-capacitor charging and discharging principle and controls the charging and discharging time constant by adjusting the R / C value. In a typical design, when the capacitor voltage reaches a threshold, the subsequent circuit is triggered, and the delay time can be calculated by the formula Calculate, where U is the power supply voltage and Vt is the trigger voltage threshold.

[0047] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage regulator diode, for example, superimposing the voltage regulator value on the transistor conduction voltage, significantly extending the delay time and reducing the capacitance requirement, etc.

[0048] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters. The only thing to note is that excessive resistance may prevent the transistor from fully conducting. Tools such as Multisim can also be used to simulate the RC charging and discharging process to verify the consistency between the theoretical calculation results and the actual waveform, ensuring timing control accuracy.

[0049] Please continue reading Figure 4 In one embodiment, the insulation detection circuit further includes a second delay circuit 302 and an anti-backflow circuit 303.

[0050] Among them, the input end of the second delay circuit 302 is connected to the output end of the second reverse circuit, the output end of the second delay circuit 302 is connected to the control end of the lower bridge arm switching switch S2, one end of the anti-backflow circuit 303 is connected to the output end of the first delay circuit 102, and the other end of the anti-backflow circuit 303 is connected to the control end of the lower bridge arm switching switch S2.

[0051] The delay time of the second delay circuit 302 is greater than the first preset time.

[0052] Here, through the delay of the second delay circuit 302 and the protection of the anti-backflow circuit 303, the present application can disconnect the lower bridge arm switching switch S2 after the switching action of the insulation detection, so that the insulation detection circuit is restored to the state where both the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 are disconnected.

[0053] In this way, the circuit stability of the energy storage battery is ensured, and the controller 101 does not need to record the current status of the upper arm switching switch S1 and the lower arm switching switch S2, thereby ensuring the simplicity and stability of the insulation detection procedure.

[0054] For example, the second delay circuit 302 can be an RC delay circuit, which is based on the resistor-capacitor charging and discharging principle and controls the charging and discharging time constant by adjusting the R / C value. In a typical design, when the capacitor voltage reaches the threshold, the subsequent circuit is triggered, and the delay time can be calculated by the formula Calculate, where U is the power supply voltage and Vt is the trigger voltage threshold.

[0055] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage regulator diode, for example, superimposing the voltage regulator value on the transistor conduction voltage, significantly extending the delay time and reducing the capacitance requirement, etc.

[0056] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters. The only thing to note is that excessive resistance may prevent the transistor from fully conducting. Tools such as Multisim can also be used to simulate the RC charging and discharging process to verify the consistency between the theoretical calculation results and the actual waveform, ensuring timing control accuracy.

[0057] The reverse circuit can use components such as PMOS inverters (such as AO3401, etc.) to achieve bidirectional conversion of high and low voltage logic signals. Its low on-resistance can reduce power consumption.

[0058] The anti-backflow circuit 303 can be implemented through a diode solution, a single MOS tube solution, a dual MOS combination solution, an ideal diode circuit, etc. Among them, the diode solution can block reverse current by connecting a diode in series; the single MOS tube solution uses the body diode and gate control of PMOS or NMOS to achieve unidirectional conduction. For example, in the PMOS anti-reverse connection circuit, the gate voltage controls the conduction state and the forward conduction voltage is reduced; the dual MOS combination solution uses PMOS and NMOS in series (such as PMOS high side + NMOS low side) to block bidirectional backflow through complementary conduction logic; the ideal diode circuit simulates the characteristics of a diode by combining a transistor and a MOS tube to achieve the effect of low forward voltage drop and fast reverse shutdown.

[0059] For details, please refer to Figure 2 , Figure 2 This is the equivalent circuit diagram for insulation testing of an energy storage converter. The insulation resistance of the positive busbar (BAT+) to ground is Rx, and the insulation resistance of the negative busbar (BAT-) to ground is Ry. The values ​​of these two insulation resistors can be used to determine whether the energy storage system is abnormal.

[0060] For example, when the upper arm switching switch S1 is disconnected, the equivalent resistance of the upper arm added to the positive bus is: .

[0061] in, .

[0062] here, This is the fourth standard equivalent resistance.

[0063] When the upper bridge arm switching switch S1 is closed, the equivalent resistance of the upper bridge arm added to the positive bus is: .

[0064] in, .

[0065] here, This is the first standard equivalent resistance.

[0066] When the lower bridge arm switching switch S2 is disconnected, the equivalent resistance of the lower bridge arm added to the positive bus is: .

[0067] in, .

[0068] here, This is the second standard equivalent resistance.

[0069] When the lower bridge arm switching switch S2 is closed, the equivalent resistance of the lower bridge arm added to the positive bus is: .

[0070] in, .

[0071] here, This is the third standard equivalent resistance.

[0072] Thus, based on the above equivalent resistance calculation formula, when the upper arm switching switch S1 and the lower arm switching switch S2 are both disconnected, assuming that the positive and negative bus voltages measured at this time are Up1 and Un1 respectively, then: .

[0073] When the upper arm switching switch S1 and the lower arm switching switch S2 are both closed, assuming that the positive and negative bus voltages measured at this time are Up2 and Un2, and Up2 and Un2 are the third test voltage and the fourth test voltage respectively, then:

[0074] .

[0075] When the upper arm switching switch S1 is closed and the lower arm switching switch S2 is open, assuming that the positive and negative bus voltages measured at this time are Up3 and Un3, and Up3 and Un3 are the first test voltage and the second test voltage respectively, then:

[0076] .

[0077] When the upper arm switching switch S1 is open and the lower arm switching switch S2 is closed, assuming that the positive and negative bus voltages measured at this time are Up4 and Un4, and Up4 and Un4 are the fifth test voltage and the sixth test voltage respectively, then:

[0078] .

[0079] Taking the example of controlling the upper arm switching switch S1 to be closed, the lower arm switching switch S2 to be opened, and then controlling the upper arm switching switch S1 to be opened and the lower arm switching switch S2 to be closed, the insulation resistance of the positive busbar BAT+ to ground is Rx, and the insulation resistance of the negative busbar BAT- to ground is Ry, as calculated by the following formula:

[0080] First, to simplify the calculation, assume:

[0081] , .

[0082] Then, the simultaneous equations:

[0083] ; .

[0084] In this way, the insulation resistance of the positive busbar BAT+ to ground can be calculated as Rx, and the insulation resistance of the negative busbar BAT- to ground can be calculated as Ry. Then, based on the insulation resistance of the positive busbar BAT+ to ground and the insulation resistance of the negative busbar BAT- to ground, it can be determined whether there is an insulation abnormality in the energy storage system.

[0085] The insulation detection method for the energy storage converter proposed in the present application adds a delay circuit between the controller 101 of the insulation detection circuit of the energy storage converter and the lower bridge arm switching switch S2, so that one interface of the controller 101 can realize the separate control of the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2. At the same time, combined with the control method of the controller 101, the insulation condition of the energy storage system is detected by setting a first preset time and a second preset time corresponding to the delay time of the delay circuit, thereby ensuring the insulation detection of the energy storage system, reducing the use of the interface of the PCS controller 101, and avoiding the reduction of the control and detection of the energy storage system by the PCS controller 101 due to the lack of an available interface.

[0086] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0087] Based on the same inventive concept, embodiments of the present application also provide an insulation detection circuit for an energy storage converter, which is used to implement the aforementioned insulation detection method for an energy storage converter. The solution provided by this circuit is similar to the solution described in the aforementioned method. Therefore, the specific limitations of one or more insulation detection circuit embodiments provided below can be found in the aforementioned limitations of the insulation detection method for an energy storage converter, and will not be further elaborated here.

[0088] Please refer to Figure 2 In an exemplary embodiment, an insulation detection circuit for an energy storage converter is provided, including a controller 101, a first delay circuit 102, an upper arm switching switch S1, and a lower arm switching switch S2. The control interface of the controller 101 is respectively connected to the control end of the upper arm switching switch S1 and the input end of the first delay circuit 102, and the output end of the first delay circuit 102 is connected to the control end of the lower arm switching switch S2.

[0089] For example, the first delay circuit 102 can be an RC delay circuit, which is based on the resistor-capacitor charging and discharging principle and controls the charging and discharging time constant by adjusting the R / C value. In a typical design, when the capacitor voltage reaches a threshold, the subsequent circuit is triggered, and the delay time can be calculated by the formula Calculate, where U is the power supply voltage and Vt is the trigger voltage threshold.

[0090] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage regulator diode, for example, superimposing the voltage regulator value on the transistor conduction voltage, significantly extending the delay time and reducing the capacitance requirement, etc.

[0091] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters. The only thing to note is that excessive resistance may prevent the transistor from fully conducting. Tools such as Multisim can also be used to simulate the RC charging and discharging process to verify the consistency between the theoretical calculation results and the actual waveform, ensuring timing control accuracy.

[0092] Please refer to Figure 3 In one embodiment, the insulation detection circuit further includes a first reverse circuit 301, the input end of the first reverse circuit 301 is connected to the output end of the first delay circuit 102, and the output end of the first reverse circuit 301 is connected to the control end of the upper bridge arm switching switch S1.

[0093] Please continue to refer to Figure 3In one embodiment, the insulation detection circuit further includes a second delay circuit 302 and an anti-backflow circuit 303, wherein the input end of the second delay circuit 302 is connected to the output end of the second reverse circuit, the output end of the second delay circuit 302 is connected to the control end of the lower bridge arm switching switch S2, one end of the anti-backflow circuit 303 is connected to the output end of the first delay circuit 102, and the other end of the anti-backflow circuit 303 is connected to the control end of the lower bridge arm switching switch S2.

[0094] For example, the second delay circuit 302 can be an RC delay circuit, which is based on the resistor-capacitor charging and discharging principle and controls the charging and discharging time constant by adjusting the R / C value. In a typical design, when the capacitor voltage reaches the threshold, the subsequent circuit is triggered, and the delay time can be calculated by the formula Calculate, where U is the power supply voltage and Vt is the trigger voltage threshold.

[0095] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage regulator diode, for example, superimposing the voltage regulator value on the transistor conduction voltage, significantly extending the delay time and reducing the capacitance requirement, etc.

[0096] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters. The only thing to note is that excessive resistance may prevent the transistor from fully conducting. Tools such as Multisim can also be used to simulate the RC charging and discharging process to verify the consistency between the theoretical calculation results and the actual waveform, ensuring timing control accuracy.

[0097] The reverse circuit can use components such as PMOS inverters (such as AO3401, etc.) to achieve bidirectional conversion of high and low voltage logic signals. Its low on-resistance can reduce power consumption.

[0098] The anti-backflow circuit 303 can be implemented through a diode solution, a single MOS tube solution, a dual MOS combination solution, an ideal diode circuit, etc. Among them, the diode solution can block reverse current by connecting a diode in series; the single MOS tube solution uses the body diode and gate control of PMOS or NMOS to achieve unidirectional conduction. For example, in the PMOS anti-reverse connection circuit, the gate voltage controls the conduction state and the forward conduction voltage is reduced; the dual MOS combination solution uses PMOS and NMOS in series (such as PMOS high side + NMOS low side) to block bidirectional backflow through complementary conduction logic; the ideal diode circuit simulates the characteristics of a diode by combining a transistor and a MOS tube to achieve the effect of low forward voltage drop and fast reverse shutdown.

[0099] In an exemplary embodiment, an energy storage system is provided, comprising: a battery pack; a thermal management subsystem; a management subsystem; and an energy storage inverter, wherein the energy storage inverter comprises the insulation detection circuit of the energy storage inverter described in any of the above embodiments, and the controller in the energy storage inverter is used to execute the insulation detection method of the energy storage inverter described in any of the above embodiments.

[0100] In an exemplary embodiment, an electrical device is provided, comprising the energy storage system described in any one of the above embodiments.

[0101] The insulation detection method, circuit, energy storage system and electrical equipment of the above-mentioned energy storage converter add a delay circuit between the controller 101 of the insulation detection circuit of the energy storage converter and the lower bridge arm switching switch S2, so that one interface of the controller 101 can realize the separate control of the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2. At the same time, combined with the control method of the controller 101, the insulation condition of the energy storage system is detected by setting a first preset time and a second preset time corresponding to the delay time of the delay circuit, thereby ensuring the insulation detection of the energy storage system, reducing the use of the PCS controller 101 interface, and avoiding the PCS controller 101 being unable to control and detect the energy storage system due to the lack of an available interface.

[0102] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, 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, they should be considered to be within the scope of this application.

[0103] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An insulation detection circuit for an energy storage converter, characterized in that: The insulation detection circuit includes a controller, a first delay circuit, an upper arm switching switch, and a lower arm switching switch, wherein the control interface of the controller is connected to the control end of the upper arm switching switch and the input end of the first delay circuit respectively, and the output end of the first delay circuit is connected to the control end of the lower arm switching switch; The insulation detection circuit further includes a first reverse circuit, the input end of the first reverse circuit is connected to the output end of the first delay circuit, and the output end of the first reverse circuit is connected to the control end of the upper arm switching switch.

2. The insulation detection circuit of the energy storage converter according to claim 1, characterized in that: The insulation detection circuit also includes a second delay circuit and an anti-backflow circuit, the input end of the second delay circuit is connected to the output end of the second reverse circuit, the output end of the second delay circuit is connected to the control end of the lower bridge arm switching switch, one end of the anti-backflow circuit is connected to the output end of the first delay circuit, and the other end of the anti-backflow circuit is connected to the control end of the lower bridge arm switching switch; The delay time of the second delay circuit is greater than the first preset time, and the first preset time is a preset voltage stabilization delay time.

3. A method for detecting insulation of an energy storage converter, characterized in that: The insulation detection circuit applied to the energy storage converter according to claim 1 or 2, the method comprising: Controlling the control interface of the controller to output a target level; After a first preset time, obtaining a first test voltage of the positive bus and a second test voltage of the negative bus; After a second preset time, obtaining a third test voltage of the positive bus and a fourth test voltage of the negative bus; determining whether the energy storage converter has insulation abnormality according to the first test voltage, the second test voltage, the third test voltage, and the fourth test voltage; The first preset time is a preset voltage stabilization delay time, and the second preset time is the sum of the delay time of the first delay circuit and the preset voltage stabilization delay time.

4. The insulation detection method for an energy storage converter according to claim 3, characterized in that: Determining whether the energy storage converter has insulation abnormality according to the first test voltage, the second test voltage, the third test voltage, and the fourth test voltage includes: Obtain a first standard equivalent resistance, a second standard equivalent resistance, a third standard equivalent resistance, and a fourth standard equivalent resistance, where the first standard equivalent resistance is the standard equivalent resistance of the upper bridge arm applied to the positive bus when the upper bridge arm switching switch is closed, the second standard equivalent resistance is the equivalent resistance of the lower bridge arm applied to the positive bus when the lower bridge arm switching switch is open, the third standard equivalent resistance is the equivalent resistance of the lower bridge arm applied to the positive bus when the lower bridge arm switching switch is closed, and the fourth standard equivalent resistance is the equivalent resistance of the upper bridge arm applied to the positive bus when the upper bridge arm switching switch is open; Calculating a first test equivalent resistance and a second test equivalent resistance according to the first test voltage, the second test voltage, the third test voltage, and the fourth test voltage, the first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance, and the fourth standard equivalent resistance; It is determined whether there is insulation abnormality in the energy storage converter according to the first test equivalent resistance, the second test equivalent resistance, a preset first equivalent resistance threshold, and a preset second equivalent resistance threshold.

5. An energy storage system, characterized in that: include: Battery pack; thermal management subsystem; Management subsystem; An energy storage converter, comprising the insulation detection circuit of the energy storage converter according to any one of claims 1-2, wherein the controller in the energy storage converter is used to execute the insulation detection method of the energy storage converter according to any one of claims 3-4.

6. An electrical device, characterized in that: The electrical equipment includes the energy storage system as claimed in claim 5.

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