Insulation detection method and circuit of energy storage converter, energy storage system and electric equipment

Abstract

The invention relates to the technical field of energy storage, and provides an insulation detection method and circuit of an energy storage converter, an energy storage system and electric equipment, and the method comprises the steps: controlling a control interface of a 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, acquiring a third test voltage of the positive bus and a fourth test voltage of the negative bus; according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage, whether insulation abnormity exists in the energy storage system is determined; wherein the first preset time is the 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 use of pins of the PCS controller can be reduced at least while stable impedance detection of the energy storage converter is ensured.

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 energy storage converter (PCS, Power Conversion System) can control the charging and discharging process of the battery, perform AC-DC conversion, and directly supply power to the AC load when there is no power grid. The PCS is composed of a DC / AC bidirectional converter, a control unit, etc. The PCS needs to receive background control instructions through communication, and control the converter to charge or discharge the battery according to the sign and size of the power instruction to adjust the active power and reactive power of the power grid. The PCS also needs to obtain battery pack status information, such as the insulation impedance of the battery, to ensure the safety of battery operation.

[0003] In the related art, since the energy storage converter needs to realize more control functions and detection functions, the use of pins is limited by various factors. Therefore, how to save pins and realize stable detection of PCS is one of the problems that energy storage converters need to solve urgently. 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 inverter to address the above technical problems, which can at least reduce the use of PCS controller pins while ensuring stable impedance detection of the energy storage inverter.

[0005] In the first aspect, the present application provides an insulation detection circuit of an energy storage inverter, the insulation detection circuit comprising a controller, a first delay circuit, an upper bridge arm switching switch and a lower bridge arm switching switch, the control interface of the controller is respectively connected to the control end of the upper bridge 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 bridge 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 bridge arm switching switch.

[0007] In one embodiment, the insulation detection circuit further 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, and the output end of the second delay circuit is connected to the control end of the lower-bridge 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 switching switch. Wherein, the delay time of the second delay circuit is greater than a first preset time, and the first preset time is a preset voltage stabilization delay time.

[0008] In a second aspect, the present application also provides an insulation detection method for a energy storage converter, which is applied to the insulation detection circuit of the energy storage converter. The insulation detection circuit includes a controller, a first delay circuit, an upper-bridge switching switch, and a lower-bridge switching switch. The control interface of the controller is respectively connected to the control end of the upper-bridge 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-bridge switching switch. The method includes: controlling the control interface of the controller to output a target level; after the 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 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; 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 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-bridge switching switch. The insulation detection circuit further 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, and the output end of the second delay circuit is connected to the control end of the lower-bridge 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 switching switch. Wherein, the delay time of the second delay circuit is greater than a first preset time, and the first preset time is a preset voltage stabilization delay time. The method further includes: after the second preset time, obtaining a fifth test voltage of the positive bus and a sixth test voltage of the negative bus; determining whether there is insulation abnormality in the energy storage converter according to 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 an 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 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. 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, 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. Determining whether there is an 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 second equivalent resistance threshold.

[0011] In one embodiment, the method further includes: calculating a third test equivalent resistance and a fourth test equivalent resistance 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 standard equivalent resistance. Determining whether there is an insulation abnormality in the energy storage converter according to the third test equivalent resistance, the fourth test equivalent resistance, a preset first equivalent resistance threshold, and a second equivalent resistance threshold.

[0012] In one embodiment, calculating the third test equivalent resistance and the fourth test equivalent resistance 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 standard equivalent resistance includes: calculating a first intermediate calculation parameter according to the first test voltage and the second test voltage. Calculating a 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 standard equivalent resistance.

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

[0014] Fourthly, the present application also provides an electrical equipment, including the energy storage system of any of the above embodiments.

[0015] In the above insulation detection method, circuit, energy storage system and electrical equipment of the power conversion system (PCS), a delay circuit is added between the controller of the insulation detection circuit of the PCS and the lower-arm switching switch, so that one interface of the controller can separately control the upper-arm switching switch and the lower-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, which not only ensures the insulation detection of the energy storage system, but also reduces the use of the PCS controller interface, avoiding the reduction of the control and detection of the energy storage system due to the unavailability of the interface of the PCS controller. Description of the Drawings

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

[0017] Figure 1 It is a schematic flowchart of an insulation detection method for a power conversion system (PCS) in an embodiment;

[0018] Figure 2 It is an equivalent circuit diagram of an insulation detection of a power conversion system (PCS) in an embodiment;

[0019] Figure 3 It is a schematic diagram of an insulation detection circuit of a power conversion system (PCS) in an embodiment; Figure 1 ;

[0020] Figure 4 It is a schematic diagram of an insulation detection circuit of a power conversion system (PCS) in an embodiment; Figure 2 .

[0021] Reference Signs 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 Embodiments

[0023] To make the objectives, technical solutions, and advantages of this application more clear and understandable, the following further elaborates on this application in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely 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, and this method is applied to the insulation detection circuit of the energy storage converter.

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

[0026] Among them, the control interface of the controller 101 is respectively connected to the control end of the upper-bridge-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-bridge-arm switching switch S2.

[0027] Specifically, the insulation detection method for 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 can be a high level.

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

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

[0032] Step S104, determine whether there is an insulation abnormality in the energy storage system according to 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 a target level, and then through the delay of the delay circuit, four test voltages required for insulation detection can be obtained, and further determine whether there is an insulation abnormality in the energy storage system.

[0034] Among them, 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 bridge arm switch or the lower bridge arm switch is controlled to act, it takes a certain amount of time for the voltage to stabilize. Only at this time can the voltage detection of the positive bus and the negative bus be accurate. Therefore, it is necessary to ensure that a certain time delay occurs after the upper bridge arm switch or the lower bridge arm switch acts before the measured voltage value can be obtained.

[0036] Similarly, after the control signal is delayed by the delay circuit and the lower bridge arm switching switch S2 is controlled, it also takes a certain amount of time to stabilize the positive bus and the negative bus. Therefore, after the second preset time, the third measured voltage of the positive bus and the fourth measured voltage of the negative bus need to be obtained.

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

[0038] Please refer to Figure 4 , in an optional embodiment, the insulation detection circuit further includes a first reverse circuit 301.

[0039] Among them, 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.

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

[0041] Specifically, the method further includes: calculating a third test equivalent resistance and a fourth test equivalent resistance 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; and determining whether there is an insulation abnormality according to the third test equivalent resistance, the fourth test equivalent resistance, a preset first equivalent resistance threshold, and a second equivalent resistance threshold.

[0042] Among them, calculating the third test equivalent resistance and the fourth test equivalent resistance 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 includes: calculating a first intermediate calculation parameter according to the first test voltage and the second test voltage; calculating a second intermediate calculation parameter according to the fifth test voltage and the sixth test voltage; and 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 are four possible combined states of the upper-bridge-arm switching switch S1 and the lower-bridge-arm switching switch S2 for detecting the positive bus and the negative bus of the energy storage battery, including: both the upper-bridge-arm switching switch S1 and the lower-bridge-arm switching switch S2 are open, both the upper-bridge-arm switching switch S1 and the lower-bridge-arm switching switch S2 are closed, the upper-bridge-arm switching switch S1 is closed and the lower-bridge-arm switching switch S2 is open, and the upper-bridge-arm switching switch S1 is open and the lower-bridge-arm switching switch S2 is closed. Selecting any two of the above four possible combined states of the upper-bridge-arm switching switch S1 and the lower-bridge-arm switching switch S2 can complete the detection of whether there is an insulation abnormality in the energy storage system.

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

[0045] In this way, when the control signal is delayed by the first delay circuit 102, while controlling the lower-bridge-arm switching switch S2 to close, the upper-bridge-arm switching switch S1 is controlled to open through the reverse circuit, thus forming the detection of the positive bus and the negative bus in the two states where the upper-bridge-arm switching switch S1 is closed and the lower-bridge-arm switching switch S2 is open, and the upper-bridge-arm switching switch S1 is open and the lower-bridge-arm switching switch S2 is closed.

[0046] Exemplarily, the first delay circuit 102 can be an RC delay circuit. Based on the resistor-capacitor charge and discharge principle, the charge and discharge time constant can be controlled 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 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. By adding a zener diode, the trigger voltage threshold can be increased. For example, the regulated voltage value can be superimposed on the triode conduction voltage, significantly extending the delay time and reducing the capacitance requirement, etc.

[0048] Here, flexible delay can be achieved by adjusting the resistor or capacitor parameters. It only needs to be noted that too large a resistor may cause the problem that the triode cannot be fully conducted. At the same time, tools such as Multisim can be used to simulate the RC charge and discharge process, which can verify the consistency between the theoretical calculation results and the actual waveform, ensuring the timing control accuracy.

[0049] Please continue to refer to Figure 4 , in one of the embodiments, 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 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 switching switch S2.

[0051] Among them, 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, after the switching action of the insulation detection in this application, the lower-bridge switching switch S2 can be disconnected, so that the insulation detection circuit returns to the state where both the upper-bridge switching switch S1 and the lower-bridge switching switch S2 are disconnected.

[0053] In this way, not only the circuit stability of the energy storage battery is ensured, but also the controller 101 does not need to record the current states of the upper-bridge switching switch S1 and the lower-bridge switching switch S2, ensuring the simplicity and stability of the insulation detection program.

[0054] Exemplarily, the second delay circuit 302 can be an RC delay circuit. Based on the resistor-capacitor charge and discharge principle, the charge and discharge time constant can be controlled 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 Perform calculations, 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. By adding a zener diode, the trigger voltage threshold can be increased. For example, the regulated voltage value can be superimposed on the conduction voltage of the triode, significantly extending the delay time and reducing the capacitance requirement, etc.

[0056] Here, flexible delay can be achieved by adjusting the resistor or capacitor parameters. Just note that an overly large resistor may cause the problem that the triode cannot fully conduct. At the same time, tools such as Multisim can be used to simulate the RC charging and discharging process, which can verify the consistency between the theoretical calculation results and the actual waveform, ensuring the timing control accuracy.

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

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

[0059] Specifically, please refer to Figure 2 , Figure 2 , which is the equivalent circuit diagram for the insulation detection of the energy storage converter. Among them, the insulation resistance of the positive bus bar BAT+ to the ground is Rx, and the insulation resistance of the negative bus bar BAT- to the ground is Ry. Whether there is an abnormality in the energy storage system can be determined through the resistance values of these two insulation resistances.

[0060] Exemplarily, when the upper bridge arm switching switch S1 is disconnected, the equivalent resistance applied to the positive bus bar by the upper bridge arm is: .

[0061] Among them, .

[0062] Here, is the fourth standard equivalent resistance.

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

[0064] Among them, .

[0065] Here, is the first standard equivalent resistance.

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

[0067] Among them, .

[0068] Here, is the second standard equivalent resistance.

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

[0070] Among them, .

[0071] Here, is the third standard equivalent resistance.

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

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

[0074] .

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

[0076] .

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

[0078] .

[0079] Taking the example of controlling the upper arm switching switch S1 to close, the lower arm switching switch S2 to open, and then controlling the upper arm switching switch S1 to open and the lower arm switching switch S2 to close, the insulation resistance of the positive bus BAT+ to ground is Rx, and the insulation resistance of the negative bus BAT- to ground is Ry 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 the ground can be calculated as Rx, and the insulation resistance of the negative busbar BAT- to the ground can be calculated as Ry. Then, based on the insulation resistance of the positive busbar BAT+ to the ground and the insulation resistance of the negative busbar BAT- to the ground, it can be determined whether there is 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 an 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, in combination 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 above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed 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 part of the steps or stages in other steps.

[0087] Based on the same inventive concept, an embodiment of the present application further provides an insulation detection circuit for an energy storage converter for implementing the insulation detection method of the energy storage converter involved above. The implementation solution provided by this circuit to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in one or more embodiments of the insulation detection circuit for the energy storage converter provided below can refer to the limitations on the insulation detection method of the energy storage converter in the above text, and will not be repeated 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 bridge arm switching switch S1, and a lower bridge arm switching switch S2. The control interfaces of the controller 101 are respectively connected to the control end of the upper bridge 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 bridge arm switching switch S2.

[0089] Exemplarily, the first delay circuit 102 can be an RC delay circuit. Based on the resistor-capacitor charge and discharge principle, the charge and discharge time constant is controlled 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 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. By adding a zener diode, the trigger voltage threshold can be increased. For example, the regulated voltage is superimposed on the triode conduction voltage, significantly extending the delay time and reducing the capacitor capacity requirement, etc.

[0091] Here, flexible delay is achieved by adjusting the resistor or capacitor parameters. Only the problem that the triode may not be fully conducting due to too large a resistor needs to be noted. At the same time, tools such as Multisim can be used to simulate the RC charge and discharge process, which can verify the consistency between the theoretical calculation results and the actual waveform, ensuring the timing control accuracy.

[0092] Please refer to Figure 3 , in one of the embodiments, 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 3, in one embodiment, the insulation detection circuit further includes a second delay circuit 302 and an anti-backflow circuit 303. 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 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 switching switch S2.

[0094] Exemplarily, the second delay circuit 302 can be an RC delay circuit. Based on the resistor-capacitor charge and discharge principle, the charge and discharge time constant is controlled 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 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. By adding a zener diode, the trigger voltage threshold can be increased. For example, the zener voltage is superimposed on the triode conduction voltage, significantly extending the delay time and reducing the capacitor capacity requirement, etc.

[0096] Here, flexible delay is achieved by adjusting the resistor or capacitor parameters. Only the problem that the triode may not be fully conducted due to too large a resistor needs to be noted. At the same time, tools such as Multisim can be used to simulate the RC charge and discharge process, which can verify the consistency between the theoretical calculation results and the actual waveform, ensuring the timing control accuracy.

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

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

[0099] In an exemplary embodiment, an energy storage system is provided, including: a battery pack; a thermal management subsystem; a management subsystem; and a power conversion system (PCS), where the PCS includes the insulation detection circuit of the PCS described in any of the above embodiments, and the controller in the PCS is configured to execute the insulation detection method of the PCS described in any of the above embodiments.

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

[0101] For the insulation detection method, circuit, energy storage system, and electrical device of the above PCS, a delay circuit is added between the controller 101 of the insulation detection circuit of the PCS and the lower-arm switching switch S2, so that one interface of the controller 101 can be used to separately control the upper-arm switching switch S1 and the lower-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, which not only ensures the insulation detection of the energy storage system, but also reduces the use of the interfaces of the PCS controller 101, and avoids the situation that the PCS controller 101 cannot control and detect the energy storage system due to the lack of available interfaces.

[0102] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this application.

[0103] The above-described embodiments merely represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application shall be subject to 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 bridge arm switching switch and a lower bridge arm switching switch. The control interface of the controller is respectively connected to the control end of the upper bridge 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 bridge arm switching switch.

2. The insulation detection circuit of the energy storage converter according to claim 1, characterized in that: 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 bridge arm switching switch.

3. The insulation detection circuit of the energy storage converter according to claim 2, 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; 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.

4. An insulation detection method for an energy storage converter, characterized in that: The insulation detection circuit applied to the energy storage converter according to claim 1, 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 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; 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.

5. The insulation detection method for the energy storage converter according to claim 4, characterized in that: The insulation detection circuit applied to the energy storage converter according to claim 2 or 3, wherein the method further comprises: After the second preset time, obtaining a fifth test voltage of the positive bus and a sixth test voltage of the negative bus; It is determined whether there is insulation abnormality in the energy storage converter according to the first test voltage, the second test voltage, the fifth test voltage, and the sixth test voltage.

6. The insulation detection method for the energy storage converter according to claim 5, 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, wherein the first standard equivalent resistance is the standard equivalent resistance of the upper bridge arm added 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 added to the positive bus when the lower bridge arm switching switch is disconnected, the third standard equivalent resistance is the equivalent resistance of the lower bridge arm added 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 added to the positive bus when the upper bridge arm switching switch is disconnected; Calculate 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.

7. The insulation detection method for the energy storage converter according to claim 6, characterized in that: The method further comprises: Calculate a third test equivalent resistance and a fourth test equivalent resistance 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 standard equivalent resistance; It is determined whether there is insulation abnormality in the energy storage converter according to the third test equivalent resistance, the fourth test equivalent resistance, the preset first equivalent resistance threshold and the second equivalent resistance threshold.

8. The insulation detection method for an energy storage converter according to claim 6, characterized in that: Calculating a third test equivalent resistance and a fourth test equivalent resistance 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 standard equivalent resistance, including: Calculating a first intermediate calculation parameter according to the first test voltage and the second test voltage; Calculating a second intermediate calculation parameter according to the fifth test voltage and the sixth test voltage; The third test equivalent resistance and the fourth test equivalent resistance are calculated 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 standard equivalent resistance.

9. An energy storage system, characterized in that: include: Battery pack; Thermal management subsystem; Management subsystem; An energy storage converter, the energy storage converter comprising an insulation detection circuit of the energy storage converter as described in any one of claims 1-3, and a controller in the energy storage converter being used to execute an insulation detection method of the energy storage converter as described in any one of claims 4-8.

10. An electrical device, characterized in that: The electrical equipment includes the energy storage system as claimed in claim 9.

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