Insulation detection method 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 technical field of energy storage, and in particular to an insulation detection method of an energy storage converter, an energy storage system and an electrical equipment. BACKGROUND

[0002] The power conversion system (PCS) can control the charging and discharging process of the battery, convert AC and DC, and directly supply power to the AC load in the absence of a power grid. The PCS is composed of a DC / AC bidirectional converter, a control unit and the like. The PCS needs to receive the background control instructions through communication, control the charging or discharging of the battery according to the sign and size of the power instruction, and realize the adjustment of the active power and the reactive power of the power grid. The PCS also needs to detect the battery pack state information such as the insulation impedance of the battery to ensure the safe operation of the battery.

[0003] In the related art, because the energy storage converter needs to realize many control functions and detection functions, the use of the pin is limited by many factors. Therefore, how to save the pin and realize stable detection of the PCS is one of the problems to be solved by the energy storage converter. SUMMARY

[0004] Therefore, it is necessary to provide an insulation detection method of an energy storage converter, an energy storage system and an electrical equipment to at least reduce the use of the PCS controller pin while ensuring stable impedance detection of the energy storage converter.

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

[0006] controlling the control interface of the controller to output a target level;

[0007] After a first preset time, obtaining a first test voltage of a positive bus and a second test voltage of a negative bus;

[0008] After a second preset time, obtaining a third test voltage of the positive bus and a fourth test voltage of the negative bus;

[0009] determining whether the energy storage converter has insulation abnormalities according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage;

[0010] The first preset time is a pre-set voltage stabilization delay time, the second preset time is a sum of a delay time of the first delay circuit and the pre-set voltage stabilization delay time, and the target level is a high level.

[0011] In some embodiments, the insulation detection circuit further comprises a first reverse circuit, an input end of the first reverse circuit being connected with an output end of the first delay circuit, and an output end of the first reverse circuit being connected with a control end of the upper bridge arm switching switch.

[0012] In some embodiments, the insulation detection circuit further comprises a second delay circuit and an anti-backflow circuit, an input end of the second delay circuit being connected with an output end of the second reverse circuit, an output end of the second delay circuit being connected with a control end of the lower bridge arm switching switch, one end of the anti-backflow circuit being connected with the output end of the first delay circuit, and the other end of the anti-backflow circuit being connected with the control end of the lower bridge arm switching switch.

[0013] The delay time of the second delay circuit is greater than the first preset time, and the first preset time is a pre-set voltage stabilization delay time.

[0014] In some embodiments, the method further comprises:

[0015] After the second preset time, a fifth test voltage of the positive bus and a sixth test voltage of the negative bus are obtained;

[0016] According to the first test voltage, the second test voltage, the fifth test voltage and the sixth test voltage, it is determined whether the energy storage converter exists insulation abnormality.

[0017] In some embodiments, according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage, it is determined whether the energy storage converter exists insulation abnormality, comprising:

[0018] The first standard equivalent resistance, the second standard equivalent resistance, the third standard equivalent resistance and the fourth standard equivalent resistance are obtained, the first standard equivalent resistance being a 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 being an equivalent resistance of the lower bridge arm added to the positive bus when the lower bridge arm switching switch is opened, the third standard equivalent resistance being an 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 being an equivalent resistance of the upper bridge arm added to the positive bus when the upper bridge arm switching switch is opened.

[0019] 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, the first test equivalent resistance and the second test equivalent resistance are calculated.

[0020] According to the first test equivalent resistance, the second test equivalent resistance, the first preset equivalent resistance threshold and the second preset equivalent resistance threshold, it is determined whether the energy storage converter has insulation abnormality.

[0021] In some embodiments, the method further comprises:

[0022] 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, the third test equivalent resistance and the fourth test equivalent resistance are calculated;

[0023] According to the third test equivalent resistance, the fourth test equivalent resistance, the first preset equivalent resistance threshold and the second preset equivalent resistance threshold, it is determined whether the energy storage converter has insulation abnormality.

[0024] In some embodiments, 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, the third test equivalent resistance and the fourth test equivalent resistance are calculated, comprising:

[0025] According to the first test voltage and the second test voltage, a first intermediate calculation parameter is calculated;

[0026] According to the fifth test voltage and the sixth test voltage, a second intermediate calculation parameter is calculated;

[0027] 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, the third test equivalent resistance and the fourth test equivalent resistance are calculated.

[0028] In some embodiments, the first delay circuit and the second delay circuit are RC delay circuits, and the method further comprises:

[0029] By adjusting the resistance value and the capacitance value in the RC delay circuit, the delay time of the RC delay circuit is controlled.

[0030] In a second aspect, the present application further provides an energy storage system, comprising: a battery pack; a thermal management subsystem; a management subsystem; an energy storage converter, wherein a controller in the energy storage converter is configured to execute the insulation detection method of the energy storage converter according to any one of the above embodiments.

[0031] In a fourth aspect, the present application further provides a power utilization device, comprising the energy storage system according to any one of the above embodiments.

[0032] The insulation detection method of the energy storage converter, the energy storage system and the electrical equipment, by adding a delay circuit between the controller of the insulation detection circuit of the energy storage converter and the lower bridge arm switching switch, the one interface of the controller can realize the separate control of the upper bridge arm switching switch and the lower bridge arm switching switch, and at the same time, combined with the control method of the controller, the insulation of the energy storage system is detected by setting the first preset time and the second preset time corresponding to the delay time of the delay circuit, which ensures the insulation detection of the energy storage system, reduces the use of the PCS controller interface, and avoids the reduction of the control and detection of the energy storage system due to the lack of available interface of the PCS controller. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 The flowchart of the insulation detection method of the energy storage converter in one embodiment;

[0035] Figure 2 The equivalent circuit diagram of the insulation detection of the energy storage converter in one embodiment;

[0036] Figure 3 The schematic diagram of the insulation detection circuit of the energy storage converter in one embodiment Figure 1 ;

[0037] Figure 4 The schematic diagram of the insulation detection circuit of the energy storage converter in one embodiment Figure 2 .

[0038] Reference signs and descriptions:

[0039] 101, controller; 102, first delay circuit; S1, upper bridge arm switching switch; S2, lower bridge arm switching switch; 301, first reverse circuit; 302, second delay circuit; 303, anti-backflow circuit; 1011, DSP chip; 1021, FPGA. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0041] Please refer to Figure 1In one example embodiment, an insulation detection method of an energy storage converter is provided, which is applied to an insulation detection circuit of the energy storage converter.

[0042] Specifically, referring to Figure 3 , the insulation detection circuit comprises a controller 101, a first delay circuit 102, an upper bridge arm switching switch S1 and a lower bridge arm switching switch S2.

[0043] The control interface of the controller 101 is connected with the control end of the upper bridge 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 with the control end of the lower bridge arm switching switch S2.

[0044] Specifically, the insulation detection method of the energy storage converter comprises:

[0045] Step S101, control the control interface of the controller 101 to output a target level.

[0046] Here, the output interface is a pin of the controller 101, and the target level can be a high level.

[0047] 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.

[0048] Step S103, after a second preset time, obtain a third test voltage of the positive bus and a fourth test voltage of the negative bus.

[0049] Step S104, determine whether the energy storage system has insulation abnormality according to the first test voltage, the second test voltage, the third test voltage and the fourth test voltage.

[0050] In this way, the controller 101 only needs to output a target level by using one control interface, and then four test voltages required for insulation detection can be obtained through the delay of the delay circuit, so as to determine whether the energy storage system has insulation abnormality.

[0051] The first preset time is a pre-set voltage stabilization delay time, and the second preset time is the sum of the delay time of the first delay circuit 102 and the pre-set voltage stabilization delay time.

[0052] 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, the voltage needs a certain time to stabilize, and at this time, the voltage detection of the positive bus and the negative bus is accurate. Therefore, the test voltage value obtained after the upper bridge arm switch or the lower bridge arm switch acts for a certain time must be ensured.

[0053] Similarly, after the control signal is delayed by the delay circuit, the upper bridge arm switching switch S2 is controlled, and a certain time is required to stabilize the positive bus and the negative bus, so the third test voltage of the positive bus and the fourth test voltage of the negative bus are obtained after the second preset time.

[0054] As an example, the controller 101 includes a DSP chip 1011 and an FPGA 1021, wherein the DSP (Digital Signal Processor) is a programmable microprocessor specially designed for digital signal processing, and its core function is to complete tasks such as signal acquisition, filtering, compression, and identification in real time through high-speed operation (such as multiplication and addition operations). The DSP (Digital Signal Processor) is a programmable microprocessor specially designed for digital signal processing, and its core function is to complete tasks such as signal acquisition, filtering, compression, and identification in real time through high-speed operation (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 scarce.

[0055] Please refer to Figure 4 In an optional embodiment, the insulation detection circuit further includes a first reverse circuit 301.

[0056] The input end of the first reverse circuit 301 is connected with the output end of the first delay circuit 102, and the output end of the first reverse circuit 301 is connected with the control end of the upper bridge arm switching switch S1.

[0057] Specifically, after the first reverse circuit 301 is added 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 the second preset time; and determining whether the energy storage system has insulation abnormalities according to the first test voltage, the second test voltage, the fifth test voltage, and the sixth test voltage.

[0058] Specifically, the method further includes: calculating third test equivalent resistances and fourth test equivalent resistances 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; and determining whether there is an insulation abnormality according to the third test equivalent resistance, the fourth test equivalent resistance, a first equivalent resistance threshold and a second equivalent resistance threshold preset.

[0059] 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 standard equivalent resistance, including: a first intermediate calculation parameter is calculated according to the first test voltage and the second test voltage; a second intermediate calculation parameter is calculated 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.

[0060] Here, it should be noted that there are four possible combinations of the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 in the detection of 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. The detection of whether the energy storage system has insulation abnormalities can be completed by selecting any two of the above four possible combinations of the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2.

[0061] However, the voltages of the positive bus and the negative bus detected in the two states of the upper bridge arm switching switch S1 being closed and the lower bridge arm switching switch S2 being open, and the upper bridge arm switching switch S1 being open and the lower bridge arm switching switch S2 being closed are the most accurate, and therefore, the application proposes an insulation detection circuit with a first reverse circuit 301.

[0062] In this way, when the control signal is delayed by the first delay circuit 102, the upper bridge arm switching switch S1 is controlled to be open while the lower bridge arm switching switch S2 is controlled to be closed, thereby forming the detection of the positive bus and the negative bus in the two states of the upper bridge arm switching switch S1 being closed and the lower bridge arm switching switch S2 being open, and the upper bridge arm switching switch S1 being open and the lower bridge arm switching switch S2 being closed.

[0063] For example, the first delay circuit 102 can be an RC delay circuit, which controls the charging and discharging time constant by adjusting the R / C value based on the resistance-capacitance charging and discharging principle. In a typical design, the subsequent circuit is triggered when the capacitor voltage reaches the threshold value, and the delay time can be calculated by the formula where U is the power supply voltage and Vt is the trigger voltage threshold.

[0064] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage stabilizing diode, for example, superimposing the voltage stabilizing value on the triode conduction voltage, significantly prolonging the delay time and reducing the capacitance capacity requirement, etc.

[0065] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters, and only the problem of triode failure to fully conduct due to excessive resistance needs to be considered. At the same time, tools such as Multisim can be used to simulate the RC charging and discharging process, and the consistency of the theoretical calculation results and the actual waveform can be verified to ensure the timing control accuracy.

[0066] Please continue to refer to Figure 4 In one embodiment, the insulation detection circuit further comprises a second delay circuit 302 and an anti-backflow circuit 303.

[0067] The input end of the second delay circuit 302 is connected with the output end of the second reverse circuit, the output end of the second delay circuit 302 is connected with the control end of the lower bridge arm switching switch S2, one end of the anti-backflow circuit 303 is connected with the output end of the first delay circuit 102, and the other end of the anti-backflow circuit 303 is connected with the control end of the lower bridge arm switching switch S2.

[0068] The delay time of the second delay circuit 302 is greater than the first preset time.

[0069] Here, through the delay of the second delay circuit 302 and the protection of the anti-backflow circuit 303, the lower bridge arm switching switch S2 can be disconnected after the switching action of the insulation detection circuit, so that the insulation detection circuit returns to the state that the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 are both disconnected.

[0070] In this way, the circuit stability of the energy storage battery is ensured, and the controller 101 does not need to record the current state of the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2, ensuring the simplicity and stability of the insulation detection program.

[0071] For example, the second delay circuit 302 can be an RC delay circuit, which controls the charging and discharging time constant by adjusting the R / C value based on the resistance-capacitance charging and discharging principle. In a typical design, the subsequent circuit is triggered when the capacitor voltage reaches the threshold value, and the delay time can be calculated by the formula where U is the power supply voltage and Vt is the trigger voltage threshold.

[0072] Optionally, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a voltage stabilizing diode, for example, superimposing the voltage stabilizing value on the triode conduction voltage, significantly prolonging the delay time and reducing the capacitance capacity requirement, etc.

[0073] Here, flexible delay is achieved by adjusting resistance or capacitance parameters, and only the problem of excessive resistance causing the transistor to fail to fully conduct needs to be noted. At the same time, tools such as Multisim can be used to simulate the RC charging and discharging process, and the consistency of the theoretical calculation results and the actual waveform can be verified to ensure the timing control accuracy.

[0074] The reverse circuit can use PMOS inverters and other elements (such as AO3401) to realize bidirectional conversion of high and low voltage logic signals, and the low on-resistance can reduce power consumption.

[0075] The anti-inversion circuit 303 can be implemented by a diode scheme, a single MOS tube scheme, a double MOS combination scheme, and an ideal diode circuit, among others. The diode scheme can block reverse current by connecting diodes in series. The single MOS tube scheme 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 on-state, and the forward conduction voltage is low. The double MOS combination scheme uses PMOS and NMOS in series (such as PMOS high side + NMOS low side) to block bidirectional inversion through complementary conduction logic. The ideal diode circuit uses a combination of transistors and MOS tubes to simulate diode characteristics, achieving low forward voltage drop and fast reverse blocking effect.

[0076] For details, please refer to Figure 2 , Figure 2 The equivalent circuit diagram for the insulation detection of the energy storage converter is shown, where 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. The values of these two insulation resistances can determine whether the energy storage system is abnormal.

[0077] For example, when the upper bridge arm switching switch S1 is open, the equivalent resistance of the upper bridge arm to the positive bus is: .

[0078] Where, .

[0079] Here, which is the fourth standard equivalent resistance.

[0080] When the upper bridge arm switching switch S1 is closed, the equivalent resistance of the upper bridge arm to the positive bus is: .

[0081] Where, .

[0082] Here, which is the first standard equivalent resistance.

[0083] When the lower bridge arm switching switch S2 is open, the equivalent resistance of the lower bridge arm added to the positive bus is: .

[0084] wherein, .

[0085] Here, is the second standard equivalent resistance.

[0086] When the lower bridge arm switching switch S2 is closed, the equivalent resistance of the lower bridge arm added to the positive bus is: .

[0087] wherein, .

[0088] Here, is the third standard equivalent resistance.

[0089] In this way, based on the above calculation formula of the equivalent resistance, when the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 are both open, assuming that the positive and negative bus voltages measured at this time are Up1 and Un1 respectively, then: .

[0090] When the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 are both closed, assuming that the positive and negative bus voltages measured at this time are Up2 and Un2 respectively, Up2 and Un2 are the third test voltage and the fourth test voltage respectively, then:

[0091] .

[0092] When the upper bridge arm switching switch S1 is closed and the lower bridge arm switching switch S2 is open, assuming that the positive and negative bus voltages measured at this time are Up3 and Un3 respectively, Up3 and Un3 are the first test voltage and the second test voltage respectively, then:

[0093] .

[0094] When the upper bridge arm switching switch S1 is open and the lower bridge arm switching switch S2 is closed, assuming that the positive and negative bus voltages measured at this time are Up4 and Un4 respectively, Up4 and Un4 are the fifth test voltage and the sixth test voltage respectively, then:

[0095] .

[0096] Taking the case of controlling the upper bridge arm switching switch S1 to be closed and the lower bridge arm switching switch S2 to be open, and then controlling the upper bridge arm switching switch S1 to be open and the lower bridge arm switching switch S2 to be closed, the insulation resistance of the positive bus BAT+ to ground Rx and the insulation resistance of the negative bus BAT- to ground Ry can be calculated by the following formulas:

[0097] First, in order to simplify the calculation, let:

[0098] , .

[0099] Then, the simultaneous equations are:

[0100] ; .

[0101] In this way, the insulation resistance of the positive bus bar BAT+ to ground can be calculated as Rx, and the insulation resistance of the negative bus bar BAT- to ground can be calculated as Ry. According to the insulation resistance of the positive bus bar BAT+ to ground and the insulation resistance of the negative bus bar BAT- to ground, it can be determined whether the energy storage system has insulation abnormalities.

[0102] The insulation detection method of the energy storage converter provided in the application increases 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 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 the first preset time and the 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 101 interface and avoids the reduction of the control and detection of the energy storage system due to the lack of available interfaces of the PCS controller 101.

[0103] It should be understood that, although each step in the flowchart involved in each embodiment as described above is displayed in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, at least part of the steps in the flowchart involved in each embodiment as described above can include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0104] Based on the same inventive concept, the application further provides an insulation detection circuit of the energy storage converter for implementing the insulation detection method of the energy storage converter. The implementation scheme for solving the problem provided by the circuit is similar to the implementation scheme described in the above method, and therefore the specific limitations in one or more insulation detection circuit embodiments of the energy storage converter provided below can refer to the limitations of the insulation detection method of the energy storage converter described above, which will not be described here again.

[0105] Please refer to Figure 2 In one exemplary embodiment, an insulation detection circuit of an energy storage converter is provided, which comprises 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 interface of the controller 101 is connected with the control end of the upper bridge 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 with the control end of the lower bridge arm switching switch S2.

[0106] For example, the first delay circuit 102 can be an RC delay circuit, which controls the charging and discharging time constant by adjusting the R / C value based on the resistance-capacitance charging and discharging principle. In a typical design, the subsequent circuit is triggered when the capacitor voltage reaches the threshold value, and the delay time can be calculated by the formula where U is the power supply voltage and Vt is the trigger voltage threshold.

[0107] Alternatively, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a stabilizing diode, for example, adding a stabilizing value to the transistor conduction voltage, which can significantly prolong the delay time and reduce the capacitance capacity requirement, etc.

[0108] Here, flexible delay is achieved by adjusting the resistance or capacitance parameters, and only the problem that excessive resistance may cause the transistor to be unable to fully conduct needs to be noted. At the same time, Multisim and other tools can be used to simulate the RC charging and discharging process, which can verify the consistency of the theoretical calculation results and the actual waveform, and ensure the timing control accuracy.

[0109] Please refer to Figure 3 In one embodiment, the insulation detection circuit further comprises a first reverse circuit 301, the input end of the first reverse circuit 301 is connected with the output end of the first delay circuit 102, and the output end of the first reverse circuit 301 is connected with the control end of the upper bridge arm switching switch S1.

[0110] Please continue to refer to Figure 3In one of the embodiments, the insulation detection circuit further comprises a second delay circuit 302 and an anti-backflow circuit 303, an input end of the second delay circuit 302 is connected with an output end of the second reverse circuit, an output end of the second delay circuit 302 is connected with a control end of the lower bridge arm switching switch S2, one end of the anti-backflow circuit 303 is connected with an output end of the first delay circuit 102, and the other end of the anti-backflow circuit 303 is connected with the control end of the lower bridge arm switching switch S2.

[0111] For example, the second delay circuit 302 can be an RC delay circuit, which controls the charging and discharging time constant by adjusting the R / C value based on the resistance-capacitance charging and discharging principle. In a typical design, the delay time can be calculated by the formula where U is the power supply voltage and Vt is the trigger voltage threshold.

[0112] Alternatively, the first delay circuit 102 can also be an improved RC circuit, which can increase the trigger voltage threshold by adding a stabilizing diode, for example, adding a stabilizing value to the transistor conduction voltage, which can significantly extend the delay time and reduce the required capacitance capacity, etc.

[0113] Here, flexible delay can be achieved by adjusting the resistance or capacitance parameters, and only the problem of excessive resistance that may cause the transistor to fail to fully conduct needs to be considered. At the same time, Multisim and other tools can be used to simulate the RC charging and discharging process, which can verify the consistency of the theoretical calculation results and the actual waveform, and ensure the timing control accuracy.

[0114] The reverse circuit can use PMOS inverters and other elements (such as AO3401) to realize bidirectional conversion of high and low voltage logic signals, and its low conduction resistance can reduce power consumption.

[0115] The anti-backflow circuit 303 can be realized by diode scheme, single MOS tube scheme, double MOS combination scheme, ideal diode circuit, etc. The diode scheme can block reverse current by connecting diodes in series; the single MOS tube scheme uses the body diode and gate control of PMOS or NMOS to realize unidirectional conduction, for example, in the PMOS anti-reverse connection circuit, the gate voltage controls the conduction state, and the forward conduction voltage drop is low; the double 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 uses a combination of transistors and MOS tubes to simulate the characteristics of diodes, achieving low forward voltage drop and fast reverse off effect.

[0116] In one example embodiment, a power storage system is provided, comprising: a battery pack; a thermal management subsystem; a management subsystem; a power storage converter, the power storage converter comprising the insulation detection circuit of any of the above embodiments, and a controller in the power storage converter configured to perform the insulation detection method of any of the above embodiments.

[0117] In one example embodiment, a power consuming device is provided, comprising the power storage system of any of the above embodiments.

[0118] The insulation detection method, circuit, power storage system and power consuming device of the above embodiments add a delay circuit between the controller 101 of the insulation detection circuit of the power storage converter and the lower bridge arm switching switch S2, so that one interface of the controller 101 can control the upper bridge arm switching switch S1 and the lower bridge arm switching switch S2 respectively. In combination with the control method of the controller 101, the insulation of the power storage system is detected by setting the first preset time and the second preset time corresponding to the delay time of the delay circuit, which ensures the insulation detection of the power storage system, reduces the use of the interface of the PCS controller 101, and avoids the situation that the PCS controller 101 cannot control and detect the power storage system due to no interface available.

[0119] The technical features of the above embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0120] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for detecting insulation of an energy storage converter, characterized in that: An insulation detection circuit applied to an energy storage converter includes a controller, a first delay circuit, an upper arm switching switch, and a lower arm switching switch. A control interface of the controller is connected to a control terminal of the upper arm switching switch and an input terminal of the first delay circuit, respectively. An output terminal of the first delay circuit is connected to a control terminal 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 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, the second preset time is the sum of the delay time of the first delay circuit and the preset voltage stabilization delay time, and the target level is a high level.

2. The insulation detection method for an 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 arm switching switch.

3. The insulation detection method for an 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; 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. The insulation detection method for an energy storage converter according to claim 2 or 3, characterized in that: The method further comprises: After a 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 the energy storage converter has insulation abnormality according to the first test voltage, the second test voltage, the fifth test voltage, and the sixth test voltage.

5. The insulation detection method for an energy storage converter according to claim 4, 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, 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.

6. The insulation detection method for an energy storage converter according to claim 5, characterized in that: The method further comprises: 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; 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, a preset first equivalent resistance threshold, and a preset second equivalent resistance threshold.

7. The insulation detection method for an energy storage converter according to claim 5, 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 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; 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.

8. The insulation detection method for an energy storage converter according to claim 2 or 3, characterized in that: The first delay circuit and the second delay circuit are RC delay circuits, and the method further includes: The delay time of the RC delay circuit is controlled by adjusting the resistance value and the capacitance value in the RC delay circuit.

9. An energy storage system, characterized in that: include: Battery pack; thermal management subsystem; Management subsystem; An energy storage converter, wherein the controller in the energy storage converter is used to execute the insulation detection method for the energy storage converter according to any one of claims 1 to 8.

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

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