Control method of direct-current guarding power supply system for electric power

Abstract

The invention relates to a control method of a direct-current guarding power supply system for electric power, the control method is applied to the direct-current guarding power supply system, and the direct-current guarding power supply system comprises a high-frequency switching power supply module, a direct-current switching power supply module and a direct-current switching power supply module, the output end of the high-frequency switching power supply module is connected with the positive direct-current bus and the negative direct-current bus; the storage battery groups are connected in series, and each storage battery group is electrically connected to the positive pole direct current bus and the negative pole direct current bus through a bidirectional direct current conversion module; each storage battery group comprises at least one storage battery; the control method comprises the following steps: step S1, a normal operation mode; s2, starting an automatic capacity checking mode of the storage battery; s3, starting an automatic activation mode of the storage battery; s4, starting a storage battery grouping equalization mode; and S5, starting a storage battery loop connectivity detection mode.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current power supply systems, and in particular relates to a control method for a direct current guard power supply system for electric power. Background Art

[0002] In the existing DC protection power supply system, in order to analyze the health status of the battery group, it is often necessary to check the capacity of the battery group. The current common solution is to configure two groups of battery groups in the DC protection power supply system, use the battery backup mode, and withdraw the battery group that needs to be checked from the DC system, and then check the capacity of the battery group. However, most of the current DC protection power supply systems are a group of batteries, so this solution cannot be applied. Alternatively, in other solutions, the charger output is directly adjusted to the minimum voltage value of the battery check capacity to discharge the battery group to achieve the effect of checking the battery capacity. However, in the process of checking the battery capacity of this solution, if the AC power supply is abnormal, the battery will be discharged because the check capacity has been emptied. At this time, the battery cannot power the DC bus, which will cause very serious consequences for the system.

[0003] To this end, the invention patent with publication number: CN114156963A discloses a battery online capacity verification method and a DC protection power supply system, constructs a battery online capacity verification method, and is applied to the DC protection power supply system. The DC protection power supply system includes: a first system structure or a second system structure; the first system structure includes: a battery pack, an AC / DC power supply module, a bidirectional DC / DC conversion module and an isolation module; the second system structure includes: a battery pack, an AC / DC power supply module and a bidirectional DC / DC conversion module; the battery pack includes: a plurality of sub-battery packs connected in series in sequence; The bidirectional DC / DC conversion module includes: a plurality of DC / DC sub-conversion modules arranged corresponding to the plurality of sub-battery groups; the method includes: step S11, determining the system structure of the DC protection power supply system; step S12, if the DC protection power supply system is a first system structure, using a first core capacity mode to control the plurality of DC / DC sub-conversion modules to perform group charging and discharging core capacity on the plurality of sub-battery groups; step S13, if the DC protection power supply system is a second system structure, using a second core capacity mode to control the plurality of DC / DC sub-conversion modules to perform group charging and discharging core capacity on the plurality of sub-battery groups.

[0004] Although the above-mentioned prior art provides the control logic of battery core capacity, the prior art still has the following technical defects: First, when a single battery is disconnected, the output voltage of the bidirectional DC conversion module forms a loop through the charging circuit of the entire battery group, resulting in abnormal sampling of the battery voltage of the bidirectional DC conversion module corresponding to the disconnected battery; Second, during the core capacity / activation process, the DC bus charges the entire battery group, affecting the accuracy of the core capacity / activation; Third, when the entire battery group is charged through the DC bus, the charging current cannot be carried out according to the charging curve when each group is charged evenly, and even overcharging occurs. This is the shortcoming of the prior art.

[0005] In view of this, it is very necessary for the present invention to provide a control method for a DC protection power supply system for electric power to solve the above-mentioned defects existing in the prior art. Summary of the invention

[0006] The purpose of the present invention is to address the technical defects existing in the above-mentioned existing technologies: first, when a single battery is disconnected, the output voltage of the bidirectional DC conversion module forms a loop through the charging circuit of the entire battery group, resulting in abnormal battery voltage sampling of the bidirectional DC conversion module corresponding to the disconnected battery; second, during the core capacity / activation process, the DC bus charges the entire battery group, affecting the accuracy of the core capacity / activation; third, the entire battery group is charged through the DC bus, resulting in the charging current being unable to follow the charging curve when each group is charged evenly, and even overcharging may occur. A control method for designing a DC protection power supply system for electric power is provided to solve the above-mentioned technical problems. To achieve the above object, the present invention provides the following technical solutions: A control method for a DC protection power supply system for electric power, the control method is applied to the DC protection power supply system, the DC protection power supply system comprising: A high-frequency switching power supply module, wherein the input end of the high-frequency switching power supply module is connected to an AC power supply, and the output end of the high-frequency switching power supply module is connected to a positive DC bus and a negative DC bus; At least three battery groups, each battery group is connected in series, each battery group is electrically connected to a positive DC bus and a negative DC bus through a bidirectional DC conversion module; each battery group includes at least one battery; A non-return diode, wherein the positive terminal of the non-return diode is connected to the positive terminal of the battery group, and the negative terminal of the non-return diode is connected to the positive DC bus; both ends of the non-return diode are connected in parallel with a relay switch; The control method comprises: Step S1: a step of a normal working mode, in which the parameters of the DC protection power supply system and the working state of the anti-reverse diode are initialized, and different working modes are switched according to specific circumstances; Step S2: starting the battery automatic capacity check mode. In this step, the starting instruction and starting conditions of the battery automatic capacity check mode are judged. If the starting instruction of the battery automatic capacity check mode is received and the starting conditions of the battery automatic capacity check mode are met, the system enters the battery automatic capacity check mode; otherwise, the system proceeds to step S3; Step S3: a step of starting the battery automatic activation mode, in which the starting instruction and starting conditions of the battery automatic activation mode are judged. If the starting instruction of the battery automatic activation mode is received and the starting conditions of the battery automatic activation mode are met, the system enters the battery automatic activation mode; otherwise, the system proceeds to step S4; Step S4: a step of starting the battery group balancing mode, in which the starting instruction and starting conditions of the battery group balancing mode are judged. If the starting instruction of the battery group balancing mode is received and the starting conditions of the battery group balancing mode are met, the system enters the battery group balancing mode; otherwise, the system proceeds to step S5; Step S5: a step of starting the battery loop connectivity detection mode. In this step, the start instruction and start conditions of the battery loop connectivity detection mode are judged. If the start instruction of the battery loop connectivity detection mode is received and the start conditions of the battery loop connectivity detection mode are met, the system enters the battery loop connectivity detection mode; otherwise, it proceeds to step S1.

[0007] Preferably, the steps of the normal operating mode include: Initialize the parameters of the DC protection power supply system and close the non-reverse diode; Initialize the charging module parameters, including: setting the equalization charge voltage to 2.35V*number of battery cells, setting the float charge voltage to 2.25V*number of battery cells, and setting the charging mode to float charge; Initialize the power supply module parameters, including: setting the output voltage to the nominal voltage of the DC bus; Initialize the parameters of the bidirectional DC conversion module, including: setting the bus side output voltage to 87.5%-100% of the DC bus nominal voltage; Determine whether it is necessary to switch to a different working mode according to the specific situation. If necessary, exit the normal working mode and switch to other modes. If not, monitor the system status to see whether the AC power input is normal. If normal, continue to close the relay switch and manage the charging of the battery pack. If the AC power input is abnormal, disconnect the relay switch and switch the charging working state to floating charge. At the same time, determine whether it is necessary to switch to a different working mode according to the specific situation.

[0008] In the normal operation mode, when the AC power input is disconnected, disconnecting the relay switch can effectively avoid the following technical problems: First, when a single battery is disconnected, the output voltage of the bidirectional DC conversion module forms a loop through the charging circuit of the entire battery group, resulting in abnormal sampling of the battery voltage of the bidirectional DC conversion module corresponding to the disconnected battery. Second, when the voltage of the entire battery group is lower than the output voltage of the bidirectional DC conversion module, the bidirectional DC conversion module outputs to charge the entire battery group, forming a current loop, causing ineffective loss of battery energy and affecting system stability.

[0009] Preferably, the steps of the battery automatic capacity verification mode in step S2 and the battery automatic activation mode in step S3 include: Disconnect the relay switch; The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group -2V; The current core capacity / activation module needs to be initialized, the current core capacity / activation module serial number is set to 1, and the current core capacity / activation module core capacity / activation stage is set to 1 (discharge stage); Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects the core capacity / activation, such as abnormal AC input, bidirectional DC conversion module failure, etc. If so, record the reason for the end of the core capacity / activation, and switch the system working mode to the normal working mode; if not, then: Determine whether the current core capacity / activation module core capacity / activation stage is 1 (discharge stage). If not, transfer to the current core capacity / activation module to charge the battery group and control it according to the charging management parameters of the battery group. If it is 1, then: Set the current core capacity / activation module discharge cut-off voltage. Set the core capacity / activation cut-off voltage according to the system parameters. The online core capacity cut-off voltage is set to 1.8V*the number of cells in this group, and the online activation cut-off voltage is set to 2.0V*the number of cells in this group. The current core capacity / activation module performs core capacity / activation discharge, and the bus-side output voltage of the current core capacity / activated bidirectional DC conversion module is adjusted to the equalizing charging voltage of the entire battery group; Determine whether the current core capacity / activation module meets the discharge end condition, that is, the battery voltage of this group is lower than the core capacity / activation cut-off voltage. If the condition is not met, the monitoring system state is entered and an abnormal situation alarm is issued; if the condition is met, then: Record the current core capacity / activated module core capacity / activated capacity; The current core capacity / activation module core capacity / activation stage is set to 2 (charging stage); The current core capacity / activation module charges the batteries of this group and controls them according to the charging management parameters of the batteries of this group; Determine whether the current core capacity / activation module meets the charging end conditions. If not, enter the monitoring system state and alarm for abnormal conditions; if the conditions are met, then: Record the current core capacity / activation module core capacity / activation complete record; The current core capacity / activation module working mode is switched to normal working state, that is, the bus side output voltage of the current core capacity / activation bidirectional DC ratio conversion module is set to 87.5%-100% of the DC bus nominal voltage; Current core capacity / activated module number +1 Determine whether the current core capacity / activated module number is greater than the number of bidirectional DC conversion modules in the system. If not, switch to the monitoring system state and alarm for abnormal situations. If yes, then: The reason for the end of nuclear capacity / activation is recorded, and the system working mode is switched to normal operation mode.

[0010] In the online nuclear capacity / activation mode, disconnecting the relay switch can solve the following technical problems: First, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, affecting the accuracy of nuclear capacity / activation; second, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, causing the nuclear capacity / activation group batteries to never reach the nuclear capacity / activation cut-off voltage, resulting in nuclear capacity / activation failure; third, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, causing overcharging of non-nuclear capacity / activation group batteries.

[0011] In the online capacity-adding / activation mode, the output voltage of the high-frequency switching power supply module is set to the battery group equalization charging voltage of -2V, which is greater than the battery group terminal voltage at any stage in the capacity-adding / activation process, including the battery group terminal voltage at the equalization charging stage of the battery group capacity-adding / activated battery. This effectively prevents the battery group discharge during the battery group capacity-adding / activation process from affecting the accuracy of capacity-adding / activation.

[0012] In the online capacity-reinforcing / activation mode, the output voltage of the current capacity-reinforcing / activated bidirectional DC conversion module is set to the average charging voltage of the entire battery group, which is greater than the output voltage of the high-frequency switching power supply module, ensuring that the DC bus is powered by the current capacity-reinforcing / activated bidirectional DC conversion module first, and the batteries in this group are discharged at the same time, so as to achieve the purpose of capacity-reinforcing / activation of this group of batteries.

[0013] Preferably, in step S4, the step of starting the battery group balancing mode includes: The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group; The current group balancing module serial number is initialized and the current group balancing module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects group balancing, such as abnormal AC input, bidirectional DC conversion module fault, etc. If there is a fault, record the reason for the end of group balancing, and switch the system working mode to normal operation mode. If there is no fault, then: The current group balancing module charges the batteries in this group according to the charging management parameters of the batteries in this group; Determine whether the current group balancing module meets the conditions for charging to end. If not, monitor the system status and alarm for abnormal situations. If the conditions are met, then: The working state of the current group balancing module is switched to the normal working mode, that is, the bus-side output voltage of the bidirectional DC conversion module of the current group balancing is set to 87.5%-100% of the DC bus nominal voltage; The current group balancing module serial number + 1; Determine whether the current group balancing module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If yes, then: The reason for the end of group balancing is recorded, and the system working mode is switched to normal operation mode.

[0014] In the group balancing mode, disconnecting the relay switch can effectively prevent the entire battery group from being charged through the DC bus, resulting in the charging current not being able to follow the charging curve when each group is balanced charged, or even overcharging.

[0015] In the group balancing mode, the output voltage of the charging module is set to the equalizing charging voltage of the entire battery group, which can effectively prevent the battery group voltage from being higher than the bus voltage when the batteries in each group are charged equally, causing the entire battery group to discharge, which in turn causes the batteries in each group to be unable to be fully charged and the group balancing goal cannot be achieved.

[0016] Preferably, the step S5 of starting the battery circuit connectivity detection mode comprises: Disconnect the relay switch; The output voltage of the charging module is adjusted to the nominal voltage of the DC bus; Determine whether the entire battery group has a short circuit. If not, record the reason for the end of the battery circuit connectivity test and switch the system working mode to the normal operating mode. If so, then: The current battery circuit connectivity detection module serial number is initialized, and the current battery circuit connectivity detection module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault in the battery circuit connectivity test, such as abnormal AC input, bidirectional DC conversion module failure, etc.; if there is a fault, record the reason for the end of the battery circuit connectivity test, and switch the system working mode to the normal working mode; if there is no fault, then: The current battery circuit connectivity detection module is discharging, and the bus-side output voltage of the bidirectional DC conversion module of the current battery circuit connectivity detection is adjusted to the average charging voltage of the entire battery group; Determine whether the battery group where the current battery circuit connectivity detection module is located has a circuit break. If not, the current battery circuit connectivity detection module working mode is switched to a normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; if it exists, then: Record the disconnection mark of the battery connectivity test of this group; The current battery circuit connectivity detection module working mode is switched to normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; Current battery circuit connectivity detection module serial number + 1; Determine whether the current battery circuit connectivity detection module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If so, record the reason for the end of the battery circuit connectivity detection and switch the system working mode to the normal operating mode.

[0017] In the battery circuit connectivity detection mode, disconnecting the relay switch can effectively prevent the output voltage of the bidirectional DC conversion module from forming a loop through the entire battery charging circuit when a single battery is broken, resulting in abnormal battery voltage sampling of the bidirectional DC conversion module corresponding to the broken battery, and the battery break cannot be effectively detected.

[0018] Preferably, in the step S2 of starting the automatic battery capacity verification mode, the start instruction and start condition of the automatic battery capacity verification mode are judged, wherein the start instruction includes: The bidirectional DC conversion module is started manually on site, the monitoring device is started manually, the background remote control is started (the monitoring device receives the start-up nuclear capacity command), and the monitoring device is started at a scheduled time; The start conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal (both the entire group and a single cell are normal), the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A (the battery is not depleted).

[0019] Preferably, in the step S3 of starting the automatic battery activation mode, the start instruction and start condition of the automatic battery activation mode are judged, and the start instruction includes: Manual start-up of the bidirectional DC conversion module on site, manual start-up of the monitoring device, remote start-up in the background (the monitoring device receives a start activation command), timed start-up of the monitoring device, and trigger conditions such as abnormal battery internal resistance and battery voltage identified by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal (both the entire group and a single cell are normal), the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A (the battery is not depleted).

[0020] Preferably, in the step S4 of starting the battery group balancing mode, the starting instruction and starting conditions of the battery group balancing mode are judged, and the starting instruction includes: The bidirectional DC conversion module is started manually on site, the monitoring device is started manually, the background remote control is started (the monitoring device receives the start group balancing command), the monitoring device is started regularly, and the voltage deviation of the battery group terminal identified by the monitoring device exceeds the set value; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, and the battery is in floating charge state.

[0021] Preferably, in the step S5 of the battery circuit connectivity detection mode, the start instruction and start condition of the battery circuit connectivity detection mode are judged, and the start instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started (the monitoring device receives the start activation command), the monitoring device is started at a scheduled time, and the abnormal trigger conditions recognized by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, and the DC bus load current is normal.

[0022] The beneficial effect of the present invention is that, through the technical solution of the present application, the following technical problems existing in the prior art are effectively solved: First, when a single battery is disconnected, the output voltage of the bidirectional DC conversion module forms a loop through the charging circuit of the entire battery group, resulting in abnormal sampling of the battery voltage of the bidirectional DC conversion module corresponding to the disconnected battery; Second, during the core capacity / activation process, the DC bus charges the entire battery group, affecting the accuracy of the core capacity / activation; Third, when the entire battery group is charged through the DC bus, the charging current cannot be carried out according to the charging curve when each group is balanced charged, and even overcharging occurs. In addition, the design principle of the present invention is reliable, the structure is simple, and it has a very broad application prospect.

[0023] It can be seen that compared with the prior art, the present invention has outstanding substantive features and significant progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0025] Figure 1 It is a principle block diagram of a DC protection power supply system to which a control method for a DC protection power supply system for electric power provided by the present invention is applied.

[0026] Figure 2 It is a flow chart of a control method of a DC guard power supply system for electric power provided by the present invention.

[0027] Figure 3 It is a detailed flow chart of a control method of a DC guard power supply system for electric power provided by the present invention.

[0028] Figure 4 It is a flow chart of the normal operation mode of the DC protection power supply.

[0029] Figure 5 It is the DC protection power supply online core capacity_activation mode flow chart.

[0030] Figure 6 It is the flow chart of the DC guard power supply group balancing mode.

[0031] Figure 7 This is the flow chart of the DC guard power supply battery circuit connectivity detection mode.

[0032] Among them, 1-high frequency switching power supply module, 2-AC power supply, 3-positive DC bus, 4-negative DC bus, 5-battery grouping, 6-bidirectional DC conversion module, 7-monitoring device, 8-reverse diode, 9-relay switch. DETAILED DESCRIPTION

[0033] The present invention will be described in detail below with reference to the accompanying drawings and through specific embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following implementation modes.

[0034] like Figures 1 to 7 As shown, this embodiment provides a control method for a DC protection power supply system for electric power, and the control method is applied to the DC protection power supply system, and the DC protection power supply system includes: A high-frequency switching power supply module 1, wherein the input end of the high-frequency switching power supply module 1 is connected to an AC power supply 2, and the output end of the high-frequency switching power supply module 1 is connected to a positive DC bus 3 and a negative DC bus 4; At least three battery groups 5, each battery group 5 is connected in series, each battery group 5 is electrically connected to the positive DC bus 3 and the negative DC bus 4 through a bidirectional DC conversion module 6; each battery group includes at least one battery; A non-return diode 8, wherein the positive terminal of the non-return diode 8 is connected to the positive terminal of the battery group, and the negative terminal of the non-return diode is connected to the positive DC bus; both ends of the non-return diode are connected in parallel with a relay switch 9; The control method comprises: Step S1: a step of a normal operation mode, in which the parameters of the DC protection power supply system and the working state of the anti-reverse diode are initialized, and different working modes are switched according to specific circumstances; Step S2: a step of starting the battery automatic capacity verification mode, in which the starting instruction and starting conditions of the battery automatic capacity verification mode are judged. If the starting instruction of the battery automatic capacity verification mode is received and the starting conditions of the battery automatic capacity verification mode are met, the system enters the battery automatic capacity verification mode; otherwise, the system proceeds to step S3; wherein the starting instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started (the monitoring device receives the start-up nuclear capacity command), and the monitoring device 7 is started at a scheduled time; The start conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal (both the entire group and a single cell are normal), the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A (the battery is not depleted).

[0035] Step S3: a step of starting the battery automatic activation mode, in which the start instruction and start conditions of the battery automatic activation mode are judged. If the start instruction of the battery automatic activation mode is received and the start conditions of the battery automatic activation mode are met, the system enters the battery automatic activation mode; otherwise, the system proceeds to step S4; wherein the start instruction includes: Manual start-up of the bidirectional DC conversion module on site, manual start-up of the monitoring device, remote start-up in the background (the monitoring device receives a start activation command), timed start-up of the monitoring device, and trigger conditions such as abnormal battery internal resistance and battery voltage identified by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal (both the entire group and a single cell are normal), the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A (the battery is not depleted).

[0036] Step S4: a step of starting the battery group balancing mode, in which the starting instruction and starting conditions of the battery group balancing mode are judged. If the starting instruction of the battery group balancing mode is received and the starting conditions of the battery group balancing mode are met, the system enters the battery group balancing mode; otherwise, the system proceeds to step S5; wherein the starting instruction and starting conditions of the battery group balancing mode are judged, and the starting instruction includes: The bidirectional DC conversion module is started manually on site, the monitoring device is started manually, the background remote control is started (the monitoring device receives the start group balancing command), the monitoring device is started regularly, and the voltage deviation of the battery group terminal identified by the monitoring device exceeds the set value; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, and the battery is in floating charge state.

[0037] Step S5: a step of starting the battery circuit connectivity detection mode, in which the start instruction and start conditions of the battery circuit connectivity detection mode are judged. If the start instruction of the battery circuit connectivity detection mode is received and the start conditions of the battery circuit connectivity detection mode are met, the system enters the battery circuit connectivity detection mode; otherwise, the system proceeds to step S1. The start instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started (the monitoring device receives the start activation command), the monitoring device is started at a scheduled time, and the abnormal trigger conditions recognized by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module (charging module, discharging module) is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, and the DC bus load current is normal.

[0038] In this embodiment, the steps of the normal operating mode include: Initialize the parameters of the DC protection power supply system and close the non-reverse diode; Initialize the charging module parameters, including: setting the equalization charge voltage to 2.35V*number of battery cells, setting the float charge voltage to 2.25V*number of battery cells, and setting the charging mode to float charge; Initialize the power supply module parameters, including: setting the output voltage to the nominal voltage of the DC bus; Initialize the parameters of the bidirectional DC conversion module, including: setting the bus side output voltage to 87.5%-100% of the DC bus nominal voltage; Determine whether it is necessary to switch to a different working mode according to the specific situation. If necessary, exit the normal operating mode and switch to other modes. If not, monitor the system status to see whether the AC power input is normal. If normal, continue to close the relay switch and manage the charging of the battery pack. If the AC power input is abnormal, disconnect the relay switch and switch the charging working state to floating charge. At the same time, determine whether it is necessary to switch to a different working mode according to the specific situation.

[0039] In the normal operation mode, when the AC power input is disconnected, disconnecting the relay switch can effectively avoid the following technical problems: First, when a single battery is disconnected, the output voltage of the bidirectional DC conversion module forms a loop through the charging circuit of the entire battery group, resulting in abnormal sampling of the battery voltage of the bidirectional DC conversion module corresponding to the disconnected battery. Second, when the voltage of the entire battery group is lower than the output voltage of the bidirectional DC conversion module, the bidirectional DC conversion module outputs to charge the entire battery group, forming a current loop, causing ineffective loss of battery energy and affecting system stability.

[0040] In this embodiment, the steps of the battery automatic capacity verification mode in step S2 and the battery automatic activation mode in step S3 include: Disconnect the relay switch; The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group -2V; The current core capacity / activation module needs to be initialized, the current core capacity / activation module serial number is set to 1, and the current core capacity / activation module core capacity / activation stage is set to 1 (discharge stage); Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects the core capacity / activation, such as abnormal AC input, bidirectional DC conversion module failure, etc. If so, record the reason for the end of the core capacity / activation, and switch the system working mode to the normal operation mode; if not, then: Determine whether the current core capacity / activation module core capacity / activation stage is 1 (discharge stage). If not, transfer to the current core capacity / activation module to charge the battery group and control it according to the charging management parameters of the battery group. If it is 1, then: Set the current core capacity / activation module discharge cut-off voltage. Set the core capacity / activation cut-off voltage according to the system parameters. The online core capacity cut-off voltage is set to 1.8V*the number of cells in this group, and the online activation cut-off voltage is set to 2.0V*the number of cells in this group. The current core capacity / activation module performs core capacity / activation discharge, and the bus-side output voltage of the current core capacity / activated bidirectional DC conversion module is adjusted to the equalizing charging voltage of the entire battery group; Determine whether the current core capacity / activation module meets the discharge end condition, that is, the battery voltage of this group is lower than the core capacity / activation cut-off voltage. If the condition is not met, the monitoring system state is entered and an abnormal situation alarm is issued; if the condition is met, then: Record the current core capacity / activated module core capacity / activated capacity; The current core capacity / activation module core capacity / activation stage is set to 2 (charging stage); The current core capacity / activation module charges the batteries of this group and controls them according to the charging management parameters of the batteries of this group; Determine whether the current core capacity / activation module meets the charging end conditions. If not, enter the monitoring system state and alarm for abnormal conditions; if the conditions are met, then: Record the current core capacity / activation module core capacity / activation complete record; The current core capacity / activation module working mode is switched to normal working state, that is, the bus side output voltage of the current core capacity / activation bidirectional DC ratio conversion module is set to 87.5%-100% of the DC bus nominal voltage; Current core capacity / activated module number +1; Determine whether the current core capacity / activated module number is greater than the number of bidirectional DC conversion modules in the system. If not, switch to the monitoring system state and alarm for abnormal situations. If yes, then: The reason for the end of nuclear capacity / activation is recorded, and the system working mode is switched to normal operation mode.

[0041] In the online nuclear capacity / activation mode, disconnecting the relay switch can solve the following technical problems: First, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, affecting the accuracy of nuclear capacity / activation; second, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, causing the nuclear capacity / activation group batteries to never reach the nuclear capacity / activation cut-off voltage, resulting in nuclear capacity / activation failure; third, prevent the DC bus from charging the entire battery group during the nuclear capacity / activation process, causing overcharging of non-nuclear capacity / activation group batteries.

[0042] In the online capacity-adding / activation mode, the output voltage of the high-frequency switching power supply module is set to the battery group equalization charging voltage of -2V, which is greater than the battery group terminal voltage at any stage in the capacity-adding / activation process, including the battery group terminal voltage at the equalization charging stage of the battery group capacity-adding / activated battery. This effectively prevents the battery group discharge during the battery group capacity-adding / activation process from affecting the accuracy of capacity-adding / activation.

[0043] In the online capacity-reinforcing / activation mode, the output voltage of the current capacity-reinforcing / activated bidirectional DC conversion module is set to the average charging voltage of the entire battery group, which is greater than the output voltage of the high-frequency switching power supply module, ensuring that the DC bus is powered by the current capacity-reinforcing / activated bidirectional DC conversion module first, and the batteries in this group are discharged at the same time, so as to achieve the purpose of capacity-reinforcing / activation of this group of batteries.

[0044] In this embodiment, in step S4, the step of starting the battery group balancing mode includes: The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group; The current group balancing module serial number is initialized and the current group balancing module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects group balancing, such as abnormal AC input, bidirectional DC conversion module fault, etc. If there is a fault, record the reason for the end of group balancing, and switch the system working mode to normal operation mode. If there is no fault, then: The current group balancing module charges the batteries in this group according to the charging management parameters of the batteries in this group; Determine whether the current group balancing module meets the conditions for charging to end. If not, monitor the system status and alarm for abnormal situations. If the conditions are met, then: The working state of the current group balancing module is switched to the normal operation mode, that is, the bus-side output voltage of the bidirectional DC conversion module of the current group balancing is set to 87.5%-100% of the DC bus nominal voltage; The current group balancing module serial number + 1; Determine whether the current group balancing module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If yes, then: The reason for the end of group balancing is recorded, and the system working mode is switched to normal operation mode.

[0045] In the group balancing mode, disconnecting the relay switch can effectively prevent the entire battery group from being charged through the DC bus, resulting in the charging current not being able to follow the charging curve when each group is balanced charged, or even overcharging.

[0046] In the group balancing mode, the output voltage of the charging module is set to the equalizing charging voltage of the entire battery group, which can effectively prevent the battery group voltage from being higher than the bus voltage when the batteries in each group are charged equally, causing the entire battery group to discharge, which in turn causes the batteries in each group to be unable to be fully charged and the group balancing goal cannot be achieved.

[0047] In this embodiment, the step S5 of starting the battery circuit connectivity detection mode includes: Disconnect the relay switch; The output voltage of the charging module is adjusted to the nominal voltage of the DC bus; Determine whether the entire battery group has a short circuit. If not, record the reason for the end of the battery circuit connectivity test and switch the system working mode to the normal operating mode. If so, then: The current battery circuit connectivity detection module serial number is initialized, and the current battery circuit connectivity detection module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault in the battery circuit connectivity test, such as abnormal AC input, bidirectional DC conversion module fault, etc.; if there is a fault, record the reason for the end of the battery circuit connectivity test, and switch the system working mode to the normal operation mode; if there is no fault, then: The current battery circuit connectivity detection module is discharging, and the bus-side output voltage of the bidirectional DC conversion module of the current battery circuit connectivity detection is adjusted to the average charging voltage of the entire battery group; Determine whether the battery group where the current battery circuit connectivity detection module is located has a circuit break. If not, the current battery circuit connectivity detection module working mode is switched to a normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; if it exists, then: Record the disconnection mark of the battery connectivity test of this group; The current battery circuit connectivity detection module working mode is switched to normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; Current battery circuit connectivity detection module serial number + 1; Determine whether the current battery circuit connectivity detection module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If so, record the reason for the end of the battery circuit connectivity detection and switch the system working mode to the normal operating mode.

[0048] In the battery circuit connectivity detection mode, disconnecting the relay switch can effectively prevent the output voltage of the bidirectional DC conversion module from forming a loop through the entire battery charging circuit when a single battery is broken, resulting in abnormal battery voltage sampling of the bidirectional DC conversion module corresponding to the broken battery, and the battery break cannot be effectively detected.

[0049] The above disclosure is only a preferred embodiment of the present invention, but the present invention is not limited thereto. Any non-creative changes that can be thought of by a person skilled in the art, as well as several improvements and modifications made without departing from the principle of the present invention, should fall within the protection scope of the present invention.

Claims

1. A control method for a DC protection power supply system for electric power, the control method is applied to a DC protection power supply system, characterized in that: The DC protection power supply system comprises: A high-frequency switching power supply module, wherein the input end of the high-frequency switching power supply module is connected to an AC power supply, and the output end of the high-frequency switching power supply module is connected to a positive DC bus and a negative DC bus; At least three battery groups, each battery group is connected in series, each battery group is electrically connected to a positive DC bus and a negative DC bus through a bidirectional DC conversion module; each battery group includes at least one battery; A non-return diode, wherein the positive terminal of the non-return diode is connected to the positive terminal of the battery group, and the negative terminal of the non-return diode is connected to the positive DC bus; both ends of the non-return diode are connected in parallel with a relay switch; The control method comprises: Step S1: a step of a normal operation mode, in which the parameters of the DC protection power supply system and the working state of the anti-reverse diode are initialized, and different working modes are switched according to specific circumstances; Step S2: starting the battery automatic capacity check mode. In this step, the starting instruction and starting conditions of the battery automatic capacity check mode are judged. If the starting instruction of the battery automatic capacity check mode is received and the starting conditions of the battery automatic capacity check mode are met, the system enters the battery automatic capacity check mode; otherwise, the system proceeds to step S3; Step S3: a step of starting the battery automatic activation mode, in which the starting instruction and starting conditions of the battery automatic activation mode are judged. If the starting instruction of the battery automatic activation mode is received and the starting conditions of the battery automatic activation mode are met, the system enters the battery automatic activation mode; otherwise, the system proceeds to step S4; Step S4: a step of starting the battery group balancing mode, in which the starting instruction and starting conditions of the battery group balancing mode are judged. If the starting instruction of the battery group balancing mode is received and the starting conditions of the battery group balancing mode are met, the system enters the battery group balancing mode; otherwise, the system proceeds to step S5; Step S5: a step of starting the battery loop connectivity detection mode. In this step, the start instruction and start conditions of the battery loop connectivity detection mode are judged. If the start instruction of the battery loop connectivity detection mode is received and the start conditions of the battery loop connectivity detection mode are met, the system enters the battery loop connectivity detection mode; otherwise, it proceeds to step S1.

2. A control method for a DC protection power supply system for electric power according to claim 1, characterized in that: The steps of the normal operation mode include: Initialize the parameters of the DC protection power supply system and close the non-reverse diode; Initialize the charging module parameters, including: setting the equalization charge voltage to 2.35V*number of battery cells, setting the float charge voltage to 2.25V*number of battery cells, and setting the charging mode to float charge; Initialize the power supply module parameters, including: setting the output voltage to the nominal voltage of the DC bus; Initialize the parameters of the bidirectional DC conversion module, including: setting the bus side output voltage to 87.5%-100% of the DC bus nominal voltage; Determine whether it is necessary to switch to a different working mode according to the specific situation. If necessary, exit the normal operating mode and switch to other modes. If not, monitor the system status to see whether the AC power input is normal. If normal, continue to close the relay switch and manage the charging of the battery pack. If the AC power input is abnormal, disconnect the relay switch and switch the charging working state to floating charge. At the same time, determine whether it is necessary to switch to a different working mode according to the specific situation.

3. A control method for a DC protection power supply system for electric power according to claim 2, characterized in that: The steps of the battery automatic capacity verification mode in step S2 and the battery automatic activation mode in step S3 include: Disconnect the relay switch; The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group -2V; The current core capacity / activation module needs to be initialized, the current core capacity / activation module sequence number is set to 1, and the current core capacity / activation module core capacity / activation stage is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects the nuclear capacity / activation. If so, record the reason for the end of nuclear capacity / activation and switch the system working mode to the normal operation mode. If not, then: Determine whether the current core capacity / activation module core capacity / activation stage is 1. If not, transfer to the current core capacity / activation module to charge the battery group and control it according to the battery charging management parameters of the battery group; if it is 1, then: Set the current core capacity / activation module discharge cut-off voltage. Set the core capacity / activation cut-off voltage according to the system parameters. The online core capacity cut-off voltage is set to 1.8V*the number of cells in this group, and the online activation cut-off voltage is set to 2.0V*the number of cells in this group. The current core capacity / activation module performs core capacity / activation discharge, and the bus-side output voltage of the current core capacity / activated bidirectional DC conversion module is adjusted to the equalizing charging voltage of the entire battery group; Determine whether the current core capacity / activation module meets the discharge end condition, that is, the battery voltage of this group is lower than the core capacity / activation cut-off voltage. If the condition is not met, the monitoring system state is entered and an abnormal situation alarm is issued; if the condition is met, then: Record the current core capacity / activated module core capacity / activated capacity; The current core capacity / activation module core capacity / activation stage is set to 2 (charging stage); The current core capacity / activation module charges the batteries of this group and controls them according to the charging management parameters of the batteries of this group; Determine whether the current core capacity / activation module meets the charging end conditions. If not, enter the monitoring system state and alarm for abnormal conditions; if the conditions are met, then: Record the current core capacity / activation module core capacity / activation complete record; The current core capacity / activation module working mode is switched to normal working state, that is, the bus side output voltage of the current core capacity / activation bidirectional DC ratio conversion module is set to 87.5%-100% of the DC bus nominal voltage; Current core capacity / activated module number +1 Determine whether the current core capacity / activated module number is greater than the number of bidirectional DC conversion modules in the system. If not, switch to the monitoring system state and alarm for abnormal situations. If yes, then: The reason for the end of nuclear capacity / activation is recorded, and the system working mode is switched to normal operation mode.

4. A control method for a DC protection power supply system for electric power according to claim 3, characterized in that: In step S4, the step of starting the battery group balancing mode includes: The output voltage of the charging module is adjusted to the average charging voltage of the entire battery group; The current group balancing module serial number is initialized and the current group balancing module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault that affects group balancing. If there is a fault, record the reason for the end of group balancing, and switch the system working mode to the normal operation mode. If there is no fault, then: The current group balancing module charges the batteries in this group according to the charging management parameters of the batteries in this group; Determine whether the current group balancing module meets the conditions for charging to end. If not, monitor the system status and alarm for abnormal situations. If the conditions are met, then: The working state of the current group balancing module is switched to the normal operation mode, that is, the bus-side output voltage of the bidirectional DC conversion module of the current group balancing is set to 87.5%-100% of the DC bus nominal voltage; The current group balancing module serial number + 1; Determine whether the current group balancing module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If yes, then: The reason for the end of group balancing is recorded, and the system working mode is switched to normal operation mode.

5. A control method for a DC protection power supply system for electric power according to claim 4, characterized in that: The step S5 of starting the battery circuit connectivity detection mode includes: Disconnect the relay switch; The output voltage of the charging module is adjusted to the nominal voltage of the DC bus; Determine whether the entire battery group has a short circuit. If not, record the reason for the end of the battery circuit connectivity test and switch the system working mode to the normal operating mode. If so, then: The current battery circuit connectivity detection module serial number is initialized, and the current battery circuit connectivity detection module serial number is set to 1; Monitor system status and alarm for abnormal situations; Determine whether there is a system fault in the battery circuit connectivity test. If there is a fault, record the reason for the end of the battery circuit connectivity test and switch the system working mode to the normal operating mode. If there is no fault, then: The current battery circuit connectivity detection module is discharging, and the bus-side output voltage of the bidirectional DC conversion module of the current battery circuit connectivity detection is adjusted to the average charging voltage of the entire battery group; Determine whether the battery group where the current battery circuit connectivity detection module is located has a circuit break. If not, the current battery circuit connectivity detection module working mode is switched to a normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; if it exists, then: Record the disconnection mark of the battery connectivity test of this group; The current battery circuit connectivity detection module working mode is switched to normal working state, that is, the output voltage of the current core capacity / activated bidirectional DC conversion module bus is set to 78.5%-100% of the DC bus nominal voltage; Current battery circuit connectivity detection module serial number + 1; Determine whether the current battery circuit connectivity detection module serial number is greater than the number of system bidirectional DC conversion modules. If not, monitor the system status and alarm for abnormal situations. If so, record the reason for the end of the battery circuit connectivity detection and switch the system working mode to the normal operating mode.

6. A control method for a DC protection power supply system for electric power according to claim 5, characterized in that: In the step S2 of starting the automatic battery capacity check mode, the start instruction and start condition of the automatic battery capacity check mode are judged, wherein the start instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started, and the monitoring device is started at a scheduled time; The start conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal, the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A.

7. A control method for a DC protection power supply system for electric power according to claim 6, characterized in that: In the step S3 of starting the automatic battery activation mode, the start instruction and start condition of the automatic battery activation mode are judged, and the start instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started, the monitoring device is started at a fixed time, and the battery internal resistance and battery voltage abnormal trigger conditions identified by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, the battery voltage is normal, the battery internal resistance is normal, the battery is in floating charge state, and the battery float charge current is less than 0.01A.

8. A control method for a DC protection power supply system for electric power according to claim 7, characterized in that: In the step S4 of starting the battery group balancing mode, the starting instruction and starting conditions of the battery group balancing mode are judged, and the starting instruction includes: The bidirectional DC conversion module is started manually on site, the monitoring device is started manually, the background remote control is started, the monitoring device is started regularly, and the voltage deviation of the battery group terminal identified by the monitoring device exceeds the set value; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, the DC bus load current is normal, and the battery is in floating charge state.

9. A control method for a DC protection power supply system for electric power according to claim 8, characterized in that: In the step S5 of the battery circuit connectivity detection mode, the start instruction and start condition of the battery circuit connectivity detection mode are judged, and the start instruction includes: The bidirectional DC conversion module is manually started locally, the monitoring device is manually started, the background remote control is started, the monitoring device is started at a fixed time, and the abnormal trigger conditions recognized by the monitoring device; The starting conditions include: The system is in normal operating mode, the AC power input is normal, the high-frequency switching power supply module is normal, the bidirectional DC conversion module is normal, the DC bus voltage is normal, and the DC bus load current is normal.

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