Energy storage battery cluster parallel control system and method and energy storage system

Abstract

The invention relates to an energy storage battery cluster parallel control system, an energy storage system, a parallel control method and a controller. The control system comprises a controller, a driving unit, a first semiconductor device, a second semiconductor device and a switching device. The first semiconductor device and the second semiconductor device are configured to have a current amplification effect and form a series branch, and the conduction directions of the first semiconductor device and the second semiconductor device are opposite on the series branch. Under the condition that the number of the switch equipment is one, the switch equipment is connected with the series branch in series or in parallel to form a control branch; when the number of the switch devices is multiple, the switch devices are divided into a first switch device and a second switch device, the first switch device is connected with the series branch in series, and the second switch device is connected with the first switch device and the series branch in parallel to form a control branch. The current on the loop is dynamically adjusted by using the conduction, cut-off and amplification effects of the semiconductor module, so that the impact of instant large current on the switch equipment when the battery clusters are connected in parallel is avoided, and the safety is high.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage, and particularly to a parallel connection control system for energy storage battery clusters, an energy storage system, a parallel connection control method for energy storage battery clusters, and a controller. Background Art

[0002] In order to meet the requirements of high voltage, large capacity, and strong current in the energy storage system, the parallel connection of battery clusters is usually adopted. When the battery clusters are connected in parallel, if there are voltage differences among the clusters, the high-voltage clusters will flow current to the low-voltage clusters, forming an uncontrolled circulating current; this uncontrolled circulating current is likely to cause overcharging and over-discharging of the system, damage the battery health, lead to thermal runaway, and even cause electrical fire safety hazards if the large current overheats.

[0003] To prevent the instantaneous large current impact when the battery clusters are connected in parallel, the currently common method is to connect a new battery cluster and an already paralleled battery cluster through a pre-charge resistor before paralleling the new battery cluster, so that charge and discharge occur between the two battery clusters. As the charge and discharge proceed, the voltage difference between the two battery clusters will decrease. When the voltage difference decreases to a safe range, the main switch in the new battery cluster circuit is closed, and the pre-charge resistor is removed to complete the parallel connection of the new battery cluster. Although this solution can solve the problem of current impact during parallel connection, this solution will cause the pre-charge resistor to overheat, and it is easy to have safety accidents when the parallel connection time is too long. In addition, other methods also include using a DC-DC converter to connect between the battery clusters or within the clusters, that is, balancing the voltages of each cluster through active energy transfer to reduce the voltage difference to suppress the circulating current. However, this solution requires complex circuit design and control algorithms, has a high cost, and due to the large number of additional devices, the system loss is large and the efficiency is low. Summary of the Invention

[0004] Based on this, it is necessary to provide a parallel connection control system for energy storage battery clusters, an energy storage system, a parallel connection control method for energy storage battery clusters, and a controller for the above technical problems.

[0005] In a first aspect, the present application provides a parallel control system for energy storage battery clusters, including a controller, a driving unit signal-connected to the controller, and a first semiconductor device, a second semiconductor device, and at least one switching device respectively signal-connected to the driving unit; both the first semiconductor device and the second semiconductor device are configured to have a current amplification effect, and the two form a series branch with opposite conduction directions on the series branch; when the number of the switching devices is one, the switching device is connected in series or in parallel with the series branch to form a control branch; when the number of the switching devices is multiple, they are divided into a first switching device and a second switching device, the first switching device is connected in series with the series branch, and the second switching device is connected in parallel with the first switching device and the series branch to form a control branch; the anode of the control branch is used to connect to the positive pole of the energy storage DC bus, and the cathode of the control branch is used to connect to the negative pole of the energy storage DC bus through a battery cluster.

[0006] In one embodiment, the first semiconductor device and the second semiconductor device are respectively a triode, a MOS transistor or a composite transistor, and the composite transistor is composed of multiple triodes, multiple MOS transistors or a triode and a MOS transistor.

[0007] In one embodiment, the switching device is a mechanical relay.

[0008] In a second aspect, the present application further provides an energy storage system, which includes a plurality of the above control systems, a plurality of battery clusters corresponding to the control systems one by one, and an energy storage DC bus, and each battery cluster is connected in parallel to the energy storage DC bus through the corresponding control system.

[0009] In a third aspect, the present application further provides a method for controlling the parallel connection of energy storage battery clusters, which is applied to the controller in the above control system. Wherein, the number of the switching devices is one and the switching device is connected in series with the series branch. The method includes:

[0010] When both the first semiconductor device and the second semiconductor device are in the cut-off state and the switching device is disconnected, in response to an instruction to connect a target battery cluster in parallel to the energy storage DC bus, a first closing instruction is sent to the driving unit; the first closing instruction is used to instruct the driving unit to close the switching device;

[0011] When it is determined that the switching device is closed, a first main control instruction is sent to the driving unit; the first main control instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off region to the amplification region to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charge and discharge between different battery clusters;

[0012] In response to detecting that the voltage difference values of all battery clusters are less than a first set threshold, send a first conduction instruction to the driving unit; the first conduction instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter the conduction region.

[0013] In one embodiment, after the step of sending the first conduction instruction to the driving unit, the method further includes:

[0014] Detect a fault signal or an exit instruction corresponding to the target battery cluster;

[0015] Send a second main control instruction to the driving unit corresponding to the target battery cluster; the second main control instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster;

[0016] In response to detecting that the output current of the target battery cluster is less than a first safety threshold, send a first cut-off instruction to the driving unit; the first cut-off instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region;

[0017] When it is determined that the first cut-off instruction has been executed, send a first disconnection instruction to the driving unit; the disconnection instruction is used to instruct the driving unit to disconnect the switching device.

[0018] In a fourth aspect, the present application further provides a method for controlling the parallel connection of energy storage battery clusters, which is applied to a controller in the above control system. Wherein, the number of the switching devices is one and the switching device is connected in parallel with the series branch. The method includes:

[0019] When the first semiconductor device and the second semiconductor device are both in the cut-off state and the switching device is disconnected, in response to an instruction to connect a target battery cluster to the energy storage DC bus, send a third main control instruction to the driving unit corresponding to the target battery cluster; the third main control instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to switch from the cut-off region to the amplification region, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charge and discharge between different battery clusters;

[0020] In response to detecting that the voltage difference values of all battery clusters are less than a second set threshold, send a second closing instruction to the driving unit; the second closing instruction is used to instruct the driving unit to close the switching device;

[0021] When it is determined that the switch device is closed, a second cut-off instruction is sent to the drive unit; the second cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0022] In one embodiment, after the step of sending the second cut-off instruction to the drive unit, the method further includes:

[0023] Detecting a fault signal or an exit instruction corresponding to the target battery cluster;

[0024] Sending a second conduction instruction to the drive unit corresponding to the target battery cluster; the second conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction region to increase the current of the series branch;

[0025] When it is determined that the current flowing through the series branch is greater than or equal to the second safety threshold, a second cut-off instruction is sent to the drive unit; the second cut-off instruction is used to instruct the drive unit to disconnect the switch device;

[0026] When it is determined that the switch device is disconnected, a fourth main control instruction is sent to the drive unit; the fourth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region, so as to control the conduction degree of the first semiconductor device and the second semiconductor device and gradually reduce the output current of the target battery cluster;

[0027] In response to detecting that the output current of the target battery cluster is less than the third safety threshold, a third cut-off instruction is sent to the drive unit; the third cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0028] In a fifth aspect, the present application further provides a method for controlling the parallel connection of energy storage battery clusters, which is applied to a controller in the above control system. Wherein, the number of the switch devices is two, and the method includes:

[0029] When the first semiconductor device and the second semiconductor device are both in the cut-off state, and the first switch device and the second switch device are both disconnected, in response to an instruction to connect a target battery cluster to the energy storage DC bus, a third closing instruction is sent to the drive unit corresponding to the target battery cluster, and the third closing instruction is used to instruct the drive unit to close the first switch device;

[0030] When it is determined that the first switching device is closed, a fifth main control instruction is sent to the drive unit; the fifth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off region to the amplification region, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charge and discharge between different battery clusters;

[0031] In response to detecting that the voltage difference value of all battery clusters is less than a third set threshold, a fourth closing instruction is sent to the drive unit; the fourth closing instruction is used to instruct the drive unit to close the second switching device;

[0032] When it is determined that the second switching device is closed, a fourth cut-off instruction is sent to the drive unit; the fourth cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region;

[0033] When it is determined that the fourth cut-off instruction is executed, a third cut-off instruction is sent to the drive unit; the third cut-off instruction is used to instruct the drive unit to disconnect the first switching device.

[0034] In one embodiment, after the step of sending the third cut-off instruction to the drive unit, the method further includes:

[0035] A fault signal or an exit instruction corresponding to the target battery cluster is detected;

[0036] A fifth closing instruction is sent to the drive unit corresponding to the target battery cluster; the fifth closing instruction is used to instruct the drive unit to close the first switching device;

[0037] When it is determined that the first switching device is closed, a third conduction instruction is sent to the drive unit corresponding to the target battery cluster; the third conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction region;

[0038] When it is determined that the third conduction instruction is executed, a fourth cut-off instruction is sent to the drive unit; the fourth cut-off instruction is used to instruct the drive unit to disconnect the second switching device;

[0039] When it is determined that the second switching device is disconnected, a sixth main control instruction is sent to the drive unit; the sixth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster;

[0040] In response to detecting that the output current of the target battery cluster is less than the fourth safety threshold, send a fifth cut-off instruction to the drive unit; the fifth cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0041] When it is determined that the execution of the fifth cut-off instruction is completed, send a fifth disconnection instruction to the drive unit; the fifth disconnection instruction is used to instruct the drive unit to disconnect the first switching device.

[0042] In a sixth aspect, an embodiment of the present application provides a controller, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of a control method for parallel connection of energy storage battery clusters.

[0043] One of the above technical solutions has the following advantages or beneficial effects: By configuring the first semiconductor device and the second semiconductor device with current amplification effects in the parallel connection control system of the energy storage battery cluster, a semiconductor module is introduced on the basis of the original switching device. Utilizing the conduction, cut-off, and amplification effects of the semiconductor module, the current on the loop is dynamically adjusted, thereby avoiding the impact of the instantaneous large current during the parallel connection of the battery clusters on the switching device or other components on the loop, ensuring circuit safety; compared with the traditional method of limiting current through a pre-charge resistor, the safety is high; compared with using a DC-DC converter, the number of devices used is reduced, the cost is lower, the system loss is reduced, the control strategy is simple, and the failure rate is low. Description of the Drawings

[0044] Figure 1 It is a schematic structural diagram of an energy storage system in an embodiment;

[0045] Figure 2 For Figure 1 It is a schematic structural diagram of the parallel connection control system of the energy storage battery cluster in

[0046] Figure 3 It is a schematic structural diagram of the parallel connection control system of the energy storage battery cluster in another embodiment;

[0047] Figure 4 It is a schematic flow diagram of the parallel connection control system of the energy storage battery cluster in still another embodiment;

[0048] Figure 5 It is a schematic flow diagram of a control method for parallel connection of energy storage battery clusters in an embodiment;

[0049] Figure 6 It is a schematic flow diagram of a control method for parallel connection of energy storage battery clusters in another embodiment;

[0050] Figure 7Schematic flowchart of the parallel control method for an energy storage battery cluster in yet another embodiment;

[0051] Figure 8 Internal structure diagram of the controller in one embodiment. Detailed implementation manners

[0052] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0053] Referring to "embodiment" herein means that the specific features, structures or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0054] The energy storage battery cluster parallel control system provided by the present application includes a controller, a driving unit signal-connected to the controller, and a first semiconductor device, a second semiconductor device and at least one switching device respectively signal-connected to the driving unit. Among them, the switching device can be a mechanical relay. Both the first semiconductor device and the second semiconductor device (the two can be collectively referred to as the semiconductor module) are configured to have a current amplification effect, and the two form a series branch and have opposite conduction directions on the series branch. It can be understood that both the first semiconductor device and the second semiconductor device have a current amplification function to have the effect of adjusting the current magnitude on the series branch. In at least one embodiment, the first semiconductor device and the second semiconductor device can be a triode, a MOS transistor or a composite transistor respectively. The composite transistor can be composed of multiple triodes, multiple MOS transistors or a triode and a MOS transistor. For example, both the first semiconductor device and the second semiconductor device can be bipolar transistors, and are NPN type and PNP type respectively; or, the first semiconductor device and the second semiconductor device can be a combination of an IGBT and a power MOSFET; or, the first semiconductor device and the second semiconductor device can be a combination of a Darlington transistor and an IGBT.

[0055] When the number of switching devices is one, the switching device is connected in series or in parallel with the series branch to form a control branch, which can be referred to Figure 2 and Figure 3 . When the number of switching devices is multiple (preferably two), they are divided into a first switching device and a second switching device. The first switching device is connected in series with the series branch, and the second switching device is connected in parallel with the first switching device and the series branch to form a control branch, which can be referred to Figure 4 ,Figure 4 The mechanical relay above can be understood as the first switching device, and the mechanical relay below can be understood as the second switching device. At the same time, the anodes of the foregoing two types of control branches can be used to connect to the positive pole of the energy storage DC bus, and the cathodes of the control branches are used to connect to the negative pole of the energy storage DC bus through the battery cluster. The connection method can refer to Figure 1 .

[0056] In one embodiment, the energy storage system provided by the present application, such as Figure 1 shown, may include a plurality of the above-mentioned control systems, a plurality of battery clusters corresponding to the control systems one by one, and an energy storage DC bus. Each battery cluster is connected in parallel to the energy storage DC bus through the corresponding control system. It should be noted that different control systems can share the same controller or the same drive unit. The specific system architecture can be changed in similar details according to the actual usage scenario and requirements. The drawings cannot be used to limit this solution.

[0057] For the above-mentioned energy storage battery cluster parallel control system and energy storage system, a composite relay combining a semiconductor module (such as a triode, MOS, IGBT, etc.) and a traditional mechanical switching device is used to connect the energy storage battery clusters in parallel, which can make the current flowing through the composite relay controllable. By adjusting the amplification factor of the semiconductor, the current passing through the semiconductor module can be made controllable, effectively reducing the impact of large current when the mechanical switching device is closed and the DC arcing when it is disconnected. On the one hand, it increases the service life of the switching device and reduces the failure risk of the switching device; on the other hand, it enables the parallel process of the battery clusters to be safely controlled without large circulating currents generated; at the same time, even if the SOC of each battery cluster is different, it can be smoothly and timely connected in parallel to the energy storage DC bus, and through mutual charge and discharge adjustment inside the battery cluster, the energy of each battery cluster can be utilized. It can be seen that the above solution can also effectively improve the system utilization rate. Compared with the traditional method of limiting current through a pre-charge resistor, it has high safety; compared with using a DC-DC converter, it reduces the number of components used, has lower cost, lower system loss, simpler control strategy, and lower failure rate.

[0058] In one embodiment, as Figure 5 shown, the present application provides a method for controlling the parallel connection of energy storage battery clusters. This method is applied to Figure 1Taking the control system in [system name] as an example for illustration, it can be specifically applied to the controller (not shown in the figure) in the above control system. At the same time, taking the first semiconductor device and the second semiconductor device as triodes as an example, both of them have a cut-off region, an amplification region, and a conduction region at this time. Of course, when the first semiconductor device and the second semiconductor device are configured as MOSFETs or IGBTs, the following amplification region and conduction region can be adaptively understood as the corresponding "linear region" and "saturation region". The three names, namely the cut-off region, the amplification region, and the conduction region, are only used to define the working states of the first semiconductor device and the second semiconductor device, that is, the cut-off region can be understood as being in a high-impedance state, the amplification region can be understood as being in a medium configuration, and the conduction region can be understood as being in a low-impedance state. These three terms cannot be used to define the types of the first semiconductor device and the second semiconductor device. When the number of switching devices is one and this switching device is connected in series with the series branch, the control method includes the following steps:

[0059] S502, when both the first semiconductor device and the second semiconductor device are in the cut-off state and the switching device is open, in response to the instruction to connect the target battery cluster in parallel to the energy storage DC bus, send a first closing instruction to the drive unit; the first closing instruction is used to instruct the drive unit to close the switching device. The first closing instruction can further be used to control the drive unit to gradually adjust the semiconductor to a preset conduction degree (such as 10%), and then close the switching device.

[0060] S504, when it is determined that the switching device is closed, send a first main control instruction to the drive unit; the first main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off region to the amplification region to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charge and discharge between different battery clusters.

[0061] Specifically, the first main control instruction can be used to instruct the drive unit to adjust the base voltage or gate voltage of the first semiconductor device and the second semiconductor device to gradually adjust the conduction degree of the first semiconductor device and the second semiconductor device, specifically depending on the types of the first semiconductor device and the second semiconductor device.

[0062] More specifically, the first main control instruction can be used to instruct the drive unit to adjust the conduction degree of the first semiconductor device and the second semiconductor device through closed-loop feedback (such as PWM duty cycle or linear drive), thereby dynamically controlling the current and gradually reducing the voltage difference value among all battery clusters.

[0063] S506, in response to detecting that the voltage difference values of all battery clusters are less than a first set threshold, sends a first conduction instruction to the drive unit; the first conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction region. The first set threshold can be set according to the actual situation, for example, 30 mV. Further, before sending the first conduction instruction to the drive unit, it can also be detected that the voltage difference values of all battery clusters have been continuously lower than the first set threshold for more than a set time (such as 5 seconds). Of course, during this process, the controller can monitor the magnitude of the current and temperature on the loop in real time and trigger a protection mechanism (such as shutting down, alarming) to cope with abnormalities.

[0064] A specific implementation of a battery cluster being connected in parallel to the energy storage DC bus is that, before the battery cluster is connected in parallel to the energy storage DC bus, the semiconductor module can first be made to enter the cut-off region, and then the mechanical relay is closed to connect the battery cluster to the energy storage DC bus. At this time, due to the existence of the high impedance state, the impact on the mechanical relay is small and it is relatively safe; after the parallel connection is completed, the high impedance state is gradually reduced to make it enter the amplification region, allowing different battery clusters to charge and discharge each other, that is, actively controlling the circulating current. When the battery clusters have completed charging and discharging each other and the voltages are basically the same, the semiconductor module is made to enter the conduction region.

[0065] In one embodiment, after S506, the energy storage battery cluster parallel connection control method further includes:

[0066] S508, detecting a fault signal or an exit instruction corresponding to the target battery cluster. Among them, the fault signal can be understood as a signal indicating that the target battery cluster has faults such as overcurrent, over-temperature, insulation failure, etc.

[0067] S510, sending a second main control instruction to the drive unit corresponding to the target battery cluster; the second main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region to control the conduction degree of the first semiconductor device and the second semiconductor device and gradually reduce the output current of the target battery cluster. For example, control the semiconductor module to enter the linear region and adjust the gate voltage (or PWM duty cycle) using closed-loop PID at a rate of 10% per second to gradually reduce the output current. In some embodiments, before S510, the method may further include determining the reliability of the fault signal or the exit instruction.

[0068] S512, in response to detecting that the output current of the target battery cluster is less than the first safety threshold, send a first cut-off instruction to the drive unit; the first cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region (which can be understood as the first semiconductor device and the second semiconductor device entering the fully off state). Sending the first cut-off instruction to the drive unit can also be an action performed in response to detecting that the output current of the target battery cluster is less than the first safety threshold and lasting for a set duration. Among them, the first safety threshold can be set to have a certain relationship with the rated value of the output current of the target battery cluster. For example, the first safety threshold is 5% of the rated value.

[0069] S514, when it is determined that the execution of the first cut-off instruction is completed, send a first disconnection instruction to the drive unit; the disconnection instruction is used to instruct the drive unit to disconnect the switching device.

[0070] The above determination that the execution of the first cut-off instruction is completed can specifically be determining that the semiconductor module enters the cut-off region and the voltage difference across the set switch is less than a certain set value (such as 2V).

[0071] In the above embodiments of the present application, the execution subject can be a controller. Of course, it can also be selected and changed according to actual situations. The parallel control method of the energy storage battery cluster in the above embodiments can avoid the arc or voltage mutation caused by directly disconnecting the switching device, and has high circuit safety. It is applicable to the situation where the number of switching devices in the control system is one and this switching device is connected in series with the series branch, that is Figure 1 the shown scenario.

[0072] A specific implementation method for a battery cluster to withdraw from the parallel energy storage DC bus is that if a battery cluster fails and needs to withdraw from the parallel state during the discharge process of the energy storage system, the entire energy storage system needs to reduce the power output to withdraw a certain cluster from the parallel. Otherwise, it will cause the relay of this cluster to be cut off under load. This solution can use the semiconductor module to adjust the current magnitude of this cluster. Without affecting the total current of the energy storage system, reduce the current of this cluster to achieve the purpose of withdrawal and improve the system utilization rate. The specific process can be: first, make the semiconductor module enter the amplification region, gradually reduce the output current, and finally enter the cut-off region. Since the current of this cluster is small at this time, there will be no safety risk when disconnecting the mechanical relay.

[0073] In one embodiment, as Figure 6 shown, the present application also provides a parallel control method for an energy storage battery cluster. Among them, the number of switching devices is one and this switching device is connected in parallel with the series branch. This solution has some similarities with the above situation where the switching device is connected in series with the series branch. To avoid redundancy, only the differences between the methods are introduced here. This method includes:

[0074] S602. When both the first semiconductor device and the second semiconductor device are in the cut-off state and the switching device is open, in response to an instruction to connect the target battery cluster to the energy storage DC bus, send a third main control instruction to the drive unit corresponding to the target battery cluster; the third main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the cut-off region to the amplification region, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charge and discharge between different battery clusters.

[0075] S604. In response to detecting that the voltage difference value of all battery clusters is less than the second set threshold, send a second closing instruction to the drive unit; the second closing instruction is used to instruct the drive unit to close the switching device.

[0076] S606. When it is determined that the switching device is closed, send a second cut-off instruction to the drive unit; the second cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0077] A specific implementation of connecting a battery cluster to the energy storage DC bus is that in order to make there be no voltage difference when the mechanical relay is closed, the mechanical relay can be disconnected first, and the semiconductor module is controlled to enter the amplification region, so that the batteries are connected in parallel to the DC bus for controllable mutual charge and discharge. When the charging between the batteries is completed, the voltage difference between the batteries is small; when the voltage difference drops to a certain value, the mechanical relay is closed, so that the semiconductor module is short-circuited by the mechanical relay, and then the semiconductor module is adjusted to enter the cut-off region. Since the internal resistance of the semiconductor module is greater than the internal resistance of the mechanical relay, the current passing through the semiconductor module will become smaller at this time, which helps to reduce the load of the semiconductor module.

[0078] In one embodiment, after S606, the energy storage battery cluster parallel connection control method further includes:

[0079] S608. Detect a fault signal or an exit instruction corresponding to the target battery cluster.

[0080] S610. Send a second conduction instruction to the drive unit corresponding to the target battery cluster; the second conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction region to increase the current in the series branch.

[0081] S612. When it is determined that the current flowing through the series branch is greater than or equal to the second safety threshold, send a second cut-off instruction to the drive unit; the second cut-off instruction is used to instruct the drive unit to open the switching device.

[0082] S614. When it is determined that the switchgear is disconnected, send a fourth main control instruction to the drive unit; the fourth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster.

[0083] S616. In response to detecting that the output current of the target battery cluster is less than the third safety threshold, send a third cut-off instruction to the drive unit; the third cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0084] In the above embodiments of the present application, the execution subject can be a controller, and of course, it can also be selected and changed according to the actual situation.

[0085] A specific implementation method for a battery cluster to withdraw from the parallel energy storage DC bus is that the semiconductor module changes back from the cut-off region to the conduction region to reduce the internal resistance of the semiconductor module, reduce the voltage difference across the semiconductor module, and increase the passing current. At this time, the mechanical relay is disconnected, and then the semiconductor module is changed back to the amplification region. After adjusting the current, it is changed back to the cut-off region.

[0086] In one embodiment, as Figure 7 shown, the present application provides a method for controlling the parallel connection of energy storage battery clusters. Among them, the number of switchgears is two, and the method includes:

[0087] S702. When both the first semiconductor device and the second semiconductor device are in the cut-off state and both the first switch device and the second switch device are disconnected, in response to the instruction to connect the target battery cluster to the energy storage DC bus, send a third closing instruction to the drive unit corresponding to the target battery cluster. The third closing instruction is used to instruct the drive unit to close the first switch device.

[0088] S704. When it is determined that the first switch device is closed, send a fifth main control instruction to the drive unit; the fifth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off region to the amplification region, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device and actively control the charge and discharge between different battery clusters.

[0089] S706. In response to detecting that the voltage difference value of all battery clusters is less than the third set threshold, send a fourth closing instruction to the drive unit; the fourth closing instruction is used to instruct the drive unit to close the second switch device.

[0090] S708. When it is determined that the second switch device is closed, send a fourth cut-off instruction to the drive unit; the fourth cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region;

[0091] S710, when it is determined that the execution of the fourth cut-off instruction is completed, send a third cut-off instruction to the drive unit; the third cut-off instruction is used to instruct the drive unit to disconnect the first switching device.

[0092] A specific implementation of a battery cluster being connected in parallel to the energy storage DC bus is as follows: close the first mechanical relay (abbreviated as the first relay), the semiconductor module enters the amplification region from the cut-off region, at this time the current slowly increases and is controlled by the amplification region, and the battery clusters start to charge and discharge with each other; when the mutual charging of the battery clusters is completed, close the second mechanical relay (abbreviated as the second relay), control the above semiconductor module to enter the cut-off region from the amplification region, and then disconnect the first relay, so that when supplying power externally normally, the current flowing through the second relay branch does not flow through the first relay branch, thereby completely isolating the first relay branch and reducing the semiconductor load.

[0093] In one embodiment, after S708, the energy storage battery cluster parallel connection control method further includes:

[0094] S712, detect a fault signal or an exit instruction corresponding to the target battery cluster.

[0095] S714, send a fifth closing instruction to the drive unit corresponding to the target battery cluster; the fifth closing instruction is used to instruct the drive unit to close the first switching device.

[0096] S716, when it is determined that the first switching device is closed, send a third conduction instruction to the drive unit corresponding to the target battery cluster; the third conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction region.

[0097] S718, when it is determined that the execution of the third conduction instruction is completed, send a fourth cut-off instruction to the drive unit; the fourth cut-off instruction is used to instruct the drive unit to disconnect the second switching device.

[0098] S720, when it is determined that the second switching device is disconnected, send a sixth main control instruction to the drive unit; the sixth main control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction region to the amplification region to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster.

[0099] S722, in response to detecting that the output current of the target battery cluster is less than the fourth safety threshold, send a fifth cut-off instruction to the drive unit; the fifth cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

[0100] S724, when it is determined that the execution of the fifth cut-off instruction is completed, send a fifth disconnection instruction to the drive unit; the fifth disconnection instruction is used to instruct the drive unit to disconnect the first switching device.

[0101] A specific implementation of a battery cluster exiting the parallel energy storage DC bus is as follows. At this time, the second relay module is in the closed state and the system is operating normally. To exit the parallel connection, first close the first relay, adjust the semiconductor module to enter the conduction region, and then disconnect the second relay. Since the series circuit is conducting, there will be no arcing at the second relay. Then, adjust the semiconductor module from the conduction region to the amplification region, reduce the current and then enter the cut-off region, and finally disconnect the first relay to complete the process of exiting the parallel connection.

[0102] In the above embodiments of the present application, the execution entity can be a controller, and of course, it can also be selected and changed according to the actual situation. In the energy storage battery cluster parallel control method of the above embodiments, through hybrid connection, on the basis of parallel connection, the electrical connection in the circuit can be physically completely disconnected; on the basis of series connection, because the semiconductor always generates heat and has losses, the parallel mechanical relay can be closed to reduce the resistance of the circuit and improve the efficiency.

[0103] In summary, the above system and method provided by the present application have at least the following technical effects:

[0104] 1. In this solution, the high-resistance state of the semiconductor module is used to reduce the conduction current of the mechanical relay contacts, thereby extending the service life of the contacts.

[0105] 2. In this solution, the high-resistance state of the semiconductor module is used to reduce the current before disconnection of the mechanical relay contacts, so that the contacts are disconnected with a small current without arcing.

[0106] 3. In this solution, by configuring a mechanical relay, the electrical connection can be completely disconnected through the contacts.

[0107] 4. When the semiconductor module is connected in parallel with the mechanical switching device, the internal resistance of the mechanical relay when it is closed is less than the internal resistance of the semiconductor, and the current mainly flows through the mechanical relay, significantly reducing the conduction loss of the system and improving the overall efficiency.

[0108] 5. This solution can be used in energy storage electrical connections, increasing the parallel safety of the energy storage system, while making the loop current reach a controllable state, controlling the charging and discharging between battery clusters, and improving the overall efficiency of the system.

[0109] 6. In this solution, each battery system can perform independent power-on and power-off operations without affecting the operation of the entire system.

[0110] 7. Compared with the solution using DCDC connection, this solution has fewer components, lower cost, and less loss.

[0111] It should be understood that for the foregoing method embodiments, although the steps in the flowcharts are sequentially shown according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowchart of the method embodiment may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or sub-steps or stages of other steps.

[0112] In one embodiment, a controller is provided. The controller can be a bus-tie controller or other type of controller. The internal structure diagram of the controller can be as Figure 8 shown. The controller includes a processor, a memory, an input / output interface, and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the controller is used to provide computing and control capabilities. The memory of the controller includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the controller is used to exchange information between the processor and external devices. The communication interface of the controller is used to communicate with external terminals in a wired or wireless manner. The wireless manner can be implemented through WIFI, a mobile cellular network, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a method for parallel control of an energy storage battery cluster. Those skilled in the art can understand that Figure 8 the structure shown in

[0113] is only a block diagram of a part of the structure related to the solution of this application, and does not constitute a limitation on the controller to which the solution of this application is applied. A specific controller may include more or fewer components than those shown in the figure, or combine certain components, or have a different component layout.

[0114] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps in the foregoing method embodiments.

[0115] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memories can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, etc., without limitation.

[0116] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification. In the above embodiments, the descriptions of the respective embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0117] As used in the embodiments of this specification, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or (module) units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or apparatuses.

[0118] As used herein, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0119] As used herein, "first / second" is merely used to distinguish similar objects and does not represent a specific order for the objects. It can be understood that "first / second" can be interchanged in a specific order or sequence when permitted. It should be understood that the objects distinguished by "first / second" can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order other than those illustrated or described herein.

[0120] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A parallel control system for energy storage battery clusters, characterized in that: The device comprises a controller, a driving unit connected to the controller by signal, and a first semiconductor device, a second semiconductor device and at least one switch device respectively connected to the driving unit by signal; the first semiconductor device and the second semiconductor device are both configured to have a current amplification function, and the two form a series branch and the conduction directions on the series branch are opposite; When the number of the switch device is one, the switch device is connected in series or in parallel with the series branch to form a control branch; when the number of the switch devices is multiple, they are divided into a first switch device and a second switch device, the first switch device is connected in series with the series branch, and the second switch device is connected in parallel with the first switch device and the series branch to form a control branch; The anode of the control branch is used to be connected to the positive electrode of the energy storage DC bus, and the cathode of the control branch is used to be connected to the negative electrode of the energy storage DC bus through a battery cluster.

2. The control system according to claim 1, characterized in that: The first semiconductor device and the second semiconductor device are respectively a triode, a MOS tube or a composite tube, and the composite tube is composed of a plurality of triodes, a plurality of MOS tubes or a triode and a MOS tube; And / or, the switching device is a mechanical relay.

3. An energy storage system, characterized in that: It comprises a plurality of control systems as claimed in claim 1 or 2, a plurality of battery clusters and energy storage DC buses corresponding to the control systems one by one, and each battery cluster is connected in parallel to the energy storage DC bus through the corresponding control system.

4. A method for controlling a battery cluster in parallel, applied to a controller in a control system as claimed in claim 1 or 2, wherein: The number of the switch device is one and the switch device is connected in series with the series branch, and the method comprises: When the first semiconductor device and the second semiconductor device are both in the off state and the switch device is disconnected, in response to an instruction to connect the target battery cluster in parallel to the energy storage DC bus, a first closing instruction is sent to the drive unit; the first closing instruction is used to instruct the drive unit to close the switch device; When it is determined that the switch device is closed, a first master control instruction is sent to the drive unit; the first master control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off area to the amplification area, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charging and discharging between different battery clusters; In response to detecting that the voltage difference value of all battery clusters is less than a first set threshold, a first conduction instruction is sent to the drive unit; the first conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter a conduction area.

5. The method according to claim 4, characterized in that After the step of sending the first conduction instruction to the driving unit, the method further includes: detecting a fault signal or an exit command corresponding to the target battery cluster; Sending a second master control instruction to a driving unit corresponding to the target battery cluster; the second master control instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to switch from a conduction area to an amplification area, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster; In response to detecting that the output current of the target battery cluster is less than a first safety threshold, sending a first cutoff instruction to the driving unit; the first cutoff instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter a cutoff region; When it is determined that the first cut-off instruction is executed, a first cut-off instruction is sent to the drive unit; the cut-off instruction is used to instruct the drive unit to disconnect the switch device.

6. A method for controlling a parallel connection of energy storage battery clusters, applied to a controller in a control system as claimed in claim 1 or 2, wherein: The number of the switch device is one and the switch device is connected in parallel with the series branch, and the method comprises: When the first semiconductor device and the second semiconductor device are both in the cut-off state and the switch device is disconnected, in response to an instruction to connect the target battery cluster in parallel to the energy storage DC bus, a third master control instruction is sent to a drive unit corresponding to the target battery cluster; the third master control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the cut-off area to the amplification area, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charging and discharging between different battery clusters; In response to detecting that the voltage difference value of all battery clusters is less than a second set threshold, sending a second closing instruction to the drive unit; the second closing instruction is used to instruct the drive unit to close the switch device; When it is determined that the switch device is closed, a second cut-off instruction is sent to the drive unit; the second cut-off instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the cut-off region.

7. The method according to claim 6, characterized in that After the step of sending the second cut-off instruction to the drive unit, the method further includes: detecting a fault signal or an exit command corresponding to the target battery cluster; Sending a second conduction instruction to the drive unit corresponding to the target battery cluster; the second conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter the conduction area to increase the current of the series branch; When it is determined that the current flowing through the series branch is greater than or equal to a second safety threshold, sending a second disconnection instruction to the drive unit; the second disconnection instruction is used to instruct the drive unit to disconnect the switch device; When it is determined that the switch device is disconnected, a fourth master control instruction is sent to the drive unit; the fourth master control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction area to the amplification area, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster; In response to detecting that the output current of the target battery cluster is less than a third safety threshold, a third cutoff instruction is sent to the driving unit; the third cutoff instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter a cutoff region.

8. A method for controlling a parallel connection of energy storage battery clusters, applied to a controller in a control system as claimed in claim 1 or 2, wherein: The number of the switch devices is two, and the method comprises: When the first semiconductor device and the second semiconductor device are both in the off state and the first switch device and the second switch device are both disconnected, in response to an instruction to connect the target battery cluster in parallel to the energy storage DC bus, a third closing instruction is sent to a drive unit corresponding to the target battery cluster, wherein the third closing instruction is used to instruct the drive unit to close the first switch device; When it is determined that the first switch device is closed, a fifth master control instruction is sent to the drive unit; the fifth master control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to gradually switch from the cut-off region to the amplification region, so as to adjust the conduction degree of the first semiconductor device and the second semiconductor device, and actively control the charging and discharging between different battery clusters; In response to detecting that the voltage difference value of all battery clusters is less than a third set threshold, sending a fourth closing instruction to the drive unit; the fourth closing instruction is used to instruct the drive unit to close the second switch device; When it is determined that the second switching device is closed, a fourth cut-off instruction is sent to the driving unit; the fourth cut-off instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter a cut-off zone; When it is determined that the fourth cut-off instruction is executed, a third cut-off instruction is sent to the drive unit; the third cut-off instruction is used to instruct the drive unit to disconnect the first switching device.

9. The method according to claim 8, characterized in that After the step of sending the third cutting instruction to the driving unit, the method further includes: detecting a fault signal or an exit command corresponding to the target battery cluster; Sending a fifth closing instruction to a drive unit corresponding to the target battery cluster; the fifth closing instruction is used to instruct the drive unit to close the first switch device; When it is determined that the first switch device is closed, a third conduction instruction is sent to a drive unit corresponding to the target battery cluster; the third conduction instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to enter a conduction area; When it is determined that the execution of the third on-instruction is completed, sending a fourth off-instruction to the drive unit; the fourth off-instruction is used to instruct the drive unit to disconnect the second switch device; When it is determined that the second switch device is disconnected, a sixth master control instruction is sent to the drive unit; the sixth master control instruction is used to instruct the drive unit to control the first semiconductor device and the second semiconductor device to switch from the conduction area to the amplification area, so as to control the conduction degree of the first semiconductor device and the second semiconductor device, and gradually reduce the output current of the target battery cluster; In response to detecting that the output current of the target battery cluster is less than a fourth safety threshold, sending a fifth cut-off instruction to the driving unit; the fifth cut-off instruction is used to instruct the driving unit to control the first semiconductor device and the second semiconductor device to enter a cut-off region; In the case where it is determined that the fifth cut-off instruction has been executed, a fifth cut-off instruction is sent to the drive unit; the fifth cut-off instruction is used to instruct the drive unit to disconnect the first switching device.

10. A controller, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 4 to 9 are implemented.

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