A control for a currentless energy storage machine

Abstract

The utility model discloses a kind of control energy storage machines of no loop current, it is related to energy storage converter technical field, comprising: unit circuit module, it is equipped with multiple groups, multiple unit circuit modules are connected in parallel between them;And circuit mechanism, it is equipped with multiple groups, each group of circuit mechanism is located in each unit circuit module, each group of circuit mechanism includes first AMP module, second AMP module and capacitor component.The energy storage machine of this control no loop current, can realize fast, high current uniformity and parallel, and the number of parallel theoretically has no upper limit, and, solve the condition that previous parallel needs single power to meet all load demand, only single power is all power 1 / N, simultaneously, N+1 or N+2 of small power unit, realize high reliability operation, the energy storage machine of this control no loop current, realize the stable parallel operation of multiple PCS systems, system current sharing problem is still important, to ensure the uniform distribution of current stress and thermal stress between modules.

Description

Technical Field

[0001] This utility model relates to the field of energy storage converter technology, specifically to an energy storage machine that controls non-circulating current. Background Technology

[0002] With the continued growth of global demand for renewable energy, photovoltaic energy storage systems are becoming increasingly widely used as an important green energy solution. In photovoltaic energy storage systems, power storage converters (PCS) play a crucial role. As the energy storage field develops, the demand for high-power energy storage systems is increasing, which inevitably places higher demands on power storage converters. Improving output power and energy storage capacity is a popular direction for expanding the application scenarios of PCS.

[0003] With the development of energy storage technology, a single energy storage converter in a high-power energy storage system cannot meet the power requirements. Therefore, parallel energy storage technology is needed, which offers advantages such as capacity expansion and improved maintainability. However, series-parallel connection can lead to voltage and current sharing issues between systems. Improper handling can reduce the lifespan or damage energy storage batteries and cause circulating currents between PCS systems, leading to equipment failure. Conventional parallel connection methods include voltage source droop parallel connection and voltage source / current source hybrid parallel connection. The voltage source droop parallel connection method has slow dynamic response, poor steady-state accuracy, and limitations on the number of parallel connections. The voltage source / current source hybrid parallel connection method does not systematically calculate the parallel current of each module, resulting in independent current regulation and a mismatch between system current and load current, causing unstable output voltage. Furthermore, the phases of the AC modules cannot be synchronized.

[0004] To address the aforementioned issues, a controllable non-circulating energy storage machine is needed to improve the response speed, quality, and parallel connection quantity of the current sharing signal output, thereby resolving the instability problem of parallel systems and maximizing efficiency. Utility Model Content

[0005] This invention provides a controllable non-circulating current energy storage machine that can achieve rapid and high current sharing in parallel operation. Theoretically, there is no upper limit to the number of parallel operations. Furthermore, it solves the problem that in the past, the power of a single unit needed to meet the entire load demand for parallel operation. Now, only the power of a single unit needs to be 1 / N of the total power. At the same time, N+1 or N+2 small power units can achieve high reliability operation and realize the stable parallel operation of multiple PCS systems. The current sharing problem of the system is still important to ensure the uniform distribution of current stress and thermal stress among modules.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a controllable non-circulating energy storage machine, comprising:

[0007] The unit circuit module is provided in multiple groups, and the multiple groups of unit circuit modules are connected in parallel; and

[0008] The circuit mechanism is provided in multiple groups, and each group of the circuit mechanism is located in each unit circuit module. Each group of the circuit mechanism includes a first AMP module, a second AMP module and a capacitor component. The first AMP module is located in the unit circuit module, the second AMP module is located in the unit circuit module, and the capacitor component is located in the unit circuit module. The capacitor component is connected to the first AMP module and the second AMP module.

[0009] Furthermore, the capacitor assembly includes:

[0010] A first capacitor assembly is disposed within the unit circuit module, and the first capacitor assembly is connected to the first AMP module; and

[0011] The second capacitor assembly is located within the unit circuit module. The second capacitor assembly is connected to the second AMP module and is also connected to the first capacitor assembly.

[0012] Furthermore, the first capacitor assembly includes a first resistor and a second resistor, one end of the first resistor is electrically connected to one end of the first AMP module, one end of the second resistor is electrically connected to one end of the first AMP module, and the other end of the second resistor is electrically connected to the other end of the first AMP module.

[0013] Furthermore, the first capacitor assembly includes a third resistor and a fourth resistor. One end of the third resistor is electrically connected to one end of the second AMP module, and the other end of the third resistor is electrically connected to the other end of the second AMP module. One end of the fourth resistor is electrically connected to one end of the second AMP module, and the other end of the fourth resistor is electrically connected to the other end of the first resistor.

[0014] Furthermore, one end of the first AMP module receives the sampled value from the current sensor, and one end of the second AMP module outputs the average current value.

[0015] This invention provides an energy storage machine for controlling non-circulating current. It has the following beneficial effects:

[0016] (1) This energy storage machine with no circulating current control can achieve fast and high current sharing in parallel operation. Theoretically, there is no upper limit to the number of parallel operations. In addition, it solves the previous requirement that the power of a single unit must meet the full load demand for parallel operation. Now, the power of a single unit only needs to be 1 / N of the total power. At the same time, the N+1 or N+2 small power units can achieve high reliability operation.

[0017] (2) The energy storage machine with no circulating current control enables the stable parallel operation of multiple PCS systems. The current sharing problem of the system is still important to ensure the uniform distribution of current stress and thermal stress between modules. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of the present invention.

[0019] In the diagram: 1. Unit circuit module; 2. Fourth resistor; 3. First resistor; 4. First AMP module; 5. Second resistor; 6. Third resistor; 7. Second AMP module. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0021] Please see Figure 1 This utility model provides a technical solution: a controllable non-circulating energy storage machine, comprising:

[0022] Unit circuit module 1, which has multiple sets, and the multiple sets of unit circuit modules 1 are connected in parallel; and

[0023] The circuit mechanism is provided in multiple groups, and each group of circuit mechanisms is located in each unit circuit module 1. Each group of circuit mechanisms includes a first AMP module 4, a second AMP module 7, and a capacitor component. The first AMP module 4 is located in the unit circuit module 1, the second AMP module 7 is located in the unit circuit module 1, and the capacitor component is located in the unit circuit module 1. The capacitor component is connected to the first AMP module 4 and the second AMP module 7.

[0024] In this implementation scheme: the first AMP module 4 and the second AMP module 7, together with the capacitor components, complete the overall usage effect. Multiple unit circuit modules 1 are connected through a current sharing bus. Under weak grid operation, high-frequency circulating current exists between parallel devices. The formation mechanism is mainly caused by the phase difference of the high-frequency carrier signals between the devices. In this parallel operation scheme, a high-frequency carrier synchronization method is used to eliminate high-frequency circulating current. Compared with carrier signals below 7.2KHz, the high-frequency circulating current caused by a phase error of 2.5uS can be ignored in engineering. In multi-machine synchronous control, an algorithm for asynchronous instruction synchronous execution is adopted to ensure that the action time error of each unit is within 2.5uS within the phase-locked loop accuracy range. Compared with the traditional PCS redundancy control strategy, it can greatly reduce the power of redundant models and achieve true N+1 redundancy. When a fault or maintenance occurs, master-slave switching is implemented, combined with the control power feedforward algorithm, for the control of parallel units. Carrier synchronization realizes a high-frequency non-circulating current control strategy, multi-machine microsecond-level synchronous control, low-power redundancy realizes high-reliability control technology, and token-based master technology.

[0025] Specifically, the capacitor assembly includes:

[0026] A first capacitor assembly is disposed within unit circuit module 1, and the first capacitor assembly is connected to the first AMP module 4; and

[0027] The second capacitor assembly is located within the unit circuit module 1. The second capacitor assembly is connected to the second AMP module 7, and the second capacitor assembly is connected to the first capacitor assembly.

[0028] In this embodiment: the first capacitor component is used for the first AMP module 4, and the second capacitor component is used for the second AMP module 7. The two work together to complete the circuit operation.

[0029] Specifically, the first capacitor assembly includes a first resistor 3 and a second resistor 5. One end of the first resistor 3 is electrically connected to one end of the first AMP module 4, one end of the second resistor 5 is electrically connected to one end of the first AMP module 4, and the other end of the second resistor 5 is electrically connected to the other end of the first AMP module 4.

[0030] In this embodiment: one end of the second resistor 5 is connected to the negative terminal of the first AMP module 4, and the other end of the second resistor 5 is connected to the end where the first resistor 3 and the first AMP module 4 are connected. The other end of the first resistor 3 is connected to the current sharing bus.

[0031] Specifically, the first capacitor assembly includes a third resistor 6 and a fourth resistor 2. One end of the third resistor 6 is electrically connected to one end of the second AMP module 7, and the other end of the third resistor 6 is electrically connected to the other end of the second AMP module 7. One end of the fourth resistor 2 is electrically connected to one end of the second AMP module 7, and the other end of the fourth resistor 2 is electrically connected to the other end of the first resistor 3.

[0032] In this embodiment: one end of the third resistor 6 is connected to the negative terminal of the second AMP module 7, one end of the fourth resistor 2 is connected to the positive terminal of the second AMP module 7, and the other end of the fourth resistor 2 is connected to the current sharing bus.

[0033] Specifically, the first AMP module 4 inputs the current sensor sampling value at one end, and the second AMP module 7 outputs the average current value at one end.

[0034] In this embodiment: the current sensor sampling value is a voltage sampling signal. The current sensor sampling value is input to the positive terminal of the first AMP module 4, and outputs an average current Iavg through the current sharing bus. This average current is used for the off-grid phase current control of each unit in parallel operation. Iavg = (Id_1 + Id_2 + ... + Id_N) / N. When off-grid, the current loop of each phase of the unit tracks the current setpoint through the PI controller, thereby ensuring that the current of each phase of each unit is consistent during off-grid operation.

[0035] In operation under weak grid conditions: In grid-connected mode, the host locks onto the grid and sends a synchronization signal with the same frequency and phase as the grid. In off-grid mode, the host sends a synchronization signal with the same rated frequency as the grid. The master and slave units lock the synchronization signal sent by the host. Through a high-efficiency phase-locking algorithm, a phase-locking accuracy of 2.5µs is achieved. In multi-machine synchronous control, a virtual EMS controller is implemented in the host. Commands are generated at specified time slices. The EMS sends action command signals to the corresponding APP of each parallel unit (including the host itself). At the specified time edge, each parallel unit acts simultaneously. When switching between master and slave, the address of the next master is pre-determined based on the size of the online slave address. When the master fails, a master token is sent to the next master. After receiving the token, the next master replies with an acknowledgment signal. The current master is deactivated, and the next master takes over. In asynchronous parallel control of slave units, when a slave fails, the slave is directly shut down and disconnected from the parallel state. When the slave recovers, it is directly reconnected.

[0036] The control method of this utility model is to control the device by manually starting and stopping the switch. The wiring diagram of the power element and the supply of power are common knowledge in the field. Since this utility model is mainly used to protect mechanical devices, the control method and wiring layout will not be explained in detail.

[0037] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A controlled non-circulating energy storage machine, characterized in that, include: Unit circuit module (1), which is provided in multiple groups, and the multiple groups of unit circuit modules (1) are connected in parallel; and The circuit mechanism is provided in multiple groups, and each group of the circuit mechanism is located in each unit circuit module (1). Each group of the circuit mechanism includes a first AMP module (4), a second AMP module (7) and a capacitor component. The first AMP module (4) is located in the unit circuit module (1), the second AMP module (7) is located in the unit circuit module (1), and the capacitor component is located in the unit circuit module (1). The capacitor component is connected to the first AMP module (4) and the capacitor component is connected to the second AMP module (7).

2. The energy storage machine for controlling non-circulating current according to claim 1, characterized in that, The capacitor component includes: A first capacitor assembly is disposed within the unit circuit module (1), and the first capacitor assembly is connected to the first AMP module (4); and The second capacitor assembly is located in the unit circuit module (1), and the second capacitor assembly is connected to the second AMP module (7), and the second capacitor assembly is connected to the first capacitor assembly.

3. The energy storage machine for controlling non-circulating current according to claim 2, characterized in that, The first capacitor assembly includes a first resistor (3) and a second resistor (5). One end of the first resistor (3) is electrically connected to one end of the first AMP module (4), one end of the second resistor (5) is electrically connected to one end of the first AMP module (4), and the other end of the second resistor (5) is electrically connected to the other end of the first AMP module (4).

4. The energy storage machine for controlling non-circulating current according to claim 3, characterized in that, The first capacitor assembly includes a third resistor (6) and a fourth resistor (2). One end of the third resistor (6) is electrically connected to one end of the second AMP module (7), and the other end of the third resistor (6) is electrically connected to the other end of the second AMP module (7). One end of the fourth resistor (2) is electrically connected to one end of the second AMP module (7), and the other end of the fourth resistor (2) is electrically connected to the other end of the first resistor (3).

5. The energy storage machine for controlling non-circulating current according to claim 4, characterized in that, The first AMP module (4) inputs the current sensor sampling value at one end, and the second AMP module (7) outputs the average current value at one end.

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