Optical storage system and controlled charging and discharging control method

Abstract

The invention provides a light storage system and a controlled charging and discharging control method, at least two energy storage units are respectively connected and are accessed to a direct current bus through an energy storage discharging path and an energy storage charging path, a controller monitors the electric quantity SOC value in a first battery energy storage unit and a second battery energy storage unit in real time, and when the electric quantity SOC value of any one battery energy storage unit is determined, the battery energy storage unit is switched to the first battery energy storage unit and the second battery energy storage unit. When the electric quantity value is equal to or exceeds the set electric quantity SOC value, the charging and discharging states of the two battery energy storage units are adjusted and switched; rapid, safe and efficient controlled charging and discharging are realized, and the service life of battery energy storage is prolonged; according to the invention, the defects in the prior art that the photovoltaic module and the energy storage module are connected in parallel on the same bus, and the condition that the photovoltaic is greater than or smaller than the load occurs randomly, so that the battery is repeatedly charged and discharged and is not controlled are overcome; and power control cannot be accurately carried out.

Description

Technical Field

[0001] The present invention belongs to the technical field of battery energy storage, and in particular relates to a photovoltaic storage system and a controlled charging and discharging control method. Background Art

[0002] The widespread popularization and application of new energy photovoltaic power generation is a development trend. However, due to the volatility and intermittency of photovoltaic power generation, it cannot meet the needs of stable power consumption of the load, and also affects the power quality of the power grid after grid connection. Therefore, the industry has extensively conducted technical research on smoothing the fluctuations of photovoltaic power generation and improving the power supply quality of photovoltaic power generation. CN 114447993 "A power control method, device, controller and photovoltaic storage system" published by the State Intellectual Property Office, as recorded in the scheme and shown in the attached drawings, uses real-time sampling, calculation and comparison of multiple reference values ​​such as battery voltage, grid voltage and bus voltage of the photovoltaic storage system to determine the corresponding power control requirements. The bus voltage does not fluctuate due to the fluctuation of photovoltaics, and the changes in load power and the voltage fluctuations of the grid all affect the accuracy of the collection, comparison and calculation of the voltage reference value; in particular, the scheme adopts its Figure 1 The photovoltaic modules and energy storage modules shown are connected in parallel on the same bus. Since the load and photovoltaic power generation have no synergistic ability, the photovoltaic power is greater than or less than the load. This causes the energy storage battery on the common bus to respond continuously in order to smooth out the photovoltaic fluctuations, causing the battery to charge and discharge repeatedly. This objectively causes the uncontrolled charging and discharging, which has a huge impact on the battery life. In severe cases, there is a risk of overcharging, overdischarging, and explosion of the battery. Therefore, the photovoltaic storage integration and photovoltaic storage complementary system need to solve the controlled charging and discharging of the battery and the real-time control of the power to ensure safe and healthy operation, and to ensure timely response and smoothing of photovoltaic power generation fluctuations. Summary of the invention

[0003] In order to solve the defects and shortcomings of the prior art, the present invention proposes a photovoltaic storage system and a controlled charging and discharging control method, wherein at least two energy storage units are respectively connected and connected to the DC bus through an energy storage discharge path and an energy storage charging path, and at the same time, the photovoltaic power generation unit is connected to the DC bus through a photovoltaic on-off and protection circuit; the DC side of the bidirectional converter is connected to the DC bus, and the AC side of the bidirectional converter is connected to the power line of the power grid; the controller is respectively connected to the photovoltaic power generation unit, the first battery energy storage unit, the second battery energy storage unit, the energy storage discharge path control circuit, the energy storage charging path control circuit, each on-off and protection circuit and each selection switch through a control bus, so as to form a photovoltaic storage system for controlled charging and discharging of the energy storage battery;

[0004] The invention is also characterized in that the operation control method of the photovoltaic storage system is:

[0005] S1: The photovoltaic energy storage system is powered on normally; the photovoltaic power generation unit, each battery energy storage unit, each circuit module and switch status parameters are detected, and an alarm is issued when abnormal, and S2 is executed when normal;

[0006] S2: Close the first selection switch, open the second selection switch, the energy storage discharge path control circuit is normal, and the first battery energy storage unit is in a unidirectional discharge path conduction; at the same time, close the fourth selection switch, open the third selection switch, the energy storage charging path control circuit is normal, and the second battery energy storage unit is in a unidirectional charging path conduction; the photovoltaic power generation unit is connected to the DC bus through the photovoltaic on-off and protection circuit.

[0007] S3: The controller monitors the SOC values ​​of the electric power in the first battery energy storage unit and the second battery energy storage unit in real time. When the SOC value of the electric power of the battery energy storage unit connected to the unidirectional discharge path is ≤ the set value L1, the second selection switch is controlled to be closed and the first selection switch is disconnected, and the third selection switch is controlled to be closed and the fourth selection switch is controlled to be disconnected; or, when the SOC value of the electric power of the battery energy storage unit connected to the unidirectional charging path is ≥ the set value H1, the third selection switch is controlled to be closed and the fourth selection switch is disconnected, and the second selection switch is controlled to be closed and the first selection switch is disconnected; adjust and switch the charge and discharge states of the two battery energy storage units; continue to re-execute S3.

[0008] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the energy storage and discharge path control circuit connected to the power line of the power grid is connected in sequence to the first selection switch, the first energy storage charge and discharge on-off and protection circuit, and the first battery energy storage unit, and is also connected in sequence to the second selection switch, the second energy storage charge and discharge on-off and protection circuit, and the second battery energy storage unit, respectively forming unidirectional discharge power paths of the first battery energy storage unit and the second battery energy storage unit.

[0009] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the energy storage charging path control circuit connected to the power line of the power grid is sequentially connected to the third selection switch, the first energy storage charging and discharging on-off and protection circuit, and the first battery energy storage unit, and is also sequentially connected to the fourth selection switch, the second energy storage charging and discharging on-off and protection circuit, and the second battery energy storage unit, respectively forming unidirectional charging power paths of the first battery energy storage unit and the second battery energy storage unit.

[0010] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the controller is connected to the bidirectional converter, the photovoltaic power generation unit, the first battery energy storage unit, the second battery energy storage unit, the energy storage discharge path control circuit, the energy storage charging path control circuit, the photovoltaic on-off and protection circuit, the first energy storage charge and discharge on-off and protection circuit, the second energy storage charge and discharge on-off and protection circuit, the first selection switch, the second selection switch, the third selection switch, and the fourth selection switch through a control bus to form a control link of the photovoltaic storage system for controlled charging and discharging of the energy storage battery.

[0011] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the first battery energy storage unit and the second battery energy storage unit are internally configured with a BMS battery management system and the controller and the bidirectional converter are connected through a control bus.

[0012] The present invention proposes a photovoltaic storage system and a controlled charging and discharging control method, wherein at least two energy storage units are respectively connected and connected to a DC bus through an energy storage discharging path and an energy storage charging path, and a controller monitors the SOC values ​​of the first battery energy storage unit and the second battery energy storage unit in real time. When the SOC value of any battery energy storage unit is equal to or exceeds the set SOC value, the charging and discharging states of the two battery energy storage units are adjusted and switched; fast, safe and efficient controlled charging and discharging are achieved, and the life of battery energy storage is improved; the present invention overcomes the defects of the prior art that photovoltaic modules and energy storage modules are connected on the same bus, and the situation that the photovoltaic power is greater than or less than the load occurs randomly, causing the battery to be repeatedly charged and discharged in an uncontrolled manner, and the defect that the acquisition and calculation of multiple voltage parameters that rely on random changes and mutual influence are adopted, so that power control cannot be performed accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the principle of a photovoltaic storage system with controlled charging and discharging of energy storage batteries.

[0014] Figure 2 The invention relates to a photovoltaic storage system and a controlled charging and discharging control method and a flow chart. DETAILED DESCRIPTION

[0015] As an implementation example, a photovoltaic storage system and a controlled charging and discharging control method are described in conjunction with the accompanying drawings. However, the described embodiment is a partial embodiment of the present invention applied to a photovoltaic storage system and a controlled charging and discharging control method, rather than a complete embodiment. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention; the technology and solutions of the present invention are not limited to the contents given in this implementation example.

[0016] like Figure 1 and Figure 2As shown, a photovoltaic storage system and a controlled charging and discharging control method are provided, wherein at least two energy storage units are respectively connected and connected to a DC bus (3) through an energy storage discharging path and an energy storage charging path, and a photovoltaic power generation unit (4) is connected to the DC bus (3) through a photovoltaic on-off and protection circuit (D1); the DC side of a bidirectional converter (1) is connected to the DC bus (3), and the AC side of the bidirectional converter (1) is connected to a power grid power line (2); a controller (10) is respectively connected to the photovoltaic power generation unit (4), a first battery energy storage unit (5), a second battery energy storage unit (6), an energy storage discharging path control circuit (7), an energy storage charging path control circuit (8), various on-off and protection circuits and various selection switches through a control bus (11), thereby forming a photovoltaic storage system for controlled charging and discharging of energy storage batteries;

[0017] The invention is also characterized in that the operation control method of the photovoltaic storage system is:

[0018] S1: The photovoltaic energy storage system is powered on normally; the photovoltaic power generation unit, each battery energy storage unit, each circuit module and switch status parameters are detected, and an alarm is issued when abnormal, and S2 is executed when normal;

[0019] S2: the first selection switch (K1) is closed, the second selection switch (K2) is opened, the energy storage discharge path control circuit (7) is normal, and the first battery energy storage unit (5) is in a unidirectional discharge path conduction; at the same time, the fourth selection switch (K4) is closed, the third selection switch (K3) is opened, the energy storage charging path control circuit (8) is normal, and the second battery energy storage unit (6) is in a unidirectional charging path conduction; the photovoltaic power generation unit (4) is connected to the DC bus (3) through the photovoltaic on-off and protection circuit (D1) normally;

[0020] S3: The controller (10) monitors the SOC values ​​of the electric power in the first battery energy storage unit (5) and the second battery energy storage unit (6) in real time. When the SOC value of the electric power of the battery energy storage unit connected to the unidirectional discharge path is less than or equal to the set value L1, the controller (10) controls the second selection switch (K2) to be closed and the first selection switch (K1) to be opened, and controls the third selection switch (K3) to be closed and the fourth selection switch (K4) to be opened; or, when the SOC value of the electric power of the battery energy storage unit connected to the unidirectional charging path is greater than or equal to the set value H1, the controller (10) controls the third selection switch (K3) to be closed and the fourth selection switch (K4) to be opened, and controls the second selection switch (K2) to be closed and the first selection switch (K1) to be opened; adjusts and switches the charging and discharging states of the two battery energy storage units; and continues to re-execute S3.

[0021] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the energy storage discharge path control circuit (7) connected to the power line (2) of the power grid is connected in sequence to the first selection switch (K1), the first energy storage charge and discharge on-off and protection circuit (D2), and the first battery energy storage unit (5), and is also connected in sequence to the second selection switch (K2), the second energy storage charge and discharge on-off and protection circuit (D3), and the second battery energy storage unit (6), respectively forming the unidirectional discharge power paths of the first battery energy storage unit (5) and the second battery energy storage unit (6).

[0022] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the energy storage charging path control circuit (8) connected to the power line (2) of the power grid is connected in sequence to the third selection switch (K3), the first energy storage charging and discharging on-off and protection circuit (D2), and the first battery energy storage unit (5), and is also connected in sequence to the fourth selection switch (K4), the second energy storage charging and discharging on-off and protection circuit (D3), and the second battery energy storage unit (6), respectively forming unidirectional charging power paths of the first battery energy storage unit (5) and the second battery energy storage unit (6).

[0023] The photovoltaic storage system and controlled charging and discharging control method are characterized in that the controller (10) is respectively connected to the bidirectional converter (1), the photovoltaic power generation unit (4), the first battery energy storage unit (5), the second battery energy storage unit (6), the energy storage discharge path control circuit (7), the energy storage charging path control circuit (8), the photovoltaic on-off and protection circuit (D1), the first energy storage charging and discharging on-off and protection circuit (D2), the second energy storage charging and discharging on-off and protection circuit (D3), the first selection switch (K1), the second selection switch (K2), the third selection switch (K3), and the fourth selection switch (K4) through a control bus (11), so as to form a control link of the photovoltaic storage system for controlled charging and discharging of the energy storage battery.

[0024] The photovoltaic energy storage system and controlled charging and discharging control method are characterized in that the first battery energy storage unit (5) and the second battery energy storage unit (6) are internally configured with a BMS battery management system and are connected to a controller (10) and a bidirectional converter (1) via a control bus (11).

[0025] The present invention provides a photovoltaic storage system and a controlled charging and discharging control method, wherein at least two energy storage units are respectively connected and connected to a DC bus through an energy storage discharge path and an energy storage charging path, and a controller (10) monitors the SOC values ​​of the first battery energy storage unit (5) and the second battery energy storage unit (6) in real time. When the SOC value of the battery energy storage unit connected to the unidirectional discharge path is equal to or exceeds the set SOC value of one battery energy storage unit, the charging and discharging states of the two battery energy storage units are adjusted and switched; fast, safe and efficient controlled charging and discharging are achieved, and the life of the battery energy storage is improved; the present invention overcomes the defects of the prior art that photovoltaic modules and energy storage modules are connected to the same bus, and the situation that the photovoltaic power is greater than or less than the load occurs randomly, causing the battery to be repeatedly charged and discharged without control, and the defect that the power control cannot be accurately performed by using the collection and calculation of multiple voltage parameters that rely on random changes and mutual influence.

[0026] Specific implementation methods are given above, but the present invention is not limited to the described implementation methods. For those skilled in the art, it does not require creative labor to design various combinations, formulas, and parameters according to the technical solution of the present invention, and changes, modifications, substitutions, and variations of the implementation methods without departing from the principles and conceptual framework of the present invention still fall within the scope of protection of the present invention.

Claims

1. A photovoltaic storage system and a controlled charging and discharging control method, wherein at least two energy storage units are respectively connected and connected to a DC bus through an energy storage discharge path and an energy storage charging path, and a photovoltaic power generation unit is connected to the DC bus through a photovoltaic on-off and protection circuit; a bidirectional converter DC side is connected to the DC bus, and a bidirectional converter AC side is connected to a power grid power line; a controller is respectively connected to the photovoltaic power generation unit, a first battery energy storage unit, a second battery energy storage unit, an energy storage discharge path control circuit, an energy storage charging path control circuit, and various on-off and protection circuits and various selection switches through a control bus, to form a photovoltaic storage system for controlled charging and discharging of energy storage batteries; Its characteristics are also that The operation control method of the photovoltaic storage system is: S1: The photovoltaic energy storage system is powered on normally; the photovoltaic power generation unit, each battery energy storage unit, each circuit module and switch status parameters are detected, and an alarm is issued when abnormal, and S2 is executed when normal; S2: The first selection switch is closed, the second selection switch is opened, the energy storage discharge path control circuit is normal, and the first battery energy storage unit is in a unidirectional discharge path conduction; At the same time, the 4th selection switch is closed, the 3rd selection switch is opened, the energy storage charging path control circuit is normal, the 2nd battery energy storage unit is in the unidirectional charging path conduction; the photovoltaic power generation unit is connected to the DC bus through the photovoltaic on-off and protection circuit normally; S3: The controller monitors the SOC values ​​of the electric power in the first battery energy storage unit and the second battery energy storage unit in real time. When the SOC value of the electric power of the battery energy storage unit connected to the unidirectional discharge path is ≤ the set value L1, the controller controls the second selection switch to be closed and the first selection switch to be opened, and controls the third selection switch to be closed and the fourth selection switch to be opened; or, when the SOC value of the electric power of the battery energy storage unit connected to the unidirectional charging path is ≥ the set value H1, the controller controls the third selection switch to be closed and the fourth selection switch to be opened, and controls the second selection switch to be closed and the first selection switch to be opened; adjust and switch the charging and discharging states of the two battery energy storage units; Continue to re-execute S3.

2. A photovoltaic storage system and a controlled charging and discharging control method according to claim 1, characterized in that: The energy storage discharge path control circuit connected to the power line of the power grid is connected in sequence to the first selection switch, the first energy storage charge and discharge on-off and protection circuit, and the first battery energy storage unit, and is also connected in sequence to the second selection switch, the second energy storage charge and discharge on-off and protection circuit, and the second battery energy storage unit, respectively constituting the unidirectional discharge power paths of the first battery energy storage unit and the second battery energy storage unit.

3. A photovoltaic storage system and controlled charging and discharging control method according to claim 1, characterized in that: The energy storage charging path control circuit connected to the power line of the power grid is connected in sequence to the third selection switch, the first energy storage charging and discharging on-off and protection circuit, and the first battery energy storage unit, and is also connected in sequence to the fourth selection switch, the second energy storage charging and discharging on-off and protection circuit, and the second battery energy storage unit, forming unidirectional charging power paths for the first battery energy storage unit and the second battery energy storage unit, respectively.

4. A photovoltaic storage system and controlled charging and discharging control method according to claim 1, characterized in that: The controller is connected to the bidirectional converter, the photovoltaic power generation unit, the first battery energy storage unit, the second battery energy storage unit, the energy storage discharge path control circuit, the energy storage charging path control circuit, the photovoltaic on-off and protection circuit, the first energy storage charge and discharge on-off and protection circuit, the second energy storage charge and discharge on-off and protection circuit, the first selection switch, the second selection switch, the third selection switch, and the fourth selection switch through a control bus to form a control link of a photovoltaic storage system for controlled charging and discharging of energy storage batteries.

5. A photovoltaic storage system and controlled charging and discharging control method according to claim 1, characterized in that: The first battery energy storage unit and the second battery energy storage unit are internally configured with a BMS battery management system and are connected to a controller and a bidirectional converter via a control bus.

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