CN-121643192-B - Control method, system, equipment and storage medium of photovoltaic charging relay

CN121643192BCN 121643192 BCN121643192 BCN 121643192BCN-121643192-B

Abstract

The application relates to the technical field of photovoltaic power generation and energy storage, in particular to a control method, a system, equipment and a storage medium of a photovoltaic charging relay, wherein the method comprises the steps of controlling a main relay in a photovoltaic charging circuit to execute on-off operation under a normal state, and recording the off times of the main relay which is controlled to be disconnected when the photovoltaic input voltage is lower than a preset voltage on threshold value; and in the locking state, monitoring at least one preset locking exit condition, and when any locking exit condition is met, controlling the system to exit the locking state, recovering the normal state and controlling the sucking and breaking operations of the main relay. The application can realize the stable control of the main relay under the fluctuation condition of the photovoltaic input and avoid the system instability and the device loss caused by frequent on-off as much as possible.

Inventors

MA HUI
QIN GENG
MENG XIAOQUN
GUO ZHIHUA
MENG ZHONGPING

Assignees

深圳市德兰明海新能源股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260116

Claims (9)

1. The control method of the photovoltaic charging relay is characterized by comprising the following steps of: in a normal state, controlling a main relay in a photovoltaic charging circuit to execute the on-off operation, and recording the off times of the main relay when the photovoltaic input voltage is lower than a preset voltage on threshold; in a preset time window, when the turn-off times of the main relay reach a preset threshold value, the control system enters a locking state, and the attraction control of the main relay is forbidden in the locking state; In the locking state, monitoring at least one preset locking exit condition, and when any locking exit condition is met, controlling a system to exit the locking state, recovering the normal state and controlling the on-off operation of the main relay; The preset locking and exiting conditions comprise a first locking and exiting condition, a second locking and exiting condition and a third locking and exiting condition; The first locking exit condition is that the time period of the current time is in a preset invalid time period; the second locking exit condition is that the photovoltaic input voltage is higher than a preset voltage starting threshold value and continuously reaches a first preset duration, and the change trend of the photovoltaic input voltage is characterized as a non-descending trend; And the third locking exit condition is that the photovoltaic input voltage is lower than a preset no-light judging threshold value and continuously reaches a second preset duration.
2. The control method according to claim 1, characterized in that in the lock state, the first lock-out condition, the second lock-out condition, and the third lock-out condition are executed in order of priority from high to low; and when the locking exit condition with higher priority is met, stopping judging the locking exit condition with lower priority, and controlling the system to exit the locking state.
3. The control method according to claim 2, wherein in the second lock-out condition, the trend of the change in the photovoltaic input voltage is obtained by calculating a difference value of the photovoltaic input voltages in adjacent sampling periods, and when the difference value is greater than or equal to zero, the trend of the change is determined as a non-falling trend.
4. The control method according to claim 3, wherein in the second lock-out condition, the voltage-on threshold and the first preset time period are set to be dynamically adjusted according to a period in which a current time is located; When the current time is in a low light period, the voltage starting threshold is increased and the first preset duration is prolonged; And when the current time is in a strong light period, maintaining or reducing the voltage starting threshold value and shortening the first preset time.
5. The control method according to any one of claims 1 to 4, characterized by further comprising the steps of, before controlling the main relay in the photovoltaic charging circuit to perform the on and off operation: under a normal state, continuously collecting the photovoltaic input voltage, and judging that the photovoltaic input is stable and effective only when the photovoltaic input voltage is higher than a preset voltage starting threshold value and continuously reaches a third preset duration, so as to execute precharge judgment; Comparing the difference value of the photovoltaic input voltage and the precharge capacitor voltage, and judging that the precharge is completed when the difference value does not exceed a preset voltage difference threshold value and continuously reaches a fourth preset time period; and when the difference exceeds a preset threshold and continuously reaches a fifth preset duration, judging that the pre-charging fails, wherein the fifth preset duration is longer than the fourth preset duration.
6. The control method according to claim 5, wherein after the determined precharge failure, when the photovoltaic input voltage is lower than the voltage on threshold for a sixth preset period of time, the precharge failure state is cleared and the collection of the photovoltaic input voltage is re-performed.
7. A control system for a photovoltaic charging relay, the control system comprising: The state control module is used for controlling a main relay in the photovoltaic charging circuit to execute the on-off operation under the normal state and recording the off times of the main relay which is controlled to be turned off when the photovoltaic input voltage is lower than a preset voltage on threshold value; the locking judgment module is used for controlling the system to enter a locking state when the turn-off times of the main relay reach a preset threshold value in a preset time window, and inhibiting the attraction control of the main relay in the locking state; the locking release module is used for monitoring at least one preset locking exit condition in the locking state, and when any locking exit condition is met, the control system exits the locking state, resumes the normal state and controls the on-off operation of the main relay; The preset locking and exiting conditions comprise a first locking and exiting condition, a second locking and exiting condition and a third locking and exiting condition; The first locking exit condition is that the time period of the current time is in a preset invalid time period; the second locking exit condition is that the photovoltaic input voltage is higher than a preset voltage starting threshold value and continuously reaches a first preset duration, and the change trend of the photovoltaic input voltage is characterized as a non-descending trend; And the third locking exit condition is that the photovoltaic input voltage is lower than a preset no-light judging threshold value and continuously reaches a second preset duration.
8. An electronic device comprising a processor and a memory, wherein the memory has a program stored therein, the program being loaded and executed by the processor to implement the method of controlling a photovoltaic charging relay according to any one of claims 1 to 6.
9. A computer-readable storage medium, characterized in that the computer-readable storage medium has stored therein a program which, when executed by a processor, is adapted to carry out the control method of a photovoltaic charging relay according to any one of claims 1-6.

Description

Control method, system, equipment and storage medium of photovoltaic charging relay Technical Field The application relates to the technical field of photovoltaic power generation and energy storage, in particular to a control method, a system, equipment and a storage medium of a photovoltaic charging relay. Background In a photovoltaic energy storage system, a photovoltaic charging circuit takes on the task of introducing direct-current electric energy output by a solar module into an energy storage battery or an inversion system, and the control performance of the photovoltaic charging circuit directly influences the charging efficiency and the system stability. The photovoltaic charging circuit generally includes a pre-charging branch for buffer charging the storage capacitor through a current limiting resistor during a system start-up phase, and a main relay for switching on when the storage capacitor is in voltage contact with the output voltage of the photovoltaic panel, thereby establishing a main charging loop. The existing circuit control method generally adopts a judgment logic of a fixed voltage threshold, namely, when the photovoltaic input voltage is higher than a set threshold, the pre-charging is started, and if the pre-charging fails or the voltage drops, the relay is disconnected to wait again. However, in a scene where the illumination condition is frequently changed, there is a significant fluctuation in the photovoltaic input voltage, and when the photovoltaic input voltage is in the threshold critical interval, a jitter phenomenon of frequent on and off of the main relay is easily caused, so that the system repeatedly performs the start and stop operations in a short time. In implementation, the frequent on-off action of the main relay not only enables the relay contacts to generate arc impact and mechanical abrasion, thereby obviously shortening the service life of the relay contacts, but also can generate continuous mechanical noise to influence the mute performance and the user experience of the product. Meanwhile, the system energy is consumed in the process of multiple invalid starting, so that the overall charging efficiency is reduced, and stable charging is difficult to realize. In view of the above problems, the prior art attempts to improve the frequent dithering phenomenon of the relay by adding hardware circuits. Specifically, a low-power load branch consisting of a MOSFET and a current-limiting resistor is connected in parallel at the photovoltaic input end, and when the photovoltaic input voltage fluctuates or illumination is unstable, the load branch is led to absorb weak current, so that the working point of the photovoltaic panel is pulled into a loaded state from an unstable region of no-load high voltage, and the output voltage of the photovoltaic panel tends to be stable. In this way, the main relay is prevented from being turned on by mistake due to the short-time rise of the voltage or from being turned off due to the short-time fall of the voltage to a certain extent, so that the dithering frequency is reduced. However, the improvement scheme requires additional configuration of the low-power load branch, so that the system structure becomes more complex, the manufacturing cost and the board layout difficulty are increased, meanwhile, the low-power load branch continuously consumes energy in the operation process, so that the system still has unnecessary energy loss in the weak light or standby stage, in addition, in order to coordinate the start-stop process of the low-power load branch and the main relay, the control logic needs to introduce more judgment links, and the complexity of software design is improved. Therefore, how to realize stable control of the main relay under the condition of fluctuation of the photovoltaic input without increasing additional hardware cost, so as to avoid system instability and device loss caused by frequent on-off as much as possible, and the method becomes a difficult problem to be solved in the field. Disclosure of Invention The application provides a control method, a system, equipment and a storage medium of a photovoltaic charging relay, which can realize stable control of a main relay under the condition of photovoltaic input fluctuation and avoid system instability and device loss caused by frequent on-off as much as possible. The application provides the following technical scheme: in a first aspect, the present application provides a control method of a photovoltaic charging relay, including the steps of: in a normal state, controlling a main relay in a photovoltaic charging circuit to execute the on-off operation, and recording the off times of the main relay when the photovoltaic input voltage is lower than a preset voltage on threshold; in a preset time window, when the turn-off times of the main relay reach a preset threshold value, the control system enters a locking state, and the attraction control of the main r