EP-4742495-A1 - CONNECTION CONTROL METHOD AND APPARATUS FOR STANDBY POWER GENERATION DEVICE FOR PHOTOVOLTAIC ENERGY STORAGE SYSTEM

Abstract

Provided is a connection control method for a standby power generation device for a photovoltaic (PV) energy storage system, including: acquiring an output feature of a PV energy storage inverter in a PV energy storage system, and denoting the output feature as a first feature; acquiring an output feature of a standby power generation device, and denoting the output feature as a second feature; adjusting the PV energy storage inverter to make a difference degree between the first feature and the second feature reach a preset threshold; and when the difference degree between the first feature and the second feature reaches the preset threshold, connecting the standby power generation device to the PV energy storage system, and outputting electric energy by using the PV energy storage inverter and/or the standby power generation device. The present disclosure provides a connection control method and apparatus for a standby power generation device for a PV energy storage system, which can not only avoid a power failure of a load in a process of switching to the standby power generation device, but also prevent load damage caused by an excessively large difference between an output feature of the PV energy storage system and the output feature of the standby power generation device during the switching.

Inventors

• Qin, Yijin
• ZHANG, ZHEN
• ZHOU, TAO

Assignees

• Shanghai Sigeyuan Intelligent Technology Co., Ltd

Dates

Publication Date

20260513

Application Date

20230727

Claims (14)

1. A connection control method for a standby power generation device for a photovoltaic (PV) energy storage system, comprising following steps: acquiring an output feature of a PV energy storage inverter in a PV energy storage system, and denoting the output feature as a first feature; acquiring an output feature of a standby power generation device, and denoting the output feature as a second feature; adjusting the PV energy storage inverter to make a difference degree between the first feature and the second feature reach a preset threshold; and when the difference degree between the first feature and the second feature reaches the preset threshold, connecting the standby power generation device to the PV energy storage system, and outputting electric energy by using the PV energy storage inverter and/or the standby power generation device.
2. The connection control method for a standby power generation device for a PV energy storage system according to claim 1, wherein both the first feature and the second feature comprise a plurality of feature parameters, and the PV energy storage inverter is adjusted to make a difference degree between at least one of the feature parameters in the first feature and a corresponding feature parameter in the second feature reach the preset threshold.
3. The connection control method for a standby power generation device for a PV energy storage system according to claim 2, wherein when difference degrees between all the feature parameters in the first feature and corresponding feature parameters in the second feature reach the preset threshold, the standby power generation device is connected to the PV energy storage system.
4. The connection control method for a standby power generation device for a PV energy storage system according to claim 2, wherein the feature parameters comprise a frequency, a phase, and an amplitude of an output voltage.
5. The connection control method for a standby power generation device for a PV energy storage system according to claim 1, further comprising following steps: after connecting the standby power generation device to the PV energy storage system, acquiring a load power of the PV energy storage system; and when determining that the load power of the PV energy storage system is greater than an output power of the standby power generation device, increasing the output power of the standby power generation device based on the load power of the PV energy storage system, and reducing an output power of the PV energy storage inverter.
6. The connection control method for a standby power generation device for a PV energy storage system according to claim 5, wherein a method for adjusting the output power of the standby power generation device is as follows: P gen = P target ∗ 1 − e − αt ; and a method for adjusting the output power of the PV energy storage inverter is as follows: P inv = P load − P target ∗ 1 − e − αt ; wherein P load represents the load power, P target represents a target output power of the standby power generation device, α represents a characteristic parameter for an adjustment curve, t represents time, and P load = P inv + P gen .
7. The connection control method for a standby power generation device for a PV energy storage system according to claim 5, wherein when the output power of the standby power generation device reaches the load power, the PV energy storage inverter is controlled to stop outputting.
8. The connection control method for a standby power generation device for a PV energy storage system according to claim 1, further comprising following steps: after connecting the standby power generation device to the PV energy storage system, acquiring a harmonic current of the standby power generation device; and adjusting, based on the harmonic current of the standby power generation device, the PV energy storage system to output a harmonic current, such that the harmonic current output by the standby power generation device is zero or tends to zero.
9. The connection control method for a standby power generation device for a PV energy storage system according to claim 1, wherein the first feature and the second feature are acquired based on a preset acquisition cycle, and acquired data is optimized.
10. The connection control method for a standby power generation device for a PV energy storage system according to claim 9, wherein a method for optimizing the acquired data comprises outlier cleaning.
11. A connection control apparatus for a standby power generation device for a PV energy storage system, based on the connection control method for a standby power generation device for a PV energy storage system according to any one of claims 1 to 10, wherein the connection control apparatus comprises: an acquisition unit configured to acquire a first feature and a second feature; a control unit configured to generate a control parameter based on the first feature and the second feature, and send the control parameter to an execution unit; and the execution unit configured to control, based on the control parameter, a standby power generation device to connect to a PV energy storage system.
12. The connection control apparatus for a standby power generation device for a PV energy storage system according to claim 11, wherein the acquisition unit is further configured to acquire an execution state of the execution unit, and the control unit generates the control parameter based on the first feature, the second feature, and the execution state.
13. The connection control apparatus for a standby power generation device for a PV energy storage system according to claim 12, wherein the acquisition unit comprises a first phase-locked calculation unit and a second phase-locked calculation unit; the first phase-locked calculation unit is configured to acquire the first feature; the second phase-locked calculation unit is configured to acquire the second feature; and the control unit comprises a synchronization control calculation unit, and the synchronization control calculation unit is configured to calculate a difference degree between the first feature and the second feature.
14. The connection control apparatus for a standby power generation device for a PV energy storage system according to claim 11, wherein the acquisition unit is further configured to acquire a harmonic current output by the standby power generation device, and the control unit comprises a harmonic current controller.

Description

TECHNICAL FIELD The present disclosure relates to the field of photovoltaic (PV) energy storage systems, and specifically, to a connection control method and apparatus for a standby power generation device for a PV energy storage system. BACKGROUND TECHNOLOGY A PV energy storage system, also referred to as a solar PV energy storage power generation system, is a power generation system composed of a PV device and an energy storage device. To prevent power outages caused by exhaustion of energy stored in a battery when the PV energy storage system operates in an off-grid mode, a standby power generation device can be connected as a standby power source. At present, the standby power generation device is mainly a gasoline or diesel generator. However, since a frequency, a phase, an amplitude, a phase sequence, and other features of an output voltage of the standby power generation device may differ significantly from those of an output voltage of a PV energy storage inverter, if the standby power generation device is directly connected to a load, the load may be damaged. CONTENT OF THE INVENTION To address the deficiencies in the prior art, the present disclosure provides a connection control method and apparatus for a standby power generation device for a PV energy storage system, which can not only avoid a power failure of a load in a process of switching to the standby power generation device, but also prevent load damage caused by an excessively large difference between an output feature of the PV energy storage system and an output feature of the standby power generation device during the switching. To achieve the above objective, the present disclosure adopts the following specific solutions: A connection control method for a standby power generation device for a PV energy storage system includes following steps: acquiring an output feature of a PV energy storage inverter in a PV energy storage system, and denoting the output feature as a first feature;acquiring an output feature of a standby power generation device, and denoting the output feature as a second feature;adjusting the PV energy storage inverter to make a difference degree between the first feature and the second feature reach a preset threshold; andwhen the difference degree between the first feature and the second feature reaches the preset threshold, connecting the standby power generation device to the PV energy storage system, and outputting electric energy by using the PV energy storage inverter and/or the standby power generation device. Preferably, both the first feature and the second feature include a plurality of feature parameters, and the PV energy storage inverter is adjusted to make a difference degree between at least one of the feature parameters in the first feature and a corresponding feature parameter in the second feature reach the preset threshold. Preferably, when difference degrees between all the feature parameters in the first feature and corresponding feature parameters in the second feature reach the preset threshold, the standby power generation device is connected to the PV energy storage system. Preferably, the feature parameters include a frequency, a phase, and an amplitude of an output voltage. Preferably, the connection control method further includes following steps: after connecting the standby power generation device to the PV energy storage system, acquiring a load power of the PV energy storage system; andwhen determining that the load power of the PV energy storage system is greater than an output power of the standby power generation device, increasing the output power of the standby power generation device based on the load power of the PV energy storage system, and reducing an output power of the PV energy storage inverter. Preferably, a method for adjusting the output power of the standby power generation device is as follows: Pgen=Ptarget∗1−e−αt;and a method for adjusting the output power of the PV energy storage inverter is as follows: Pinv=Pload−Ptarget∗1−eαt; where Pload represents the load power, Ptarget represents a target output power of the standby power generation device, α represents a characteristic parameter of an adjustment curve, t represents time, and Pload = Pinv + Pgen. Preferably, when the output power of the standby power generation device reaches the load power, the PV energy storage inverter is controlled to stop outputting. Preferably, after the standby power generation device is connected to the PV energy storage system, a harmonic current of the standby power generation device is acquired; and based on the harmonic current of the standby power generation device, the PV energy storage system is adjusted to output a harmonic current, such that the harmonic current output by the standby power generation device is zero or tends to zero. Preferably, the first feature and the second feature are acquired based on a preset acquisition cycle, and acquired data is optimized. Preferab