CN105262127A - A power adaptive control method for a photovoltaic power generation hybrid energy storage system - Google Patents

Abstract

The invention discloses a power self-adaptive control method of a photovoltaic power generation hybrid energy storage system. The system consists of a photovoltaic battery array-converting sunlight energy into electric energy, a battery energy storage unit, a super capacitor energy storage unit-two energy storage power sources It constitutes a hybrid energy storage device, a DC bus, an AC bus, a converter and various loads; the battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters, and the photovoltaic power generation unit is connected to the DC bus through DC/AC The inverter is connected to the AC bus, and the DC bus is connected to the AC bus through DC/AC inverter, and different control strategies are adopted. The battery DC/DC converter adopts power control, and the supercapacitor DC/DC converter is used for DC bus voltage control. . The whole system adopts an adaptive power control strategy to realize the coordinated control of the system, so that the advantages of battery energy storage and supercapacitor energy storage are brought into play, and a good power throughput effect is obtained.

Description

A power adaptive control method for a photovoltaic power generation hybrid energy storage system

technical field

The invention relates to the technical fields of micro-grid, renewable energy power generation and energy storage, and in particular to a power adaptive control method of a photovoltaic power generation hybrid energy storage system.

Background technique

Micro-grid flexibly controls the characteristics of distributed power generation, which is a powerful supplement to large-scale power grids and plays an important role in the power system. It provides an effective way to promote the development and utilization of renewable energy, energy conservation, emission reduction, and green power consumption. The microgrid is integrated into the grid and also operates independently. With the continuous increase of renewable energy generation capacity, the impact of power fluctuations on the safe operation of the grid and power quality during microgrid island operation is becoming more and more obvious. The use of energy storage devices plays a role in stabilizing power fluctuations to a certain extent. However, it is difficult for a single energy storage device to meet the requirements of power control and energy management at the same time.

Using the complementary characteristics of hybrid energy storage, a relatively smooth and stable power output can be obtained, and power fluctuations caused by wind power and energy storage equipment access can be avoided. This patent proposes to combine supercapacitors and batteries to form a hybrid energy storage system. By applying an adaptive control strategy, the energy storage system of the microgrid can respond quickly in the island operation mode, thereby meeting the power quality requirements and loads of the microgrid during operation. power requirements.

Contents of the invention

The purpose of the present invention is to provide a power adaptive control method of a photovoltaic power generation hybrid energy storage system.

A power adaptive control method for a photovoltaic power generation hybrid energy storage system. The system consists of a photovoltaic cell array-converting sunlight into electrical energy, a battery energy storage unit, a supercapacitor energy storage unit-two energy storage power sources to form a hybrid energy storage device, DC bus, AC bus, converter and various loads; the battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters, and the photovoltaic power generation unit is connected to the DC bus through a DC/AC inverter. To the AC bus, the DC bus is connected to the AC bus through DC/AC inverter to provide power for the load; the energy storage device of this system uses two sets of DC/DC converters, the DC/DC converter allows energy to flow in both directions, and uses different The control strategy of the battery DC/DC converter is used for power control, and the supercapacitor DC/DC converter is used for DC bus voltage control.

The system includes a battery DC/DC converter, the battery voltage is detected, and the reference current signal is obtained by dividing it with its reference power signal, and the bridge arm is controlled according to its size to make it work in the charging and discharging state of the battery; at the same time, the reference The signal is compared with the actual current signal of the battery and sent to the PI current regulator to control the PWM output of the converter.

The system provides a supercapacitor DC/DC converter control topology diagram. The supercapacitor adopts voltage control. By detecting the DC bus voltage and comparing it with the reference voltage, it is sent to the voltage PI regulator to obtain a current reference signal, which is used to control The bridge arm of the DC/DC converter realizes the charging and discharging control of the supercapacitor. At the same time, the reference current signal is compared with the measured current signal of the supercapacitor and sent to the current PI regulator to control the PWM output of the DC/DC converter.

The whole system adopts an adaptive power control strategy to realize the coordinated control of the system; when the microgrid is operating in an island, according to the change of power demand, the supercapacitor will give priority to compensating the power shortage, and through the adaptive control strategy, the power shortage will be gradually transferred to the microgrid. The battery bears; when the DC bus voltage is stable, the power shortage of the microgrid island operation is fully compensated by the battery; when the power shortage is too large and the battery cannot be fully compensated, the supercapacitor energy storage device bears part of the remaining power shortage; when the power shortage exceeds According to the power bearing range of the hybrid energy storage system, some secondary loads are targeted to be removed according to the load conditions.

The invention relates to the technical fields of micro-grid, renewable energy power generation and energy storage, in particular to the control of a hybrid energy storage system in a photovoltaic power generation system, and is mainly used in a photovoltaic power generation Adaptive Control. This patent provides a structural diagram of a photovoltaic power generation hybrid energy storage system, which is composed of a photovoltaic cell array, a battery energy storage unit, a supercapacitor energy storage unit, a DC bus, an AC bus, a converter and various loads. The battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters. The battery DC/DC converter is used for power control, and the supercapacitor DC/DC converter is used for DC bus voltage control. Construction of different control strategies for hybrid energy storage systems. The photovoltaic power generation unit is connected to the AC bus through the DC/AC inverter, and the DC bus is connected to the AC bus through the DC/AC inverter to provide power for the load. The whole system adopts an adaptive power control strategy to realize the coordinated control of the system, so that the advantages of battery energy storage and supercapacitor energy storage are brought into play, and a good power throughput effect is obtained.

Description of drawings

Figure 1 Structural diagram of photovoltaic power generation hybrid energy storage system;

Figure 2 Control topology diagram of battery DC/DC converter;

Figure 3 Supercapacitor DC/DC converter control topology.

detailed description

In order to enable those engaged in the related fields of photovoltaic power generation technology and energy storage technology to better understand the solutions of the present invention, the implementation manners of the present invention will be described in detail below with reference to the accompanying drawings.

The structure of the photovoltaic power generation hybrid energy storage system is shown in Figure 1. The system consists of a photovoltaic cell array, a battery energy storage unit, a supercapacitor energy storage unit, a DC bus, an AC bus, a converter, and various loads. The battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters, the photovoltaic power generation unit is connected to the AC bus through the DC/AC inverter, and the DC bus is connected to the AC bus through the DC/AC inverter. Provide power to the load.

The photovoltaic power generation hybrid energy storage system adopts the DC/DC converter plus DC/AC inverter mode, in which the DC/DC converter allows energy to flow in both directions, and the battery and supercapacitor adopt different control strategies. The battery is an energy storage device with a slow response speed. The battery DC/DC converter adopts power control, the super capacitor has fast power throughput, and the super capacitor DC/DC converter is used for DC bus voltage control. The battery DC/DC converter control topology is shown in Figure 2. The voltage of the battery is detected, and the reference current signal is obtained by dividing it with the reference power signal, and the bridge arm is controlled according to its size to make it work in the charging and discharging state of the battery; at the same time, the reference signal is compared with the actual current signal of the battery and sent to Enter the PI current regulator to control the converter PWM output.

The supercapacitor DC/DC converter topology is shown in Figure 3. The DC bus voltage is detected, compared with the reference voltage, and sent to the voltage PI regulator to obtain a current reference signal, which is used to control the bridge arm of the DC/DC converter. Realize the charging and discharging control of the supercapacitor. At the same time, the reference current signal is compared with the measured current signal of the supercapacitor, and sent to the current PI regulator to control the PWM output of the DC/DC converter.

When the microgrid is operating in an isolated island and lacks the voltage and frequency support of the external power grid, it is necessary to implement a certain adaptive power control strategy for the supercapacitor and battery hybrid energy storage system, and maintain the balance of internal power supply and demand through the internal self-regulation of the microgrid. The specific adaptive power control strategy is: when the microgrid is running in an isolated island, according to the change of power demand, the supercapacitor compensates the power shortage first, and gradually transfers the power shortage to the battery through the adaptive control strategy. In this way, on the one hand, the supercapacitor It does not need to carry out power control for a long time and is easy to implement. On the other hand, the battery power throughput and switching are relatively smooth, which improves the charging and discharging effect. When the DC bus voltage is stable, the power deficit of the microgrid island operation is fully compensated by the battery. When the power shortage is too large, so that the battery cannot fully compensate, the supercapacitor energy storage device bears part of the remaining power shortage. When the power shortage exceeds the power tolerance range of the hybrid energy storage system, some secondary loads will be removed in a targeted manner according to the load conditions.

Referring to Figure 1, this system provides a structural diagram of a photovoltaic power generation hybrid energy storage system, which consists of a photovoltaic cell array, battery energy storage unit, super capacitor energy storage unit, DC bus, AC bus, converter and various loads, etc. . The battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters, the photovoltaic power generation unit is connected to the AC bus through the DC/AC inverter, and the DC bus is connected to the AC bus through the DC/AC inverter. Provide power to the load.

Referring to Figure 2, this system provides the control topology diagram of the battery DC/DC converter. The battery energy storage system adopts power control. The specific strategy is to detect the battery voltage and divide it with its reference power signal to obtain the reference current signal. According to Its size controls the bridge arm to make it work in the charging and discharging state of the battery; at the same time, the reference signal is compared with the actual current signal of the battery and sent to the PI current regulator to control the PWM output of the converter. The voltage should be selected and designed according to the actual system Current sensing device and PI regulator parameters.

Referring to Figure 3, this system provides a supercapacitor DC/DC converter topology diagram. The supercapacitor adopts voltage control. By detecting the DC bus voltage and comparing it with the reference voltage, it is sent to the voltage PI regulator to obtain a current reference signal. The signal It is used to control the bridge arm of the DC/DC converter to realize the charge and discharge control of the supercapacitor. At the same time, the reference current signal is compared with the measured current signal of the supercapacitor and sent to the current PI regulator to control the PWM output of the DC/DC converter. According to the actual system, select and design the voltage and current detection device and PI regulator parameters.

The whole system adopts an adaptive power control strategy: when the microgrid is running in an island, according to the change of power demand, the supercapacitor compensates the power shortage first, and gradually transfers the power shortage to the battery through the adaptive control strategy. When the DC bus voltage is stable, the power deficit of the microgrid island operation is fully compensated by the battery. When the power shortage is too large, so that the battery cannot fully compensate, the supercapacitor energy storage device bears part of the remaining power shortage. When the power shortage exceeds the power tolerance range of the hybrid energy storage system, some secondary loads will be removed in a targeted manner according to the load conditions.

The above content is a detailed description of the present invention in conjunction with the preferred technical solutions. It cannot be determined that the specific implementation of the invention is limited to these. Simple deduction and replacement made without departing from the idea of the present invention should be regarded as protection of the present invention. scope.

Claims (4)

1. A power self-adaptive control method for a photovoltaic power generation hybrid energy storage system, characterized in that: the system consists of a photovoltaic cell array - converting solar energy into electrical energy, a battery energy storage unit, a supercapacitor energy storage unit - two storage The energy source constitutes a hybrid energy storage device, a DC bus, an AC bus, a converter, and various loads; the battery energy storage unit and the supercapacitor energy storage unit are connected to the DC bus through their respective DC/DC converters, and the photovoltaic power generation unit is connected through DC The /AC inverter is connected to the AC bus, and the DC bus is connected to the AC bus through DC/AC inverter to provide power for the load; the energy storage device of this system uses two sets of DC/DC converters, and the DC/DC converter allows energy bidirectional flow, and adopts different control strategies, the battery DC/DC converter is used for power control, and the supercapacitor DC/DC converter is used for DC bus voltage control. 2. The power adaptive control method of a photovoltaic power generation hybrid energy storage system according to claim 1, characterized in that: the system includes a battery DC/DC converter, the battery voltage is detected, and the reference power signal is used to Divide the reference current signal to obtain the reference current signal, and control the bridge arm according to its size to make it work in the charging and discharging state of the battery; at the same time, the reference signal is compared with the actual current signal of the battery, and sent to the PI current regulator to control the PWM output of the converter. 3. The power adaptive control method of a photovoltaic power generation hybrid energy storage system according to claim 1, characterized in that: the system provides a supercapacitor DC/DC converter control topology diagram, and the supercapacitor adopts voltage control, through Detect the DC bus voltage, compare it with the reference voltage, and send it to the voltage PI regulator to obtain the current reference signal, which is used to control the bridge arm of the DC/DC converter to realize the charge and discharge control of the supercapacitor. At the same time, the reference current signal and The measured current signal of the supercapacitor is compared and sent to the current PI regulator to control the PWM output of the DC/DC converter. 4. The power adaptive control method of a photovoltaic power generation hybrid energy storage system according to claim 1, characterized in that: the entire system adopts an adaptive power control strategy to realize coordinated control of the system; the microgrid is in an isolated island During operation, according to the change of power demand, the supercapacitor compensates the power deficit first, and gradually transfers the power deficit to the battery through an adaptive control strategy; when the DC bus voltage is stable, the power deficit of the microgrid island operation is all compensated by the battery; When the power shortage is too large and the battery cannot be fully compensated, the supercapacitor energy storage device will bear part of the remaining power shortage; when the power shortage exceeds the power tolerance range of the hybrid energy storage system, according to the load situation, some secondary loads will be cut off in a targeted manner .