Photovoltaic power generation system

摘要

A photovoltaic power generation system includes a photovoltaic power generation module, a capacitor, a DC/AC voltage converter, a filter, a relay, a PWM controller, a calculation module, a control module, and a grid. The control module traces the maximum power of the photovoltaic power generation module, and detects whether the grid is abnormal or not. Finally, the DC power outputted from the photovoltaic power generation module is transferred to the AC power and outputted to the grid via the DC/AC voltage converter by using the PWM controller.

主权项

1. A photovoltaic power generation system, comprising:
a photovoltaic power generation module including a output end, and the photovoltaic power generation module receives a photovoltaic energy and converts the photovoltaic energy to an electricity with a DC voltage and a DC current; a capacitor connected to the output end of the photovoltaic power generation module in parallel for receiving and outputting the DC voltage; a DC/AC voltage converter including a first input end connected to the capacitor in parallel, a second input end, and a output end, the DC/AC voltage converter converting the DC voltage to an AC voltage and generating an AC current; a filter including an input end electrically connected to the output end of the DC/AC voltage converter, and an output end, the filter filtering noises in the AC voltage and the AC current; a relay including an input end electrically connected to the output end of the filter, and an output end; a grid including an input end electrically connected to the output end of the relay, and an output end; a control module including a first input end electrically connected to the output end of the photovoltaic power generation module, a second input end electrically connected to the output end of the filter, and an output end; a calculation module including a first input end electrically connected to the output end of the control module, a second input end electrically connected to the output end of the filter, and an output end; and a PWM controller including an input end electrically connected to the output end of the calculation module, and an output end electrically connected to the second input end of the DC/AC voltage converter; wherein the first input end of the control module is for receiving the DC voltage and the DC current of the photovoltaic power generation module, and the control module tracks a power maximum value of the photovoltaic power generation module to calculate a maximum power point voltage in accordance with the DC voltage and the DC current, and the second input end of the control module receives the AC current and the AC voltage from the output end of the filter and a rated current of the DC/AC voltage converter, and the control module calculates a first real power and a first reactive power of the DC/AC voltage converter, and a voltage phase angle of the grid in accordance with the AC voltage and the AC current from the filter, and the control module calculates a second real power and a second reactive power of the grid in accordance with the AC voltage from the filter and the rated current of the DC/AC voltage; wherein when the grid became abnormal, the control module outputs an output signal, compares the first real power with the second real power to output a selection signal, and outputs a command current to the first input end of the calculation module in accordance with the selection signal and the output signal, and the first input end and the second input end of the calculation module respectively receives the command current and the AC current from the output end of the filter to calculate an error between the AC current and the command current to compensate the error so as to output a command voltage to the PWM controller, and the PWM controller outputs a PWM control signal in accordance with the command voltage, and the PWM control signal controls the DC voltage of the capacitor to reach the maximum power point voltage and controls the AC current outputted from the DC/AC voltage converter to be as required for the grid; and wherein the number of the DC/AC voltage converter is one.