Structure and control method of an off-grid Stirling power supply system

Abstract

The invention discloses an off-grid Stirling power supply system structure and a control method. The system structure comprises a Stirling engine, a three-phase asynchronous motor, a bidirectional PWM (pulse width modulation) inverter, a bidirectional DC / DC converter, a user side inverter, a storage battery, a direct-current voltage transmitter and a controller, wherein the three-phase asynchronous motor is connected with the Stirling engine, the bidirectional PWM inverter is connected with the three-phase asynchronous motor, the bidirectional DC / DC converter is connected with the bidirectional PWM inverter, the user side inverter is connected with the bidirectional PWM inverter and the bidirectional DC / DC converter, the storage battery is connected with the bidirectional DC / DC converter, and the controller is used for controlling the operating state of the bidirectional PWM inverter and the user side inverter according to direct-current bus voltage acquired by the direct-current voltage transmitter. The system structure can realize self-starting of the Stirling engine and provide a reactive power channel for the three-phase asynchronous motor, the asynchronous motor, a user and the storage battery can be balanced, so that off-grid operation of the Stirling engine is realized, and the high-efficiency Stirling engine and the asynchronous motor are wider in application.

Description

technical field [0001] The invention relates to an off-grid Stirling power supply system structure and a control method. Background technique [0002] At present, energy conservation and emission reduction have become the focus of social attention. Among them, solar energy and wind energy are more and more widely used due to their abundant resources, cleanness, and wide distribution. The existing off-grid wind power supply system, the usual system The structure includes a wind generator, a rectifier, an inverter, a battery, and an unloader. The wind generator is connected to the inverter and the battery through the rectifier, the inverter is connected to the user, and the battery is connected to the user through the inverter. The wind power Generators usually use permanent magnet synchronous generators or brushless excitation synchronous generators. Even if asynchronous generators are used, capacitors will be used to compensate the reactive power required for the excitation ...

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Problems solved by technology

[0002] At present, energy conservation and emission reduction have become the focus of social attention. Among them, solar energy and wind energy are more and more widely used due to their abundant resources, cleanness, and wide distribution. The existing off-grid wind power supply system, the usual system The structure includes a wind generator, a rectifier, an inverter, a battery, and an unloader. The wind generator is connected to the inverter and the battery through the rectifier, the inverter is connected to the user, and the battery is connected to the user through the inverter. The wind power Generators usually use permanent magnet synchronous generators or brushless excitation synchronous generators. Even if asynchronous generators are used, capacitors will be used to compensate the reactive power required for the excitation of asynchronous generators. Since the above generators only work in the power generation state, so Connected to it is a rectifier that rectifies the alternating current output by the generator into direct current. For changes in load and wind conditions, the system is stabilized by changing the pitch and adjusting the charging and discharging current of the battery. Grid-type solar power supply system, the usual system structure includes solar battery components, batteries and inverters, solar battery components are connected to inverters through batteries, and inverters are connected to users. The above two off-grid power supply systems are aimed at their respective fields , used in the Stirling power generation system, which cannot solve the self-starting problem of the Stirling engine, and also has the disadvantages of insufficient resource utilization, unstable DC bus voltage, and low power generation efficiency

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