Direct current-direct current converting circuit uniform power control method suitable for photovoltaic micro-grid system

Abstract

The invention provides a direct current-direct current converting circuit uniform power control method suitable for a photovoltaic micro-grid system. By the adoption of the direct current-direct current converting circuit uniform power control method suitable for the photovoltaic micro-grid system, the MPPT function and the limiting power control function can be achieved, it can be guaranteed that the system stably operates during grid connection and grid disconnection and the output power is optimal, and a certain energy storage and management capacity can be achieved under the condition of grid disconnection. The uniform power control method is based on perturbation and observation. The achievement of a limiting power control method is changed according to the fact whether an energy storage device is full or exceeds a limiting current. In order to improve the rapidness of the limiting power control method, a variable-step-size perturbation and observation method is further introduced, and the steady-state performance and the dynamic performance are considered at the same time. According to the direct current-direct current converting circuit uniform power control method suitable for a photovoltaic micro-grid, the MPPT function and the limiting power control function can be combined organically, implementation is easy, and operation of the photovoltaic micro-grid system can be effectively expanded; in this way, the utilization efficiency of renewable energy power generation is improved easily, and high application value and good popularization prospect are achieved.

Description

technical field [0001] The invention relates to a unified power control method for a direct-to-direct conversion circuit in a photovoltaic microgrid system, which belongs to the microgrid system control technology in the field of new energy power generation and electric energy conversion. Background technique [0002] With the continuous and rapid development of social economy, my country's energy development is facing problems such as the widening gap between energy supply and demand, insufficient oil reserve resources, and serious environmental pollution. In order to achieve the sustainable development of energy, social economy and environment, the development and utilization of solar energy and other renewable energy distributed power generation technology is one of the important ways to solve the energy crisis. However, the direct connection of photovoltaic inverters has disadvantages such as high cost, relatively difficult control, and impact on the power grid. For thi...

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Problems solved by technology

If existing distributed power sources such as photovoltaic inverters are used, since they can only operate in MPPT mode, the output power cannot be controlled

Coupled with the randomness of the power load, the system cannot manage the charging and discharging of the energy storage device when the off-grid mode is running.

In addition, when the output power of the distributed power supply is too large, that is, when the limit of the energy storage device is exceeded, the system needs to forcibly cut off the operation of photovoltaics, which is not conducive to the smooth and stable operation of the system, and also reduces the utilization rate of new energy to a certain extent.

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