Coordination And Control Of Distributed Photovoltaic Power Generation System

Distributed photovoltaic(PV) power system and the user have a close distance, can be close to power to the load and to be transported directly to the power grid. The electricity of some special power users can be solved, and existing distribution network’s operating economy can be supported. Distributed PV systems inappropriate switch in the on-grid and off-grid states will bring a lot of problems and challenges for power systems normal operation and stability. In order to fully coordinate the contradiction between the grid and distributed PV power generation system, this paper improves a coordinated control strategy, overall coordinate distributed PV system smooth handover in on-grid and off-grid two large states. Specific work includes:First, based on analysis structure features and state output characteristics of inverter device, uses PV inverter device control policy based on direct instantaneous current control algorithm. The control algorithm direct control of the instantaneous current in the inverter side, simple structure, good output waveform effect. Analysis main circuit structure of PV inverter device, for specific analysis of instantaneous current control algorithm based on direct current pulse width modulation method, the correctness of the algorithm used by matlab simulation and experimental verification, then analyzes the energy storage device’s power configuration principle and control method.Second, improve a coordinated control strategy. More effective coordination of distributed PV power generation system in grid connected mode, from the network of maximum power tracking model, from the network load power matching operation mode, from the network met limited resection model consists of four kinds of modes of smooth handover.The power balance calculation distributed PV systems, energy storage, grid and load the corresponding algorithm design, coordinate smooth switch between the operating state, so that PV cells operating at maximum output power of the state as far as possible.Analysis an energy storage device operating mode under coordinate energy control, reducing the battery charge and discharge times, to avoid overcharge and over-discharge. Building simulation platform, verify the feasibility of the proposed control strategy.Third, distributed PV Coordinated Control System hardware and software design. Hardware design includes a master control system circuit design, multi-function expansion circuit design, the inverter device IGBT snubber circuit design, temperature sensor selection and error correction and any more. Software design includes DSP programming design, F28335 and human-machine interface communication design. The improved control strategy coordinated implementation through coordinated control system hardware and software design.Fourth, the design of the experimental platform. Including distributed PV power generation system test platform design and human-computer interaction system design. It describes the experimental platform circuit parameters selection, PV power generation system inverter device physical map and electrical wiring diagram. Designed touch-screen user interface, the DSP communication with the touch screen was introduced. Complete the relevant experiments on experimental platform.