Research On The Cascade Multi-level Active Power Filter And Fault-tolerant Technology

Due to power electronic equipment in the coal mine for the extensive use of the grid, causing serious power quality problems, especially harmonic pollution, seriously affecting the safety of coal for the power grid. Active Power Filter is currently one of the common measures and compensation can effectively suppress harmonics. But with the grid voltage electrical equipment to improve the level of power of the increasingly high-pressure, low and medium power of APF has been unable to meet the needs of modern power systems. Therefore suitable for high-voltage power cascade multi-level research APF has important practical significance.This paper studies the coal supply system applicable to 6KV cascade multi-level APF, multi-level analysis focuses on the topology of the strengths and weaknesses in the active power filter applications, and propose a suitable APF cascade multi-level inverter structure. Fault-tolerant technology to study the topology of the main research applies to redundant fault-tolerant technology topologies, as well as the cascade inverter failure causes and troubleshooting methods. Multi-level control theory, and select the carrier phase shift PWM control method as the basic topology. Research commonly harmonic detection algorithm, an improved ip-iq harmonic detection algorithm based on the algorithm does not need PLL circuit, and has a high precision, real-time, a small amount of computation and so on. Research on multi-level cascade control method APF DC capacitor voltage, the phase equilibrium and stability control made a total voltage of the DC capacitor and capacitor voltage control of each control strategy. Finally, the design of multi-level cascade APF system prototype.Simulation results show that the proposed harmonic detection algorithm, multi-level inverter topology and control algorithm can be applied to power system harmonic compensation, which is very progressive.