Three-phase full-bridge uninterruptible power supply control method with no need for load current sensor

Abstract

The present invention discloses a three-phase full-bridge uninterruptible power supply control method with no need for a load current sensor. A three-phase uninterruptible power supply is widely applied to a distributed generation system, and is especially suitable for power supply of key loads such as the war industry, the medical treatment and advanced experiment devices, but the control methodmostly needs a load current sensor to ensure good robustness and control precision. An economical control strategy based on the Lyapunov large signal asymptotic stability principle is provided. Basedon the Lyapunov large signal asymptotic stability principle, an observer for real-time estimation of a load current and a corresponding control law are derived so as to omit three load current sensorsand greatly reduce the implementation cost. The zero steady-state error tracking control of a command voltage by the output voltage of the three-phase uninterruptible power supply is achieved, and good dynamic performances for various complex working conditions such as the resistance load jumping and non-linear load jumping are shown.

Description

technical field [0001] The invention belongs to the technical field of distributed power generation and micro-grid, and in particular relates to a three-phase full-bridge uninterruptible power supply control method without a load current sensor. Background technique [0002] Distributed power generation technology is of great significance for the consumption of renewable energy, coping with global climate change, and improving the energy structure and power quality in remote areas. Among them, uninterruptible power supply technology has received extensive attention and research in recent years. This technology is mainly used in the power supply of key loads such as military industry, medical treatment, data centers, and high-end experimental equipment, so as to solve the problem of voltage sag, improve the reliability of power supply, and improve power quality. However, the uncertainty and nonlinear factors at the load end often pose a greater threat to the power quality of...

AI Technical Summary

Problems solved by technology

Model Predictive Control (MPC) control can achieve the same control goal at a lower switching frequency, thereby reducing switching losses, but this method is computationally expensive and at the cost of variable switching frequency, which is not conducive to filtering

An extended Lyapunov function-based method eliminates the steady-state error problem caused by the classic Lyapunov function-based control strategy by artificially introducing an outer voltage loop, but this strategy still requires three load current sensors, high implementation cost

[0005] In the existing technology, there are and only control strategies based on Lyapunov's principle that can strictly guarantee the global large-signal asymptotic stability of the controlled system theoretically.

However, the uninterruptible power supply control strategy based on this principle still requires real-time sampling of the load current, which is expensive to implement. It is urgent to find a more economical control strategy to reduce the number of sensors while ensuring the same control effect.

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