STATE ESTIMATOR BASED VOLTAGE CONTROL METHOD AND APPARATUS OF AN INVERTER WITH OUTPUT LC FILTER FOR APPLICATION TO UNINTERRUPTABLE POWER SUPPLY

摘要

The present invention relates to an uninterruptable power supply which applies state estimating module type instantaneous output voltage control device and method of an inverter having an LC filter. The present invention comprises an uninterruptable power unit including; a three-phase inverter having one or more IGBT switches; an LC filter which removes high frequency of three-phase alternating current power inputted through the inverter; and a three-phase resistivity load in which the three-phase alternating current power which passes through the filter is inputted. The present invention comprises; a state estimating unit which samples and senses a three-phase capacitor voltage inputted in the LC filter and a current of the inverter and expresses uncertainty and maximally makes a convergence speed to a normal state regarding values of a range which a maximum gain of inductance, capacitance, and three-phase resistivity load resistance is possible; and a closed loop control unit which produces a control value using the inductor current and capacitor voltage estimated in the state estimating unit and outputs the control value to the IGBT switch. Therefore, the preset invention maximally makes the convergence speed to a normal state regarding a possible change value of the inductance, the capacitance, and load resistance and can design an optimum state estimating unit which considers model uncertainty. The present invention designs the closed loop control unit which outputs a voltage of a multi-variable type using a state value for estimating the state of a next step by utilizing the state estimating unit and can provide a transient response performance capable of rapidly handling the load change. The present invention provides an output voltage having the standard frequency and size without the load change and provides a reliable control performance in the parameter uncertainty and a nonlinear load. [Reference numerals] (11) Three-phase inverter; (12) LC filter; (13) Three-phase resistivity load; (20) Status estimating unit; (30) Closed loop control unit