| 摘要 |
PURPOSE:To eliminate the waveform distortion of the output AC of an inverter by accurately forming switching control signals without providing an absolute value circuit, and accurately controlling to switch the switching elements of the sides of the bridge of a main circuit. CONSTITUTION:A command signal of a command signal output unit 17 of a controller 24 and a comparison signal of a comparison signal output unit 19 are superposed and combined to form the first and second superposed signals, and the levels of the both superposed signals and positive and negative reference levels are compared by the first and second comparators 37, 45 to form the first and second comparison pulses. The first and second low frequency switching control signals are formed by repeating the trigger start of a low frequency switching control signal output unit by either one leading edge of the both comparison pulses. The first and second pulse width modulation switching control signals are formed by the first and second logic gates 53, 57 on the basis of the first and second comparison pulse signals and the first and second low frequency switching control signals. |
