| 摘要 |
PURPOSE:To obtain sine-wave output voltage having small higher-harmonic content by forming all of the rise of base signal wave-forms given to each transistor of a main circuit at the same timing. CONSTITUTION:A three phase inverter is formed in such a manner that triangular waves uased as the reference and sine waves are compared, ON-OFF signals are made up and a sine-wave approximate PWM is controlled by using the signals. All rise time t1, t2, t5, t8, t11, t14 are formed at the same timing without changing the time integrated value of base signal wave-forms UB', VB', WB', -UB', -VB', -WB' given to each transistor constituting the inverter according to sampling periods. Thus, output voltage close to sine waves is obtained between mutual output terminals. |
