A New Controlled Current Type Inverter with Improved Performance

A new current-commutating method applying the action of the mutually coupled inductances is described and is termed the coupled reactor commutating (CRC) method. With this method a unique self-excited controlled current type inverter is constructed. The CRC inverter not only gives an efficient voltage adjustment function, but it also liberates men from the task of treating reactive powers. An example of the application to the induction motor drives is described in which an overall efficiency as high as 85 percent has been reached. The troublesome problem of parasitic torque pulsation in the low-revolution range, which is inherent in the controlled current type inverters, is also resolved by the torque-smoothing current control method with the CRC inverter.