| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a controller for an electric motor which can suppress a surge voltage during the PAM control without causing the increase of a switching loss of the PWM control when the electric motor is controlled by using the PAM control and the PWM control together. <P>SOLUTION: The controller 11 executes the PAM control during high torque driving of the electric motor M and the PWM control during low torque driving. The controller 11 is provided with an inverter part 13, which converts a DC voltage outputted from a step-up chopper circuit 12 to an AC voltage, and a switching means which delays a switching speed of switching elements SW1-SW6 at the inverter part 13 during the high torque driving of the electric motor M compared with during the low torque driving. Two resistors R1, R2 are connected in series to a gate of each switching element SW1-SW6. And at the same time, a switch S is connected in parallel to one resistor R1. The switching speed of the switching elements SW1-SW6 is changed by turning on/off the switch S. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
