Abstract: A motor control unit (1) includes a white noise generator (8), an instruction switch (9) for switching between an input control instruction (Vins) and a white noise output of the white noise generator (8), a controller (10) for feedback controlling the motor drive velocity, a detection unit (13) for detecting and sampling the real velocity of a motor or a load at a predetermined period, a first Fourier transformer (15) for Fourier-transforming the control instruction data (Cins) together with the sampled velocity data (Vm), and a first frequency characteristic operation unit (16) for calculating the frequency characteristics in a range from the velocity instruction (Cins) to the sampled velocity (Vm) based on output data of the first Fourier transformer (15), thus obtaining the frequency characteristics in a short period without necessity of a servo-analyzer.

Abstract: A PWM inverter output circuit enabling circuit integration, having a fast response characteristic, and unaffected by dv/dt transients is provided. A predrive circuit 17 drives a power circuit 11 comprising first and second power elements P1 and P2 by controlling the gate and source potential of the power elements P1 and P2 based on a stored control state. The control state is detected from a logic signal output from an input signal processor 13, which converts a command signal instructing turning on and off the power elements P1 and P2 to predetermined logic signals. Operating power is drawn from a main dc power source V1, a control power source V2, and a power supply capacitor C1 that is charged using an output voltage from the control power source V2. The gates and sources of the power elements P1 and P2 are connected together.

Abstract: An output circuit for a PWM inverter is provided which has an N-type first power device and a P-type second power device. Gates of the first and second power devices are connected to each other. Also, emitters of the first and second power devices are connected to each other. An input electrode control circuit controls the voltage applied to the common gates with respect to the common emitters. The voltage may be a positive or negative value, or zero. The input electrode control circuit controls the conduction states of the two power devices based upon the states of input light emitting devices associated with a first and second photocoupler (current generator). When both of the photocouplers are not lit, no current is generated and the conduction states of the power devices are instantaneously interrupted.

Abstract: A driving apparatus of an induction motor applied for drive of a fan of an air conditioner has a voltage limiter unit for limiting an upper limit of an output voltage of an inverter circuit, a voltage slow-up unit for converting an output signal of an output voltage commanding unit into a signal which increases gradually when that output signal rises, a voltage slow-down unit for converting the output signal of the output voltage commanding unit into a signal which decreases gradually when that output signal falls, and a feed interruption processing unit for setting the output signal value of the output voltage commanding unit to 0 when interrupting feeding and delivering a feed interruption signal at the termination of the lapse of a predetermined time.