Abstract: A control board includes a plate 7 for the control board including a first printed board for mounting a control section 56 and a first connecter 9; and a removable terminal stand plate 1 including a second printed board for mounting a terminal stand 3, input circuit section 4 and output circuit section 5, and a second connector. The first and second connectors are connected to each other.

Abstract: A power converting apparatus is comprised of an inverter unit arranged by a switching semiconductor element 51a for an upper arm and another switching semiconductor element 51d for a lower arm, and for turning ON/OFF the switching semiconductor elements to thereby convert DC power inputted from a DC power supply into AC power; and control means 10a for judging as to whether or not an abnormal operation is present based upon an output of a comparator 11a for judging as to whether or not a detection voltage detected by a voltage detecting circuit 61 is substantially equal to a voltage of the positive polarity; an output of a comparator 11b for judging as to whether or not a detection voltage detected by the voltage detecting circuit 61 is substantially equal to a voltage of the negative polarity; and an output signal of an igniting signal for ON/OFF-controlling the switching semiconductor elements, this voltage detecting circuit 61 detecting an output voltage of the inverter unit via a voltage dividing resistor

Abstract: A control device for a PWM controlled converter having a voltage control portion for comparing with a voltage set value a detected value of a DC voltage output from the PWM controlled converter, connected through reactors to a 3-phase AC power source, for controlling AC input currents supplied from the 3-phase AC power source, to thereby produce current reference signals; an AC reference signal generating portion for generating AC reference signals synchronized with the 3-phase AC power source; a current instruction portion for producing current instruction signals formed by varying the amplitudes of the AC reference signals output from the AC reference signal generating portion in accordance with the current reference signals, and a current control portion for producing control signals to the PWM controlled converter so that the AC input currents vary as instructed by the current instruction signals.

Abstract: An apparatus and method for detecting a ground fault occurring on an output side of an inverter circuit, which includes a converter circuit for rectifying an alternating current into a direct current, a capacitor for smoothing the direct current, an inverter circuit for converting the smoothed direct current into a predetermined frequency and voltage through the on/off operation of switching elements connected in parallel with diodes, and a PWM signal generator for controlling the on/off of the switching elements.