Abstract: A protection circuit equipped magnetic energy recovery switch including a magnetic energy recovery switch having at least two reverse-conductive type semiconductor switches and two capacitors employs a protection circuit and control method for protecting the capacitors against an overvoltage or short-circuited discharge, and protecting the reverse-conductive type semiconductor switches and a load against an overvoltage or overcurrent, and can be used as a controller or a current limiter.

Abstract: In order to protect Magnetic Energy Recovery Switch (MERS) against an overvoltage and an overcurrent a voltage detection unit is provided for detecting the capacitor voltage of the MERS and control means is provided to control so as to turn ON the switch of the discharge circuit connected in parallel with the capacitor to make the capacitor discharge the electric charge thereof when the output of the voltage detection unit exceeds a predetermined value. Moreover, a current detection unit is interposed between the AC power supply and the load for detecting the current flowing to the load, and the current limiting is carried out by making the duty ratio of the ON/OFF of the pulse of the gate control signals of the MERS switches smaller than 0.5, when the output of the current detection unit exceeds a predetermined value.

Abstract: Reverse conducting type semiconductor switches are arranged in a bride from, an energy storage capacitor is connected with its DC terminal to obtain a magnetic energy regeneration switch, and then an induction coil is connected to its AC terminal. An AC pulse current of variable frequency is obtained by applying a gate signal to the semiconductor switch to thereby turn it ON/OFF; since a voltage is generated automatically by regenerating magnetic energy, a DC power supply is connected to the opposite ends of the capacitor through a smoothing coil, thus injecting power.

Abstract: In order to provide a pulse power supply device using regenerating magnetic energy stored in a discharge circuit to a capacitor so as to use it as next discharge energy and supplying a bipolar pulse current with high repetition, a bridge circuit is composed of four inverse-conductive semiconductor switches, a charged energy source capacitor is connected to a DC terminal of the bridge circuit, and an inductive load is connected to its AC terminal. A control signal is supplied to gates of the inverse-conductive semiconductor switches, and a control is made so that when a discharge current rises, is maintained, or is reduced, all the gates are turned off, and the magnetic energy of the electric current can be automatically regenerated to the energy source capacitor by a diode function of the switches. Further, a large current power supply is inserted into a discharge circuit so as to replenish energy loss due to discharge, thereby enabling high-repetition discharge.

Abstract: In order to provide a pulse power supply device using regenerating magnetic energy stored in a discharge circuit to a capacitor so as to use it as next discharge energy and supplying a bipolar pulse current with high repetition, a bridge circuit is composed of four inverse-conductive semiconductor switches, a charged energy source capacitor is connected to a DC terminal of the bridge circuit, and an inductive load is connected to its AC terminal. A control signal is supplied to gates of the inverse-conductive semiconductor switches, and a control is made so that when a discharge current rises, is maintained or is reduced, all the gates are turned off, and the magnetic energy of the electric current can be automatically regenerated to the energy source capacitor by a diode function of the switches. Further, a large-current power supply is inserted into a discharge circuit so as to replenish energy loss due to discharge, thereby enabling high-repetition discharge.

Abstract: The present invention relates to an alternating-current power supply device which can improve a power factor of an alternating-current load, realizes low cost and miniaturization, and recovers magnetic energy. The alternating-current power supply device includes a bridge circuit composed of four reverse conducting semiconductor switches, a capacitor that is connected between direct-current terminals of the bridge circuit and absorbs the magnetic energy at the time of cutting off the current, an alternating-current voltage source that is connected to the induction load in series and is inserted between alternating-current terminals of the bridge circuit, and a control circuit that gives a control signal to gates of the respective reverse conducting semiconductor switches and controls on/off states of the respective reverse conducting semiconductor switches.