Abstract: A management or control of a power router is more appropriately performed when a power network system in which power cells are asynchronously connected with each other. A plurality of power conversion legs bi-directionally convert power, one ends thereof are connected with a direct current bus and the other ends thereof are connected with an external connection destination as an external connection terminal. A control unit controls operations of the plurality of power conversion legs. The control unit receives a control instruction including a designation of an activation target leg and a designation of an operation mode of the activation target leg. The control unit determines whether the activation target leg can be activated in a designated operation mode. The control unit activates the activation target leg in the designated operation mode when the activation target leg can be activated in the designated operation mode.

Abstract: A switching power supply apparatus which effectively utilizes energy accumulated in a leak inductance of a circuit to enhance the efficiency. The switching power supply apparatus having a switch element on/off controlled by a driving signal generated from a driver circuit, wherein a first capacitor and a first diode are inserted in series between both terminals of the switch , and a second capacitor and a second diode are further connected in series between a connecting point of the first capacitor and the first diode and a grounding terminal of the switch element to use charges accumulated on the second capacitor as a voltage source.

Abstract: An inverter for DC/AC conversion includes an inverter bridge controlled by a PWM controller. The inverter has a first control loop for performing PWM control in accordance with the difference between the instantaneous AC value of an inverter output and an amplitude of waveform data read out from an AC waveform memory. The inverter also has a second control loop for multiplying the amplitude value of the waveform data by a coefficient adjusted on the basis of the error between the means AC current or voltage value of the inverter outputs and a target control value, and performing PWM control in accordance with waveform data having the adjusted amplitude. By using a delta scheme of finely increasing/decreasing at a time the coefficient by which waveform data is multiplied, an inverter with a high control precision and high stability can be obtained.

Abstract: A stabilized power supply unit designed to supply the power from the commercial power source as far as the commercial power source is normal but supply the power from a battery that can be made available by an automatic switching device when the commercial power source has failed, wherein the AC voltage from the commercial power source is rectified by a rectification circuit to obtain almost equal DC currents on both the positive and negative sides of the common line while the commercial power source is normal. Said DC voltage is chopped by the boosting chopper circuit to boost the voltage on both the positive and negative sides. The boosted voltage is converted into the AC voltage through the DC-AC inverter, and the high-frequency component of the AC voltage is compressed through the filter in order to be outputted as an AC voltage of specified frequency.