Abstract: A common mode filter circuit comprises a common mode transformer unit, an inverter, and a capacitor unit. Each of the first common mode transformer, the second common mode transformer, and the third common mode transformer comprises a first secondary wound wire, a second secondary wound wire, a third secondary wound wire, and a primary wound wire. A ratio of a number of turns of the primary wound wire to a number of turns of the first secondary wound wire, a ratio of a number of turns of the primary wound wire to a number of turns of the second secondary wound wire, and a ratio of a number of turns of the primary wound wire to a number of turns of the third secondary wound wire are each 3:1 in each of the first common mode transformer, the second common mode transformer, and the third common mode transformer.

Abstract: A power conversion device, including: a voltage detector that detects a common mode voltage generated upon a switching operation of a power semiconductor device; a voltage superimposer that superimposes the common mode voltage detected by the voltage detector onto an output of the power conversion device to cancel the common mode voltage having a frequency greater than or equal to a switching frequency generated upon the switching operation of the power semiconductor device; and a residual voltage detector that detects the common mode voltage of the power conversion device superimposed by the voltage superimposer. The voltage superimposer includes a feedback mechanism for adding and superimposing the common mode voltage detected by the residual voltage detector onto the output of the power conversion device. The voltage detector includes a first choke coil and a first capacitor.

Abstract: A power conversion device, including: a voltage detector that detects a common mode voltage generated upon a switching operation of a power semiconductor device; a voltage superimposer that superimposes the common mode voltage detected by the voltage detector onto an output of the power conversion device to cancel the common mode voltage having a frequency greater than or equal to a switching frequency generated upon the switching operation of the power semiconductor device; and a residual voltage detector that detects the common mode voltage of the power conversion device superimposed by the voltage superimposer. The voltage superimposer includes a feedback mechanism for adding and superimposing the common mode voltage detected by the residual voltage detector onto the output of the power conversion device. The voltage detector includes a first choke coil and a first capacitor.

Abstract: A power conversion device that converts electric power by having a power semiconductor element perform a switching operation includes a voltage detector detecting a common mode voltage generated in the switching operation of the power semiconductor element, a voltage control power supply that generates a voltage opposite in polarity to and as high as the common mode voltage with a circuit that amplifies power of the common mode voltage detected by the voltage detector, and a voltage superimposition structure canceling the common mode voltage not lower than a switching frequency generated in the switching operation of the power semiconductor element, by superimposing the voltage generated by the voltage control power supply on an output from the power conversion device.

Abstract: A power conversion device which converts electric power by having a power semiconductor element perform a switching operation includes voltage detection means for detecting a common mode voltage generated in the switching operation of the power semiconductor element, a voltage control power supply which generates a voltage which is opposite in polarity to and as high as the common mode voltage with a circuit which amplifies power of the common mode voltage detected by the voltage detection means, and voltage superimposition means for canceling the common mode voltage not lower than a switching frequency generated in the switching operation of the power semiconductor element, by superimposing the voltage generated by the voltage control power supply on an output from the power conversion device.

Abstract: An air conditioning system including a refrigerant circuit having a compressor, a three port switching valve, a four port reversing valve, an outdoor heat exchanger, a first throttle device including a first decompression device, a second throttle device including a first decompression device, an indoor heat exchanger and an accumulator connected in series by use of refrigerant pipes; a first bypass circuit which is constructed to carry out heat exchange with the intake pipe connecting between the accumulator and the compressor, and which is connected as a bypass to the pipe connecting between the first and second throttle devices; a second bypass circuit having a check valve to bypass the first decompression device; a third bypass circuit having a check valve to bypass the second decompression device; a fourth bypass circuit which is connected as a bypass to the pipe between the first and second throttle devices, and which is smaller than the discharge pipe in inside diameter; and a fifth bypass circuit whic