Abstract: In an inverter driving circuit and an air conditioner having the same, the circuit elements constituting the inverter driving circuit are arranged and connected through wirings along a power supply path so that those circuit elements and wirings which are located at the front stage of a noise filter are spatially separated from those circuit elements and wirings which are located at the rear stage of the noise filter. A power source of a controller for the inverter driving circuit is supplied with an alternating power from a neutral point and one of three phases (R,S,T) of the noise filter, and a high-frequency noise occurring in a transistor module is intercepted by a smoothing circuit and a rectifying circuit, so that the noise contamination into the controller can be prevented. The voltage to be supplied to the controller may be a low voltage.

Abstract: In air conditioner having a power-variable compressor, an inverter for varying the driving frequency of the compressor through V/f control, a controller for supplying a variable-frequency control instruction in accordance with the air conditioning load to the inverter, and an input voltage detector for detecting a source voltage input to the inverter, the controller includes reference means for beforehand storing V/f value data corresponding to plural voltage sections to which a predetermined range of the input voltage to the inverter is divided at a predetermined voltage interval, and selects data representing the ratio (V/f) of the output voltage (V) corresponding to the detected input voltage and the driving frequency (f) from the reference means to output the variable frequency control instruction to the inverter so that an air conditioning operation is carried out in accordance with the air conditioning load.