Inverter apparatus

An inverter apparatus for driving an electric motor comprising:

• magnetic flux command signal generating means for generating a magnetic flux command signal having a frequency signal which is proportional to an inverter output frequency from an outside source,
• an inverter part for supplying electric power to the electric motor, the inverter part having an output voltage,
• integrating means for integrating the output voltage of the inverter part, the integrating means outputting a motor voltage integrating signal,
• error amplifying means for amplifying an error between the motor voltage integrating signal and said magnetic flux command signal,
• triangular wave generating means for generating a carrier frequency signal having a non-audible range which is higher in frequency than an audible range, and
• comparing means for generating a pulse width modulating signal in response to a comparison of the error amplified by the error amplifying means and the carrier frequency signal formed by said triangular wave generating means.

An inverter apparatus for driving an electric motor comprising:

• a power supply,
• a converter part connected to the power supply,
• an inverter part connected to the convertor part and supplying an electric power to the electric motor,
• integrating means, connected with an output side of the inverter part, for integrating an output voltage of said inverter part,
• magnetic flux command signal generating means for generating a magnetic flux command signal of a frequency which is proportional to an inverter output frequency signal from an outside source,
• error amplifying means for amplifying an error between the magnetic flux command signal and the integrated output voltage from said integrating circuit,
• triangular wave generating means for generating a triangular wave having a non-audible carrier frequency signal which is higher in frequency than an audible region,
• comparing means for comparing the amplified error from said error amplifying means and said triangular wave, and
• driver means, responsive to an output signal from said comparing means, for driving said inverter part.