Control device for driving motor to freely switch between frequency conversion state and power frequency state

The utility model relates to a control device for driving a motor to freely switch between a frequency conversion state and a power frequency state, which comprises a frequency conversion incoming wire switch, a frequency conversion going wire switch, a power frequency running switch, a synchronizing unit, an input voltage transformer, an input current transformer, a frequency conversion output voltage transformer, an output current transformer, a programmable logic controller (PLC) and a human-machine interface. The human-machine interface is provided with operation buttons composed of a frequency-conversion to power-frequency button and a power-frequency to frequency-conversion button. The PLC is provided with a microprocessor CPU. The PLC is respectively connected with the frequency conversion incoming wire switch, the frequency conversion going wire switch, the power frequency running switch, the synchronizing unit, the human-machine interface and a frequency converter. The control device is novel in conception, reasonable in structure and convenient to use. The switching operation is realized by means of buttons on the human-machine interface. Therefore, the device is convenient to operate, high in degree of automation, stable and reliable, which well solves the difficulty in the prior art that an existing motor must be shut down to be switched between the frequency conversion state and the power frequency state so as to influence the production process.