The Brain Control of Electic Motor in Smooth Start
Abstract: The system in hardware use the versatity of the sanling transducer to control the electric motor with the plan that the answer of voltage is divided by frequency is uniform. The method make the start voltage of the large capacity electric motor rise graudually to descrease the start current and to protect the motor and the surrounding equipment.
The system in software design use microprocessor to control the sanling transducer in long-range that configure and monitor the functional parametor,measure and display the frequency and the phase-shift between two signals which come from the input and the output of the sanling transducer respectively.When the frequency and the phase-shift become the same ,the microprocessor send up the signal to finish the start.The functional parametor is entered by serial communicate port of the microprocessor and is sent out and accepted precisely in a agreement which is configured in advance between microprocessor and sanling transducer.Digital technology is adopted to measure the phase-shift in direct ratio the differentiating pulse width of the two signals.The method of the frepuency measure is :transform voltage signal into pulse signal in beforehand,then measure the pulse signal in a second.And all the design is programmed with weifu in assemble language.With simply hardwares. The system is easy to adjust and achieve. Tests prove that the system meets the requirements.
Keywords: transducer microprocessor conmunication The test of the frequency and the phase-shift
