The problem of the efficiency of electromotor and temperature rise

No matter the transducer of the sort of form, all produce the harmonic voltage of different level and electricity in move, make electromotor moves below blame sine voltage, electric current. Refus data introduces, it is with the sine wave PWM that uses generally at present transducer exemple, its are low second harmonic is basically 0, those who remain is one times bigger than carrier wave frequency wave heft is right-and-left Gao Cixie: 2u 1 (U is compared for modulation) .

Gao Cixie wave can cause copper of bad news of electromotor stator copper, rotor (aluminous) of bad news, iron bad news and additional loss increase, most remarkable is rotor copper (aluminous) bad news. Because asynchronous electromotor rotates in order to receive the synchronous rotate speed of correspondence of place of frequency of close Yu Jibo, accordingly, voltage of Gao Cixie wave with bigger turn poor cut rotor guides hind, can produce very big rotor loss. Besides, the add copper waste time that because place of collect skin effect arises,still needs a consideration. These loss can make electromotor additional and calorific, loss of efficiency, output power is reduced, below the condition of blame sine power source that runs at transducer output like electromotor of asynchronous of will common three-phase, its temperature rise should increase 10%~20% commonly.