Methods of inverter voltage control by superimposed chopping

摘要: An adjustable speed polyphase a-c motor drive featuring an inverter in which the same power switching devices, typically SCRs, are controlled to provide both variable frequency and voltage motor. This is accomplished by sequentially operating selected devices a time ratio mode of operation within principal thereof. During successive 60 electrical degree intervals three phase inverter, two phases connected source potential one polarity device remaining other subjected switching.