Three-phase passive inverter circuit diagram

The main circuit of the three- phase passive inverter circuit is shown in the figure. A three-phase bridge is composed of 6 unidirectional electronic switches , and each bridge arm is connected in parallel with a diode for freewheeling.

The power supply in the figure is marked with a box. In application, the DC power supply may be a voltage source or a current source. The output characteristics of the inverter are different depending on the power supply used. The opening sequence of the electronic switch is as follows: 1→2→3→4→5→6→1 in the figure. Make the three-phase load voltage a symmetrical three-phase alternating current.

Electronic switches can use fully controlled power electronic devices like single-phase bridge circuits, such as GTR, IGBT, GTO, etc. However, because the power of three-phase bridge inverter circuits is generally relatively large, ordinary thyristors are also used with certain commutation auxiliary circuits to realize the switching function. The capacity of fully controlled devices in sub-type circuits has not yet been increased to meet the needs of larger The requirements for power inverter circuits are relatively common. Now with the development of fully controlled device production technology, generally medium and small inverter circuits use fully controlled devices as electronic switches . However, the thyristors and auxiliary commutation circuits produced in the past A considerable number of inverters are still used in production equipment.

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