Current vector controlled deadtime for multilevel inverters
AssigneeFairchild Korea Semiconductor Ltd.
InventorsSampat Shekhawat, Myoungho Lee, Yongtaek Lee, Jacobo Aguillon-Garcia, Bongjoo Choi
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Abstract
A multilevel inverter circuit includes an inverter control circuit that controls switching of main and neutral switches. The inverter control circuit receives current vector information indicating flow direction of an AC current output of the multilevel inverter circuit. The inverter control circuit eliminates dead time between switching of a neutral switch and a main switch depending on whether the AC current output is flowing towards a load or away from the load. Among other advantages, elimination of dead time improves the total harmonic distortion of the sinusoidal AC voltage output of the multilevel inverter circuit.
Claims20
A method of operating a multilevel inverter circuit, the method comprising:
- modulating a first main switch and a first neutral switch during generation of a positive half cycle of an output of the multilevel inverter circuit, the first main switch switching on and off to connect and disconnect an output node of the multilevel inverter circuit to a positive node, the first neutral switch switching on and off to connect and disconnect the output node of the multilevel inverter circuit to a neutral potential;
- detecting a flow direction of alternating current (AC) current output of the multilevel inverter circuit;
- and
- in response to detecting that the AC current output of the multilevel inverter is flowing in a positive direction towards a load, eliminating dead time between switching of the first neutral switch and the first main switch during the generation of the positive half cycle of the output of the multilevel inverter circuit.
A method of operating a multilevel inverter circuit, the method comprising:
- generating a first half cycle of an alternating current (AC) voltage output of the multilevel inverter circuit;
- detecting a flow direction of AC current output of the multilevel inverter circuit;
- and
- eliminating dead time between switching of a first neutral switch and a first main switch of the multilevel inverter circuit during generation of the first half cycle of the AC voltage output based on the flow direction of the AC current output of the multilevel inverter circuit.
A multilevel inverter circuit comprising:
- a main positive switch coupled to a positive voltage source;
- a main minus switch coupled to a negative voltage source;
- a neutral positive switch coupled to a neutral potential and the main positive switch;
- a neutral minus switch coupled to the neutral potential and the main minus switch;
- and
- an inverter control circuit having control outputs coupled to the main positive switch, the main minus switch, the neutral positive switch, and the neutral minus switch and having an input coupled to receive current vector information indicating direction of flow of an AC current output of the multilevel inverter circuit, the inverter control circuit being configured to remove dead time between switching of the neutral minus switch and the main positive switch and between switching of the neutral positive switch and the main minus switch based on the current vector information.
Dependencies are inferred from the claim text.