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US 9,871,436 B1Granted
Three-phase three-level inverter with reduced common mode leakage current
AssigneeToshiba International Corporation
InventorsDa Jiao, Yu Liu
Life of this patent
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Abstract
A system and methods for reducing common mode leakage current for a three-phase three-level inverter using a single modulation waveform, implemented by a controller using a space vector diagram is disclosed.
Claims19
A system, comprising:
- a direct current (DC) connection comprising a DC power source, and a first and a second terminal coupled to the DC power source;
- an inverter coupled to the DC connection, the inverter including three phases of at least one switching device, each phase of at least one switching device coupled to a different output terminal of the inverter, wherein each phase of at least one switching device is individually operable in one of a first mode, a second mode, and a third mode, and wherein the inverter is characterized by a plurality of switching states corresponding to all possible combinations of the first mode, the second mode, and the third mode in which the three phases of switching devices can operate simultaneously;
- and
- a controller coupled to the switching devices, wherein the controller is operable to generate a sequence of switching signals provided to the switching devices using one modulation waveform to operate the inverter in a subset of switching states from the plurality of switching states based, at least in part, on common mode voltages associated with a space vector diagram including a plurality of vectors, each vector representing at least one switching state of the inverter.
1 more element
A method of controlling a power system, comprising:
- coupling a three-phase inverter to a first terminal and a second terminal of a DC connection;
- coupling each phase of the inverter to at least one switching device;
- coupling each at least one switching device to a different output terminal of the inverter;
- generating a plurality of switching signals to individually operate each phase of the at least one switching devices in one of a first mode, a second mode, and a third mode;
- identifying a plurality of switching states that correspond to all possible combinations of the first mode, the second mode, and the third mode in which the three phases of the inverter can simultaneously operate, wherein the plurality of switching states correspond to the plurality of switching signals;
- identifying a subset of switching states from the plurality of switching states based, at least in part, on common mode voltages associated with the plurality of switching states;
- and
- generating output voltages at the output terminals by applying a sequence of switching signals corresponding to a sequence of the subset of switching states using one modulation waveform.
5 more elements
A method, comprising:
- determining all possible switching states for a three-phase inverter;
- determining common mode voltages associated with each determined switching state;
- selecting a subset of the determined switching states corresponding to lower common mode voltages;
- generating a sequence of switching states that only incorporates switching states from the subset of the determined switching states;
- and
- generating a sequence of switching signals corresponding to the sequence of switching signals using one modulation waveform.
3 more elements
Dependencies are inferred from the claim text.