Three-phase pulse width modulation method and system for alternating current motor
OwnerSeung Ki Sul, Hyeoun Dong Leeinventors
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Abstract
A three-phase pulse width modulation method in a motor control system which drives a three-phase AC motor that determines a current switching pattern of a converter and then moves switching points of three phases of an inverter so that a switching point of a phase among the three-phases of the converter accords with a switching point of a phase among the three-phases of the inverter in accordance with the determined switching pattern, thereby reducing a voltage generated between the three-phase Ac motor and a ground, that is the size of the pulse number of a common-mode voltage.
Claims11
A method of modulating a three-phase pulse width of a three-phase pulse width modulating system for an alternating current AC motor, the three-phase pulse width modulating system including an inverter and a converter, the three-phase pulse width modulation method, comprising the following steps:
- (a) determining a current switching pattern of the converter;
- and
- (b) changing switching points of three phases of the inverter so that a switching point of a phase among the three phases of the converter accords with a switching point of a phase among the three phases of the inverter in accordance with the determined switching pattern.
A system which includes an inverter and a converter for modulating a three-phase pulse width of an AC motor, the system, comprising:
- a control unit for outputting three first pole voltage commands and three second pole voltage commands;
- a first driving unit for outputting a first driving signal to the converter in accordance with the three first pole voltage commands;
- and
- a second driving unit for outputting a second driving signal to the inverter in accordance with the three second pole voltage commands, wherein the control unit compares a switching interval of each phase of the inverter to a switching interval of each phase of the converter, for thereby according an on-time of one of the three second pole voltage commands with an on-time of one of the three first pole voltage commands.
A system which includes an inverter and a converter for modulating a three-phase pulse width of an AC motor, the system, comprising:
- a control unit for outputting three first pole voltage commands and three second pole voltage commands;
- a first driving unit for outputting a first driving signal to the converter in accordance with the three first pole voltage commands;
- and
- a second driving unit for outputting a second driving signal to the inverter in accordance with the three second pole voltage commands, wherein the control unit determines a current sector by combining output voltage vectors of the converter and output voltage vectors of the inverter, for thereby according an on-time of one of the three second pole voltage commands with an on-time of one of the three first pole voltage commands in accordance with the determined sector.
Dependencies are inferred from the claim text.