Electric motor drive control system and control method thereof
First Claim
1. An electric motor drive control system, comprising:
- a DC power source;
a converter configured to allow step up of an output voltage of said DC power source, for variably controlling the output voltage of said DC power source in accordance with a voltage command value and outputting to a DC power line;
an inverter performing power conversion between an AC power driving an electric motor and a DC power on said direct power supply line, by a plurality of switching elements, so that said electric motor operates in accordance with an operation command; and
a controller setting said voltage command value of said converter;
whereinsaid controller includesa first loss estimating unit for estimating power loss at said DC power source based on a preset loss characteristic,a second loss estimating unit for estimating power loss at said converter based on a preset loss characteristic,a third loss estimating unit for estimating power loss at said inverter based on a preset loss characteristic, anda voltage command value generating unit calculating a minimum necessary voltage in correspondence with an induction voltage of said electric motor, based on a state of operation of said electric motor, establishing a DC voltage on said DC power line that minimizes total power loss including a sum of power losses estimated by said first to third loss estimating units, within a candidate voltage range not smaller than said minimum necessary voltage and not larger than an output upper limit voltage of said converter, and setting said voltage command value in accordance with the established DC voltage.
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Accused Products
Abstract
A voltage command value of a converter is set by executing the step of determining a candidate voltage of a system voltage VH as a converter output voltage in a voltage range from the minimum necessary voltage corresponding to induction voltage of a motor generator and a maximum output voltage of the converter; the step of estimating power loss at the battery, converter, inverter and motor generator, at each candidate voltage, and calculating total sum of estimated power loss of the overall system; and the step of setting the voltage command value VH# based on the candidate voltage that minimizes the total sum of estimated power losses among the candidate voltages.
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Citations
10 Claims
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1. An electric motor drive control system, comprising:
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a DC power source; a converter configured to allow step up of an output voltage of said DC power source, for variably controlling the output voltage of said DC power source in accordance with a voltage command value and outputting to a DC power line; an inverter performing power conversion between an AC power driving an electric motor and a DC power on said direct power supply line, by a plurality of switching elements, so that said electric motor operates in accordance with an operation command; and a controller setting said voltage command value of said converter;
whereinsaid controller includes a first loss estimating unit for estimating power loss at said DC power source based on a preset loss characteristic, a second loss estimating unit for estimating power loss at said converter based on a preset loss characteristic, a third loss estimating unit for estimating power loss at said inverter based on a preset loss characteristic, and a voltage command value generating unit calculating a minimum necessary voltage in correspondence with an induction voltage of said electric motor, based on a state of operation of said electric motor, establishing a DC voltage on said DC power line that minimizes total power loss including a sum of power losses estimated by said first to third loss estimating units, within a candidate voltage range not smaller than said minimum necessary voltage and not larger than an output upper limit voltage of said converter, and setting said voltage command value in accordance with the established DC voltage. - View Dependent Claims (2, 3, 4, 5)
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6. A method of controlling an electric motor drive control system, wherein
said electric motor drive control system includes a DC power source, a converter configured to allow step up of an output voltage of said DC power source, for variably controlling the output voltage of said DC power source in accordance with a voltage command value and outputting to a DC power line, and an inverter performing power conversion between an AC power driving an electric motor and a DC power on said direct power supply line, by a plurality of switching elements, so that said electric motor operates in accordance with an operation command; -
said method of control comprising the steps of; estimating power loss at said DC power source based on a preset loss characteristic; estimating power loss at said converter based on a preset loss characteristic; estimating power loss at said inverter based on a preset loss characteristic; calculating a minimum necessary voltage in correspondence with an induction voltage of said electric motor, based on a state of operation of said electric motor; establishing a DC voltage on said DC power line that minimizes total power loss including a sum of said estimated power losses, within a candidate voltage range not smaller than said minimum necessary voltage and not larger than an output upper limit voltage of said converter; and setting said voltage command value in accordance with the established DC voltage. - View Dependent Claims (7, 8, 9, 10)
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Specification