Motor control device and electric power steering system
First Claim
1. A motor control device, comprising:
- a control signal output device that generates and outputs motor control signals; and
a driving circuit that outputs three-phase driving electric power based on the motor control signals, whereinthe driving circuit is formed by connecting switching arms, the switching arms formed by serially connecting pairs of switching elements that are turned ON or OFF based on the motor control signals, in correspondence with respective phases, in parallel with one another,each of the switching arms respectively have current sensors that detect phase current values of the respective phases corresponding to the switching arms at low potential sides thereof,the control signal output device generates the motor control signals based on phase current values of the respective phases, detected at a time at which all low potential side switching elements of the respective switching arms are turned ON,when an ON time of any one of the low potential side switching elements is shorter than the detection time, the control signal output device estimates a phase current value of a currently undetectable phase based on the phase current values of the respective phases, each of the respective phases are phases other than the currently undetectable phase, andat the time of detection of the respective phases, motor control signals corresponding to the currently undetectable phase are output, andthe motor control signals corresponding to the currently undetectable phase are motor control signals that cause the driving circuit to;
(i) keep ON a high potential side switching element of the pair of switching elements and (ii) keep OFF a low potential side switching element of the pair of switching elements.
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Abstract
A motor control device with which both high-accuracy current detection and improvement in voltage utilization factor are achieved is provided. When an ON time of any one of low potential side switching elements corresponding to respective phases in a driving circuit is shorter than a detection time of a current value, a microcomputer estimates a phase current value of a current undetectable phase based on current values of two phases other than the current undetectable phase corresponding to the said FET. Then, at the time of current detection using the blind correction, during current detection for two phases, other than the current undetectable phase, based on which the blind correction is performed, motor control signals for maintaining switching states of a switching arm corresponding to the current undetectable phase are output.
18 Citations
7 Claims
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1. A motor control device, comprising:
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a control signal output device that generates and outputs motor control signals; and a driving circuit that outputs three-phase driving electric power based on the motor control signals, wherein the driving circuit is formed by connecting switching arms, the switching arms formed by serially connecting pairs of switching elements that are turned ON or OFF based on the motor control signals, in correspondence with respective phases, in parallel with one another, each of the switching arms respectively have current sensors that detect phase current values of the respective phases corresponding to the switching arms at low potential sides thereof, the control signal output device generates the motor control signals based on phase current values of the respective phases, detected at a time at which all low potential side switching elements of the respective switching arms are turned ON, when an ON time of any one of the low potential side switching elements is shorter than the detection time, the control signal output device estimates a phase current value of a currently undetectable phase based on the phase current values of the respective phases, each of the respective phases are phases other than the currently undetectable phase, and at the time of detection of the respective phases, motor control signals corresponding to the currently undetectable phase are output, and the motor control signals corresponding to the currently undetectable phase are motor control signals that cause the driving circuit to;
(i) keep ON a high potential side switching element of the pair of switching elements and (ii) keep OFF a low potential side switching element of the pair of switching elements. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of providing motor control signals, comprising:
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detecting, by each current sensor of a plurality of switching arms of a driving circuit, phase current values of respective phases corresponding to the switching arms at low potential sides thereof; generating, by a control signal output device, motor control signals based on phase current values of the respective phases, detected at a time at which all low potential side switching elements of the switching arms are turned ON; when an ON time of any one of low potential side switching elements of the switching arms is shorter than the detection time, estimating, by the control signal output device, a phase current value of a currently undetectable phase based on the phase current values of the respective phases, each of the respective phases are phases other than the currently undetectable phase; and outputting, by the control signal output device at the time of detection of the respective phases, motor control signals corresponding to the currently undetectable phase; wherein the motor control signals corresponding to the currently undetectable phase are motor control signals that cause the driving circuit to;
(i) keep ON a high potential side switching element of the pair of switching elements and (ii) keep OFF a low potential side switching element of the pair of switching elements.
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Specification