Motor drive apparatus, electric actuator and electric power steering apparatus
First Claim
1. A motor drive apparatus comprising:
- a 3-phase a.c. driven motor;
an inverter for driving said motor based on a battery voltage;
a first current detector for detecting a direct current flowing to said inverter;
a plurality of second current detectors for detecting the motor current flowing to said motor; and
a controller for controlling the drive of said inverter based on the current value detected by said first and/or second current detectors, and for driving the motor while controlling the torque of said motor;
wherein said controller converts the drive waveform of said inverter into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWM carrier wave; and
continuously changes the ratio of superimposing said high-order harmonics, based on said battery voltage.
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Accused Products
Abstract
The disclosure concerns a a motor drive apparatus, an electric actuator and an electric power steering apparatus capable of continuous torque control up to the high drive speed and high torque area, in order to enable quick acceleration and deceleration. A controller comprises a voltage saturation detecting apparatus for detecting the voltage saturation of the output voltage of an inverter circuit, based on the battery voltage, and a waveform controller that converts the drive waveform of the inverter circuit into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWN carrier wave; and continuously changes the ratio of superimposing the high-order harmonics in response to the voltage saturation detected by a voltage saturation detecting means. This arrangement allows the controller to continuously change the drive waveform of the inverter circuit.
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Citations
11 Claims
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1. A motor drive apparatus comprising:
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a 3-phase a.c. driven motor; an inverter for driving said motor based on a battery voltage; a first current detector for detecting a direct current flowing to said inverter; a plurality of second current detectors for detecting the motor current flowing to said motor; and a controller for controlling the drive of said inverter based on the current value detected by said first and/or second current detectors, and for driving the motor while controlling the torque of said motor; wherein said controller converts the drive waveform of said inverter into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWM carrier wave; and
continuously changes the ratio of superimposing said high-order harmonics, based on said battery voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A motor drive apparatus comprising:
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a 3-phase a.c. driven motor; an inverter for driving said motor based on a battery voltage; a first current detector for detecting a direct current flowing to said inverter; a plurality of second current detectors for detecting the motor current flowing to said motor; and a controller for controlling said inverter by PWM based on the current value detected by said first andior second current detectors, and for driving the motor while controlling the torque of said motor;
wherein said controller comprises;a step of comparing a PWM pulse width of each chase with a predetermined value; and a step of obtaining the motor current of the chase whose PWM pulse width is wider than the predetermined value based on the motor current of at least one of other phases and the direct current if the PWM pulse width of the phase is wider than the predetermined value.
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10. An electric actuator comprising:
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a 3-phase a.c. driven motor; an inverter for driving said motor based on a battery voltage; a first current detector for detecting a direct current flowing to said inverter; a plurality of second current detectors for detecting the motor current flowing to said motor; a controller for controlling the drive of said inverter based on the current value detected by said first and/or second current detectors, and for driving the motor while controlling the torque of said motor; and a torque transmitter for transmitting the drive torque of said motor to a driven member; wherein said controller converts the drive waveform of said inverter into the waveform created by superimposing harmonics of high odd-numbered order on a sinusoidal wave as a fundamental wave of the modulated wave modulated by a PWM carrier wave; and
continuously changes the ratio of superimposing said high-order harmonics, based on said battery voltage. - View Dependent Claims (11)
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Specification