Measurement of speed and direction of coasting permanent magnet synchronous motor
First Claim
1. A method for substantially matching a frequency of an electronic drive inverter with a speed of rotation of an unpowered, coasting electric motor including a number of motor pole pairs without activating switches of said electronic drive inverter said method comprising:
- determining an electrical frequency of a back emf signal generated at one of a terminal of the motor and a switching node of the inverter when the motor is coasting; and
determining a mechanical motor frequency and thus said speed of rotation by dividing the electrical frequency by the number of motor pole pairs.
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Accused Products
Abstract
A method for determining the speed of rotation of an unpowered, coasting electric motor, driven, when powered, by an electronic inverter, and without activating switches of the inverter. The steps include determining an electrical frequency of a back emf signal generated at a terminal of the motor or switching node of the inverter when the motor is coasting and determining the mechanical motor frequency and thus speed of rotation by dividing the electrical frequency by the number of motor pole pairs.
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Citations
15 Claims
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1. A method for substantially matching a frequency of an electronic drive inverter with a speed of rotation of an unpowered, coasting electric motor including a number of motor pole pairs without activating switches of said electronic drive inverter said method comprising:
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determining an electrical frequency of a back emf signal generated at one of a terminal of the motor and a switching node of the inverter when the motor is coasting; and determining a mechanical motor frequency and thus said speed of rotation by dividing the electrical frequency by the number of motor pole pairs. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for substantially matching a drive frequency of an active motor control with a speed of rotation of an unpowered, coasting Permanent Magnet Synchronous motor including a number of motor pole pairs, without engaging said active motor control, said method comprising:
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monitoring a back emf signal generated at a terminal of said motor when said motor is coasting to determine an electrical frequency of said back emf signal; and determining said speed of rotation by dividing said electrical frequency by said number of motor pole pairs. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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Specification