Motor and drive control system thereof
View Patent ↗Provided is a motor having a magnetic polar unit in which a permanent magnetic polar array having arranged therein alternately a plurality of permanent magnetic polar elements in alternate opposite poles is made to face a plurality of electromagnetic coil arrays alternately excited at opposite poles, and the permanent magnetic polar array is made to move thereby; wherein the motor further comprises a sensor for detecting the periodical magnetic change accompanying the movement of the permanent magnetic polar array, the output of the sensor is directly returned as a direct drive waveform to the electromagnetic coils, and this drive circuit forms the excitation signal based on the return signal.
1. An electric motor comprising:
a movable body with a plurality of permanent magnets continuously disposed thereon, the plurality of permanent magnets being alternately magnetized at opposite polarities;
a stator having an array of electromagnetic coils disposed thereon, the array of electromagnetic coils being spaced apart from the movable body so that the array of electromagnetic coils does not come into contact with the movable body;
a drive circuit that moves the movable body based on an attraction/repulsion between the movable body and the electromagnetic coils generated by supplying an excitation current to the array of electromagnetic coils to alternatively magnetize the electromagnetic coils at opposite polarities; and
a magnetic sensor, disposed at a position fixed with respect to the array of electromagnetic coils, that linearly detects a periodic magnetic field change caused by movement of the permanent magnets and outputs an analog value,
wherein the drive circuit inputs an alternative current signal as the analog value output by the sensor and creates a Pulse Wide Modulation pattern for exciting the electromagnetic coils by performing Pulse Wide Modulation control, and directly supplies the electromagnetic coils with the pattern;
wherein the drive circuit comprises a frequency-voltage converter, hysteresis level setting part, and window comparator;
wherein the frequency-voltage converter converts the frequency of the output value of the magnetic sensor into a voltage value;
wherein the hysteresis level setting part sets a hysteresis level based on the voltage value; and
wherein the window comparator compares the output of the magnetic sensor and the hysteresis level, and creates the Pulse Wide Modulation pattern for exciting the electromagnetic coils.
2. The electric motor according to claim 1 , wherein when an electric angle between a heteropolar arrangement constituting a pair is 2π, the sensor is able to linearly detect a position of the moveable body in a 2π area.
3. The electric motor according to claim 2 , further comprising an amplifier that amplifies the output analog value of the sensor.
4. The electric motor according to claim 1 , comprising a pair of said stators, wherein the movable body is disposed between the pair of stators.
5. An electric motor comprising:
a first unit with a plurality of permanent magnets continuously disposed thereon, the plurality of permanent magnets being alternately magnetized at opposite polarities;
a second unit having an array of electromagnetic coils disposed thereon, the array of electromagnetic coils being spaced apart from the first unit so that the array of electromagnetic coils does not come into contact with the first unit;
a drive circuit that moves the first unit based on an attraction/repulsion between the first unit and the second unit generated by supplying an excitation current to the array of electromagnetic coils to alternatively magnetize the electromagnetic coils at opposite polarities; and
a magnetic sensor, disposed at a position fixed with respect to the array of electromagnetic coils, that linearly detects a periodic magnetic field change caused by movement of the permanent magnets and outputs an analog value,
wherein the drive circuit inputs an alternative current signal as the analog value output by the sensor and creates a Pulse Wide Modulation pattern for exciting the electromagnetic coils by performing Pulse Wide Modulation control, and directly supplies the electromagnetic coils with the pattern;
wherein the drive circuit comprises a frequency-voltage converter, hysteresis level setting part, and window comparator;
wherein the frequency-voltage converter converts the frequency of the output value of the magnetic sensor into a voltage value;
wherein the hysteresis level setting part sets a hysteresis level based on the voltage value; and
wherein the window comparator compares the output of the magnetic sensor and the hysteresis level, and creates the Pulse Wide Modulation pattern for exciting the electromagnetic coils.
6. The electric motor according to claim 5 , wherein the first unit is a movable body and the second unit is a stator.