Motor control device
A motor control device that can use a sensor input circuit that has a low response speed. The motor control device comprises a first magnetic pole position detection unit, a second magnetic pole position detection unit, and a control unit. The first magnetic pole position detection unit detects the pre-rotation position of a magnetic pole of a rotor based on detection results from a magnetic pole sensor. The second magnetic pole position detection unit detects the position of the magnetic pole of the rotor based on the current flowing in a plurality of drive windings that drive the rotor. The control unit performs control that makes the rotor start rotating based on detection results from the first magnetic pole position detection unit and control that makes the rotating rotor rotate based on detection results from the second magnetic pole position detection unit.
1 . A motor control device, comprising:
a processor configured to detect a position of a magnetic pole before a start of rotation of a rotor having the magnetic pole in response to a detection result of a magnetic pole sensor;
a current sensor configured to detect the position of the magnetic pole of the rotor in accordance with a current driving the rotor and flowing through a plurality of drive windings;
a controller configured to perform:
control of starting rotation of the rotor in a first speed range based on a detection result of the processor, and
control of rotating the rotor in a second speed range based on a detection result of the current sensor, wherein the second speed range is faster than the first speed range; and
a signal input circuit configured to connect the processor to the magnetic pole sensor or connect the processor to a signal from outside of the motor control device, wherein
the processor is configured to switch between processing the detection result of the magnetic pole sensor and processing the signal from outside of the motor control device,
a signal state response speed of the signal input circuit is slower than a signal state change of the magnetic pole sensor corresponding to a rotational period of the rotor in the second speed range.
2 . The motor control device according to claim 1 , wherein the magnetic pole sensor is a Hall sensor.
3 . The motor control device according to claim 1 , wherein one or more magnetic pole sensors are disposed for each of the plurality of drive windings.
4 . The motor control device according to claim 1 , wherein magnetic pole sensors are disposed at equal intervals between the plurality of drive windings.
5 . The motor control device according to claim 1 , wherein
the processor is configured to estimate a stop position of the magnetic pole when the rotor is stopped based on the magnetic pole sensor, and
after the rotor is stopped, the controller is configured to maintain a position of the magnetic pole at the stop position estimated by the processor, and
the controller controls starting rotation of the rotor in accordance with a detection result of the magnetic pole sensor and the stop position.
6 . The motor control device according to claim 5 , wherein the processor is configured to estimate the stop position of the magnetic pole in accordance with a rotation speed of the rotor.
7 . The motor control device according to claim 6 , wherein
the processor is configured to detect a change in a value of the magnetic pole sensor while the rotor is stopped,
the motor control device further comprises a switch configured to:
switch between the detected position of the magnetic pole before a start of rotation and the stop position based on the detected change in the value, and
transmit the switched position to the controller, and
the controller is configured to start rotation of the rotor in accordance with the switched position transmitted by the switch.
8 . The motor control device according to claim 1 , wherein the processor is configured to:
detect a failure of the magnetic pole sensor; and
estimate a stop position of the magnetic pole in response to detecting the failure, wherein
control of starting the rotor is further performed in accordance with the stop position of the magnetic pole estimated by the processor.
9 . The motor control device according to claim 1 , further comprising:
a signal input circuit configured to input a signal from outside to the controller, wherein
the magnetic pole sensor transmits the detection result to the processor via the signal input circuit.
10 . The motor control device according to claim 9 , wherein
the processor is configured to set a usage of a signal in the signal input circuit to a usage of position detection of a magnetic pole.
11 . The motor control device according to claim 9 , further comprising:
a power supply circuit configured to supply power for input and output to the outside, wherein
the magnetic pole sensor is supplied with power for the magnetic pole sensor itself via the power supply circuit.
12 . The motor control device according to claim 8 , wherein the processor is configured to estimate the stop position of the magnetic pole using a high-frequency superposition method that supplies the motor with a high-frequency search output that the rotor does not follow without using the magnetic pole sensor.