Motor drive control device and motor drive control method

Abstract

The present invention provides a motor drive control device and a motor drive control method, which can convert the actual speed of the motor into a rotation pulse signal of any multiple and then output it. The drive control device (1) comprises: a position detection sensor (50), which detects the position of the rotor and outputs a Hall signal (Sh); and a speed conversion microcomputer (40), which uses a timer to output a speed output signal of any multiple relative to the actual speed of the motor (10) based on a power-on switching timing signal (St) based on the Hall signal (Sh). The speed conversion microcomputer (40) detects the switching between the high level and the low level of the power-on switching timing signal (St), and uses a timer to measure the high level or low level period of the power-on switching timing signal (St) from the switching edge after a given number of times, calculates the switching adjustment period based on the measurement result, and sets the switching adjustment period to the timer.

Description

Technical Field

[0001] The invention relates to a drive control device of a motor and a drive control method of a motor. Background Art

[0002] In a common system using a motor, a rotation pulse signal indicating the actual rotation speed of the motor is output to the system. However, depending on the system, it is sometimes necessary to output a given rotation pulse signal that is not a rotation pulse signal indicating the actual rotation speed of the motor.

[0003] In order to meet such needs, Patent Document 1 discloses a motor drive control device and a motor drive control method that can multiply a rotation pulse signal by n (n is a natural number greater than or equal to 2) times and output the result.

[0004] (Prior art literature)

[0005] (Patent Document)

[0006] Patent document 1: Japanese Patent Application Publication No. 2016-100980. Summary of the invention

[0007] (Problem to be solved by the invention)

[0008] In the system of Patent Document 1, only a rotation pulse signal of n (integer) times the actual rotation speed of the motor can be output, and a rotation pulse signal of an arbitrary multiple cannot be output.

[0009] To this end, an object of the present invention is to provide a motor drive control device and a motor drive control method that can convert the actual rotation speed of the motor into a rotation pulse signal of any multiple and then output it.

[0010] (Technical solutions to solve problems)

[0011] The drive control device of the motor comprises: a position detection unit, which detects the position of the rotor and outputs a position detection signal; and a microcomputer for speed conversion, which uses a timer to output a speed output signal of any multiple of the actual speed of the motor according to a power switching timing signal based on the position detection signal.

[0012] Preferably, the speed conversion micromachine is constructed to detect the switching between the high level and the low level of the power-on switching timing signal, use the timer to measure the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal starting from the switching edge after a given number of times, calculate the switching adjustment period (ΔT1a, ΔT2a) based on the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal, and set the switching adjustment period (ΔT1a, ΔT2a) to the timer.

[0013] Preferably, the switching adjustment period (ΔT1a, ΔT2a) is calculated based on the output coefficient Sc of the speed output signal, and the switching edge after the given number of times is calculated based on the measurement timing count ISC of the power-on switching timing signal. The output coefficient Sc of the speed output signal is determined based on the speed of the speed output signal and the number of power-on switches NT required to switch the power-on switching timing signal once. The measurement timing count ISC is determined based on the speed of the speed output signal, the output coefficient Sc of the speed output signal, the output coefficient PS of the previous speed output signal, and the number of power-on switches NT required to switch the power-on switching timing signal once.

[0014] Preferably, the rotation speed output signal is generated by adding a predetermined high-level or low-level period (ΔT1, ΔT2) of the energization switching timing signal to the switching adjustment period (ΔT1a, ΔT2a).

[0015] Preferably, the speed conversion microcomputer comprises: an input signal detection unit, which detects the switching of the high level and the low level of the power-on switching timing signal, and uses the timer to measure the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal from the switching edge after a given number of times; an output signal operation unit, which calculates the output timing of the speed output signal according to the power-on switching timing signal; and an output signal generation unit, which uses the timer to output the speed output signal according to the calculated output timing.

[0016] Preferably, when the position detection unit is a Hall element, the energization switching timing signal is a signal based on a Hall signal of the Hall element, and when the position detection unit is a Hall IC, the energization switching timing signal is a Hall signal of the Hall IC.

[0017] In the drive control method of the motor, the position of the rotor is detected by a position detection unit and a position detection signal is output, and a microcomputer for speed conversion uses a timer to output a speed output signal that is an arbitrary multiple of the actual speed of the motor according to a power switching timing signal based on the position detection signal.

[0018] (Effects of the Invention)

[0019] In the motor drive control device and motor drive control method of the present invention, a rotation pulse signal of any multiple can be converted and outputted with a simple structure using only one timer and not limited to an integer multiple of the actual rotation speed of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic configuration diagram of a motor drive control device according to an embodiment of the present invention.

[0021] Figure 2 This is an example of a timing chart of input and output signals of a microcomputer for rotating speed conversion according to an embodiment of the present invention.

[0022] Figure 3 This is a main flow chart of processing using a microcomputer for rotating speed conversion according to one embodiment of the present invention.

[0023] Figure 4 It is a flow chart of the timing calculation of input and output signals.

[0024] Figure 5 This is another example of the timing chart of input and output signals of the rotation speed conversion microcomputer according to the embodiment of the present invention. DETAILED DESCRIPTION

[0025] Figure 1 1 is a schematic diagram showing the structure of a motor drive control device 1 according to an embodiment of the present invention.

[0026] The drive control device 1 for the motor 10 includes a motor drive unit 20 , a motor control unit 30 , a microcomputer 40 for rotating speed conversion, and a position detection sensor (an example of a position detection unit) 50 .

[0027] When in operation, the motor 10 outputs a rotation pulse signal of 2 pulses per revolution (PL=2 in Table 1), for example, 11000 rpm (actual rotation speed of the motor 10). The drive control device 1 drives and controls the motor 10 by means of commands from a system not shown.

[0028] The motor control unit 30 supplies the motor drive control signal Sp to the motor drive unit 20 . The motor drive unit 20 supplies current to the motor 10 based on the motor drive control signal Sp to drive the motor 10 to rotate, and detects the position of the rotor with the position detection sensor 50 .

[0029] The position detection sensor 50 can be any sensor such as a Hall element or a Hall IC. When the position detection sensor 50 is a Hall element, the Hall signal Sh is input to the position calculation circuit 21 in the motor drive unit 20, and the position calculation circuit 21 outputs the position detection signal Sr. In the present embodiment, the position detection signal Sr is a signal based on the Hall signal Sh.

[0030] The motor control unit 30 supplies the energization switching timing signal St to the rotation speed conversion microcomputer 40 based on the position detection signal Sr.

[0031] Although not shown in the figure, the microcomputer 40 for rotating speed conversion has a CPU, a memory, and a timer as a hardware configuration.

[0032] The CPU executes a program stored in the memory to convert the actual rotation speed of the motor into a rotation speed output signal (hereinafter also referred to as an FG output signal) which is 9 / 11 times the actual rotation speed of the motor.

[0033] The timer is, for example, a 16-bit register and measures the elapsed time. In the case of an incremental mode, the timer increases its value as time passes and changes from 0 to (2 16 -1) When an overflow interrupt occurs, the timer notifies the CPU that a given time has passed.

[0034] The rotation speed conversion microcomputer 40 includes an input signal detection unit 41 , an output signal calculation unit 42 , and an output signal generation unit 43 .

[0035] The input signal detection unit 41 detects the switching between the high level and the low level of the energization switching timing signal St, and uses a timer to measure the high level or low level period of the energization switching timing signal St from the switching edge after a given number of times.

[0036] The output signal calculation unit 42 calculates the output timing of the rotation speed output signal (FG output signal) based on the energization switching timing signal St.

[0037] The output signal generating unit 43 outputs a rotation speed output signal (FG output signal) using a timer according to the calculated output timing.

[0038] Figure 2 This is an example of a timing chart of input and output signals of the rotation speed conversion microcomputer 40 according to one embodiment of the present invention.

[0039] The timing chart shows an FG output signal (reference) based on the actual rotation speed, an energization switching timing signal St (input signal) input to the rotation speed conversion microcomputer 40 , and a rotation speed output signal (FG output signal) output from the rotation speed conversion microcomputer 40 .

[0040] In the present embodiment, as a specific example, a case where the actual rotation speed of the motor of 11000 rpm is converted into an FG output signal of 9000 rpm in the rotation speed conversion microcomputer 40 is considered.

[0041] Starting from time t1, if the power-on switching timing signal St has been switched (toggle) twice (the number of switching times is based on the measurement timing count ISC described later) in the input signal detection unit 41, an interruption occurs at time t2, and a timer is used to measure the low level period ΔT1 (ΔT1=3) of the power-on switching timing signal St.

[0042] The output signal calculation unit 42 calculates the first switching adjustment period ΔT1a (ΔT1a=2) from the low period ΔT1 of the energization switching timing signal St using a given calculation formula described later.

[0043] At time t3, the output signal generating unit 43 sets the first switching adjustment period ΔT1a=2 in the timer, and when an overflow interrupt of this time comes, the FG output signal is switched and output (time t4).

[0044] Furthermore, after time t3, in the input signal detection unit 41, if the power-on switching timing signal St has been switched three times (the number of switching times is based on the measurement timing count ISC described later), an interruption occurs at time t5, and a timer is used to measure the low level period ΔT2 (ΔT2=3) of the power-on switching timing signal St.

[0045] The output signal calculation unit 42 calculates the second switching adjustment period ΔT2a (ΔT2a=1) from the low-level period ΔT2 of the energization switching timing signal St using a given calculation formula described later.

[0046] At time t6, the output signal generating unit 43 sets the second switching adjustment period ΔT2a=1 in the timer, and when an overflow interrupt of this time comes, the FG output signal is switched and output (time t7).

[0047] After time t6, when the input signal detection unit 41 detects that the energization switching timing signal St has switched four times (the number of switching times is based on a timing counter ISFGC described later), the output signal generation unit 43 switches and outputs the FG output signal (time t8).

[0048] exist Figure 2 In FIG. 1 , the upward arrow indicates the start timing of the cycle calculation of the FG output signal.

[0049] The sum of the first switching adjustment period (ΔT1a=2) and the second switching adjustment period (ΔT2a=1) is the switching adjustment period. By adding the given high level and low level periods (3×3=9) of the power-on switching timing signal St to the switching adjustment period (ΔT1a+ΔT2a=3), the actual speed of the motor at 11000 rpm can be converted into an FG output signal (speed output signal) of 9000 rpm.

[0050] Therefore, in this embodiment, since the input signal detection unit 41 and the output signal generation unit 43 can share one timer, it is possible to generate an FG output signal of any multiple such as 9 / 11 by using a simple structure of only one timer and not limited to an integer multiple of the actual rotational speed of the motor.

[0051] Figure 3 This is a main flowchart of the processing performed by the rotation speed conversion microcomputer 40 according to one embodiment of the present invention.

[0052] In step S1, initialization is performed. The initialization includes, for example:

[0053] Initialization of the measurement timing count (ISC) of the input signal (power-on switching timing signal St) (ISC=0);

[0054] Initialization of the output coefficient (Sc) of the FG output signal (Sc=0);

[0055] Initialization (ISFGC=0) of the timing count (ISFGC) for outputting the FG output signal in synchronization with the input signal (power-on switching timing signal St);

[0056] Initialization of the output coefficient (PS) of the previous FG output signal (PS=0);

[0057] Calculate the number of energization switching times per revolution N (N = P / 2 x 6 = 12) based on the current number of poles (P = 4 poles); and

[0058] Calculate the number of energization switching times NT (NT=N / (PL×2)=3) required to switch the input signal (energization switching timing signal St) once.

[0059] The variables are summarized in Table 1.

[0060] (Table 1)

[0061]

[0062] In step S2, the interrupt is enabled.

[0063] In step S3, the timing of the input and output signals is calculated.

[0064] Figure 4 This is a flowchart for calculating the timing of input and output signals. Figure 4 as well as Figure 2 , explaining the method of speed conversion.

[0065] (First processing)

[0066] In step S31, the output coefficient Sc of the FG output signal is obtained. Specifically, the output coefficient Sc=(11+0)%3=2.

[0067] In step S32, it is determined whether the output coefficient of the FG output signal is Sc = 0. In the first processing, the output coefficient Sc of the FG output signal is not zero (No), so the process proceeds to step S33.

[0068] In step S33, the measurement timing count ISC of the input signal (hereinafter referred to as the energization switching timing signal St) is obtained. Specifically, the measurement timing count ISC=(11-2+0) / 3-1=2.

[0069] like Figure 2 As shown, the measurement timing count ISC=2 means that counting starts from time t1, and the low level period ΔT1 of the power-on switching timing signal St is measured from the second edge (time t2) of the power-on switching timing signal St. That is, as described above, starting from time t1, the input signal detection unit 41 generates an interrupt at time t2 when the power-on switching timing signal St has switched twice based on the measurement timing count ISC=2.

[0070] Furthermore, the output coefficient Sc=2 of the FG output signal indicates that the first switching adjustment period is set to ΔT1a=2, and the FG output signal is switched at time t4.

[0071] In step S34, for the next calculation, the output coefficient Sc=2 of the current FG output signal is stored as the output coefficient PS of the previous FG output signal, and the first processing is terminated.

[0072] (Second processing)

[0073] In step S31, the output coefficient Sc of the FG output signal is obtained. Specifically, the output coefficient Sc=(11+2)%3=1.

[0074] In step S32, similarly to the first time, since the output coefficient Sc is not zero (No), the process proceeds to step S33.

[0075] In step S33 , the measurement timing count ISC of the energization switching timing signal St is obtained. Specifically, the measurement timing count ISC=(11−1+2) / 3−1=3.

[0076] like Figure 2 As shown, the measurement timing count ISC=3 means that counting starts from time t3, and from the third edge (time t5) of the energization switching timing signal St, the low period ΔT2 of the energization switching timing signal St is measured.

[0077] Furthermore, the output coefficient Sc=1 of the FG output signal indicates that the second switching adjustment period ΔT2a=1 is set and the FG output signal is switched at time t7.

[0078] In step S34, for the next calculation, the output coefficient Sc=1 of the current FG output signal is stored as the output coefficient PS of the previous FG output signal, and the second processing is terminated.

[0079] (Third processing)

[0080] In step S31, the output coefficient Sc of the FG output signal is obtained. Specifically, the output coefficient Sc=(11+1)%3=0.

[0081] In step S32, since the output coefficient Sc of the FG output signal is zero (Yes), the process proceeds to step S35.

[0082] In step S35 , the measurement timing count ISC of the energization switching timing signal St is set to ISC=0, and the timing count ISFGC for outputting the FG output signal in synchronization with the energization switching timing signal St is set to ISFGC=3+1=4.

[0083] like Figure 2 As shown, the timing count ISFGC=4 means that counting starts from time t6, and the FG output signal is switched at the fourth edge (time t8) of the energization switching timing signal St.

[0084] In step S34, for the next calculation, the output coefficient Sc=0 of the current FG output signal is stored as the output coefficient PS of the previous FG output signal, and the third processing is terminated.

[0085] The present invention is not limited to the above-described embodiment, and various modifications can be made.

[0086] For example, the position detection unit can also be set to a sensorless method without a position detection sensor. In this case, a signal that can detect the coil voltage (back electromotive force voltage) of the motor and is based on the back electromotive force voltage is used instead of the power switching timing signal St. In addition, an encoder can be used instead of the Hall sensor.

[0087] Furthermore, in this embodiment, the position detection sensor 50 is a Hall element, but it may also be a Hall IC. In this case, the Hall signal can be directly input to the microcomputer for speed conversion as a power-on switching timing signal, and a speed output signal can be generated based on this.

[0088] Furthermore, in the present embodiment, the motor control unit 30 and the microcomputer 40 for speed conversion are respectively recorded as separate components. However, in the case where the motor control unit 30 has an unused timer, the same processing (processing of generating an arbitrary multiple of FG output signals) can be performed within the motor control unit 30 even without the microcomputer 40 for speed conversion being externally configured.

[0089] Furthermore, in this embodiment, after time t3, if the energization switching timing signal St has switched three times, the low period ΔT2 of the energization switching timing signal St is measured using a timer, and at time t6, the second switching adjustment period ΔT2a is set in the timer. Figure 2 In the example, the low period ΔT2 of the energization switching timing signal St is measured during the period "N" immediately before reaching the second switching adjustment period ΔT2a. However, the low period ΔT2 of the energization switching timing signal St may be measured during the period "L" or "M".

[0090] Furthermore, the motor 10 can have any number of poles and phases.

[0091] In addition, the present invention is not limited to the case where the actual speed of the motor of 11000 rpm is converted into the FG output signal (speed output signal) of 9000 rpm, but can also convert the actual speed of the motor into any multiple. Figure 4 as well as Figure 5 , discuss the situation of converting the actual speed of the motor of 10000 rpm into the FG output signal of 9000 rpm.

[0092] In the case of this transformation, Figure 4 In the example, it is assumed that "11" in steps S31 and S33 is read as "10".

[0093] In the first processing, in step S31, the output coefficient Sc=1 is obtained, and in step S33, the measurement timing count ISC=2 is obtained.

[0094] In the second processing, in step S31, the output coefficient Sc=2 is obtained, and in step S33, the measurement timing count ISC=2 is obtained.

[0095] In the third processing, in step S31, the output coefficient Sc=0 is obtained, and in step S35, the timing counter ISFGC=4 is obtained.

[0096] Figure 5 This is another example of the timing chart of the input and output signals of the rotation speed conversion microcomputer 40 according to the embodiment of the present invention.

[0097] Starting from time t1, the input signal detection unit 41 measures the timing count ISC (ISC=2) of the power-on switching timing signal St processed for the first time. When the input signal (hereinafter referred to as the power-on switching timing signal St) has switched twice, an interrupt occurs at time t2, and a timer is used to measure the low period ΔT1 (ΔT1=3) of the power-on switching timing signal St.

[0098] The output signal calculation unit 42 calculates the first switching adjustment period ΔT1a (ΔT1a=1) from the low period ΔT1 of the energization switching timing signal St based on the output coefficient Sc (Sc=1) of the FG output signal of the first process.

[0099] At time t3 , the output signal generating unit 43 sets the first switching adjustment period ΔT1a=1 in the timer, and when an overflow interrupt of this time comes, the FG output signal is switched and output (time t4 ).

[0100] In addition, after time t3, the input signal detection unit 41 measures the timing count ISC (ISC=2) of the power-on switching timing signal St processed for the second time. If the power-on switching timing signal St has been switched twice, an interruption occurs at time t5, and a timer is used to measure the low level period ΔT2 (ΔT2=3) of the power-on switching timing signal St.

[0101] The output signal calculation unit 42 calculates the second switching adjustment period ΔT2a (ΔT2a=2) from the low period ΔT2 of the energization switching timing signal St based on the output coefficient Sc (Sc=2) of the FG output signal in the second process.

[0102] At time t6 , the output signal generating unit 43 sets the second switching adjustment period ΔT2a=2 in the timer, and when an overflow interrupt of this time comes, the FG output signal is switched and output (time t7 ).

[0103] After time t6 , when the input signal detection unit 41 detects that the energization switching timing signal St has switched four times based on the timing counter ISFGC (ISFGC=4), the output signal generation unit 43 switches and outputs the FG output signal (time t8 ).

[0104] (Description of the label)

[0105] 1a…drive control device, 10…motor, 20…motor drive unit, 21…position calculation circuit, 30…motor control unit, 40…microcomputer for speed conversion, 41…input signal detection unit, 42…output signal calculation unit, 43…output signal generation unit, Sp…motor drive control signal, Sr…position detection signal, Sh…Hall signal, St…power-on switching timing signal.

Claims

1. A motor drive control device, characterized in that: have: A position detection unit, which detects the position of the rotor and outputs a position detection signal; A microcomputer for speed conversion, which uses a timer to output a speed output signal of an arbitrary multiple of the actual speed of the motor according to a power-on switching timing signal based on the position detection signal, The speed conversion micromachine is composed of: detecting the switching between the high level and the low level of the power-on switching timing signal, and measuring the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal using the timer starting from the switching edge after a given number of times, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the high level or low level period (ΔT1, ΔT2) of the energization switching timing signal. and setting the switching adjustment period (ΔT1a, ΔT2a) to the timer, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the output coefficient (Sc) of the rotation speed output signal. The switching edge after the given number of times is counted based on the measured timing count (ISC) of the energized switching timing signal, The output coefficient (Sc) of the rotation speed output signal is determined according to the rotation speed of the rotation speed output signal and the number of energization switching times (NT) required to switch the energization switching timing signal once. The measurement timing count (ISC) is determined based on the rotation speed of the rotation speed output signal, the output coefficient (Sc) of the rotation speed output signal, the output coefficient (PS) of the previous rotation speed output signal, and the number of power-on switching times (NT) required to switch the power-on switching timing signal once.

2. The motor drive control device according to claim 1, wherein: The rotation speed output signal is generated by adding the switching adjustment period (ΔT1a, ΔT2a) to a predetermined high-level or low-level period (ΔT1, ΔT2) of the energization switching timing signal.

3. A motor drive control device, characterized in that: have: A position detection unit, which detects the position of the rotor and outputs a position detection signal; A microcomputer for speed conversion, which uses a timer to output a speed output signal of an arbitrary multiple of the actual speed of the motor according to a power-on switching timing signal based on the position detection signal, The speed conversion micromachine is composed of: detecting the switching between the high level and the low level of the power-on switching timing signal, and measuring the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal using the timer starting from the switching edge after a given number of times, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the high level or low level period (ΔT1, ΔT2) of the energization switching timing signal. and setting the switching adjustment period (ΔT1a, ΔT2a) to the timer, The rotation speed output signal is generated by adding the switching adjustment period (ΔT1a, ΔT2a) to a predetermined high-level or low-level period (ΔT1, ΔT2) of the energization switching timing signal.

4. The motor drive control device according to any one of claims 1 to 3, wherein: The microcomputer for speed conversion has: an input signal detection unit, which detects the switching between the high level and the low level of the power-on switching timing signal, and uses the timer to measure the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal starting from the switching edge after a given number of times; an output signal calculation unit, which calculates the output timing of the speed output signal according to the power-on switching timing signal; An output signal generating unit outputs the rotation speed output signal using the timer according to the calculated output timing.

5. The drive control device for a motor according to any one of claims 1 to 3, wherein: When the position detection unit is a Hall element, the energization switching timing signal is a signal based on a Hall signal of the Hall element. In a case where the position detection unit is a Hall IC, the energization switching timing signal is a Hall signal of the Hall IC.

6. A method for controlling a motor drive, characterized in that: The steps include: The position detection unit detects the position of the rotor and outputs a position detection signal. The microcomputer for speed conversion uses a timer to output a speed output signal of an arbitrary multiple of the actual speed of the motor according to a power-on switching timing signal based on the position detection signal. Through the speed conversion microcomputer, detecting the switching between the high level and the low level of the power-on switching timing signal, and measuring the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal using the timer starting from the switching edge after a given number of times, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the high level or low level period (ΔT1, ΔT2) of the energization switching timing signal. and setting the switching adjustment period (ΔT1a, ΔT2a) to the timer, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the output coefficient (Sc) of the rotation speed output signal. The switching edge after the given number of times is counted based on the measured timing count (ISC) of the energized switching timing signal, The output coefficient (Sc) of the rotation speed output signal is determined according to the rotation speed of the rotation speed output signal and the number of energization switching times (NT) required to switch the energization switching timing signal once. The measurement timing count (ISC) is determined based on the rotation speed of the rotation speed output signal, the output coefficient (Sc) of the rotation speed output signal, the output coefficient (PS) of the previous rotation speed output signal, and the number of power-on switching times (NT) required to switch the power-on switching timing signal once.

7. A method for controlling a motor drive, characterized in that: The steps include: The position detection unit detects the position of the rotor and outputs a position detection signal. The microcomputer for speed conversion uses a timer to output a speed output signal of an arbitrary multiple of the actual speed of the motor according to a power-on switching timing signal based on the position detection signal. Through the speed conversion microcomputer, detecting the switching between the high level and the low level of the power-on switching timing signal, and measuring the high level or low level period (ΔT1, ΔT2) of the power-on switching timing signal using the timer starting from the switching edge after a given number of times, The switching adjustment period (ΔT1a, ΔT2a) is calculated based on the high level or low level period (ΔT1, ΔT2) of the energization switching timing signal. and setting the switching adjustment period (ΔT1a, ΔT2a) to the timer, The rotation speed output signal is generated by adding the switching adjustment period (ΔT1a, ΔT2a) to a predetermined high-level or low-level period (ΔT1, ΔT2) of the energization switching timing signal.

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