JPH0947071A - Controller for brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize high speed, small size and low price by converting the output signal from a mover position detector into a three-phase constant amplitude sine wave signal thereby producing a high quality analog signal, i.e., a sine wave signal, and performing sine wave driving using the high quality sine wave signal. SOLUTION: A mover position detection means 2 detects the position of a mover and outputs three-phase sine wave signals CU, CV, CW having phase difference of 120 deg. electric angle corresponding to the position. The zero point voltage is controlled constant for the three-phase sine wave signals CU, CV, CM outputted from the mover position detection means 2 thus outputting three- phase constant amplitude sine wave signals RU, RV, RW from an amplitude regulation means 3. A multiplier means 5 then multiplies the three-phase constant amplitude sine wave signals RU, RV, RW by an external torque command signal to produce three-phase current control signals representative of the ratio of driving current or voltage for respective phases of a three-phase brushless motor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a brushless motor mounted on office automation equipment, factory automation equipment, and home electric appliances.

[0002]

2. Description of the Related Art In recent years, OA equipment, FA equipment and home electric appliances tend to have higher functionality, higher performance and lower price.
Along with this, motors mounted on these devices are required to have high functionality, high efficiency, low cost and miniaturization.

Conventionally, an AC servomotor has been used as such a highly functional motor.

An example of such a brushless motor control device is shown below.

FIG. 8 shows a circuit configuration diagram of a conventional brushless motor control device. In FIG. 8, 1 is a three-phase brushless motor, and 20 is rectangular wave signals A and B having a phase difference of 90 degrees in electrical angle according to the position of the mover and a rectangular wave signal Z once per rotation. An optical encoder 21 outputs rectangular wave commutation signals CS1, CS2, CS3 having a phase difference of 120 degrees at an electrical angle corresponding to the position of the mover, and 21 is a digital encoder based on the output signal from the optical encoder 20. Reference numeral 22 is a counting means for outputting a position signal, 22 is a storage means for outputting a three-phase digital sine wave signal from the digital position signal from the counting means 21, and 23 is a three-phase digital sine wave signal from the storage means 22. D / A to convert a three-phase analog sine wave signal
Reference numeral 5 is a converter, and 5 is a multiplying means for multiplying the torque command signal which is an external signal by the three-phase analog sine wave signal from the D / A converter 23 and outputting a three-phase current control signal. Is a drive means for controlling the drive current or drive voltage of each phase of the three-phase brushless motor 1 based on the three-phase current control signal from the multiplication means 5.

The operation of the conventional brushless motor controller constructed as described above will be described below.

The output of the optical encoder 20 outputs a digital position signal which is the current position of the mover from the counting means 21 and is input to the storage means 22. The storage means 22 outputs a three-phase digital sine wave signal, which is the ratio of the drive current or drive voltage of each phase of the three-phase brushless motor 1 during sine wave drive. This three-phase digital sine wave signal is converted into a three-phase analog sine wave signal which is an analog signal by a D / A converter, and the torque command signal from the outside is multiplied by the three-phase analog sine wave signal to thereby generate the three-phase brushless signal. A three-phase current control signal, which is the ratio of the drive current or drive voltage of each phase of the motor 1, is obtained. With this three-phase current control signal, the drive means 6 can control the drive current or drive voltage of each phase of the three-phase brushless motor 1, and the sine wave drive of the brushless motor can be performed.

[0008]

However, the above conventional structure has the following problems.

First, in the conventional brushless motor controller shown in FIG. 8, there are six signals from the optical encoder 20, and the counting means 21 processes the six signals to obtain the position of the mover. The circuit of the counting means 21 is complicated, and the scale becomes large, which causes a problem of delay time and an increase in price. In addition, the D / A converter 23
The output three-phase analog sine wave signal also becomes a stepped sine wave because it is converted from a digital signal to an analog signal, and does not become a high-quality sine wave. Further, the optical encoder 20 for detecting the mover position is also expensive and it is difficult to reduce the cost.

As described above, the conventional brushless motor control device has many problems.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a controller for a brushless motor which can obtain a high-quality sine wave and can be manufactured at a low cost.

[0012]

To achieve this object, a brushless motor controller according to the present invention detects the positions of a three-phase brushless motor and a mover, and an electrical angle corresponding to each position is 120 degrees. A mover position detecting means for outputting a three-phase sine wave signal having a phase difference, and a three-phase constant amplitude sine wave signal for adjusting the amplitude of the three-phase sine wave signal output from the mover position detecting means to a constant value. And a three-phase current control which is a ratio of the drive current or drive voltage of each phase of the three-phase brushless motor by multiplying the torque command signal by the three-phase constant amplitude sine wave signal output from the amplitude adjustment means. And a driving unit that controls a driving current or a driving voltage of each phase of the three-phase brushless motor based on a three-phase current control signal output from the multiplying unit. The child position detecting means is composed of a magnetic body having a pole tooth structure for focusing the surface magnetic flux of the mover of the three-phase brushless motor, and a magnetoelectric conversion element for converting the focused magnetic flux into an electric signal, The value of the sine wave signal is zero when the value of each phase sine wave signal which is output six times during one cycle of the three-phase sine wave signal output from the mover position detecting means by the amplitude adjusting means becomes zero. Amplitude adjustment signals for two phases other than the above phase are obtained, and a three-phase constant amplitude sine wave signal is output based on the amplitude adjustment signal and the three-phase sine wave signal.

[0013]

With this configuration, the output signal of the mover position detecting means is converted into a three-phase constant amplitude sine wave signal to obtain a sine wave which is a high quality analog signal, and the sine wave is driven by this high quality sine wave. In addition, a simple analog circuit configuration enables speeding up, wire saving, downsizing, and cost reduction, and a costless brushless motor controller that does not require an expensive optical encoder. Can be realized.

[0014]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a controller for a brushless motor according to the first embodiment of the present invention. In FIG. 1, 1 is a three-phase brushless motor, 2 is a movable position that detects the position of a mover, and outputs three-phase sine wave signals CU, CV, CW having a phase difference of 120 degrees at an electrical angle according to the position. The slave position detecting means 3 controls the voltages of the three-phase sine wave signals output from the mover position detecting means 2 at the time of their zero points to be constant, and outputs three-phase constant amplitude sine wave signals RU, RV, RW. Amplitude adjusting means 5 for multiplying the three-phase constant amplitude sine wave signals RU, RV, RW output from the amplitude adjusting means 3 by a torque command signal to obtain the drive current or drive voltage of each phase of the three-phase brushless motor 1. Multiplier means 6 for outputting a three-phase current control signal which is a ratio, 6 is based on the three-phase current control signal outputted from the multiplier means 5, and the three-phase brushless motor 1
Is a drive unit that controls the drive current or drive voltage of each phase.

The operation of the brushless motor control device configured as described above will be described. FIG. 2 shows a three-phase sine wave signal CU output from the mover position detection means 2.
CV, CW and three-phase constant amplitude sine wave signals RU, RV, RW output from the amplitude adjusting means 3 are represented. First, the operation of the amplitude adjusting means 3 will be described. First, consider the case when the CU becomes zero, that is, when the CU is at point A1. At this time, CV is B1 point, and the value at this time is v
CW is C1 point, and the value at this time is w. Also, the converted RV is the D1 point, the value is d, and the RW is E
It is 1 point and the value is e. Here, since the three-phase constant amplitude sine wave signals RU, RV, RW have the same amplitude,
The value d and the value e are

[0017]

[Equation 1]

The above relationship is established, and the absolute value at this time is defined as a. Also, CV and CW respectively

[0019]

[Equation 2]

[0020]

(Equation 3)

[0021] Here, Mv and Mw are C
Amplitudes of V and CW, and θ indicates a mover position (electrical angle). These (Equation 2) and (Equation 3) are the values v,
Using the value w and the value a

[0022]

(Equation 4)

[0023]

(Equation 5)

The constant amplitude sine wave signals RV and RW can be obtained by performing the above conversion. Where a / | v
|, A / | w | indicates the amplitude adjustment signal. By performing such conversion at A2 point and A3 point similarly,

[0025]

(Equation 6)

It is possible to obtain the three-phase constant amplitude sine wave signals RU, RV, RW represented by (Equation 4) and (Equation 5). Where M
u represents the amplitude of the CU, u represents the value of the CU at point A2, and a / | u | represents the amplitude adjustment signal. Where A2
Point, A3 point and other zero points (three-phase sine wave signal CU,
Since the operation similar to that of the point A1 is performed at all times when the values of CV and CW are zero), the description thereof will be omitted. The three-phase constant-amplitude sine wave signals RU, RV, RW thus obtained are each multiplied by an external torque command signal in the multiplication means 5, and the ratio of the drive current or drive voltage of each phase of the three-phase brushless motor 1 is multiplied. It is possible to obtain a three-phase current control signal that is And
By controlling the drive current or drive voltage of each phase of the three-phase brushless motor 1 on the basis of the three-phase current control signal in the drive means 6, it is possible to drive the sine wave of the brushless motor.

Here, the difference from the conventional brushless motor control device is that the sine wave in the conventional brushless motor control device is a digital sine wave signal, whereas the sine wave is an analog sine wave signal. By using this analog sine wave signal, speedup, wire saving, downsizing and cost reduction are possible. Further, by using the amplitude adjusting means 3, the amplitude of the three-phase analog sine wave signal is always constant, and this high-quality sine wave can be used for sine wave driving.

FIG. 3 shows a specific structure of the mover position detecting means 2. In FIG. 3, 30 is a mover of the three-phase brushless motor 1, 31 is a magnetic body having a pole tooth structure for focusing the surface magnetic flux (surface magnetic flux having a sinusoidal distribution) of the mover, and 32 is This is a magneto-electric conversion element that converts the focused magnetic flux into an electric signal. In addition, the magnetic body 31 and the magneto-electric conversion element 32 have an electrical angle of 12
The mover 3 has a structure for three phases so as to provide a phase difference of 0 degree.
It is possible to obtain a three-phase sine wave signal according to the position of 0.
The mover position detecting means 2 can also be configured by a hall element or a conductive pattern. In this way, a means for detecting the position can be realized at low cost, and it is not necessary to use an expensive encoder like the AC servo motor. The driving means 6 can be realized by a PWM driving circuit.

Thus, the output signal of the mover position detecting means is converted into a three-phase constant amplitude sine wave signal to obtain a high-quality sine wave, and the sine wave can be driven by this high-quality sine wave. In addition, since it has a simple analog circuit configuration and requires only two signal lines for the mover position detecting means 2, speedup, wire saving, miniaturization and cost reduction are possible, and no expensive optical encoder is required. Thus, a low-cost brushless motor controller can be realized.

(Second Embodiment) A second embodiment of the present invention will be described below.

FIG. 4 shows a brushless motor controller according to a second embodiment of the present invention. 4 is different from the brushless motor control device shown in FIG. 1 in that the position / speed converting means 7 for converting the output signal of the amplitude adjusting means 3 into the speed signal S, the output of the position / speed converting means 7 and the speed command. A speed error amplifier 8 for outputting the torque command signal from the signal is added.

The operation of the brushless motor control device configured as described above will be described. Here, the position / speed conversion means 7 and the speed error amplifier 8 will be described.

FIG. 5 shows the operations of the three-phase constant amplitude sine wave signals RU, RV, RW input to the position / speed converting means 7 and the position / speed converting means 7. In FIG. 5, α point, β point, γ point, δ point, ε point, and ζ point are points at which the values of two signals among the three-phase constant amplitude sine wave signals RU, RV, and RW match. Also, ι point, κ point, λ point, μ point, ν
Points and ξ are points at which the values of RU, RW, and RV are zero. Here, if there are n points (α points, ι points, etc.) described above during t seconds in FIG. 5,

[0034]

(Equation 7)

It can be converted to the frequency f as follows. Since this frequency f is in proportion to the actual rotation of the mover,
The speed signal S is

[0036]

(Equation 8)

It can be expressed as follows. Here, m is a frequency-velocity conversion coefficient. In this way, the velocity signal S can be obtained from the three-phase constant amplitude sine wave signals RU, RV, RW. Further, in the speed error amplifier 8, the torque command signal can be obtained by smoothing and amplifying the difference between the speed signal S and the speed command signal from the outside. A process of operating the controller of the brushless motor based on the obtained torque command signal is omitted here. As described above, in the brushless motor control device of FIG. 1, the torque command signal is converted from the position / speed converting means 7 for converting the output signal of the amplitude adjusting means 3 into the speed signal S, and the output of the position / speed converting means 7 and the speed command signal. By adding the speed error amplifier 8 for outputting the speed control system, the speed control system can be realized with a simple structure, and the structure is a simple analog circuit. It is possible to realize a brushless motor control device that can be made compact, wire-saving, miniaturized, and inexpensive.

(Embodiment 3) Hereinafter, a third embodiment of the present invention will be described.

FIG. 6 shows a controller for a brushless motor according to the third embodiment of the present invention. 6, the difference from the brushless motor control device shown in FIG. 4 is that the output signal of the amplitude adjusting means 3 is converted into rectangular wave signals PA and PB having a 90-degree phase difference in the two-phase electrical angle. The means 9 and the position error amplifier 10 for outputting the speed command signal from the output signal of the rectangular wave converter 9 and the position command signal are added.

The operation of the brushless motor control device configured as described above will be described. Here, the rectangular wave conversion means 9 and the position error amplifier 10 will be described.

FIG. 7 shows the operations of the three-phase constant amplitude sine wave signals RU, RV, RW input to the position / speed converting means 7 and the rectangular wave converting means 9. In FIG. 7, α point, β point, γ point, δ point, ε point, and ζ point are points where the values of two signals among the three-phase constant amplitude sine wave signals RU, RV, and RW coincide. Also, ι point, κ point, λ point, μ point, ν
Points ξ are points at which the values of RU, RV, and RW become zero.
Here, as a method of obtaining the rectangular wave signal PA from the three-phase constant amplitude sine wave signals RU, RV, RW, two points out of the α point, γ point, ε point, that is, the three phase constant amplitude sine wave signals RU, RV, RW are used. A rectangular wave rises at the point where the values of the two signals match and the value is a positive value, and 2 points out of β point, δ point, ζ point, that is, three-phase constant amplitude sine wave signals RU, RV, RW. The rectangular wave signal PA can be obtained by performing conversion such that the rectangular wave falls when the values of the two signals match and the value is a negative value. Similarly, the method of obtaining the rectangular wave signal PB is the κ point, μ point, ξ point, that is, the three-phase constant amplitude sine wave signal R
When the values of U, RV, RW become zero while monotonically increasing, the rectangular wave rises, and the ι point, λ point, ν point, that is, the values of the three-phase constant amplitude sine wave signals RU, RV, RW are A rectangular wave signal PB can be obtained by performing a conversion in which the rectangular wave falls at a point where it monotonically decreases and becomes zero.

The rectangular wave signals PA and PB thus obtained
Is input to the position error amplifier 10 and the difference from the position command signal from the outside is smoothed and amplified to obtain the speed command signal. A description of the process of operating the controller of the brushless motor based on the obtained speed command signal is omitted here. As described above, in the brushless motor control device of FIG. 1, the torque command signal is converted from the position / speed converting means 7 for converting the output signal of the amplitude adjusting means 3 into the speed signal S, and the output of the position / speed converting means 7 and the speed command signal. And the output signal of the amplitude adjusting means 3 at a two-phase electrical angle of 9
A rectangular wave converting means 9 for converting into rectangular wave signals PA and PB having a phase difference of 0 degree, and a position error amplifier 10 for outputting a speed command signal from an output signal of the rectangular wave converting means 9 and a position command signal.
By adding the above, the position control system can be realized with a simple structure, and the analog circuit structure is simple. Since only two signal lines are required for the mover position detecting means 2, speedup, wire saving,
It is possible to realize a brushless motor control device that can be reduced in size and price.

[0043]

As described above, the present invention detects the positions of the three-phase brushless motor and the mover, and outputs a three-phase sine wave signal having a phase difference of 120 degrees at an electrical angle corresponding to the position. Mover position detecting means, amplitude adjusting means for adjusting the amplitude of the three-phase sine wave signal output from the mover position detecting means to a constant and outputting a three-phase constant amplitude sine wave signal, and output from the amplitude adjusting means Multiplying means for multiplying the three-phase constant amplitude sine wave signal by the torque command signal to output a three-phase current control signal which is a ratio of the drive current or drive voltage of each phase of the three-phase brushless motor; Drive means for controlling the drive current or drive voltage of each phase of the three-phase brushless motor based on the output three-phase current control signal, and the amplitude adjusting means is output from the mover position detecting means. phase When the value of the sine wave signal of each phase which is six times during one period of the string wave signal becomes zero, an amplitude adjustment signal for two phases other than the phase where the value of the sine wave signal becomes zero is obtained, and the amplitude is adjusted. A three-phase constant amplitude sine wave signal is output based on the adjustment signal and the three-phase sine wave signal, and the mover position detecting means has a pole for focusing the surface magnetic flux of the mover of the three-phase brushless motor. Three-phase current control, which is composed of a magnetic material having a tooth structure and a magnetoelectric conversion element that converts the focused magnetic flux into an electric signal, and is output based on the three-phase constant amplitude sine wave signal and the torque command signal. A control device for a brushless motor, which can be driven by a sine wave by a signal and can be reduced in price, can be realized.

Further, the controller for the brushless motor is provided with a position / velocity converting means for converting the output signal of the amplitude adjusting means into a speed signal, and the speed error amplifier is provided with the output of the position / velocity converting means and the speed command signal. Of the three-phase constant-amplitude sine-wave signal and the number of zero-phase voltage of each phase of the three-phase constant-amplitude sine-wave signal output by the amplitude adjusting means, the position-speed converting means for outputting the torque command signal The number of coincident two-phase voltage values is counted within a certain period of time, and a speed signal is output from the counted value to further enhance the above-mentioned effect, and speed control of the mover of the brushless motor is performed. It is possible to realize a brushless motor control device capable of

Further, a rectangular wave converting means for converting the three-phase constant amplitude sine wave signal of the amplitude adjusting means into a rectangular wave signal having a phase difference of 90 degrees at the two-phase electrical angle, and an output signal of the rectangular wave converting means. And a position error amplifier that outputs the speed command signal from the position command signal to the controller of the brushless motor, and the rectangular wave converting means outputs two phases of the three-phase constant amplitude sine wave signal output by the amplitude adjusting means. The square wave rises when the voltage values are positive and the values are positive, the square wave rises when the two-phase voltage values of the three-phase constant-amplitude sine wave signal match, and the square wave is negative. A rectangular wave signal is obtained by the conversion of falling, and the rectangular wave rises at the point where the voltage of each phase of the three-phase constant amplitude sine wave signal output by the amplitude adjusting means becomes zero while monotonically increasing, The voltage of each phase decreases to zero while decreasing monotonically By configuring so that the other rectangular wave signal is obtained by the conversion in which the rectangular wave falls at the time, the above-mentioned effect is further enhanced, and a brushless motor control device capable of position control of the mover of the brushless motor is provided. It can be realized.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a controller for a brushless motor according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the brushless motor control device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a specific configuration example of a mover position detecting means in the first embodiment of the present invention.

FIG. 4 is a system configuration diagram of a brushless motor control device according to a second embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of a brushless motor control device according to a second embodiment of the present invention.

FIG. 6 is a system configuration diagram of a brushless motor control device according to a third embodiment of the present invention.

FIG. 7 is an operation explanatory diagram of a brushless motor control device according to a third embodiment of the present invention.

FIG. 8 is a system configuration diagram of a conventional brushless motor control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Three-phase brushless motor 2 Mover position detecting means 3 Amplitude adjusting means 5 Multiplying means 6 Driving means 7 Position speed converting means 8 Speed error amplifier 9 Rectangular wave converting means 10 Position error amplifier 20 Optical encoder 21 Counting means 22 Storage means 23 D / A converter 30 mover 31 magnetic body 32 magnetoelectric conversion element

Claims (6)

[Claims] 1. A three-phase brushless motor, a mover position detecting means for detecting a position of a mover, and outputting a three-phase sine wave signal having a phase difference of 120 degrees at an electrical angle according to the position, Amplitude adjusting means for adjusting the amplitude of the three-phase sine wave signal output from the mover position detecting means and outputting a three-phase constant amplitude sine wave signal, and three-phase constant amplitude sine wave signal output from the amplitude adjusting means. Multiplying means for multiplying the torque command signal and outputting a three-phase current control signal which is a ratio of the drive current or drive voltage of each phase of the three-phase brushless motor, and based on the three-phase current control signal output from the multiplying means. Drive means for controlling the drive current or drive voltage of each phase of the three-phase brushless motor, and the amplitude adjusting means for one cycle of the three-phase sine wave signal output from the mover position detecting means. 6 When the value of the sine wave signal of each phase becomes zero, an amplitude adjustment signal for two phases other than the phase where the value of the sine wave signal becomes zero is obtained, and the amplitude adjustment signal and the three-phase sine wave signal are obtained. A controller for a brushless motor, which is configured to output a three-phase constant amplitude sine wave signal and which controls a drive current or a drive voltage of each phase of the three-phase brushless motor based on an output signal of the amplitude adjusting means. 2. A magnetic body having a pole tooth structure for focusing the surface magnetic flux of the mover of the three-phase brushless motor by the mover position detecting means, and a magnetoelectric conversion element for converting the focused magnetic flux into an electric signal. The controller for the brushless motor according to claim 1, wherein the three-phase sine wave signal is output by the following. 3. A three-phase brushless motor, and a mover position detecting means for detecting the position of the mover and outputting a three-phase sine wave signal having a phase difference of 120 degrees at an electrical angle according to the position, Amplitude adjusting means for adjusting the amplitude of the three-phase sine wave signal output from the mover position detecting means to a constant value and outputting a three-phase constant amplitude sine wave signal, and three-phase constant amplitude sine wave output from the amplitude adjusting means Multiplying means for multiplying the signal by the torque command signal to output a three-phase current control signal which is a ratio of the drive current or drive voltage of each phase of the three-phase brushless motor, and a three-phase current control signal output from the multiplying means Drive means for controlling the drive current or drive voltage of each phase of the three-phase brushless motor based on the above, position-speed conversion means for converting the output signal of the amplitude adjustment means into a speed signal, and the position-speed conversion means Output and a speed error amplifier that outputs the torque command signal from the speed command signal, and the amplitude adjusting means is provided six times during one cycle of the three-phase sine wave signal output from the mover position detecting means. When the value of each phase sine wave signal becomes zero, an amplitude adjustment signal for two phases other than the phase where the value of the sine wave signal becomes zero is obtained, and based on the amplitude adjustment signal and the three-phase sine wave signal. It is configured to output a three-phase constant amplitude sine wave signal, and the position / velocity conversion means outputs the three-phase constant amplitude sine wave signal output by the amplitude adjusting means in such a manner that the voltage of each phase becomes zero and the three-phase constant amplitude The number of times that the voltage values of two phases among the three phases of the sine wave signal match is configured to count within a certain fixed time, and a speed signal is output from the counted value, and the speed output from the position speed conversion means. Signal and external speed command signal Brushless motor controller which controls the mover speed of Shiresumota. 4. A magnetic body having a pole tooth structure for focusing the surface magnetic flux of the mover of the three-phase brushless motor by the mover position detecting means, and a magnetoelectric conversion element for converting the focused magnetic flux into an electric signal. The controller for a brushless motor according to claim 3, wherein a three-phase sine wave signal is output by the. 5. A three-phase brushless motor, a mover position detecting means for detecting the position of the mover, and outputting a three-phase sine wave signal having a phase difference of 120 degrees at an electrical angle according to the position, Amplitude adjusting means for adjusting the amplitude of the three-phase sine wave signal output from the mover position detecting means to a constant value and outputting a three-phase constant amplitude sine wave signal, and three-phase constant amplitude sine wave output from the amplitude adjusting means Multiplying means for multiplying the signal by the torque command signal to output a three-phase current control signal which is a ratio of the drive current or drive voltage of each phase of the three-phase brushless motor, and a three-phase current control signal output from the multiplying means Drive means for controlling the drive current or drive voltage of each phase of the three-phase brushless motor based on the above, position-speed conversion means for converting the output signal of the amplitude adjustment means into a speed signal, and the position-speed conversion means And a speed error amplifier for outputting the torque command signal from the speed command signal, and the three-phase constant amplitude sine wave signal of the amplitude adjusting means is converted into a rectangular wave signal having a 90-degree phase difference in two-phase electrical angle. Three-phase output from the mover position detection means, which includes a rectangular wave conversion means and a position error amplifier which outputs the speed command signal from the output signal and the position command signal of the rectangular wave conversion means. When the value of the sine wave signal of each phase which is six times in one cycle of the sine wave signal becomes zero, the amplitude adjustment signals for two phases other than the phase where the value of the sine wave signal becomes zero are obtained, and the amplitude is adjusted. It is configured to output a three-phase constant amplitude sine wave signal based on the adjustment signal and the three-phase sine wave signal, and the position-speed conversion means of each phase of the three-phase constant amplitude sine wave signal output by the amplitude adjustment means. The number at which the voltage becomes zero and the three-phase constant The number of times that the voltage values of two phases of the three phases of the sine wave signal match is configured to be counted within a certain fixed time, and a speed signal is output from the counted value, and the rectangular wave conversion means is the amplitude adjustment means. The two-phase voltage values of the three-phase constant amplitude sine wave signal match and the square wave rises when the value is a positive value, and the two-phase voltage value of the three-phase constant amplitude sine wave signal Coincide with each other and a rectangular wave falls when the value is a negative value, one rectangular wave signal is obtained by conversion, and the voltage of each phase of the three-phase constant amplitude sine wave signal output by the amplitude adjusting means monotonically increases. However, the rectangular wave rises at the point of becoming zero, and the rectangular wave falls at the point of becoming zero while the voltage of each phase monotonically decreases, so that the other rectangular wave signal is obtained by the conversion, Position signal output from the rectangular wave conversion means and external position command signal A controller for a brushless motor, which controls the position of a mover of the three-phase brushless motor by means of: 6. A magnetic body having a pole tooth structure for focusing the surface magnetic flux of the mover of the three-phase brushless motor by the mover position detecting means, and magnetoelectric conversion for converting the focused magnetic flux into an electric signal. The controller for the brushless motor according to claim 5, wherein a three-phase sine wave signal is output by the element.