JP2010124653A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique that enables measurement of the value of a current flowing through an electromagnetic coil of a motor, without using a shunt resistance. <P>SOLUTION: A motor controller includes a speed input unit which receives the relative speed of a first driving member and a second drive member possessed by the motor; a calculating unit which calculates the value of a current flowing through the electromagnetic coil based on the relative speed, a supply voltage value that is the value of a voltage supplied to the motor, the resistance value of the electromagnetic coil possessed by the motor; and a counter electromotive force constant of the motor, and a control unit which controls the motor based on the calculated current value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to control of an electric motor.

  Conventionally, as a technique related to a brushless motor, for example, one disclosed in Patent Document 1 is known.

JP 2001-298882 A

By the way, in order to perform torque control, some conventional servo motors measure the current value flowing through an electromagnetic coil using a shunt resistor to control the current value. However, the torque control technology using this shunt resistor has the following problems.
1. Power loss 2. Heat generation due to shunt resistance 3. Insufficient dynamic range for current measurement 4. S / N ratio degradation due to current measurement 5. A filtering circuit is required to perform current measurement. The wiring of the AMP circuit for current measurement is messy. Furthermore, robots, etc. use multiple servo motors, so there was a strong demand for a control method that eliminates shunt resistance for torque control. It was not realized.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a technique capable of measuring the value of a current flowing through an electromagnetic coil of an electric motor without using a shunt resistor. . Moreover, it aims at providing the technique which can control an electric motor, without using shunt resistance.

  In order to solve at least a part of the problems described above, the present invention can take the following forms or application examples.

[Application Example 1]
A control device for an electric motor,
A speed input unit that inputs a relative speed between the first drive member and the second drive member of the electric motor;
Based on the relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of the electromagnetic coil that the electric motor has, and a back electromotive force constant of the electric motor, A calculation unit for calculating a current value flowing;
A control unit for controlling the electric motor based on the calculated current value;
A control device comprising:
According to the apparatus of Application Example 1, the value of the current flowing through the electromagnetic coil of the motor can be measured without using a shunt resistor. In addition, since the shunt resistor can be omitted, it is possible to suppress power loss and heat generation due to the shunt resistor.

[Application Example 2]
An electric motor control apparatus according to Application Example 1,
The calculation unit further calculates a target current value based on a target torque value that is a target value of torque generated by the electric motor and a torque constant of the electric motor,
The said control part is a control apparatus which performs feedback control which adjusts the average value of the said supply voltage value based on the said calculated electric current value and the said target electric current value.
According to the apparatus of the application example 2, since feedback control is performed, the electric motor can be appropriately controlled.

[Application Example 3]
A control device for an electric motor,
A speed input unit that inputs a relative speed between the first drive member and the second drive member of the electric motor;
The relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of an electromagnetic coil that the electric motor has, a counter electromotive force constant of the electric motor, a torque constant of the electric motor, An arithmetic unit that calculates an average voltage index value associated with an average value of the supply voltage values based on a target torque value that is a target value of torque generated by the electric motor;
A control unit for controlling the electric motor based on the calculated average voltage index value;
A control device comprising:
According to the apparatus of Application Example 3, the electric motor can be controlled without using a shunt resistor.

[Application Example 4]
An electric motor comprising the control device according to any one of Application Examples 1 to 3.

[Application Example 5]
An electric motor mounting device including the electric motor according to Application Example 4.

[Application Example 6]
The electric motor mounting device described in Application Example 5,
The motor mounting device is an electronic device.

[Application Example 7]
The electric motor mounting device described in Application Example 5,
The motor mounted device is a projector.

[Application Example 8]
The electric motor mounting device described in Application Example 5,
The electric motor mounting device is a moving body.

[Application Example 9]
The electric motor mounting device described in Application Example 5,
The motor mounted device is a robot.

  Note that the present invention can be realized in various modes. For example, the present invention can be realized in the form of an electric motor control method and apparatus, a control system, an integrated circuit for realizing the functions of the method or apparatus, a computer program, a recording medium recording the computer program, and the like. The present invention can also be realized in the form of an electric motor including the control device according to the present invention, an electronic device including the electric motor, a projector, a portable device, a robot, a moving body, and the like.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
B. Second embodiment:
C. Variation:

A. First embodiment:
FIG. 1 is an explanatory diagram showing the configuration of a brushless servomotor as an embodiment of the present invention. This motor includes a motor main body 100, a drive control circuit 200, and a rotary encoder 300. The motor body 100 includes a stator coil 10 and a rotor 30 that rotates about a rotation shaft 112. Note that the rotary encoder 300 is of a type that measures the transmitted light that passes through the slit disk.

  FIG. 2 is a block diagram showing the configuration of the drive control circuit of the brushless motor. The drive control circuit 200 includes a CPU 220, a drive signal generation unit 240, and two-phase driver circuits 250A and 250B. The two magnetic sensor outputs SSA and SSB are converted into digital multilevel signals by the AD converter 260 and supplied to the drive signal generator 240. Further, the position signal REP of the rotary encoder 300 is also supplied to the drive signal generation unit 240. The drive signal generator 240 generates a two-phase drive signal based on these signals SSA, SSB, and REP. The driver circuits 250A and 250B drive the two-phase electromagnetic coil groups 11 and 12 in the motor main body 100 in accordance with these two-phase drive signals.

  FIG. 3 is an explanatory diagram showing the internal configuration of the driver circuit. The driver circuits 250A and 250B for each phase constitute an H-type bridge circuit. For example, the A-phase driver circuit 250A drives the A-phase coil 11 according to the drive signals DRVA1 and DRVA2. Arrows denoted by reference signs IA1 and IA2 indicate directions of currents flowing through the drive signals DRVA1 and DRVA2, respectively. The same applies to the other phases. As the driver circuit, circuits having various configurations including a plurality of driving transistors can be used.

  FIG. 4 is an explanatory diagram showing the internal configuration and operation of the drive signal generator 240 (FIG. 2). For convenience of illustration, only the circuit element for the A phase is shown here, but the same circuit element is also provided for the B phase.

  The drive signal generation unit 240 includes a basic clock generation circuit 510, a 1 / N frequency divider 520, a PWM unit 530, a forward / reverse direction value register 540, a multiplier 550, an encoding unit 560, and a voltage command. A value register 580, an excitation interval setting unit 590, and a measurement unit 420 are provided. The A-phase magnetic sensor output SSA is supplied to the encoding unit 560 and the excitation interval setting unit 590. The position signal REP of the rotary encoder 300 is supplied to the measuring unit 420.

  The basic clock generation circuit 510 is a circuit that generates a clock signal PCL having a predetermined frequency, and is composed of, for example, a PLL circuit. The frequency divider 520 generates a clock signal SDC having a frequency 1 / N of the clock signal PCL. The value of N is set to a predetermined constant value. The value of N is set in the frequency divider 520 by the CPU 220 in advance. The PWM unit 530 is supplied from the clock signals PCL and SDC, the multiplication value Ma supplied from the multiplier 550, the forward / reverse direction indication value RI supplied from the forward / reverse direction indication value register 540, and the encoding unit 560. A phase drive signal is generated according to the positive / negative sign signal Pa and the excitation interval signal Ea supplied from the excitation interval setting unit 590. This operation will be described later.

  In the forward / reverse direction value register 540, a value RI indicating the rotation direction of the motor is set by the CPU 220. In the present embodiment, the motor rotates forward when the forward / reverse direction instruction value RI is at L level, and reverses when it is at H level. Other signals Ma, Pa, and Ea supplied to the PWM unit 530 are determined as follows.

  The output SSA of the magnetic sensor 40A is supplied to the encoding unit 560. The encoding unit 560 converts the range of the magnetic sensor output SSA and sets the value of the middle point of the sensor output to 0. As a result, the sensor output value Xa generated by the encoding unit 560 takes values in a predetermined range on the positive side (for example, +127 to +0) and a predetermined range on the negative side (for example, −0 to −127). However, what is supplied from the encoding unit 560 to the multiplier 550 is the absolute value of the sensor output value Xa, and the sign of the sensor output value Xa is supplied to the PWM unit 530 as the sign signal Pa. The voltage command value register 580 stores the voltage command value Ya given from the measurement unit 420. The operation of the measurement unit 420 will be described later.

  The voltage command value Ya functions as a value for setting an average voltage of the motor together with an excitation interval signal Ea described later, and takes a value of 0 to 1.0, for example. If the excitation interval signal Ea is set so that the entire excitation interval is set without providing the non-excitation interval, Ya = 0 means that the average voltage is zero, and Ya = 1.0 is This means that the average voltage is the maximum value. As will be described later, in the motor of this embodiment, the voltage command value Ya and the excitation interval signal Ea are determined by servo control (PID control) corresponding to the measured current value Isx. Therefore, the motor of this embodiment can be used as a servo motor.

  The multiplier 550 in FIG. 4A multiplies the sensor output value Xa output from the encoding unit 560 and the voltage command value Ya to produce an integer, and supplies the multiplication value Ma to the PWM unit 530. 4B to 4E show the operation of the PWM unit 530 when the multiplication value Ma takes various values. Here, it is assumed that the entire period is an excitation interval and there is no non-excitation interval. The PWM unit 530 is a circuit that generates one pulse with a duty of Ma / N during one cycle of the clock signal SDC. That is, as shown in FIGS. 4B to 4E, the duty of the pulses of the A-phase drive signals DRVA1 and DRVA2 increases as the multiplication value Ma increases. The first drive signal DRVA1 is a signal that generates a pulse only when the magnetic sensor output SSA is positive, and the second drive signal DRVA2 is a signal that generates a pulse only when the magnetic sensor output SSA is negative. However, in FIGS. 4B to 4E, these are described together. For convenience, the second drive signal DRVA2 is drawn as a negative pulse.

  5A to 5C are explanatory diagrams illustrating the correspondence between the waveform of the magnetic sensor output and the waveform of the drive signal generated by the PWM unit 530. FIG. In the figure, “Hiz” means a high impedance state in which the electromagnetic coil is in an unexcited state. As described with reference to FIG. 4, the A-phase drive signals DRVA1 and DRVA2 are generated by PWM control using an analog waveform of the magnetic sensor output SSA. Therefore, if these A-phase drive signals DRVA1 and DRVA2 are used, an effective voltage corresponding to a change in the magnetic sensor output SSA can be supplied to each coil.

  Further, the PWM unit 530 outputs a drive signal only in the excitation interval set by the excitation interval signal Ea supplied from the excitation interval setting unit 590, and does not output a drive signal in a region other than the excitation interval (non-excitation interval). It is configured as follows. FIG. 5B shows the drive signal waveform when the entire interval is set to the excitation interval EP. FIG. 5C shows drive signal waveforms when the excitation interval EP and the non-excitation interval NEP are set by the excitation interval signal Ea. In the excitation interval EP of FIG. 5C, the drive signal pulse of FIG. 5B is generated as it is, and no drive signal pulse is generated in the non-excitation interval NEP. In this way, when the excitation interval EP and the non-excitation interval NEP are set, no voltage is applied to the coil in the vicinity of the middle point of the sensor output (this corresponds to the vicinity of the middle point of the back electromotive force waveform). Therefore, it is possible to further improve the efficiency of the motor. The excitation interval EP is preferably set to a symmetrical interval centered on the peak of the sensor output waveform (which is substantially equal to the back electromotive force waveform), and the non-excitation interval NEP is the middle of the sensor output waveform. It is preferable to set a symmetrical section centered on a point (center point).

  FIG. 6 is a block diagram illustrating an example of an internal configuration of the PWM unit 530 (FIG. 4). The PWM unit 530 includes a counter 531, an EXOR circuit 533, and a drive waveform forming unit 535. These operate as follows.

  FIG. 7 is a timing chart showing the operation of the PWM unit 530 during normal rotation of the motor. In this figure, two clock signals PCL and SDC, forward / reverse direction instruction value RI, excitation interval signal Ea, multiplication value Ma, positive / negative sign signal Pa, count value CM1 in counter 531 and counter 531 The output S1, the output S2 of the EXOR circuit 533, and the output signals DRVA1 and DRVA2 of the drive waveform forming unit 535 are shown. The counter 531 repeats the operation of down-counting the count value CM1 to 0 in synchronization with the clock signal PCL every period of the clock signal SDC. The initial value of the count value CM1 is set to the multiplication value Ma. In FIG. 7, a negative value is also drawn as the multiplication value Ma for convenience of illustration, but the counter 531 uses the absolute value | Ma |. The output S1 of the counter 531 is set to H level when the count value CM1 is not 0, and falls to L level when the count value CM1 becomes 0.

  The EXOR circuit 533 outputs a signal S2 indicating an exclusive OR of the positive / negative sign signal Pa and the forward / reverse direction instruction value RI. When the motor rotates normally, the forward / reverse direction instruction value RI is at the L level. Therefore, the output S2 of the EXOR circuit 533 is the same signal as the positive / negative sign signal Pa. The drive waveform forming unit 535 generates drive signals DRVA1 and DRVA2 from the output S1 of the counter 531 and the output S2 of the EXOR circuit 533. That is, out of the output S1 of the counter 531, the signal during the period in which the output S2 of the EXOR circuit 533 is at the L level is output as the first drive signal DRVA1, and the signal during the period in which the output S2 is at the H level Output as. In the vicinity of the right end of FIG. 7, the excitation interval signal Ea falls to the L level, thereby setting the non-excitation interval NEP. Accordingly, in this non-excitation interval NEP, none of the drive signals DRVA1, DRVA2 is output and the high impedance state is maintained.

  FIG. 8 is a timing chart showing the operation of the PWM unit 530 during motor reverse rotation. During reverse rotation of the motor, the forward / reverse direction instruction value RI is set to H level. As a result, the two drive signals DRVA1 and DRVA2 are interchanged from FIG. 7, and as a result, it can be understood that the motor reverses.

  FIG. 9 is an explanatory diagram showing the internal configuration and operation of the excitation interval setting unit 590. The excitation interval setting unit 590 includes an electronic variable resistor 592, voltage comparators 594, 596, and an OR circuit 598. The resistance value Rv of the electronic variable resistor 592 is set by the CPU 220. Voltages V1 and V2 across the electronic variable resistor 592 are applied to one input terminal of a voltage comparator 594,596. A magnetic sensor output SSA is supplied to the other input terminal of the voltage comparators 594 and 596. Output signals Sp and Sn of the voltage comparators 594 and 596 are input to the OR circuit 598. The output of the OR circuit 598 is an excitation interval signal Ea for distinguishing between the excitation interval EP and the non-excitation interval NEP.

  FIG. 9B shows the operation of the excitation interval setting unit 590. Both-end voltages V1 and V2 of the electronic variable resistor 592 are changed by adjusting the resistance value Rv. Specifically, both-end voltages V1 and V2 are set to values having the same difference from the median value (= VDD / 2) of the voltage range. When the magnetic sensor output SSA is higher than the first voltage V1, the output Sp of the first voltage comparator 594 becomes H level. On the other hand, when the magnetic sensor output SSA is lower than the second voltage V2, The output Sn of the second voltage comparator 596 becomes H level. The excitation interval signal Ea is a signal obtained by taking the logical sum of these output signals Sp and Sn. Therefore, as shown in the lower part of FIG. 9B, the excitation interval signal Ea can be used as a signal indicating the excitation interval EP and the non-excitation interval NEP. The excitation interval EP and the non-excitation interval NEP are set by the measurement unit 420 updating the value of the variable resistance value Rv.

  As can be understood from the above description, in the brushless motor of this embodiment, the multiplication value Ma (duty of the drive signal) is adjusted by the voltage command value Ya, and the excitation interval EP and the non-excitation interval NEP are adjusted by the excitation interval signal Ea. Can do. In other words, in the brushless motor of the present embodiment, it is possible to adjust the ratio of the period during which the power supply voltage is supplied to the brushless motor by adjusting the voltage command value Ya and the variable resistance value Rv.

  FIG. 10 is an explanatory diagram schematically showing a circuit configuration from the power source to the electromagnetic coil of the motor body. The driver circuit 250 and the electromagnetic coil 11 are connected to the power source 24. The power supply 24 supplies the electromagnetic coil 11 with a power supply voltage Es (hereinafter also referred to as a supply voltage value Es). The electromagnetic coil 11 is simulated by an internal resistance 31 and a counter electromotive force Eg. The resistance value of the internal resistor 31 is Rdc. The counter electromotive force Eg is a voltage generated when the motor is driven.

  FIG. 11 is a block diagram illustrating an internal configuration of the measurement unit 420. The measurement unit 420 includes a supply voltage value storage unit 421, a resistance value storage unit 422, a back electromotive force constant storage unit 423, and a PWM value storage unit 424. The measurement unit 420 further includes a rotation speed input unit 425, a target torque value setting unit 426, a torque constant storage unit 427, a calculation unit 428, a PID control unit 429, and a conversion unit 430.

The supply voltage value storage unit 421 stores the supply voltage value Es supplied from the power source 24 (FIG. 11) to the electromagnetic coil 11. The resistance value storage unit 422 stores the resistance value Rdc of the internal resistance 31 (FIG. 11). The resistance value storage unit 422 may calculate the resistance value Rdc from the temperature of the internal resistance 31 or the like. The back electromotive force constant storage unit 423 stores the back electromotive force constant Ke of the motor body 100. The PWM value storage unit 424 stores the PWM value D _old [%].

This PWM value D _old is a value indicating the ratio of the length of the period during which power is supplied to the electromagnetic coil 11 to the entire period when PWM control is performed on the motor. That is, as a result of the PWM control performed on the motor, the length of the period during which power is supplied to the electromagnetic coil 11 is 0.6, and the length of the period during which no power is supplied to the electromagnetic coil 11 is 0. In the case of 4, the PWM value D _old = 60%. As described above, the length of the period during which power is supplied to the electromagnetic coil 11 is determined by the voltage command value Ya and the variable resistance value Rv. The CPU 220 calculates the PWM value D _old from the voltage command value Ya and the resistance value Rv, and supplies the PWM value D _old to the PWM value storage unit 424.

  The rotational speed input unit 425 converts the position signal REP from the rotary encoder 300 into a rotational speed N [rpm], and supplies the rotational speed N to the calculation unit 428. As the rotary encoder 300, it is preferable to use a high-resolution encoder. In order to remove the unstable region near the stop state, the rotational speed input unit 425 may set N = 0 [rpm] when N = 0.001 [rpm] or less, for example. Further, the rotational speed input unit 425 may predict and calculate the value of the future rotational speed N from the value of the past rotational speed N.

  The target torque value setting unit 426 sets a target torque value Tt generated by the motor. The target torque value Tr is supplied to the calculation unit 428. The torque constant storage unit 427 stores the torque constant Kt in the motor main body 100.

次に、演算部４２８は、以下の式（２）にしたがって、モータに発生する逆起電力Ｅｇを算出する。

また、演算部４２８は、以下の式（３）にしたがって、駆動平均電圧値Ｅａｖを算出する。

そして、演算部４２８は、以下の式（４）にしたがって、電磁コイル１１に流れる電流値Ｉｓｘを算出する。

また、演算部４２８は、以下の式（５）にしたがって、目標電流値Ｉｔを算出する。

The calculation unit 428 calculates the rotational speed ω [rad / s] of the motor according to the following equation (1).

Next, the calculating part 428 calculates the counter electromotive force Eg generated in the motor according to the following formula (2).

Moreover, the calculating part 428 calculates the drive average voltage value Eav according to the following formula | equation (3).

And the calculating part 428 calculates the electric current value Isx which flows into the electromagnetic coil 11 according to the following formula | equation (4).

Moreover, the calculating part 428 calculates the target current value It according to the following formula | equation (5).

  FIG. 12 is a table showing calculation results by the calculation unit 428. In FIG. 7, the supply voltage value Es = 150 [V], the resistance value Rdc = 80 [Ω], and the counter electromotive force constant Ke = 0.4 [Vs / rad]. According to FIG. 7, when the rotational speed N is 10 [rpm], 100 [rpm], 1000 [rpm], and 1500 [rpm], the current values Isx are 0.18 [A], 0. It can be understood that the values are calculated as 32 [A], 0.41 [A], and 0.15 [A].

The PID control unit 429 (FIG. 11) receives the current value Isx and the target current value It, performs PID control, and determines the updated PWM value D _new . That is, the PID control unit 429 obtains a deviation (Isx−It) between the measured current value Isx and the target current value It, and performs the proportional operation, the integral operation, and the differential operation with respect to this deviation, thereby obtaining the updated PWM value D _new . decide. Note that the update PWM value D _new may be determined using a control method other than the PID control. The updated PWM value D _new is supplied to the conversion unit 430.

Conversion unit 430, the percentage of time that the power supply to the electromagnetic coil 11 is supplied so as to update PWM value D _{new new,} to calculate the resistance Rv between the voltage command value Ya. The updated voltage command value Ya and resistance value Rv are supplied to the voltage command value register 580 and the excitation interval setting unit 590, respectively. As a result, the drive signal is generated so that the current value Isx follows the target current value It. That is, the drive signal is generated so that the torque generated by the motor follows the target torque value. Note that the CPU 220 can rewrite the target torque value. Further, the resistance value Rv (that is, the ratio of the excitation interval EP) may always be maintained at a constant value (for example, EP = 100%).

  Thus, in the brushless motor in the present embodiment, the measurement unit 420 calculates the current value Isx, so that the shunt resistance can be omitted. And it becomes possible to suppress the power loss and heat_generation | fever by shunt resistance. Further, in the brushless motor in the present embodiment, the drive signal can be generated so as to follow the target torque value Tt.

B. Second embodiment:
FIG. 13 is a block diagram illustrating an internal configuration of the measurement unit 420b in the second embodiment. The measurement unit 420b in the second embodiment is different from the first embodiment shown in FIG. 11 in that the PWM value storage unit 424 and the PID control unit 429 are omitted and the operation of the calculation unit 428b is different. This is different from the measurement unit 420 in the example.

ここで、更新供給電圧値Ｅ_newは、目標トルク値Ｔｒを発生するために要求される供給電圧値の平均値に関連付けられた値である。すなわち、更新供給電圧値Ｅ_newは、本発明における「平均電圧指標値」に相当する。
そして、演算部４２８ｂは、以下の式（７）にしたがって、更新ＰＷＭ値Ｄ_new［％］を算出する。

変換部４３０は、第１実施例と同様に、電磁コイル１１に電源が供給される期間の割合が更新ＰＷＭ値Ｄ_newとなるように、電圧指令値Ｙａと抵抗値Ｒｖを算出する。換言すれば、変換部４３０は、供給電圧値の平均値が更新供給電圧値Ｅ_newとなるように、電圧指令値Ｙａと抵抗値Ｒｖの値を算出する。 Similar to the calculation unit 428 of the first embodiment, the calculation unit 428b calculates the rotational speed ω, the back electromotive force Eg, and the target current value It according to the above formulas (1), (2), and (5). To do. Next, the computing unit 428b calculates an updated supply voltage value E _new [V] according to the following equation (6).

Here, the updated supply voltage value E _new is a value associated with the average value of the supply voltage values required to generate the target torque value Tr. That is, the updated supply voltage value E _new corresponds to the “average voltage index value” in the present invention.
Then, the calculation unit 428b calculates the updated PWM value D _new [%] according to the following equation (7).

Conversion unit 430, like the first embodiment, the percentage of time that the power supply to the electromagnetic coil 11 is supplied so as to update PWM value D _{new new,} to calculate the resistance Rv between the voltage command value Ya. In other words, the converter 430 calculates the voltage command value Ya and the resistance value Rv so that the average value of the supply voltage values becomes the updated supply voltage value E _new .

14 to 17 are tables showing calculation results by the calculation unit 428b. FIG. 14 shows a calculation result when the rotation speed N is constant (N = 100) and the target torque value Tt is changed. Thus, it can be understood that even when the rotational speed N is constant, the updated PWM value D _new also changes when the target torque value Tt changes.

FIG. 15 shows the case where the target torque value Tt is set to 0.001 [Nm] and the target torque value Tt is set to −0.005 [Nm] when the rotational speed N changes. The calculation result of is shown. Incidentally, if the update PWM value D _{new new} indicates negative, CPU 220 sets a moving direction value RI to H level, to generate a driving force of the reverse rotation to the motor.

  FIG. 16 shows the calculation result when the target torque value Tt is also changed when the rotational speed N is changed. FIG. 17 is a table in which the rotational position of the motor is added to FIG. Note that the measurement unit may perform PID control based on the target rotation position and the rotation position actually detected by the rotary encoder 300 to control the position of the motor.

Thus, in the second embodiment, since the measurement unit 420b to properly calculate the update PWM value D _{new new,} it is possible to appropriately control the motor.

C. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
The present invention is applicable to various devices. For example, the present invention can be applied to motors of various devices such as a fan motor, a clock (hand drive), a drum-type washing machine (single rotation), a roller coaster, and a vibration motor. When the present invention is applied to a fan motor, the various effects described above (low power consumption, low vibration, low noise, low rotation unevenness, low heat generation, long life) are particularly remarkable. Such fan motors are, for example, various devices such as digital display devices, in-vehicle devices, fuel cell computers, fuel cell digital cameras, fuel cell video cameras, fuel cell mobile phones, and other fuel cell equipment. It can be used as a fan motor for the device. The motor of the present invention can also be used as a motor for various home appliances and electronic devices. For example, the motor according to the present invention can be used as a spindle motor in an optical storage device, a magnetic storage device, a polygon mirror drive device, or the like. The motor according to the present invention can also be used as a motor for a moving body or a robot.

  FIG. 18 is an explanatory diagram showing a projector using a motor according to an embodiment of the present invention. The projector 3100 includes three light sources 3110R, 3110G, and 3110B that emit red, green, and blue color lights, and three liquid crystal light valves 3140R, 3140G, and 3140B that modulate these three color lights, respectively. A cross dichroic prism 3150 that synthesizes the modulated three-color light, a projection lens system 3160 that projects the combined three-color light onto the screen SC, a cooling fan 3170 for cooling the inside of the projector, and a projector 3100 And a control unit 3180 for controlling the whole. As the motor for driving the cooling fan 3170, the various brushless motors described above can be used.

  FIGS. 19A to 19C are explanatory views showing a fuel cell type mobile phone using a motor according to an embodiment of the present invention. FIG. 19A illustrates an appearance of the mobile phone 3200, and FIG. 19B illustrates an example of an internal configuration. The mobile phone 3200 includes an MPU 3210 that controls the operation of the mobile phone 3200, a fan 3220, and a fuel cell 3230. The fuel cell 3230 supplies power to the MPU 3210 and the fan 3220. The fan 3220 is used to blow air from the outside of the mobile phone 3200 to supply air to the fuel cell 3230 or to discharge moisture generated by the fuel cell 3230 from the inside of the mobile phone 3200 to the outside. It is. Note that the fan 3220 may be disposed on the MPU 3210 as shown in FIG. 19C to cool the MPU 3210. As the motor that drives the fan 3220, the various brushless motors described above can be used.

  FIG. 20 is an explanatory view showing an electric bicycle (electric assist bicycle) as an example of a moving body using a motor / generator according to an embodiment of the present invention. In this bicycle 3300, a motor 3310 is provided on the front wheel, and a control circuit 3320 and a rechargeable battery 3330 are provided on a frame below the saddle. The motor 3310 assists traveling by driving the front wheels using the electric power from the rechargeable battery 3330. In addition, the electric power regenerated by the motor 3310 is charged in the rechargeable battery 3330 during braking. The control circuit 3320 is a circuit that controls driving and regeneration of the motor. As the motor 3310, the various brushless motors described above can be used.

  FIG. 21 is an explanatory diagram showing an example of a robot using a motor according to an embodiment of the present invention. The robot 3400 includes first and second arms 3410 and 3420 and a motor 3430. The motor 3430 is used when horizontally rotating the second arm 3420 as a driven member. As the motor 3430, the above-described various brushless motors can be used.

  FIG. 22 is an explanatory diagram showing a railway vehicle using a motor according to an embodiment of the present invention. The railway vehicle 3500 has a motor 3510 and wheels 3520. The motor 3510 drives the wheel 3520. Further, the motor 3510 is used as a generator during braking of the railway vehicle 3500, and electric power is regenerated. As the motor 3510, the above-described various brushless motors can be used.

C2. Modification 2:
In the first embodiment, feedback control is performed using PID control, but various feedback control techniques such as P control and PI control can be used instead.

C3. Modification 3:
In the above embodiment, the supply voltage value Es is fixed, the PWM control, the control of the voltage command value Ya, and the control of the excitation interval EP are performed to change the average value of the voltage supplied to the electromagnetic coil. Instead of this, the voltage supplied to the electromagnetic coil may be changed by changing the supply voltage value Es without performing the PWM control, the control of the voltage command value Ya, and the control of the excitation interval EP. . In this case, a brushed DC motor may be used as the electric motor. Further, the supply voltage value Es may be changed together with the PWM control, the control of the voltage command value Ya, and the control of the excitation interval EP.

C4. Modification 4:
In the above embodiment, a part of the functions realized by software may be realized by hardware, or a part of the functions realized by hardware may be realized by software.

C5. Modification 5:
In the above embodiment, the motor is described as a two-phase motor, but the present invention can also be applied to a one-phase motor or a motor having three or more phases.

It is explanatory drawing which shows the structure of the brushless servomotor as one Example of this invention. It is a block diagram which shows the structure of the drive control circuit of a brushless motor. It is explanatory drawing which shows the internal structure of a driver circuit. 6 is an explanatory diagram showing an internal configuration and operation of a drive signal generation unit 240. FIG. 5 is an explanatory diagram showing a correspondence relationship between a waveform of a magnetic sensor output and a waveform of a drive signal generated by a PWM unit 530. FIG. 3 is a block diagram illustrating an example of an internal configuration of a PWM unit 530. FIG. It is a timing chart which shows operation | movement of the PWM part 530 at the time of motor forward rotation. It is a timing chart which shows operation | movement of the PWM part 530 at the time of motor reverse rotation. It is explanatory drawing which shows the internal structure and operation | movement of the excitation area setting part 590. FIG. It is explanatory drawing which shows typically the circuit structure from a power supply to the electromagnetic coil of a motor main body. 3 is a block diagram showing an internal configuration of a measurement unit 420. FIG. It is a table | surface which shows the calculation result by the calculating part 428. It is a block diagram which shows the internal structure of the measurement part 420b in 2nd Example. It is a table | surface which shows the calculation result by the calculating part 428b. It is a table | surface which shows the calculation result by the calculating part 428b. It is a table | surface which shows the calculation result by the calculating part 428b. It is a table | surface which shows the calculation result by the calculating part 428b. It is explanatory drawing which shows the projector using the motor by the Example of this invention. It is explanatory drawing which shows the fuel cell type mobile telephone using the motor by the Example of this invention. It is explanatory drawing which shows the electric bicycle (electric assisted bicycle) as an example of the moving body using the motor / generator by the Example of this invention. It is explanatory drawing which shows an example of the robot using the motor by the Example of this invention. It is explanatory drawing which shows the rail vehicle using the motor by the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Stator coil 11 ... Electromagnetic coil 24 ... Power supply 30 ... Rotor 31 ... Internal resistance 40A ... Magnetic sensor 100 ... Motor body 112 ... Rotating shaft 200 ... Drive control circuit 220 ... CPU
DESCRIPTION OF SYMBOLS 240 ... Drive signal production | generation part 250 ... Driver circuit 260 ... AD conversion part 300 ... Rotary encoder 420 ... Measurement part 420b ... Measurement part 421 ... Supply voltage value memory | storage part 422 ... Resistance value memory | storage part 423 ... Back electromotive force constant memory | storage part 424 ... PWM value storage unit 425 ... rotational speed input unit 426 ... target torque value setting unit 427 ... torque constant storage unit 428 ... calculation unit 428b ... calculation unit 429 ... PID control unit 430 ... conversion unit 510 ... basic clock generation circuit 520 ... frequency division 530 ... PWM unit 531 ... Counter 533 ... EXOR circuit 535 ... Drive waveform forming unit 540 ... Forward / reverse direction value register 550 ... Multiplier 560 ... Encoding unit 580 ... Voltage command value register 590 ... Excitation section setting unit 592 ... Electronic Variable resistor 594 ... Voltage comparator 596 ... Voltage comparator 3100 ... Projector DESCRIPTION OF SYMBOLS 110 ... Light source 3140 ... Liquid crystal light valve 3150 ... Cross dichroic prism 3160 ... Projection lens system 3170 ... Cooling fan 3180 ... Control part 3200 ... Mobile phone 3220 ... Fan 3230 ... Fuel cell 3300 ... Bicycle 3310 ... Motor 3320 ... Control circuit 3330 ... Charge Battery 3400 ... Robot 3410 ... First arm 3420 ... Second arm 3430 ... Motor 3500 ... Railway vehicle 3510 ... Motor 3520 ... Wheel

Claims (13)

A control device for an electric motor,
A speed input unit that inputs a relative speed between the first drive member and the second drive member of the electric motor;
Based on the relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of the electromagnetic coil that the electric motor has, and a back electromotive force constant of the electric motor, A calculation unit for calculating a current value flowing;
A control unit for controlling the electric motor based on the calculated current value;
A control device comprising: The motor control device according to claim 1,
The calculation unit further calculates a target current value based on a target torque value that is a target value of torque generated by the electric motor and a torque constant of the electric motor,
The said control part is a control apparatus which performs feedback control which adjusts the average value of the said supply voltage value based on the said calculated electric current value and the said target electric current value. A control device for an electric motor,
A speed input unit that inputs a relative speed between the first drive member and the second drive member of the electric motor;
The relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of an electromagnetic coil that the electric motor has, a counter electromotive force constant of the electric motor, a torque constant of the electric motor, An arithmetic unit that calculates an average voltage index value associated with an average value of the supply voltage values based on a target torque value that is a target value of torque generated by the electric motor;
A control unit for controlling the electric motor based on the calculated average voltage index value;
A control device comprising:   An electric motor comprising the control device according to any one of claims 1 to 3.   An electric motor mounting apparatus comprising the electric motor according to claim 4. The electric motor mounting device according to claim 5,
The motor mounting device is an electronic device. The electric motor mounting device according to claim 5,
The motor mounted device is a projector. The electric motor mounting device according to claim 5,
The electric motor mounting device is a moving body. The electric motor mounting device according to claim 5,
The motor mounted device is a robot. An electric motor control method,
A step of inputting a relative speed between the first drive member and the second drive member of the electric motor;
Based on the relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of the electromagnetic coil that the electric motor has, and a back electromotive force constant of the electric motor, A step of calculating a flowing current value;
Controlling the electric motor based on the calculated current value;
A control method comprising: An electric motor control method,
A step of inputting a relative speed between the first drive member and the second drive member of the electric motor;
The relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of an electromagnetic coil that the electric motor has, a counter electromotive force constant of the electric motor, a torque constant of the electric motor, Calculating an average voltage index value associated with the average value of the supply voltage values based on a target torque value that is a target value of torque generated by the electric motor;
Controlling the electric motor based on the calculated average voltage index value;
A control method comprising: A computer program for causing a computer to execute control processing of an electric motor,
A function of inputting a relative speed between the first drive member and the second drive member of the electric motor;
Based on the relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of the electromagnetic coil that the electric motor has, and a back electromotive force constant of the electric motor, A function to calculate the current value flowing,
A function of controlling the electric motor based on the calculated current value;
A computer program for causing the computer to realize the above. A computer program for causing a computer to execute control processing of an electric motor,
A function of inputting a relative speed between the first drive member and the second drive member of the electric motor;
The relative speed, a supply voltage value that is a voltage value of a voltage supplied to the electric motor, a resistance value of an electromagnetic coil that the electric motor has, a counter electromotive force constant of the electric motor, a torque constant of the electric motor, A function of calculating an average voltage index value associated with an average value of the supply voltage values based on a target torque value that is a target value of torque generated by the electric motor;
A function of controlling the electric motor based on the calculated average voltage index value;
A computer program for causing the computer to realize the above.

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