Motor control device, brushless DC motor, actuator, and EGR valve device

Abstract

The motor control device (200) includes: a target rotational position acquisition section (31) that acquires a target rotational position (TRP) of a rotor (5) in a motor main body section (400); a rotational position calculation section (32) that calculates a rotational position (RP) of the rotor (5) using a pulse signal (PS) output by a rotational position sensor (23) of the motor main body section (400); a rotational speed calculation section (33) that calculates a rotational speed (N) of the rotor (5) based on the rotational position (RP); a first duty ratio calculation section (34) that calculates a first duty ratio (DR1) for controlling the motor main body section (400) based on the target rotational position (TRP) and the rotational position (RP); a second duty ratio calculation section (35) that calculates a second duty ratio (DR2) corresponding to an upper limit value of an absolute value of the first duty ratio (DR1) based on a first order function including a variable corresponding to the rotational speed (N); and a control signal output section (36) that outputs a control signal corresponding to the first duty ratio (DR1) when an absolute value of the first duty ratio (DR1) is smaller than an absolute value of the second duty ratio (DR2), and outputs a control signal corresponding to the second duty ratio (DR2) when the absolute value of the second duty ratio (DR2) is smaller than the absolute value of the first duty ratio (DR1).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a motor control device, a brushless DC motor, an actuator, and an EGR valve device. BACKGROUND

[0002] Conventionally, an actuator is used in opening degree control of a valve in an automobile. Specifically, for example, the actuator is used in opening degree control of an EGR (Exhaust Gas Recirculation) valve, opening degree control of a wastegate valve, or opening degree control of a throttle valve. In addition, an electric motor is used in this actuator. Specifically, for example, a brushless DC (Direct Current) motor is used.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2005-124359 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] From the viewpoint of protecting electronic components in the electric motor and the viewpoint of suppressing temperature rise in the electric motor, it is required to control the current value in the electric motor to a value smaller than a prescribed value. On the other hand, from the viewpoint of increasing the torque of the electric motor, it is sometimes required to increase the current value in the electric motor. In this case, it is preferable to control the current value in the electric motor to a value (hereinafter referred to as "maximum value") that is smaller than the prescribed value and is near the prescribed value.

[0008] In order to achieve this control, it is considered to use feedback of the current value (for example, refer to Patent Document 1). However, in this case, from the viewpoint of achieving feedback of the current value and the viewpoint of performing an operation of the current value based on the feedback, there is a problem that the circuit structure of the electric motor becomes complicated.

[0009] The present disclosure is proposed in order to solve the above problem, and aims at controlling the current value to a value smaller than a prescribed value by a simple circuit structure.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] The motor control device according to the present disclosure is characterized by including: a target rotational position acquisition unit that acquires a target rotational position of a rotor in a motor main body unit; a rotational position calculation unit that calculates a rotational position of the rotor using a pulse signal output by a rotational position sensor of the motor main body unit; a rotational speed calculation unit that calculates a rotational speed of the rotor based on the rotational position; a first duty calculation unit that calculates a first duty for controlling the motor main body unit based on the target rotational position and the rotational position; a second duty calculation unit that calculates a second duty corresponding to an upper limit value of an absolute value of the first duty based on a first linear function including a variable corresponding to the rotational speed; and a control signal output unit that outputs a control signal corresponding to the first duty when an absolute value of the first duty is smaller than an absolute value of the second duty, and outputs a control signal corresponding to the second duty when the absolute value of the second duty is smaller than the absolute value of the first duty, a slope value of the first linear function being calculated based on a second linear function having a difference value of a temperature around a substrate of the motor main body unit with respect to a reference temperature as a variable, the slope value increasing when the difference value increases, and the slope value decreasing when the difference value decreases.

[0012] Effects of the Invention

[0013] According to the present disclosure, since the configuration is as described above, it is possible to control the current value to a value smaller than a prescribed value with a simple circuit configuration. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 FIG. 1 is a cross-sectional view showing a main part of a brushless DC motor including a motor control device according to Embodiment 1.

[0015] Figure 2 FIG. 2 is an explanatory diagram showing an example of a pulse signal output by each magnetic sensor and an example of a timing at which a power supply state to each phase is an on state.

[0016] Figure 3 FIG. 3 is a block diagram showing a main part of a brushless DC motor including a motor control device according to Embodiment 1.

[0017] Figure 4 FIG. 4 is an explanatory diagram showing a curve of a second duty corresponding to a first linear function having a positive intercept.

[0018] Figure 5 FIG. 5 is an explanatory diagram showing a curve of a second duty corresponding to a first linear function having a negative intercept.

[0019] Figure 6 FIG. 6 is an explanatory diagram showing a graph of a second duty calculated by a second duty calculation unit.

[0020] Figure 7 is a block diagram showing a hardware structure of a main part of the motor control device according to Embodiment 1.

[0021] Figure 8 is a block diagram showing another hardware structure of a main part of the motor control device according to Embodiment 1.

[0022] Figure 9 is a block diagram showing another hardware structure of a main part of the motor control device according to Embodiment 1.

[0023] Figure 10 is a flowchart showing an operation of the motor control device according to Embodiment 1.

[0024] Figure 11 is a flowchart showing an operation of the second duty ratio operation section and the control signal output section in the motor control device according to Embodiment 1.

[0025] Figure 12 is a characteristic diagram showing an example of torque with respect to rotation speed.

[0026] Figure 13 is an explanatory diagram showing another example of a pulse signal output by each magnetic sensor and another example of timing at which the power supply state to each phase is an on state.

[0027] Figure 14 is a block diagram showing a main part of an actuator including a brushless DC motor including the motor control device according to Embodiment 1.

[0028] Figure 15 is a block diagram showing a main part of an EGR valve device including an actuator including a brushless DC motor including the motor control device according to Embodiment 1. DETAILED DESCRIPTION

[0029] Hereinafter, in order to describe the present disclosure in more detail, a mode for carrying out the present disclosure is described with reference to the drawings.

[0030] Embodiment 1.

[0031] Figure 1 is a cross-sectional view showing a main part of a brushless DC motor including the motor control device according to Embodiment 1. Figure 2 is an explanatory diagram showing an example of a pulse signal output by each magnetic sensor and an example of timing at which the power supply state to each phase is an on state. Figure 3 is a block diagram showing a main part of a brushless DC motor including the motor control device according to Embodiment 1. Refer to Figures 1-3The brushless DC motor including a motor control device according to Embodiment 1 will be described.

[0032] like Figure 1 As shown, the brushless DC motor 100 has a generally cylindrical stator 1. The stator 1 includes a stator core 2, an insulator 3, and coils 4. The rotor 5 passes through the stator 1. In other words, the stator 1 is disposed on the outer periphery of the rotor 5. The rotor 5 includes a main magnet 6, a rotor core 7, a resin-molded portion 8, and a shaft 9. The main magnet 6 is disposed opposite to the stator 1. In addition, the rotor 5 includes a sensor magnet 10. The sensor magnet 10 is disposed opposite to the substrate 16 described later. The rotor 5 is rotatably supported relative to the stator 1 by bearings 11 and 12.

[0033] In the diagram, RA represents the rotation axis of rotor 5. RD1 represents the rotation direction of rotor 5. RD2 represents another rotation direction of rotor 5. Hereinafter, the direction corresponding to either rotation direction RD1 or RD2 is sometimes referred to as the "forward rotation direction." Conversely, the direction corresponding to the other rotation direction is sometimes referred to as the "reverse rotation direction." That is, the forward rotation direction is the direction corresponding to the forward rotation of rotor 5. On the other hand, the reverse rotation direction is the direction corresponding to the reverse rotation of rotor 5.

[0034] The housing portion 15 of the brushless DC motor 100 is formed by the outer shell 13 and the cover plate 14. The stator 1, rotor 5, and bearings 11 and 12 are housed in the housing portion 15. The front end of the shaft 9 protrudes outward from the frame portion 15. In addition, a base plate 16 is housed in the frame portion 15.

[0035] Multiple circuits are provided on the substrate 16. These circuits include a control circuit (i.e., a motor control device 200), a power supply circuit 21, and a drive circuit 22. In addition, multiple sensors are provided on the substrate 16. These sensors include a rotational position sensor 23 and a temperature sensor 24.

[0036] The power supply circuit 21 uses power supplied by the external power source 300 to provide operating power to the motor control device 200. Additionally, the power supply circuit 21 uses power supplied by the external power source 300 to provide operating power to the rotary position sensor 23. The external power source 300 is located outside the brushless DC motor 100. The external power source 300 is, for example, a vehicle battery. Figure 1 The external power supply 300 is not shown in the diagram.

[0037] The drive circuit 22 drives the rotor 5 by supplying a current to the coil 4 using the power supplied from the external power source 300 under the control of the motor control device 200. Here, the brushless DC motor 100 is of a three-phase type. The drive circuit 22 includes two switching elements SE_H, SE_L corresponding to each phase. More specifically, the drive circuit 22 includes a switching element SE_H_U corresponding to the high side of the U phase, a switching element SE_L_U corresponding to the low side of the U phase, a switching element SE_H_V corresponding to the high side of the V phase, a switching element SE_L_V corresponding to the low side of the V phase, a switching element SE_H_W corresponding to the high side of the W phase, and a switching element SE_L_W corresponding to the low side of the W phase. Each of the switching elements SE uses a FET (Field Effect Transistor).

[0038] First, the state of the switching element SE_H_U is continuously controlled to the off state, and the state of the switching element SE_L_U is continuously controlled to the on state, whereby the supply state to the U phase becomes the on state. Also, the state of the switching element SE_H_V is continuously controlled to the off state, and the state of the switching element SE_L_V is continuously controlled to the on state, whereby the supply state to the V phase becomes the on state. Also, the state of the switching element SE_H_W is continuously controlled to the off state, and the state of the switching element SE_L_W is continuously controlled to the on state, whereby the supply state to the W phase becomes the on state. Hereinafter, these states are collectively referred to as "first on state".

[0039] Second, the switching element SE_H_U is driven by PWM (Pulse Width Modulation), and the switching element SE_L_U is driven by PWM, whereby the supply state to the U phase becomes the on state. Also, the switching element SE_H_V is driven by PWM, and the switching element SE_L_V is driven by PWM, whereby the supply state to the V phase becomes the on state. Also, the switching element SE_H_W is driven by PWM, and the switching element SE_L_W is driven by PWM, whereby the supply state to the W phase becomes the on state. Hereinafter, these states are collectively referred to as "second on state".

[0040] During the rotation of the rotor 5, the supply state to the U phase, the supply state to the V phase, and the supply state to the W phase become the on state in turn. In other words, the rotor 5 is rotated by making the supply state to the U phase, the supply state to the V phase, and the supply state to the W phase become the on state in turn. Figure 2 An example of timing at which the supply state to each phase becomes the on state.

[0041] The rotation position sensor 23 includes a magnetic sensor MS corresponding to each phase. That is, the rotation position sensor 23 includes a magnetic sensor MS_U corresponding to the U phase, a magnetic sensor MS_V corresponding to the V phase, and a magnetic sensor MS_W corresponding to the W phase. Each magnetic sensor MS uses a Hall IC (Integrated Circuit).

[0042] Here, each magnetic sensor MS is arranged opposite to the rotor 5. As described above, the sensor magnet 10 is provided on the rotor 5, and the sensor magnet 10 is arranged opposite to the substrate 16. The number of magnetic poles in the sensor magnet 10 is set to the same value as the number of excitations in the brushless DC motor 100.

[0043] Thus, in the rotation of the rotor 5, a pulse signal PS is output by each magnetic sensor MS. More specifically, a pulse signal PS_U is output by the magnetic sensor MS_U. In addition, a pulse signal PS_V is output by the magnetic sensor MS_V. In addition, a pulse signal PS_W is output by the magnetic sensor MS_W. Figure 2 An example of the pulse signal PS output by each magnetic sensor MS is shown.

[0044] The temperature sensor 24 uses, for example, a thermistor. The temperature sensor 24 detects the temperature T in the brushless DC motor 100.

[0045] Thus, the main part of the brushless DC motor 100 is configured. Hereinafter, the part in the brushless DC motor 100 other than the motor control device 200 is sometimes collectively referred to as a "motor main body part". That is, the brushless DC motor 100 includes the motor control device 200 and the motor main body part 400.

[0046] Hereinafter, the configuration of the brushless DC motor 100 will be described with reference to Figure 3 The motor control device 200 will be described. In Figure 3 In the motor main body part 400, parts other than the power supply circuit 21, the drive circuit 22, the rotation position sensor 23, and the temperature sensor 24 are omitted from the drawing.

[0047] As shown in Figure 3 The motor control device 200 includes a target rotation position acquisition part 31, a rotation position calculation part 32, a rotation speed calculation part 33, a first duty calculation part 34, a second duty calculation part 35, and a control signal output part 36. In addition, an external control device 500 is provided outside the brushless DC motor 100. The external control device 500 is constituted by, for example, an ECU (Electronic Control Unit) that is superior to the motor control device 200.

[0048] The external control device 500 outputs an instruction signal to the motor control device 200. The output instruction signal contains a target rotational position TRP of the rotor 5 at each time t n The target rotational position acquisition section 31 acquires the output instruction signal. Thus, the target rotational position acquisition section 31 acquires the target rotational position TRP of the rotor 5 at each time t n

[0049] The target position calculation section 32 acquires the pulse signal PS output from each magnetic sensor MS. The rotational position calculation section 32 uses the acquired pulse signal PS to calculate the rotational position RP of the rotor 5 at each time t n

[0050] The rotational speed calculation section 33 acquires the rotational position RP calculated by the rotational position calculation section 32. The rotational speed calculation section 33 uses the acquired rotational position RP to calculate the rotational speed (hereinafter referred to as "rotational speed") N of the rotor 5.

[0051] More specifically, the rotational speed calculation section 33 calculates, for the rotational position RP at each timing (t n ), a differential value ΔRP with respect to the rotational position RP at the preceding timing (t n-1 ). The rotational speed calculation section 33 calculates the rotational speed N at the corresponding timing (t n ) on the basis of the calculated differential value ΔRP.

[0052] The first duty ratio calculation section 34 acquires the target rotational position TRP acquired by the target rotational position acquisition section 31, the rotational position RP calculated by the rotational position calculation section 32, and the rotational speed N calculated by the rotational speed calculation section 33. The first duty ratio calculation section 34 uses the acquired target rotational position TRP, the acquired rotational position RP, and the acquired rotational speed N to calculate a duty ratio (hereinafter referred to as "first duty ratio") DR1 for controlling each switching element SE.

[0053] That is, the first duty ratio calculation section 34 calculates, for the rotational position RP at each timing (t n ), a deviation ΔP1 with respect to the target rotational position TRP at the corresponding timing (t n ). In addition, the first duty ratio calculation section 34 calculates, for the target rotational position TRP at each timing (t n ), a deviation ΔP2 with respect to the target rotational position TRP at the preceding timing (t n-1 ). The first duty ratio calculation section 34 uses the calculated deviation ΔP1, the calculated deviation ΔP2, and the acquired rotational speed N to calculate the first duty ratio DR1 by a prescribed calculation formula.

[0054] ​​This operation formula is composed of, for example, a combination of I-PD control and feedforward control (FF control). At this time, the first duty ratio operation section 34 uses the above-mentioned calculated deviation ΔP1 as a coefficient in an integral term (I term). In addition, the first duty ratio operation section 34 uses the above-mentioned acquired rotational speed N as a coefficient in a proportional term (P term). In addition, the first duty ratio operation section 34 uses the above-mentioned calculated deviation ΔP2 as a coefficient in a feedforward term (FF term).

[0055] Thus, the first duty ratio DR1 is calculated. That is, the first duty ratio DR1 is calculated in accordance with feedback of the rotational position RP. When the rotor 5 is driven in the forward direction, the first duty ratio DR1 is set to a positive value. On the other hand, when the rotor 5 is driven in the reverse direction, the first duty ratio DR1 is set to a negative value.

[0056] The second duty ratio operation section 35 acquires information indicating the positive or negative of the first duty ratio DR1 calculated by the first duty ratio operation section 34 (hereinafter referred to as "positive / negative information"). In addition, the second duty ratio operation section 35 acquires the rotational speed N detected by the rotational speed operation section 33. The second duty ratio operation section 35 calculates a duty ratio corresponding to an upper limit value of the absolute value of the first duty ratio DR1 (hereinafter referred to as "second duty ratio") DR2 using the acquired positive / negative information and the acquired rotational speed N.

[0057] More specifically, in the case where the above-mentioned calculated first duty ratio DR1 is a positive value, the second duty ratio operation section 35 calculates the second duty ratio DR2 using a linear function shown in the following formula (1). On the other hand, in the case where the above-mentioned calculated first duty ratio DR1 is a negative value, the second duty ratio operation section 35 calculates the second duty ratio DR2 using a linear function shown in the following formula (2).

[0058] DR2 = aN + b (1)

[0059] DR2 = aN - b (2)

[0060] That is, the linear function used in the calculation of the second duty ratio DR2 includes a variable corresponding to the rotational speed N. In addition, the linear function used in the calculation of the second duty ratio DR2 includes a slope value a and an intercept value b. The positive or negative of the intercept value b is set in accordance with the positive or negative of the first duty ratio DR1.

[0061] Figure 4 A curve indicating the second duty ratio DR2 corresponding to the linear function shown in formula (1). That is, Figure 4 A curve indicating the second duty ratio DR2 corresponding to the linear function having a positive intercept (+b). On the other hand, Figure 5 A curve indicating the second duty ratio DR2 corresponding to the linear function shown in formula (2). That is, Figure 5represents a curve of the second duty ratio DR2 corresponding to a linear function having a negative intercept (-b). In contrast to this, Figure 6 represents a curve of the second duty ratio DR2 calculated by the second duty ratio calculation section 35.

[0062] Here, the second duty ratio calculation section 35 sets the slope value a as follows. In addition, the second duty ratio calculation section 35 sets the intercept value b as follows.

[0063] That is, the second duty ratio calculation section 35 acquires the temperature T in the brushless DC motor 100 from the temperature sensor 24. The second duty ratio calculation section 35 calculates a difference value AT of the acquired temperature T with respect to a prescribed reference temperature T_ref. In addition, the second duty ratio calculation section 35 acquires the power supply voltage V in the brushless DC motor 100 from the power supply circuit 21.

[0064] The second duty ratio calculation section 35 calculates K by the following equation (3), and calculates the slope value a by the following equation (4). Here, ke represents a phase induced voltage constant. a represents a temperature coefficient of a magnetic force. β represents a prescribed constant.

[0065] K = ke x (1 + a x AT) (3)

[0066] a = K / (V x β) (4)

[0067] The second duty ratio calculation section 35 calculates R by the following equation (5), and calculates the intercept value b by the following equation (6). Here, r represents a phase resistance. γ represents a temperature coefficient of the resistance. i_lim represents a phase current limit value. δ represents a prescribed constant. The phase current limit value i_lim corresponds to a maximum value allowed for the current value i in each phase.

[0068] R = r x (1 + γ x AT) (5)

[0069] b = R x i_lim / (V x δ) (6)

[0070] Thus, the slope value a is set to different values in accordance with the difference value AT, and is set to different values in accordance with the power supply voltage V. In addition, the slope value a is set to a value corresponding to the phase induced voltage constant ke. Thus, the intercept value b is set to different values in accordance with the difference value AT, and is set to different values in accordance with the power supply voltage V. In addition, the intercept value b is set to a value corresponding to the phase resistance r. In addition, the intercept value b is set to a value corresponding to the phase current limit value i_lim.

[0071] The control signal output section 36 acquires the first duty ratio DR1 calculated by the first duty ratio calculation section 34, and acquires the second duty ratio DR2 calculated by the second duty ratio calculation section 35. The control signal output section 36 compares the absolute value of the acquired first duty ratio DR1 with the absolute value of the acquired second duty ratio DR2. The control signal output section 36 outputs a control signal corresponding to the result of the comparison. The output control signal is input to the corresponding switching element SE. Thus, the control of the drive circuit 22 by the motor control device 200 is realized. As a result, the power supply to each phase is realized (refer to Figure 2 ), and the rotor 5 is driven.

[0072] Here, when the absolute value of the first duty ratio DR1 is smaller than the absolute value of the second duty ratio DR2, the control signal output section 36 outputs a control signal corresponding to the first duty ratio DR1. On the other hand, when the absolute value of the second duty ratio DR2 is smaller than the absolute value of the first duty ratio DR1, the control signal output section 36 outputs a control signal corresponding to the second duty ratio DR2. Thus, as described above, the second duty ratio DR2 corresponds to the upper limit value of the absolute value of the first duty ratio DR1. In other words, the duty ratio (hereinafter referred to as "control duty ratio") DR corresponding to the control signal output by the control signal output section 36 is controlled to a value smaller than the upper limit value.

[0073] More specifically, when the rotor 5 in the forward rotation is driven in the forward direction, the control duty ratio DR becomes a value within the region Al shown in FIG. 8. In addition, when the rotor 5 in the reverse rotation is driven in the reverse direction, the control duty ratio DR becomes a value within the region A2 shown in FIG. 8. In addition, when the rotor 5 in the reverse rotation is driven in the forward direction, the control duty ratio DR becomes a value within the region A3 shown in FIG. 8. In addition, when the rotor 5 in the forward rotation is driven in the reverse direction, the control duty ratio DR becomes a value within the region A4 shown in FIG. 8. Figure 6 Figure 6 Figure 6 Figure 6

[0074] Thus, the main part of the motor control device 200 is configured.

[0075] Hereinafter, the processing performed by the target rotational position acquisition section 31 will be sometimes collectively referred to as "target rotational position acquisition processing". In addition, the processing performed by the rotational position calculation section 32 will be sometimes collectively referred to as "rotational position calculation processing". In addition, the processing performed by the rotational speed calculation section 33 will be sometimes collectively referred to as "rotational speed calculation processing". In addition, the processing performed by the first duty ratio calculation section 34 will be sometimes collectively referred to as "first duty ratio calculation processing". In addition, the processing performed by the second duty ratio calculation section 35 will be sometimes collectively referred to as "second duty ratio calculation processing". In addition, the processing performed by the control signal output section 36 will be sometimes collectively referred to as "control signal output processing".​​​​

[0076] Hereinafter, the functions that the target rotational position acquisition section 31 has are sometimes collectively referred to as "target rotational position acquisition functions". In addition, the functions that the rotational position calculation section 32 has are sometimes collectively referred to as "rotational position calculation functions". In addition, the functions that the rotational speed calculation section 33 has are sometimes collectively referred to as "rotational speed calculation functions". In addition, the functions that the first duty ratio calculation section 34 has are sometimes collectively referred to as "first duty ratio calculation functions". In addition, the functions that the second duty ratio calculation section 35 has are sometimes collectively referred to as "second duty ratio calculation functions". In addition, the functions that the control signal output section 36 has are sometimes collectively referred to as "control signal output functions".

[0077] Hereinafter, the "F1" label is sometimes used for the target rotational position acquisition functions. In addition, the "F2" label is sometimes used for the rotational position calculation functions. In addition, the "F3" label is sometimes used for the rotational speed calculation functions. In addition, the "F4" label is sometimes used for the first duty ratio calculation functions. In addition, the "F5" label is sometimes used for the second duty ratio calculation functions. In addition, the "F6" label is sometimes used for the control signal output functions.

[0078] Next, the hardware structure of the main part of the motor control device 200 will be described with reference to Figures 7-9 to Fig. 6.

[0079] As shown in Fig. 6, the motor control device 200 has a processor 41 and a memory 42. In the memory 42, programs corresponding to the plurality of functions (containing the target rotational position acquisition functions, the rotational position calculation functions, the rotational speed calculation functions, the first duty ratio calculation functions, the second duty ratio calculation functions, and the control signal output functions) F1 to F6 are stored. The processor 41 reads and executes the programs stored in the memory 42. Thereby, the plurality of functions F1 to F6 are realized. Figure 7 Alternatively, as shown in Fig. 7, the motor control device 200 has a processing circuit 43. The processing circuit 43 performs processing corresponding to the plurality of functions F1 to F6. Thereby, the plurality of functions F1 to F6 are realized.

[0080] Figure 8 Alternatively, as shown in Fig. 7, the motor control device 200 has a processing circuit 43. The processing circuit 43 performs processing corresponding to the plurality of functions F1 to F6. Thereby, the plurality of functions F1 to F6 are realized.

[0081] Alternatively, as shown in Fig. 7, the motor control device 200 has a processing circuit 43. The processing circuit 43 performs processing corresponding to the plurality of functions F1 to F6. Thereby, the plurality of functions F1 to F6 are realized. Figure 9

[0082] ​​The processor 41 is constituted by one or more processors. Each processor uses, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), a microprocessor, a microcontroller, or a DSP (Digital Signal Processor).

[0083] The memory 42 is constituted by one or more nonvolatile memories. Alternatively, the memory 42 is constituted by one or more nonvolatile memories and one or more volatile memories. That is, the memory 42 is constituted by one or more memories. Each memory uses, for example, a semiconductor memory or a magnetic disk. More specifically, each volatile memory uses, for example, a RAM (Random Access Memory). In addition, each nonvolatile memory is, for example, a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electricaly Erasable Programmable Read Only Memory), a solid state drive, or a hard disk drive.

[0084] The processing circuit 43 is constituted by one or more digital circuits. Alternatively, the processing circuit 43 is constituted by one or more digital circuits and one or more analog circuits. That is, the processing circuit 43 is constituted by one or more processing circuits. Each processing circuit uses, for example, an ASIC (Application Specific Integrated Circuit), a PLD (Programmabel Logic Device), a FPGA (Field Programmable Gate Array), a SoC (System on a Chip), or a system LSI (Large Scale Integration).

[0085] Here, when the processor 41 is constituted by a plurality of processors, the correspondence relationship between the plurality of functions F1 to F6 and the plurality of processors is arbitrary. That is, each of the plurality of processors can read and execute a program corresponding to one or more functions corresponding to each of the plurality of functions F1 to F6. Alternatively, the processor 41 can include a dedicated processor corresponding to each of the plurality of functions F1 to F6.

[0086] Furthermore, when memory 42 is composed of multiple memories, the correspondence between the multiple functions F1 to F6 and the multiple memories is arbitrary. That is, each of the multiple memories can store a program corresponding to more than one of the corresponding functions F1 to F6. Alternatively, memory 42 can include dedicated memories corresponding to each of the multiple functions F1 to F6.

[0087] Furthermore, when the processing circuit 43 is composed of multiple processing circuits, the correspondence between the multiple functions F1 to F6 and the multiple processing circuits is arbitrary. That is, each of the multiple processing circuits can perform processing corresponding to more than one of the functions F1 to F6. Alternatively, the processing circuit 43 can include a dedicated processing circuit corresponding to each of the multiple functions F1 to F6.

[0088] Next, refer to Figure 10 The flowchart shown illustrates the operation of the motor control device 200. Figure 10 The process shown is repeatedly executed when specified conditions are met (e.g., when the external power supply 300 to the brushless DC motor 100 is in a conducting state).

[0089] First, the target rotation position acquisition unit 31 performs target rotation position acquisition processing (step ST1). Next, the rotation position calculation unit 32 performs rotation position calculation processing (step ST2). Next, the rotation speed calculation unit 33 performs rotation speed calculation processing (step ST3). Next, the first duty cycle calculation unit 34 performs first duty cycle calculation processing (step ST4). Next, the second duty cycle calculation unit 35 performs second duty cycle calculation processing (step ST5). Next, the control signal output unit 36 ​​performs control signal output processing (step ST6).

[0090] Next, refer to Figure 11 The flowchart shown illustrates the operation of the second duty cycle calculation unit 35 and the control signal output unit 36. That is, it explains the processing performed in steps ST5 and ST6.

[0091] First, the second duty cycle calculation unit 35 acquires the temperature T and the power supply voltage V (step ST11). The temperature T is acquired from the temperature sensor 24. The power supply voltage V is acquired from the power supply circuit 21.

[0092] Next, the second duty cycle calculation unit 35 uses the temperature T and power supply voltage V obtained in step ST11 to set the slope value a and the intercept value b (step ST12). At this time, the slope value a is set to the value based on equations (3) and (4). In addition, the intercept value b is set to the value based on equations (5) and (6).

[0093] Next, the second duty ratio operation section 35 determines the positive or negative of the first duty ratio DRl calculated in step ST4 using the positive or negative information output in step ST4 (step ST13). In the case where the first duty ratio DRl is a positive value (step ST13 is "Yes"), the second duty ratio operation section 35 calculates the second duty ratio DR2 according to equation (1) (step ST14). On the other hand, in the case where the first duty ratio DRl is a negative value (step ST13 is "No"), the second duty ratio operation section 35 calculates the second duty ratio DR2 according to equation (2) (step ST15)

[0094] Next, the control signal output section 36 compares the absolute value of the first duty ratio DRl calculated in step ST4 with the absolute value of the second duty ratio DR2 calculated in step ST14 or ST15 (step ST16). When the absolute value of the first duty ratio DRl is smaller than the absolute value of the second duty ratio DR2 (step ST16 is "Yes"), the control signal output section 36 outputs the control signal corresponding to the first duty ratio DRl (step ST17). On the other hand, when the absolute value of the second duty ratio DR2 is smaller than the absolute value of the first duty ratio DRl (step ST16 is "No"), the control signal output section 36 outputs the control signal corresponding to the second duty ratio DR2 (step ST18). The control signal output in step ST17 or ST18 is input to the corresponding switching element SE.

[0095] Next, the effects of the brushless DC motor 100 will be described.

[0096] First, the control duty ratio DR can be a value smaller than a prescribed value (more specifically, an upper limit value corresponding to the second duty ratio DR2). Thus, it is possible to control the current value I (more specifically, the current value i in each phase) in the brushless DC motor 100 to a value smaller than a prescribed value. In addition, by the operation formula in the first duty ratio operation section 34, it is also possible to control the current value I to a maximum value.

[0097] At this time, the first duty ratio operation section 34 calculates the first duty ratio DRl with feedback of the rotational position RP. More specifically, the first duty ratio operation section 34 calculates the first duty ratio DRl using the target rotational position TRP, the rotational position RP, and the rotational speed N. In addition, the second duty ratio operation section 35 calculates the second duty ratio DR2 based on a first order function including a variable corresponding to the rotational speed N. That is, when the current value I is controlled to a value smaller than a prescribed value, feedback of the current value I can not be needed. Thus, compared to the case where feedback of the current value I is used, it is possible to simplify the circuit structure in the brushless DC motor 100.

[0098] In other words, the same control as the control using the feedback of the current value I can be achieved without using the feedback of the current value I. Specifically, for example, the control that changes the applied voltage in the brushless DC motor 100 while making the torque TR and the current value I in the brushless DC motor 100 constant can be achieved. That is, generally, as the rotation speed N becomes larger, the counter electromotive force that hinders the generation of the torque TR gradually becomes larger. In contrast, since the control duty ratio DR can be continuously changed, the above control can be achieved. Figure 12 is a characteristic diagram that shows an example of the torque TR (i.e., the current value I) with respect to the rotation speed N.

[0099] Second, the motor control device 200 is provided on the substrate 16. In other words, the motor control device 200 is integrally configured with the motor main body 400. Thereby, the motor control device 200 does not need to be provided outside the motor main body 400. As a result, the brushless DC motor 100 can be made compact.

[0100] Third, the main magnet 6 is provided on the rotor 5, and the sensor magnet 10 is provided on the rotor 5. In other words, the main magnet 6 and the sensor magnet 10 are integrally configured with the rotor 5. Thereby, the magnetization position of the sensor magnet 10 can be inhibited from deviating from the magnetization position of the main magnet 6. As a result, the rotation position RP calculated by the rotation position calculation section 32 can be inhibited from deviating from the actual rotation position RP.

[0101] Fourth, the slope value a and the intercept value b are respectively set to different values according to the difference value AT of the temperature T with respect to the reference temperature T_ref. In addition, the slope value a and the intercept value b are respectively set to different values according to the power supply voltage V. More specifically, the slope value a is set to a value based on the equations (3) and (4). In addition, the intercept value b is set to a value based on the equations (5) and (6). Thereby, for the variation of the magnetic force and the variation of the resistance caused by the variation of the temperature T and the variation of the power supply voltage V, the slope value a and the intercept value b can be respectively set to appropriate values. In other words, for these variations, each of the regions Al, A2, A3, and A4 can be set within an appropriate range.

[0102] Fifth, according to the positive or negative of the first duty ratio DR1, the brushless DC motor 100 can be driven in the forward direction, of course, and can be driven in the reverse direction. Thereby, the brushless DC motor 100 can be used for various purposes. In other words, the use of the brushless DC motor 100 can be increased.

[0103] Next, a modified example of the brushless DC motor 100 will be described.

[0104] The first duty cycle calculation unit 34 can also output positive and negative information to the control signal output unit 36 ​​instead of outputting positive and negative information to the second duty cycle calculation unit 35.

[0105] In this case, the second duty cycle calculation unit 35 calculates the second duty cycle DR2 based on equation (1), and also calculates the second duty cycle DR2 based on equation (2). That is, the second duty cycle calculation unit 35 calculates the second duty cycle DR2 with each timing (t) n The two second duty cycles DR2 corresponding to the first duty cycle DR1 are calculated. The second duty cycle calculation unit 35 outputs the two calculated second duty cycles DR2 to the control signal output unit 36. The control signal output unit 36 ​​uses positive and negative information to select one of the two calculated second duty cycles DR2 that corresponds to the positive and negative of the first duty cycle DR1.

[0106] The control signal output unit 36 ​​compares the absolute value of the selected second duty cycle DR2 with the absolute value of the first duty cycle DR1. When the absolute value of the selected second duty cycle DR2 is smaller than the absolute value of the first duty cycle DR1, the control signal output unit 36 ​​outputs a control signal corresponding to the selected second duty cycle DR2.

[0107] Next, other variations of the brushless DC motor 100 will be described.

[0108] Moving averages may also be used in at least one of the following operations: the rotational position RP calculation in the rotational position calculation unit 32, the rotational speed N calculation in the rotational speed calculation unit 33, the first duty cycle DR1 calculation in the first duty cycle calculation unit 34, the acquisition of temperature T in the second duty cycle calculation unit 35, the acquisition of power supply voltage V in the second duty cycle calculation unit 35, and the calculation of second duty cycle DR2 in the second duty cycle calculation unit 35.

[0109] That is, the rotation position calculation unit 32 can also be used for M consecutive timings (t1 to t2). M For the M rotational positions RP_1 to RP_M corresponding to the given position, calculate the moving average of the M rotational positions RP_1 to RP_M. In this case, the above moving average can also be used to calculate the rotational speed N. In addition, the above moving average can also be used to calculate the first duty cycle DR1. Here, M is an integer greater than or equal to 2.

[0110] In addition, the speed calculation unit 33 can also be used for M consecutive timings (t1 to t2). M For the M rotational speeds N_1 to N_M corresponding to the given values, calculate the moving average of the M rotational speeds N_1 to N_M. In this case, the above moving average can also be used to calculate the first duty cycle DR1. In addition, the above moving average can also be used to calculate the second duty cycle DR2.

[0111] In addition, the first duty cycle calculation unit 34 can also be used for M consecutive timing cycles (t1 to t2). M For each of the M first duty cycles DR1_1 to DR1_M, calculate the moving average of the M first duty cycles DR1_1 to DR1_M. In this case, the first duty cycle calculation unit 34 can also replace the calculation of the moving average of the M first duty cycles DR1_1 to DR1_M. n The first duty cycle DR1 corresponding to the above is output to the control signal output unit 36, and the moving average value is output to the control signal output unit 36.

[0112] In addition, the second duty cycle calculation unit 35 can also be used for M consecutive timing cycles (t1 to t2). M For the M temperatures T_1 to T_M corresponding to the given conditions, calculate the moving average of the M temperatures T_1 to T_M. In this case, the moving average can also be used to set the slope value a. Additionally, the moving average can also be used to set the intercept value b.

[0113] In addition, the second duty cycle calculation unit 35 can also be used for M consecutive timing cycles (t1 to t2). M Given M power supply voltages V_1 to V_M, calculate the moving average of these M voltages. In this case, the moving average can also be used to set the slope value a. Furthermore, the moving average can also be used to set the intercept value b.

[0114] In addition, the second duty cycle calculation unit 35 can also be used for M consecutive timing cycles (t1 to t2). M The second duty cycle calculation unit 35 can also calculate the moving average of the M second duty cycles DR2_1 to DR2_M corresponding to each timing (t). n The second duty cycle DR2 corresponding to the above is output to the control signal output unit 36, and the above moving average value is output to the control signal output unit 36.

[0115] Alternatively, the control signal output unit 36 ​​can also be configured for M consecutive timing signals (t1 to t2). M The control signal output unit 36 ​​can also output a control signal corresponding to the above-mentioned moving average value for the M control duty cycles DR_1 to DR_M.

[0116] By using these moving averages, the following effect can be obtained. That is, for the detection values ​​of each sensor (including the rotary position sensor 23 and the temperature sensor 24), sometimes the values ​​are correlated with M consecutive time intervals (t1~t2). MAn error occurs in at least one of the M corresponding detection values. In this case, the influence of the aforementioned error can be reduced. As a result, the operating quantity θ corresponding to the control signal output by the control signal output unit 36 ​​can be stabilized.

[0117] On the other hand, by not using these moving averages, the computational load in the motor control device 200 can be reduced. In other words, by reducing the number of parts in the motor control device 200 that calculate moving averages, the computational load in the motor control device 200 can be reduced. In particular, for parameters with a low probability of error occurrence, it is preferable not to use moving averages.

[0118] Next, other variations of the brushless DC motor 100 will be described.

[0119] As described above, the number of magnetic poles in the sensor magnet 10 can be set to the same value as the number of excitation poles in the brushless DC motor 100. Alternatively, the number of magnetic poles in the sensor magnet 10 can be set to an integer multiple of the number of excitation poles in the brushless DC motor 100.

[0120] Specifically, for example, the number of magnetic poles of the sensor magnet 10 can also be set to twice the number of excitations of the brushless DC motor 100. Figure 13 This is an example of timing when the power supply state of each phase is in the on state under this condition. Additionally, Figure 13 This represents an example of the pulse signal PS output by each magnetic sensor MS in this case.

[0121] Therefore, with Figure 2 Compared to the example shown, the period of the pulse signal PS output by each magnetic sensor MS can be made 1 / 2. As a result, the control resolution of the drive circuit 22 controlled by the motor control device 200 can be increased by two times.

[0122] Next, a specific example of the application of the brushless DC motor 100 will be explained.

[0123] like Figure 14 As shown, the brushless DC motor 100 can also be used in the actuator 600. The actuator 600 includes the brushless DC motor 100 and the actuator output section 700. The actuator output section 700 includes, for example, an output shaft that is mechanically connected to the shaft 9 of the rotor 5.

[0124] The actuator 600 is used, for example, for controlling the opening of an EGR valve, an exhaust valve, or a throttle valve. In this case, the output shaft of the actuator output unit 700 is mechanically connected to the valve body of the aforementioned valve. The opening of the aforementioned valve changes as the rotor 5 rotates. On the other hand, the opening of the aforementioned valve is maintained by maintaining the rotational position RP of the rotor 5.

[0125] Here, the actuator output unit 700 may also include a component (e.g., a spring) that generates a so-called "return torque". In this case, the opening degree of the valve can be controlled by balancing the return torque generated by the aforementioned component with the torque TR generated by the brushless DC motor 100. Specifically, for example, the opening degree of the valve can also be controlled by balancing the torque TR in the opening direction of the valve body with the return torque in the closing direction of the valve body.

[0126] Next, a specific example of the use of actuator 600 will be explained.

[0127] like Figure 15 As shown, the actuator 600 can also be used in the EGR valve assembly 800. The EGR valve assembly 800 includes the actuator 600 and the EGR valve 900. The output shaft of the actuator output unit 700 is mechanically connected to the valve body of the EGR valve 900. The opening degree of the EGR valve 900 changes as the rotor 5 rotates. On the other hand, the opening degree of the EGR valve 900 is maintained by maintaining the rotational position RP of the rotor 5. That is, the opening degree of the EGR valve 900 is controlled by the actuator 600.

[0128] As described above, the motor control device 200 according to Embodiment 1 includes: a target rotation position acquisition unit 31 for acquiring a target rotation position TRP of the rotor 5 in the motor body 400; a rotation position calculation unit 32 for calculating the rotation position RP of the rotor 5 using a pulse signal PS output by a rotation position sensor 23 of the motor body 400; a speed calculation unit 33 for calculating the rotational speed N of the rotor 5 based on the rotational position RP; and a first duty cycle calculation unit 34 for calculating the speed N of the motor body 400 based on the target rotation position TRP and the rotational position RP. The system includes a first duty cycle DR1; a second duty cycle calculation unit 35, which calculates a second duty cycle DR2 corresponding to the upper limit of the absolute value of the first duty cycle DR1 based on a linear function containing a variable corresponding to the rotational speed N; and a control signal output unit 36, which outputs a control signal corresponding to the first duty cycle DR1 when the absolute value of the first duty cycle DR1 is smaller than the absolute value of the second duty cycle DR2, and outputs a control signal corresponding to the second duty cycle DR2 when the absolute value of the second duty cycle DR2 is smaller than the absolute value of the first duty cycle DR1. Therefore, when controlling the current value I in the motor (e.g., the brushless DC motor 100) to a value less than a predetermined value, feedback of the current value I is not required. As a result, the circuit structure of the motor can be simplified. Furthermore, the control duty cycle DR can be continuously changed.

[0129] Further, the slope value a in the linear function is set to different values in accordance with a difference value ΔT of the temperature T in the motor main body 400 from a reference temperature T_ref, and the intercept value b in the linear function is set to different values in accordance with the difference value ΔT. Thus, for a variation in the temperature T, the slope value a and the intercept value b can be set to appropriate values, respectively.

[0130] Further, the slope value a in the linear function is set to different values in accordance with the power supply voltage V in the motor main body 400, and the intercept value b in the linear function is set to different values in accordance with the power supply voltage V. Thus, for a variation in the power supply voltage V, the slope value a and the intercept value b can be set to appropriate values, respectively.

[0131] Further, the slope value a in the linear function is set to a value corresponding to the phase inductance constant ke in the motor main body 400. Thus, in accordance with the phase inductance constant ke, the slope value a can be set to an appropriate value.

[0132] Further, the intercept value b in the linear function is set to a value corresponding to the phase current limit value i_lim in the motor main body 400. Thus, in accordance with the phase current limit value i_lim, the intercept value b can be set to an appropriate value. As a result, generation of an overcurrent can be avoided.

[0133] Further, a moving average is used in the operation of the first duty ratio DR1. Thus, the operation amount θ can be stabilized.

[0134] Further, a moving average is used in the operation of the second duty ratio DR2. Thus, the operation amount θ can be stabilized.

[0135] Further, the motor control device 200 is integrally constituted with the motor main body 400. Thus, the motor (e.g., the brushless DC motor 100) can be made compact.

[0136] Further, the positive and negative of the first duty ratio DR1 is set in accordance with the driving direction of the rotor 5, and the positive and negative of the intercept value b in the linear function is set in accordance with the positive and negative of the first duty ratio DR1. Thus, not only the rotor 5 can be driven in the forward direction, but also the rotor 5 can be driven in the reverse direction. As a result, the use of the motor (e.g., the brushless DC motor 100) can be increased.

[0137] Further, the brushless DC motor 100 according to Embodiment 1 includes the motor control device 200 and the motor main body 400. Thus, the brushless DC motor 100 using the motor control device 200 can be realized.

[0138] Further, the rotation position sensor 23 uses the magnetic sensor MS, and a magnet (sensor magnet 10) is used in the generation of the pulse signal PS in the motor body portion 400, and the number of magnetic poles in the magnet (sensor magnet 10) is set to the same value as the number of excitations in the motor body portion 400. Thus, the pulse signal PS corresponding to each phase can be generated.

[0139] Further, the rotation position sensor 23 uses the magnetic sensor MS, and a magnet (sensor magnet 10) is used in the generation of the pulse signal PS in the motor body portion 400, and the number of magnetic poles in the magnet (sensor magnet 10) is set to the same value as the number of excitations in the motor body portion 400. Thus, the pulse signal PS corresponding to each phase can be generated.

[0140] Further, the actuator 600 according to Embodiment 1 includes the brushless DC motor 100. Thus, the actuator 600 using the brushless DC motor 100 can be implemented.

[0141] Further, the actuator 600 is used for the opening degree control of the EGR valve 900, the opening degree control of the wastegate valve, or the opening degree control of the throttle valve. Thus, the actuator 600 can be used for the opening degree control of the valve for vehicle.

[0142] Further, the EGR valve device 800 according to Embodiment 1 includes the actuator 600 and the EGR valve 900, and the opening degree of the EGR valve 900 is controlled by the actuator 600. Thus, the EGR valve device 800 using the actuator 600 can be implemented.

[0143] Further, any structural element of the embodiments can be modified within the scope of the disclosure, or any structural element can be omitted in the embodiments.

[0144] Industrial Applicability

[0145] The motor control device according to the disclosure can be used for a brushless DC motor, for example. The brushless DC motor according to the disclosure can be used for an actuator, for example. The actuator according to the disclosure can be used for an EGR valve device, for example. The EGR valve device according to the disclosure can be used for an automobile, for example.

[0146] Explanation of Reference Signs

[0147] 1 stator, 2 stator core, 3 insulator, 4 coil, 5 rotor, 6 main magnet, 7 rotor core, 8 resin molding portion, 9 shaft, 10 sensor magnet, 11 bearing, 12 bearing, 13 housing, 14 cover plate, 15 housing portion, 16 substrate, 21 power supply circuit, 22 drive circuit, 23 rotation position sensor, 24 temperature sensor, 31 target rotation position acquisition portion, 32 rotation position calculation portion, 33 rotation speed calculation portion, 34 first duty ratio calculation portion, 35 second duty ratio calculation portion, 36 control signal output portion, 41 processor, 42 memory, 43 processing circuit, 100 brushless DC motor, 200 motor control device, 300 external power supply, 400 motor main body portion, 500 external control device, 600 actuator, 700 actuator output portion, 800 EGR valve device, 900 EGR valve

Claims

1. A motor control device, characterized in that, include: A target rotation position acquisition unit acquires the target rotation position of the rotor in the motor body. The rotational position calculation unit calculates the rotational position of the rotor using pulse signals output from the rotational position sensor of the motor body. A rotational speed calculation unit calculates the rotational speed of the rotor based on the rotational position; A first duty cycle calculation unit calculates a first duty cycle for controlling the main body of the motor based on the target rotation position and the rotation position. The second duty cycle calculation unit calculates a second duty cycle corresponding to the upper limit value of the absolute value of the first duty cycle based on a first linear function containing a variable corresponding to the rotational speed. as well as The control signal output unit outputs a control signal corresponding to the first duty cycle when the absolute value of the first duty cycle is smaller than the absolute value of the second duty cycle, and outputs a control signal corresponding to the second duty cycle when the absolute value of the second duty cycle is smaller than the absolute value of the first duty cycle. The slope value of the first linear function is calculated based on a second linear function with the difference between the temperature around the substrate of the motor body and the reference temperature as the variable. When the difference increases, the slope value increases, and when the difference decreases, the slope value decreases.

2. The motor control device as described in claim 1, characterized in that, The intercept value of the first linear function is calculated based on a third linear function with the difference value as the variable. When the difference value increases, the intercept value increases; when the difference value decreases, the intercept value decreases.

3. The motor control device as described in claim 1, characterized in that, The slope of the first linear function is set to a different value depending on the power supply voltage of the motor body. The intercept value of the first linear function is set to a different value according to the power supply voltage.

4. The motor control device as described in claim 1, characterized in that, The slope of the first linear function is set to a value corresponding to the phase induced voltage constant in the main body of the motor.

5. The motor control device as described in claim 2, characterized in that, The intercept value of the first linear function is set to a value corresponding to the phase current limit value in the main body of the motor.

6. The motor control device as described in claim 1, characterized in that, A moving average is used in the calculation of the first duty cycle.

7. The motor control device as described in claim 1, characterized in that, The moving average is used in the calculation of the second duty cycle.

8. The motor control device as described in claim 1, characterized in that, It is integrally formed with the main body of the motor.

9. The motor control device as described in claim 1, characterized in that, The sign of the first duty cycle is set according to the driving direction of the rotor. The sign of the intercept value of the first linear function is set according to the sign of the first duty cycle.

10. A brushless DC motor, characterized in that, include: The motor control device as described in claim 1; and The main body of the electric motor.

11. The brushless DC motor as described in claim 10, characterized in that, The rotational position sensor uses a magnetic sensor. A magnet is used in the generation of the pulse signal in the main body of the electric motor. The number of magnetic poles of the magnet is set to the same value as the number of excitation poles of the main body of the motor.

12. The brushless DC motor as described in claim 10, characterized in that, The rotational position sensor uses a magnetic sensor. A magnet is used in the generation of the pulse signal in the main body of the electric motor. The number of magnetic poles of the magnet is set to an integer multiple of the number of excitations of the main body of the motor.

13. An actuator, characterized in that, Including the brushless DC motor as described in claim 10.

14. The actuator as claimed in claim 13, characterized in that, Used for controlling the opening of EGR valves, exhaust valves, or throttle valves.

15. An EGR valve device, characterized in that, include: The actuator as described in claim 13; as well as EGR valve, The opening degree of the EGR valve is controlled by the actuator.

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