Driver

Abstract

To suitably control superimposed power when power to be supplied to an external device is superimposed on driving power for driving a motor in order to supply power to the external device.SOLUTION: A driver that supplies driving power to a motor having an extraction unit that extracts a part of power supplied from outside and a supply unit that supplies power extracted by the extraction unit to an external device, or to a motor power line in which the extraction unit and the supply unit are provided, comprises: a first control unit having a first feedback system and configured to be capable of feedback control of a driving current related to driving of the motor out of a current supplied to the motor; a second control unit having a second feedback system and configured to be capable of feedback control for generating an additional current that corresponds to power to be supplied to an external device, out of the current supplied to the motor; and an output unit that superimposes the additional current on the driving current and outputs it.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a driver.

Background Art

[0002] For a motor that drives a load for various purposes, it is necessary to grasp the state of the motor in order to accurately execute its control. Generally, a detection device such as an encoder is used. In order to drive the encoder, power must be supplied. Generally, a servo system (for example, a driver) and an encoder are connected by a cable, and power supply may be performed via the cable. As another method, Patent Document 1 discloses a configuration in which power is wirelessly supplied from the outside to an encoder that performs wireless communication with the servo system side.

[0003] Also, Patent Document 2 discloses a configuration in which power required for driving an external device such as an encoder is superimposed on the driving power of the motor and supplied to the motor at once, and then a part of the supplied power is extracted by the motor to supply power to the external device. In this technology, the supply power for the external device is superimposed by adjusting the d-axis current value in the driving current of the motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although the power consumed by the encoder attached to the motor is small compared to the power consumption of the motor, since it is necessary to constantly monitor the state of the driven motor, a stable power supply is required. It is common to supply power by connecting the encoder and the motor driver with a wired cable. In that case, in addition to the power line of the motor, it is necessary to wire the cable related to the encoder, which may increase the wiring work load and the cost due to the cable.

[0006] Also, in the form of power supply to an external device such as an encoder, as disclosed in the prior art, when the supply power to the external device is superimposed on the drive power for motor drive, in order to stably maintain the power supply to the external device, it is desired to preferably control the superimposed power. However, when the control for motor drive and the control for power supply to the external device are executed by a common feedback control block, the control of the superimposed power suitable for each control is not necessarily preferably performed.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide a technique for preferably controlling the superimposed power when the supply power to the external device is superimposed on the drive power for motor drive for power supply to the external device.

Means for Solving the Problems

[0008] The driver disclosed in the present application includes an extraction unit that extracts a part of the power supplied from the outside, and a supply unit that supplies the power extracted by the extraction unit to an external device, and is configured to supply power to a motor or to a motor power line provided with the extraction unit and the supply unit. Then, the driver receives an input of a feedback signal related to the operation of the motor It has a first feedback system including one or more first controllers, and a first control unit configured to be able to feedback-control a drive current related to driving of the motor among the supply currents to the motor. It has a second feedback system including one or more second controllers into which at least a part of the feedback signal is input and formed differently from the first feedback system, and a second control unit configured to be able to perform feedback control for generating an additional current corresponding to the power supplied to the external device among the supply currents to the motor. An output unit that superimposes the additional current generated via the second control unit on the drive current generated via the first control unit and outputs supply power to the motor.

[0009] The motor may be a single-phase AC motor or a three-phase AC motor. Also, the connection mode of the coils in the winding part of the motor may be a so-called delta connection or a star connection (or Y connection). Also, regarding the winding method of the coils of the winding part with respect to the stator of the motor, it may be a distributed winding or a concentrated winding. That is, in the motor of the present invention, there is no particular intention to limit the specific formation of the winding part.

[0010] And as long as the extraction unit is arranged so that power can be extracted from the winding part of the motor or the power line connecting the motor and the driver, the specific form and configuration of the extraction unit are not limited to a specific mode. For example, the extraction unit may be arranged so that a transformer structure is formed in which a part of the power supplied to the winding part of the motor or the power line is input to its primary coil, and configured to extract a part of the power through the transformer structure. The transformer structure may be either a single-winding transformer or a multi-winding transformer. In the case of a single-winding transformer, the secondary coil refers to a coil that shares a part of the primary coil between the two.

[0011] Then, from the secondary coil of the transformer structure, an alternating current corresponding to the alternating current flowing through the primary coil and the turns ratio of the transformer structure (the ratio of the number of turns of the secondary coil to the number of turns of the primary coil) is extracted. Then, the supply unit rectifies the extracted alternating current and supplies it to an external device. Note that the supply unit may, if necessary, transform the rectified voltage into a voltage suitable for driving the external device. Also, the supply unit can supply more stable power to the external device by storing the rectified power in a secondary battery.

[0012] Here, in order to supply power to the external device, an additional current for power supply to the external device, generated via the second control unit, is superimposed on the drive current for motor drive, generated via the first control unit by the output unit, and power is output from the driver to the motor. The first control unit has a first feedback system for generating a drive current related to motor drive, and includes one or more first controllers. The first controller is a controller corresponding to the drive control of the motor, and proportional gains, integral gains, etc. of position, speed, etc. are appropriately set according to the purpose of the drive control. On the other hand, the second control unit has a second feedback system for generating an additional current corresponding to the power supplied to the external device, and includes one or more second controllers. The second controller is a controller corresponding to the generation of the additional current.

[0013] The first feedback system of the first control unit and the second feedback system of the second control unit are configured to enable independent feedback control from each other. Therefore, basically, the generation of the drive current of the motor and the generation of the additional current do not affect each other, and appropriate feedback control is performed for each. Since the motor and the external device are devices that perform different operations, and naturally there are also differences in the power that should be supplied, by the driver having the first control unit and the second control unit having different feedback systems as disclosed in the present application, when superimposing the power supplied to the external device on the drive power of the motor for power supply to the external device, it becomes possible to suitably control the superimposed power.

[0014] Here, in the above driver, the first feedback system of the first control unit further has a low-pass filter having a first cut-off frequency set based on the rotational speed of the motor, and the second feedback system of the second control unit may further have a high-pass filter having a second cut-off frequency set in relation to the power extraction by the extraction unit. In the feedback control of motor drive, a signal having a frequency corresponding to the rotational speed (number of revolutions) of the motor flows. Since there is generally a physical upper limit value in the rotational speed of the motor, there is also an upper limit value in the frequency of the signal flowing through the first feedback system. In other words, a signal having a frequency exceeding the said frequency may be a signal (for example, noise) not related to motor drive. Therefore, it is preferable to provide a low-pass filter in the first feedback system. The first cut-off frequency of the low-pass filter is set in consideration of the upper limit value of the rotational speed of the above motor.

[0015] Also, in the feedback control regarding the additional current for power supply to an external device, a current having a frequency taking into account the power extraction by the extraction unit flows. In particular, when the extraction unit adopts an extraction form such as a transformer structure as described above, it is possible to efficiently extract power on the secondary side by flowing a current having a relatively high frequency to the primary side of the extraction unit. That is, in order to efficiently perform the power extraction by the extraction unit, it is preferable that a current having a certain degree of high frequency flows through the second feedback system, and thus it is preferable to provide a high-pass filter in the second feedback system. The second cut-off frequency of the high-pass filter is set in consideration of the efficiency of the power extraction by the above extraction unit.

[0016] Here, in the driver up to the above, the first control unit may be configured to enable feedback control related to the q-axis current and the d-axis current for driving the motor. In that case, the second control unit is configured to enable feedback control related to the d-axis current as the additional current for power supply to the external device, and the output unit superimposes the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor derived by the first control unit, and may output the power supplied to the motor. The q-axis current and the d-axis current are, respectively, a current component that generates torque and a current component that changes the magnetic flux in the rotor in the vector control of the motor. In this way, in the second feedback system of the second control unit, by using the d-axis current as the additional current and the d-axis current as the additional current, it is possible to preferably execute power supply to the external device while suppressing the influence on the operation of the motor as much as possible.

[0017] Here, in the above driver, the d-axis current as the additional current may include an element whose current value fluctuates with the passage of time. As the transition in which the current value fluctuates with the passage of time, a transition in a sine wave shape, a transition in a rectangular wave shape, a transition in a triangular wave shape, etc. can be adopted. Further, the frequency of the fluctuating element included in the d-axis current as the additional current may be a value higher than the frequency corresponding to the maximum rotational speed of the motor.

[0018] Here, in the above driver, the second control unit may be further configured to enable feedback control related to the q-axis current as the additional current for power supply to the external device. That is, the second control unit may be configured to enable feedback control related to the d-axis current and the q-axis current as the additional current for power supply to the external device. In this case, the output unit may superimpose the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor derived by the first control unit, and superimpose the q-axis current as the additional current derived by the second control unit on the q-axis current for driving the motor derived by the first control unit, and output the power supplied to the motor. By using the d-axis current and the q-axis current as the additional current in this way, the power supply capacity to the external device can be enhanced.

[0019] Also in the above-described form, the d-axis current and / or the q-axis current as the additional current may include elements whose current values vary with the passage of time. As the transition in which the current value varies with the passage of time, a transition in a sine wave shape, a rectangular wave shape, a triangular wave shape, etc. can be adopted. Further, the frequency of the varying element included in the d-axis current and / or the q-axis current as the additional current may be a value higher than the frequency corresponding to the maximum rotational speed of the motor.

[0020] Here, another form of the feedback control in the second control unit will be mentioned. That is, the first control unit is configured to enable feedback control related to the q-axis current and the d-axis current for driving the motor, and the second control unit may be configured to enable feedback control related to the q-axis current as the additional current for power supply to the external device. In this form, feedback control related to the d-axis current as the additional current is not performed. By using the q-axis current as the additional current in this way, power supply to the external device can also be suitably executed.

[0021] Also in the above-described embodiment, the q-axis current as the additional current may include an element in which the current value varies over time. As the transition in which the current value varies over time, a transition having a sine wave shape, a rectangular wave shape, a triangular wave shape, or the like can be adopted. Further, the frequency of the varying element included in the q-axis current as the additional current may be a value higher than the frequency corresponding to the maximum rotational speed of the motor.

Advantages of the Invention

[0022] When superimposing the power supplied to an external device on the driving power for driving a motor for power supply to the external device, the superimposed power can be suitably controlled.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] <First Embodiment> FIG. 1 is a diagram showing a schematic configuration of a control system for controlling the drive of a motor. First, the control system will be described. The control system is a PLC (Programmable Logic Controller) 5 is connected to network 1 as a host controller. A plurality of servo drivers (hereinafter referred to as "drivers") 4 are connected to the network 1 so as to be able to exchange signals with the PLC 5. In FIG. 1, the functional configuration of one driver 4 is described in detail as a representative, but the other drivers 4a and 4b also have the same functional configuration as the driver 4. Further, the motor 2 is connected to the driver 4 by a power line 11 and receives supply of driving power. Similarly, the motors 2a and 2b receive supply of driving power from the drivers 4a and 4b via power lines 11a and 11b, respectively. Hereinafter, the structures of the motor and the driver will be described based on the motor 2 and the driver 4 as representatives.

[0025] Here, the motor 2 is driven and controlled according to commands from the PLC 5 in order to drive a predetermined load device. As an example, various mechanical devices (for example, the arm of an industrial robot or a conveying device) can be exemplified as the load device, and the motor 2 is incorporated in the device as an actuator that drives the load device. Further, the motor 2 is an AC servo motor. As an alternative, the motor 2 may be an induction motor or a DC motor. The motor 2 includes a stator having a winding portion formed by winding a coil around a stator core, and a rotor incorporated with a permanent magnet, and an encoder 22 having a detection disk that rotates in conjunction with the rotation of the rotor and capable of detecting the rotation state of the rotor. The rotation detection by the encoder 22 may be in an incremental method or an absolute method.

[0026] The detection signal by the encoder 22 is wirelessly transmitted to the driver 4 via a communication unit 42 included in the driver 4 described later. The transmitted detection signal is used for servo control in a control unit 41 included in the driver 4 also described later. The detection signal by the encoder 22 includes, for example, position information about the rotation position (angle) of the rotation axis of the motor 2, information about the rotation speed of the rotation axis, and the like.

[0027] Here, the driver 4 includes a control unit 41, a communication unit 42, and a power conversion unit 43. The control unit 41 is a functional unit that controls servo of the motor 2 based on commands from the PLC 5. The control unit 41 receives an operation command signal regarding the operation (motion) of the motor 2 and a detection signal output from the encoder 22 from the PLC 5 via the network 1, and calculates a servo control regarding the driving of the motor 2, that is, a command value regarding the operation of the motor 2. The control unit 41 executes feedback control using a position controller, a speed controller, a current controller, and the like. Further, the control unit 41 is configured to control other controls than the servo control of the motor 2 performed by the driver 4.

[0028] The communication unit 42 is a functional unit that controls wireless communication between the encoder 22 and the driver 4. When starting wireless communication, the communication unit 42 of the driver 4 identifies the encoder that is the communication target of itself, and thereby specifies that the encoder 22 is the target of wireless communication. Therefore, the communication unit 42 does not perform wireless communication in a mixed-wire state with the encoder of the motor 2a or the encoder of the motor 2b. Similarly, the encoder of the motor 2a and the encoder of the motor 2b each perform wireless communication only with the drivers 4a and 4b. The power conversion unit 43 supplies driving power to the motor 2 via the power line 11 based on the command value regarding the operation of the motor 2 calculated by the control unit 41. Note that for the generation of this supplied power, the AC power sent from the AC power supply 7 to the driver 4 is used. In this embodiment, the driver 4 is of a type that receives three-phase AC, but it may also be of a type that receives single-phase AC. As an alternative method, the driver 4 may be of a type that receives DC.

[0029] Next, the schematic configuration of the motor 2 will be described with reference to FIG. 2. The motor 2 is a three-phase (U-phase, V-phase, W-phase) AC motor and includes a motor body 21 and an encoder 22. The motor body 21 includes a rotor 212 and a stator 213. A permanent magnet is incorporated in the rotor 212 and is rotatably supported. In the stator 213, a coil is wound around a stator core formed of electromagnetic steel sheets, and a winding portion 25 is formed. In this embodiment, the connection mode of each phase in the winding portion 25 is a Y connection, but it may be a delta connection instead. Also, in this embodiment, the winding method of the coil around the stator core may be either a distributed winding or a concentrated winding. The configuration shown in FIG. 2 is only schematic, and the technical idea of the present invention can be applied regardless of the specific configuration of the motor.

[0030] The power line 11 for supplying driving power from the driver 4 is connected to the connector 211. The connector 211 is connected to each phase of the winding portion 25. In the motor 2, a transformer structure (see 53, 63, 73 shown in FIG. 3. Details will be described later.) is arranged with respect to the winding portion 25, and an extraction unit 214 is provided that extracts a part of the driving power supplied to the coil of the winding portion 25 as the power for the encoder by using the transformer structure. That is, the extraction unit 214 extracts a current that can be used as the driving current of the encoder 22 on the secondary coil side by flowing the alternating current flowing through the winding portion 25 of the motor body 21 to the primary coil side of the transformer structure.

[0031] The extraction unit 214 extracts the power from the alternating current output from the secondary coil of the transformer structure as the power for the encoder 22. Therefore, it is rectified by the supply unit 215 and stepped up or down to a DC voltage suitable for driving the encoder 22 by the DC-DC converter provided in the supply unit 215 as necessary. The supply unit 215 is electrically connected to the encoder 22 so that DC power can be supplied to the encoder 22 side, particularly to the processing unit 221 that performs the rotation detection process of the rotor 212, in a state where the encoder 22 is attached to the motor body 21. Further, the supply unit 215 may have a secondary battery that can store the rectified DC power. In that case, power can be supplied to the encoder 22 even during a period when no driving current flows through the winding portion 25 or during a period when the driving current is extremely low.

[0032] Also, in the motor 2 of the present embodiment, by utilizing the extraction process by the extraction unit 214, it is configured such that a predetermined signal can be exchanged between the winding part 25 of the motor body 21 and the processing part 221 of the encoder 22. The exchange of the predetermined signal is realized by the signal exchange unit 216 using the above transformer structure. When sending a predetermined signal from the winding part 25 to the processing part 221, a current with the predetermined signal superimposed on the coil of the winding part 25 is passed, and as the current flows through the primary coil side of the transformer structure, the extraction unit 214 can generate a current corresponding to the predetermined signal on the secondary coil side of the transformer structure. Then, the signal exchange unit 216 passes this extracted corresponding current to the processing part 221. In this case, in order to accurately transmit the information carried by the predetermined signal, the signal exchange unit 216 does not perform rectification processing on the corresponding current extracted by the extraction unit 214. On the other hand, when the extracted corresponding current is weak, the signal exchange unit 216 may perform a predetermined amplification process.

[0033] Also, when sending a predetermined signal from the processing part 221 to the winding part 25, by passing a current including the predetermined signal through the secondary coil side of the transformer structure via the signal exchange unit 216, the extraction unit 214 generates a current corresponding to the predetermined signal on the primary coil side of the transformer structure and can pass it through the coil of the winding part 25. In this case as well, the signal exchange unit 216 may perform a predetermined amplification process on the predetermined signal. Since the coil of the winding part 25 is electrically connected to the driver 4 via the power line 11, a predetermined signal can be transmitted from the encoder 22 to the driver 4 via the current corresponding to the predetermined signal issued from the processing part 221. As described above, although wireless communication via the communication part 42 is configured to be possible between the encoder 22 and the driver 4, the exchange of the predetermined signal via the signal exchange unit 216 is a useful communication form under certain conditions such as the state before the wireless communication becomes possible.

[0034] Next, the winding portion 25 of the motor body 21 and the arrangement of the transformer structure provided for the winding portion 25 will be described with reference to FIG. 3. The winding portion 25 includes three-phase winding portions L5, L6, and L7 of the U-phase, V-phase, and W-phase. The connection mode of the winding portion of each phase is a Y-connection, and the junction of each winding portion is the neutral point. For the U-phase winding portion L5, in FIG. 3, its inductance component is indicated by 51 and its resistance component is indicated by 52. Similarly, for the V-phase winding portion L6, its inductance component is indicated by 61 and its resistance component is indicated by 62. Further, for the W-phase winding portion L7, its inductance component is indicated by 71 and its resistance component is indicated by 72.

[0035] And a transformer structure forming the extraction unit 214 is arranged in each phase. Specifically, in the U-phase, the primary coil 531 of the U-phase transformer structure 53 is connected in series to the winding portion L5. In the V-phase, the primary coil 631 of the V-phase transformer structure 63 is connected in series to the winding portion L6. In the W-phase, the primary coil 731 of the W-phase transformer structure 73 is connected in series to the winding portion L7. Then, the secondary coil 532 of the U-phase transformer structure 53, the secondary coil 632 of the V-phase transformer structure 63, and the secondary coil 732 of the W-phase transformer structure 73 are connected to the supply unit 215. Further, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange unit 216.

[0036] Note that the turns ratio of the transformer structure for each phase (the ratio of the number of turns of the secondary coil to the number of turns of the primary coil) is basically the same, but it may also be different. Further, in the form shown in FIG. 3, the transformer structure is arranged in all three phases, and the secondary coils thereof are connected to the supply unit 215 and the signal exchange unit 216. However, the transformer structure may be arranged in only some of the three phases, and the secondary coils thereof may be connected to the supply unit 215 and the signal exchange unit 216. As an alternative, the transformer structure may be arranged in all three phases, the secondary coils of some of the transformer structures may be connected to the supply unit 215, and the secondary coils of the remaining transformer structures may be connected to the signal exchange unit 216. In this case, the turns ratio of the transformer structure connected to the supply unit 215 and responsible for supplying power to the encoder 22 and the turns ratio of the transformer structure connected to the signal exchange unit 216 and responsible for exchanging a predetermined signal with the encoder 22 may be appropriately set according to their respective purposes. For example, the two may be different.

[0037] By adopting the winding portion 25 and the transformer structures 53, 63, and 73 configured as described above, a part of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction unit 214 as the driving power of the encoder 22. According to this configuration, when the motor 2 is driving, the power of the encoder 22 is always stably supplied. Further, for this reason, a cable for wiring to the encoder 22 is not required, so that the cable wiring work is greatly reduced and the cost thereof can be suppressed.

[0038] Here, the circuit equation of the motor 2 when a single-phase transformer is adopted as the transformer structure in the motor 2 of the form shown in FIG. 3 is considered. The characteristics of the transformer structure for each phase are the same. In the mathematical expressions shown below, the voltages Vu, Vv, Vw, the currents Iu, Iv, Iw represent the output voltages and currents of each phase of the driver 4, Lu, Lv, Lw represent the self-inductances of each phase of the motor 2, and Muv, Mvw, Mwu represent the mutual inductances between the phases of the motor 2. Further, ωe represents the electrical angular frequency, Φuvw represents the maximum number of magnetic flux linkages of the armature winding, R represents the winding resistance, Ke represents the induced voltage constant, and s is a differential operator. Also, the voltages Vux2, Vvx2, Vwx2, the electric The fluxes Iux2, Ivx2, and Iwx2 represent the output voltage and current on the secondary side of the transformer structure. Lx1, Lx2, and Mx represent the primary-side inductance, secondary-side inductance, and mutual inductance of the transformer structure, respectively. Rx1 and Rx2 represent the winding resistances of the primary and secondary sides of the transformer structure. Also, θe is the electrical angle.

[0039] The circuit equations of the motor 2 are represented by the following equations (1) and (2).

Equation

Equation

[0040] Furthermore, by performing the conversion process from the three-phase UVW to the two-phase dq and the conversion process from the fixed coordinate system to the rotating coordinate system, the circuit equations shown in the following equations (3) and (4) are obtained.

Equation

Equation

[0041] Furthermore, the secondary-side power Pdqx of the transformer structure is represented by the following equation (5). Also, the d-axis current idx2 and q-axis current iqx2 on the secondary side of the transformer structure are represented by the following equation (6). In the mathematical expressions shown below, RL represents the load resistance of the external device (encoder 22) to which power is supplied through the transformer structure forming the extraction unit 214. The d-axis current idx2 and q-axis current iqx2 on the secondary side of the transformer structure are represented by the following equation (6). In the mathematical expressions shown below, RL represents the load resistance of the external device (encoder 22) to which power is supplied through the transformer structure forming the extraction unit 214.

Equation

Number

[0042] Then, based on Equation 5 and Equation 6, the power Pdqt of the steady-state characteristics on the secondary side of the transformer structure is represented by the following Equation 7.

Number

[0043] As can be understood from Equation 7, the power extracted by the transformer structure is determined by the d-axis current id and q-axis current iq supplied from the driver 4 to the motor 2 via the power line 11, and the electrical angular frequency ωe related to the rotational speed of the motor. On the other hand, originally, in order to make the motor 2 be in a desired operating state, that is, a state of outputting a desired torque at a desired rotational speed, the d-axis current id and q-axis current iq should be supplied. However, if the d-axis current id and q-axis current iq are determined with priority given to extracting power by the transformer structure, it may affect the stability of the operating state of the motor, which is not preferable.

[0044] Therefore, in the present embodiment, as shown in FIG. 4, according to the region to which the operating state of the motor 2 belongs, the method for determining the motor drive current for power extraction by the transformer structure, that is, for power supply to the encoder 22, is switched. The rotational speed of the motor 2 shown in FIG. 4 is assumed to have a speed region up to ωmax at maximum. In the present disclosure, by suitably using the q-axis current and d-axis current supplied from the driver 4 to the motor 2, power supply to the encoder 22 via power extraction by the transformer structure is realized.

[0045] Here, based on FIG. 4, the power supply according to the operating state of the motor 2 will be described. First, the region R1 will be described. The region R1 is a so-called high-speed high-torque region. Generally, as the rotational speed of the motor 2 increases, the voltage output of the driver saturates due to the induced voltage and smooth rotation becomes difficult. In such a case, it is necessary to appropriately set the d-axis current in order to promote smooth rotation of the motor. Therefore, when the operating state of the motor 2 belongs to the region R1, the control of the d-axis current id (which is distinguished from the d-axis current required for the original drive of the motor and means the d-axis current additionally superimposed on the d-axis current required for the original drive) for power supply to the encoder 22 via the transformer structure is not performed, and the power supply from the driver 4 is carried out. Based on the above, the region R1 is set as the region where Pdqt represented by Equation 7 is greater than a predetermined threshold power. Therefore, for the regions excluding the region R1, in order to supply power to the encoder 22 via the transformer structure, it is necessary to control the d-axis current id for the supply. Therefore, the regions excluding the region R1 are divided into a region R2 where the rotational speed of the motor 2 is higher than the threshold speed ω0 and a region R3 where the rotational speed of the motor 2 is equal to or lower than the threshold speed ω0. The threshold speed ω0 is related to the efficiency of power extraction in the transformer structure. When the rotational speed of the motor 2 is higher than the threshold speed ω0, the efficiency of power extraction in the transformer structure is relatively high. When the rotational speed of the motor 2 is equal to or lower than the threshold speed ω0, the efficiency of power extraction in the transformer structure is relatively low. Therefore, with the threshold speed ω0 as the boundary condition, the control modes of the d-axis current id for power supply to the encoder 22 via the transformer structure are made different between the region R2 and the region R3.

[0046]

[0047] ​Next, control regarding power supply to the encoder 22 via the transformer structure according to each region shown in FIG. 4 will be described with reference to FIG. 5. The power supply control shown in FIG. 5 is control regarding power supply to the motor 2 that is repeatedly executed by the control unit 41 of the driver 4. Note that since power supply to the motor 2 is realized using known vector control, detailed description of the vector control will be omitted.

[0048] First, in S101, the operating state (operating point) of the motor 2 is specified. Specifically, based on FIG. 4, the rotational speed and torque of the motor 2 are specified. Thereafter, in S102, it is determined whether it is necessary to control the d-axis current value in order to supply power to the encoder 22 based on the operating state specified in S101. That is, when the operating state of the motor 2 belongs to the region R1 shown in FIG. 4, it is determined that control of the d-axis current value is not necessary (that is, a negative determination), and the process proceeds to S104. On the other hand, when the operating state of the motor 2 does not belong to the region R1 shown in FIG. 4, it is determined that control of the d-axis current value is necessary (that is, an affirmative determination), and the process proceeds to S103.

[0049] In S104, power is supplied to the encoder 22 without adjusting the d-axis current value. That is, when the operating state of the motor 2 belongs to the region R1, Pdqt represented by Equation 7 is greater than a predetermined threshold power, so that a certain amount of power can be extracted by the transformer structure as the motor 2 operates even without adjusting the d-axis current value. Therefore, continuous power supply to the encoder 22 is realized, and the operating state of the motor 2 is stably maintained.

[0050] Here, when an affirmative determination is made in S102 and the process proceeds to S103, in S103, it is determined whether the operating state of the motor 2 belongs to R3 in the low rotation region. Specifically, when the rotational speed of the motor 2 is equal to or lower than the threshold speed ω0 shown in FIG. 4, an affirmative determination is made in S103, and when it is higher than the threshold speed ω0, a negative determination is made in S103. When an affirmative determination is made in S103, the process proceeds to S105, and when a negative determination is made, the process proceeds to S106.

[0051] Here, when the rotational speed of the motor 2 is low, the efficiency of power extraction by the transformer structure is low, so the power actually extracted by the transformer structure becomes unstable. On the other hand, due to constraints such as the structure and size of the motor 2, it is not easy to arrange a sensor or the like for accurately detecting the power extracted by the transformer structure on the secondary side of the transformer structure for the control of the d-axis current. Therefore, in this embodiment, the power estimation model shown in FIG. 6 is adopted when controlling the d-axis current value. The power estimation model is included in the control unit 41. The power estimation model is configured to estimate the extracted power by the transformer structure. By adopting such a configuration, power supply can be suitably performed through the control of the d-axis current without using a sensor for power detection. Supply can be suitably performed.

[0052] When the power expected to be extracted by the transformer structure is set as the desired power (i.e., the command value regarding power) Pdqx*, in the upper part of FIG. 6, a block diagram for generating the estimated value Pdqx^ of the power through the control of the d-axis current value is shown. In the block diagram, the desired power The estimated value Pdqx^ is generated. In order to obtain the force Pdqx*, the estimated power value Pdqx^ is fed back and the difference is added to the controller. In the controller, a predetermined gain C is multiplied by the difference, and further, a sine wave of the first frequency generated by the signal generation unit is multiplied. The process of multiplying the sine wave of the first frequency associates the variation of the d-axis current with the passage of time. As a result, the d-axis current includes an element that varies with the passage of time (that is, an element that varies with the passage of time among the command values of the d-axis current) idac*. This element idac* that varies with the passage of time is related to the element pac shown in FIG. 7(b) described later. Then, the idac*, the element iddc* that does not vary with the passage of time among the command values of the d-axis current, the command value iq* of the q-axis current, and the electrical angular frequency ωe related to the rotational speed of the motor 2 are input to the power estimator, and the estimated power value Pdqx^ is obtained. That is, parameters related to the drive current of the motor 2 (iq*, iddc*, idac*) and parameters related to the rotational speed (ωe) are input to the power estimator. And Equation 5 is applied to the power estimator. In FIG. 6, an initial value id0* is included together with the element iddc* that does not vary with the passage of time, but generally the initial value id0* is considered to be zero and is fine. Note that the feedback control of the d-axis current and the q-axis current supplied to the motor 2 based on each command value will be described later with reference to FIG. 8.

[0053] Here, based on FIG. 7, the element that varies with the passage of time and the element that does not vary with the passage of time in the d-axis current will be described. The d-axis current shown in the upper part (a) of FIG. 7 does not change with the passage of time and has a constant value. For such a d-axis current, there is no element that varies with the passage of time, and it includes only an element that does not vary with the passage of time (the element referred to as pdc in the figure is referred to). On the other hand, the d-axis current shown in the lower part (b) of FIG. 7 changes with the passage of time with a certain bias applied. For such a d-axis current, in addition to the element that does not vary with the passage of time (the element referred to as pdc in the figure), with the passage of time and It will include elements that vary (the elements referred to as pac in the figure).

[0054] Therefore, the element idac* that varies with the passage of time in the d-axis current generated in FIG. 6 is reflected in the pac in FIG. 7, and the element iddc* that does not vary with the passage of time in the d-axis current is reflected in the pdc in FIG. 7. Furthermore, regarding the frequency of the element idac*, it is set to a value higher than the frequency corresponding to the maximum rotational speed of the motor 2. Thereby, power extraction by the transformer structure can be realized within a range that does not affect the operation of the motor 2 as much as possible.

[0055] The d-axis current and q-axis current supplied to the motor 2 are controlled according to the control block shown in FIG. 8 based on the respective command values idac*, id0* + iddc*, iq* regarding the d-axis current and q-axis current. Each parameter in the control block shown in FIG. 8 is as follows. Vd: d-axis voltage, Vq: q-axis voltage, Id: d-axis current, Iq: q-axis current Ra: winding resistance, Ld: d-axis inductance, Lq: q-axis inductance Ψf: magnet flux, ω: electrical angular frequency, s: differential operator Also, the region 200 surrounded by the dotted line in FIG. 8 models the motor 2, and each block b103, b104, b113, b114 included therein is derived from the following voltage equation of the motor (Equation 8).

Equation

[0056] Here, the control block constructed on the control unit 41 side of the driver 4 will be described. In this control block, first, feedback control of the d-axis current and q-axis current necessary for driving control of the motor 2 is performed. Specifically, with respect to the command value id0* + iddc* for the d-axis current for driving control of the motor 2, the d-axis current of the motor 2 on the region 200 side is fed back via the feedback path fb1, and the blocks b101 and b102, which are controllers, act on the difference between the two. The block b101 is a controller for executing PI control in the feedback control of the d-axis current, and the block b102 is a block related to the interference between the d-axis and q-axis on the motor 2 side. Both are arranged on the forward path L1 in the feedback control.

[0057] Furthermore, a filter b151 is arranged on the feedback path fb1. The filter b151 is a so-called low-pass filter. Since the d-axis current to be fed back via the feedback path fb1 includes elements whose current values do not change with the passage of time shown in FIG. 7, the cut-off frequency of the filter b151 is set so that other elements, that is, elements whose current values change with the passage of time, are not fed back.

[0058] Similarly, with respect to the command value iq* for the q-axis current for driving control of the motor 2, the q-axis current of the motor 2 on the region 20 0 side is fed back via the feedback path fb2, and the blocks b111 and b112, which are controllers, act on the difference between the two. The block b111 is a controller for executing PI control in the feedback control of the q-axis current, and the block b112 is a block related to the interference between the d-axis and q-axis on the motor 2 side. Both are arranged on the forward path L2 in the feedback control. Note that for the q-axis current, a filter corresponding to the filter b151 is not arranged on its feedback path fb2.

[0059] Thus, in the control unit 41 of the driver 4, feedback control related to the drive current (the above command value id0* + iddc* and command value iq*) for driving the motor 2 is executed via the feedback path fb1 and the feedback path fb2. That is, the feedback control corresponds to the feedback control by the first control unit disclosed in the present application. In the feedback control, feedback control related to the power supply to the encoder 22, which is an external device, is not performed.

[0060] Next, the feedback control related to the power supply to the encoder 22 will be described. The feedback control is executed in a feedback system different from the feedback control related to the drive current for driving the motor 2. Specifically, with respect to the command value idac* (see also FIG. 7) for the d-axis current for power supply to the encoder 22, the d-axis current of the motor 2 on the region 200 side is fed back via the feedback path fb3, and the controller block b121 acts on the difference between the two. The block b121 is a controller for executing PI control in the feedback control of the d-axis current for power supply to the encoder 22, and is arranged on the forward path L3 in the feedback control. Further, a filter b152 is arranged on the feedback path fb3. The filter b152 is a so-called high-pass filter. Since the d-axis current fed back via the feedback path fb3 takes into account the power extraction in the above-described transformer structure and includes elements whose current values vary with the passage of time shown in FIG. 7, the cut-off frequency of the filter b152 is set so that other elements, that is, elements whose current values do not vary with the passage of time, are not fed back. Also, since the PI control by the block b121 is for controlling the power supply to the encoder 22, it may have a configuration different from the blocks b101 and b111 for PI control for motor drive.

[0061] Thus, in the control unit 41 of the driver 4, the feedback control related to the drive current (the above command value idac*) for power supply to the encoder 22 is performed via the feedback path fb3. That is, the feedback control corresponds to the feedback control by the second control unit disclosed in the present application. In this feedback control, the feedback control regarding the d-axis current for drive control of the motor 2 is not performed.

[0062] Note that the output of the feedback control related to the drive current for power supply to the encoder 22 is added to the feedback control (d-axis side feedback control) related to the drive current for driving the motor 2 and output to the motor 2 side. That is, this process corresponds to the superimposing process of the current (additional current) for power supply on the drive current of the motor 2 by the output unit disclosed in the present application.

[0063] Thus, according to the feedback control in the control block shown in FIG. 8, basically, the generation of the drive current of the motor 2 and the generation of the current for power supply to the encoder 22 are performed without affecting each other, and the feedback control suitable for each is performed. Since the motor 2 and the encoder 22 are devices that perform different operations from each other and there are naturally differences in the transition of the power to be supplied, by executing the feedback control adapted to each in this way, it becomes possible to suitably realize the driving of the motor 2 and the power supply to the encoder 22.

[0064] Now, returning to FIG. 5. In S105 which is performed when the operating state of the motor 2 belongs to region R3, as shown in FIG. 7(b), the d-axis current value is feedback-controlled in a manner that varies with the passage of time using the power estimation model shown in FIG. 6. That is, the power to be supplied to the encoder 22 is superimposed on the drive current of the motor through the feedback control of the d-axis current value. In such a form, the d-axis current value after control becomes a value that varies with a constant amplitude and a constant frequency over time, with a bias due to an element that does not vary over time added. By varying the d-axis current value in this way over time, it is possible to compensate for the reduction in the efficiency of power extraction due to the transformer structure, and by including elements that do not vary over time, suitable drive control of the motor 2 can also be achieved simultaneously.

[0065] Also, in S106 which is performed when the operating state of the motor 2 belongs to region R2, as shown in FIG. 7(a), the d-axis current value is controlled in a manner that does not vary with the passage of time using the power estimation model shown in FIG. 6. That is, the power to be supplied to the encoder 22 is superimposed on the drive current of the motor through the control of the d-axis current value. In region R2, since the rotational speed of the motor 2 is relatively high, the efficiency of power extraction by the transformer structure can be kept relatively high. Therefore, by defining the d-axis current with elements that do not vary over time, more efficient power supply can be achieved.

[0066] From the above, according to the power supply control shown in FIG. 5, the influence on the operating state of the motor 2 is minimized While suppressing, a stable power supply to the encoder 22 can be achieved. In particular, when the operating state of the motor 2 belongs to the region R3, a suitable power supply to the encoder 22 can be achieved by feedback control of the d-axis current via the feedback path fb3, despite the low rotational speed of the motor 2. Note that the feedback control of the d-axis current via the feedback path fb3 is not limited to the case where the operating state of the motor 2 belongs to the region R3, and can also be executed in all operating regions. That is, in all operating regions of the motor 2, the d-axis current for power supply to the encoder 22 is generated in a manner that varies with time, and in that case, by performing feedback control of the d-axis current via the feedback path fb3, a suitable power supply to the encoder 22 can be achieved.

[0067] <Second Embodiment> Next, a second embodiment of the control block formed in the control unit 41 of the driver 4 will be described with reference to FIG. 9. In the first embodiment, power was supplied to the encoder 22 using the d-axis current, but in this embodiment, not only the d-axis current but also the q-axis current is used for power supply to the encoder 22. Therefore, there are differences in the control block configuration for feedback control regarding the q-axis current between this embodiment and the first embodiment shown in FIG. 8. Also, the q-axis current supplied by the motor 2 is a combination of an element iq* that does not vary with time and an element iqac* that varies with time, similar to the d-axis current shown in the first embodiment (see FIG. 7(b)). Specifically, in this embodiment, feedback control of the d-axis current and q-axis current necessary for driving control of the motor 2 is performed, and the control block configuration is different in that the filter 153 is arranged in the feedback path fb2, but is the same in other respects. Therefore, only the filter 153 will be described. The filter 153 is equivalent to the filter 151 in terms of function. The filter b153 is a so-called low-pass filter. Since the q-axis current to be fed back via the feedback path fb2 includes an element whose current value does not vary with time as shown in FIG. 7, the cut-off frequency of the filter b153 is set so that other elements, that is, elements whose current value varies with time, are not fed back.

[0068] On the other hand, with respect to the command value iqac* for the q-axis current for power supply to the encoder 22 , the q-axis current of the motor 2 on the region 200 side is fed back via the feedback path fb4, and a block b131 corresponding to the controller acts on the difference between the two. The block b131 is a controller for executing PI control in the feedback control of the q-axis current for power supply to the encoder 22, and is arranged on the forward path L4 in the feedback control. Regarding the frequency of the element iqac*, the maximum It is set to a value higher than the frequency corresponding to the large rotation speed. Thereby, power extraction by the transformer structure can be realized within a range that does not affect the operation of the motor 2 as much as possible.

[0069] Also, a filter b154 is arranged on the feedback path fb4. The filter b154 is a so-called high-pass filter. The q-axis current to be fed back via the feedback path fb4 is considered in view of the power extraction in the above-described transformer structure and includes elements whose current values fluctuate over time as shown in FIG. 7. Therefore, the cut-off frequency of the filter b154 is set so that other elements, that is, elements whose current values do not fluctuate over time, are not fed back.

[0070] Thus, in the control unit 41 of the driver 4, the feedback control related to the drive current (the above command values idac* and iqac*) for power supply to the encoder 22 is executed via the feedback paths fb3 and fb4. That is, the said feedback control corresponds to the feedback control by the second control unit disclosed in the present application. In the said feedback control, the feedback control regarding the d-axis current and the q-axis current for driving control of the motor 2 is not performed.

[0071] Note that the output of the feedback control related to the drive current for power supply to the encoder 22 is added to the feedback control related to the drive current for driving the motor 2 on each of the d-axis side and the q-axis side and output to the motor 2 side. That is, this process corresponds to the superimposing process of the current (additional current) for power supply on the drive current of the motor 2 by the output unit disclosed in the present application.

[0072] As described above, according to the feedback control in the control block shown in FIG. 9, currents for power supply to the encoder 22 can be generated on each of the d-axis and the q-axis, so that a relatively large power supply is realized. Then, in the generation of the drive current of the motor 2 on each axis and the generation of the current for power supply to the encoder 22, appropriate feedback control is performed respectively, whereby it becomes possible to suitably realize the drive of the motor 2 and the power supply to the encoder 22.

[0073] <Other modification examples of the control block> As another modification example of the control block formed in the control unit 41 of the driver 4, with regard to the feedback control related to the current generation for power supply to the encoder 22, it may be implemented only on the q-axis side without implementing it on the d-axis side. That is, in the control block shown in FIG. 9, "with respect to the command value idac* related to the d-axis current for power supply to the encoder 22, the region The d-axis current of the motor 2 on the 200 side is fed back via the feedback path fb3, and a control block in which the block b121, which is a controller, acts on the difference between the two is deleted can be adopted. In this case, the filter b151 on the feedback path fb1 can also be deleted.

[0074] <The third embodiment> In the first embodiment, the power estimation model shown in FIG. 6 was adopted when the rotational speed of the motor 2 was low (when it was below the threshold speed ω0). However, in this embodiment, in all rotational speed regions of the motor 2, that is, in the range where the rotational speed is 0 to ωmax, the power estimation model shown in FIG. 6 is adopted to estimate the d-axis current value, and the control of the d-axis current value for power supply is executed. Moreover, the frequency of the sine wave generated by the signal generation unit in the power estimation model is set to a fixed value regardless of the rotational speed of the motor. As a result, the d-axis current superimposed for power supply by the power supply control shown in FIG. 5 becomes of the type that varies with time as shown in FIG. 7(b), and the predetermined frequency related to the time variation is a constant frequency regardless of the rotational speed of the motor 2.

[0075] By adopting such a configuration, sensors and the like for accurately detecting the power extracted by the transformer structure for controlling the d-axis current become unnecessary, and the motor 2 that enables power supply can be downsized. Further, as described above, since the frequency related to the time variation of the d-axis current superimposed for power supply to the encoder 22 is constant, a transformer structure that enables more efficient power extraction can be designed in consideration of the predetermined frequency for power extraction in the transformer structure. In other words, since the frequency of the current flowing into the transformer structure is always constant, it is not necessary to correspond to a wide range of frequencies, and the transformer structure for power extraction can be simplified. This contributes to the downsizing of the transformer structure, and thus it becomes easier to downsize the motor 2.

[0076] And, even when the control of the d-axis current value for power supply is performed in all rotation speed regions of the motor 2, that is, in the range where the rotation speed is 0 to ωmax, by performing the feedback control of the d-axis current via the feedback path fb3, regardless of the rotation speed of the motor 2, a suitable power supply to the encoder 22 can be realized.

[0077] <Fourth Embodiment> A modification example of the transformer structure forming the extraction unit 214 will be described with reference to FIGS. 10 and 11. First, a description will be given with reference to FIG. 10. Since the configuration of the winding portion 25 of the motor body 21 is the same as that of the embodiment shown in FIG. 3, a detailed description thereof will be omitted. In this embodiment, for each of the three-phase winding portions L5, L6, and L7, the primary coil 531 of the transformer structure 53 corresponding to the U phase is connected in parallel, and the primary coil 631 of the transformer structure 63 corresponding to the V phase is connected in parallel, and the primary coil 731 of the transformer structure 73 corresponding to the W phase is connected in parallel. Specifically, the line L50 including the primary coil 531, the line L60 including the primary coil 631, and the line L70 including the primary coil 731 are Y-connected, and the other ends are connected to the winding portion L5 of the U phase, the winding portion L6 of the V phase, and the winding portion L7 of the W phase, respectively. Then, the secondary coil 532 of the transformer structure 53, the secondary coil 632 of the transformer structure 63 of the V phase, and the secondary coil 732 of the transformer structure 73 of the W phase are connected to the supply unit 215. Further, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange unit 216.

[0078] Note that also in this embodiment, the turns ratios of the transformer structures of each phase are basically the same, but they may be different. Also, in the form shown in FIG. 10, transformer structures corresponding to all three phases are arranged, and their secondary coils are connected to the supply unit 215 and the signal exchange unit 216. However, the transformer structures may be arranged so as to correspond to only some of the three phases, and their secondary coils may be connected to the supply unit 215 and the signal exchange unit 216. As an alternative, transformer structures corresponding to all three phases may be arranged, the secondary coils of some of the transformer structures may be connected to the supply unit 215, and the secondary coils of the remaining transformer structures may be connected to the signal exchange unit 216. In this case, the turns ratios of the transformer structures connected to the supply unit 215 and responsible for supplying power to the encoder 22 and the turns ratios of the transformer structures connected to the signal exchange unit 216 and responsible for exchanging predetermined signals with the encoder 22 may be appropriately set according to their respective purposes.

[0079] By adopting the winding part 25 and the transformer structures 53, 63, and 73 configured in this way, a part of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction part 214 as the driving power of the encoder 22. According to this configuration, when the motor 2 is driving, the power of the encoder 22 is always stably supplied. Also, for this reason, no cable for wiring to the encoder 22 is required, so the cable wiring work is greatly reduced and its cost can be suppressed.

[0080] Next, an explanation will be given based on FIG. 11. Regarding the configuration of the winding part 25 of the motor body 21, since it is the same as that of the above-described embodiment, a detailed description thereof will be omitted. However, in this embodiment, the coil components 51, 61, and 71 of the winding portions L5, L6, and L7 of each phase are used as the primary coils 531, 631, and 731 of the transformer structures 53, 63, and 73 corresponding to each phase. Specifically, in the U phase, the coil component 51 is used as the primary coil 531 to form the transformer structure 53. In the V phase, the coil component 61 is used as the primary coil 631 to form the transformer structure 63. In the W phase, the coil component 71 is used as the primary coil 731 to form the transformer structure 73. Therefore, in the third embodiment, the secondary coils 532, 632, and 732 of the transformer structures 53, 63, and 73 of each phase are wound around the stator core together with the main coils of the winding part that are also primary coils, so that the transformer structures 53, 63, and 73 of each phase are formed. Then, the secondary coil 532 of the transformer structure 53, the secondary coil 632 of the transformer structure 63 of the V phase, and the secondary coil 732 of the transformer structure 73 of the W phase are connected to the supply part 215. Further, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange part 216.

[0081] Note that also in this embodiment, the winding ratios of the transformer structures of each phase are basically the same, but they may be different. Also, in the form shown in FIG. 11, transformers corresponding to all three phases The structure is arranged, and its secondary coil is connected to the supply unit 215 and the signal exchange unit 216. However, the transformer structure may be arranged to correspond to only some of the three phases, and its secondary coil may be connected to the supply unit 215 and the signal exchange unit 216. Alternatively, a transformer structure corresponding to all of the three phases may be arranged, the secondary coil of some of the transformer structures may be connected to the supply unit 215, and the secondary coil of the remaining transformer structures may be connected to the signal exchange unit 216. In this case, the turns ratio of the transformer structure connected to the supply unit 215 and responsible for supplying power to the encoder 22 and the turns ratio of the transformer structure connected to the signal exchange unit 216 and responsible for the exchange of a predetermined signal with the encoder 22 may be suitably set according to their respective purposes.

[0082] By adopting the winding part 25 and the transformer structures 53, 63, 73 configured in this way, a part of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction unit 214 as the driving power of the encoder 22. According to this configuration, when the motor 2 is driving, the power of the encoder 22 is always stably supplied. Also, for this reason, no cable for wiring to the encoder 22 is required, so the cable wiring work is greatly reduced and its cost can be suppressed.

[0083] Furthermore, although the transformer structures 53, 63, 73 shown in FIGS. 3, 10, and 11 are double-wound type transformer structures, as a modification, a single-wound type transformer structure can also be adopted. For example, when a single-wound type transformer structure is adopted in the form shown in FIG. 10, the winding part 25 of the motor 2 is used as the primary coil, and a part of the winding part 25 is used as the secondary coil, thereby forming the transformer structures 53, 63, 73. That is, the secondary coil part in the winding part 25 is shared between the primary side and the secondary side.

[0084] <The Fifth Embodiment> In the embodiments described above, the power extracted by the extraction unit 214 is supplied to the encoder 22. However, the extracted power can also be supplied to devices other than the encoder 22. For example, power may be supplied to a sensor device (such as a temperature sensor or a vibration sensor) disposed inside or outside the motor 2. In that case, a port that serves as a connection port for a cable with the sensor and is suitable for power supply may be provided on the motor body 21.

[0085] <Sixth Embodiment> This embodiment will be described with reference to FIG. 12. FIG. 12 is a diagram showing a schematic configuration of the motor 2 according to this embodiment. Note that the motor 2 of this embodiment is provided with an extraction unit 214 having a transformer structure with respect to the winding unit 25, similar to the form shown in FIG. 2. The transformer structure of the extraction unit 214 can adopt a structure substantially the same as the structures shown in FIGS. 3, 10, and 11. Further, in this embodiment, an extraction unit 214b capable of extracting power is also provided for the power line 11 connected to the connector 211. The power extraction by the extraction unit 214b is also realized by incorporating a transformer structure that is electrically identical to the transformer structure shown in FIG. 3 or the like into the power line 11.

[0086] The power extracted by the extraction unit 214b can be subjected to predetermined rectification processing or the like and supplied as power to devices such as a temperature sensor or a vibration sensor disposed outside the motor 2. Further, the extracted power can be stored in a secondary battery to supply stable power to the temperature sensor or the like. Note that in the motor 2 shown in FIG. 12, the power extracted by the extraction unit 214 is supplied to the encoder 22. However, instead of that, the power extracted by the extraction unit 214b may be supplied to the encoder 22, or the power extracted by both of the extraction units 214 and 214b may be supplied to the encoder 22. Further, in the motor 2, the extraction unit 214 may not be provided, and the encoder 22 may receive power supply from a built-in battery or from the driver 4.

[0087] Thus, in the motor 2 of the present disclosure, it is possible to extract power not only from the winding portion 25 but also from the power line 11, and supply power to the encoder 22, an external sensor, etc., thereby greatly reducing the wiring load for power supply in the servo system.

[0088] <Appendix 1> A driver (4) for supplying power to a motor (2) including an extraction unit (214) that extracts a part of the power supplied from the outside, and a supply unit (215) that supplies the power extracted by the extraction unit (214) to an external device, or to a motor power line (11) provided with the extraction unit (214) and the supply unit (215), wherein it has a first feedback system including one or a plurality of first controllers (b101, b111) to which a feedback signal related to the operation of the motor (2) is input, and a first control unit configured to be able to feedback-control a drive current related to the drive of the motor among the supply currents to the motor; it has a second feedback system including one or a plurality of second controllers (b121) to which at least a part of the feedback signal is input and formed to be different from the first feedback system, and a second control unit configured to be able to perform feedback control for generating an additional current corresponding to the power supplied to the external device among the supply currents to the motor; an output unit that superimposes the additional current generated via the second control unit on the drive current generated via the first control unit and outputs supply power to the motor (2); A driver comprising. <Appendix 2> The first feedback system of the first control unit further has a low-pass filter (b151) having a first cut-off frequency set based on the rotational speed of the motor (2); The second feedback system of the second control unit further has a high-pass filter (b152) having a second cut-off frequency set in relation to the power extraction by the extraction unit. The driver according to Appendix 1. <Appendix 3> The first control unit is configured to enable feedback control related to the q-axis current and the d-axis current for driving the motor (2). The second control unit is configured to enable feedback control related to the d-axis current as the additional current for power supply to the external device. The output unit superimposes the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor (2) derived by the first control unit, and outputs the power supplied to the motor. The driver according to Appendix 1 or Appendix 2. <Appendix 4> The d-axis current as the additional current includes an element (pac) whose current value varies with time. The driver according to Appendix 3. <Appendix 5> The frequency of the varying element included in the d-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed (ωmax) of the motor (2). The driver according to Appendix 4. <Appendix 6> The first control unit is configured to enable feedback control related to the q-axis current and the d-axis current for driving the motor (2). The second control unit is the q-axis current as the additional current for power supply to the external device configured to enable feedback control related thereto. The output unit superimposes the q-axis current as the additional current derived by the second control unit on the q-axis current for driving the motor derived by the first control unit, and outputs the power supplied to the motor (2). The driver according to Appendix 1 or Appendix 2. <Appendix 7> The q-axis current as the additional current includes an element (pac) whose current value varies with time. The driver according to Appendix 6. <Appendix 8> The frequency of the fluctuating element included in the q-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed (ωmax) of the motor (2). The driver according to Appendix 7. <Appendix 9> The second control unit is further configured to enable feedback control related to the q-axis current as the additional current for power supply to the external device. The output unit superimposes the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor derived by the first control unit, and superimposes the q-axis current as the additional current derived by the second control unit on the q-axis current for driving the motor derived by the first control unit, and outputs the power supplied to the motor. The driver according to Appendix 3. <Appendix 10> The d-axis current as the additional current includes an element (pac) whose current value fluctuates over time. The driver according to Appendix 9. <Appendix 11> The frequency of the fluctuating element included in the d-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed (ωmax) of the motor (2). The driver according to Appendix 10. <Appendix 12> The q-axis current as the additional current includes an element (pac) whose current value fluctuates over time. The driver according to Appendix 9. <Appendix 13> The frequency of the fluctuating element included in the q-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed (ωmax) of the motor (2). The driver according to Appendix 12.

Description of Reference Numerals

[0089] 2 Motor 4 Servo Driver 22 Encoder 25 Winding Part 53, 63, 73 Transformer Structure 214 Extraction Unit 215 Supply Unit fb1, fb2 Feedback Paths fb3, fb4 Feedback Paths b151, b153 Filters (Low - pass Filters) b152, b154 Filters (High - pass Filters)

Claims

1. A driver that supplies power to a motor including an extraction unit that extracts a part of the power supplied from the outside and a supply unit that supplies the power extracted by the extraction unit to an external device, or to a motor power line provided with the extraction unit and the supply unit, having a first feedback system including one or more first controllers to which a feedback signal related to the operation of the motor is input, and a first control unit configured to be able to feedback-control a drive current related to the drive of the motor among the supply currents to the motor; having a second feedback system including one or more second controllers to which at least a part of the feedback signal is input and formed differently from the first feedback system, and a second control unit configured to be able to perform feedback control for generating an additional current corresponding to the power supplied to the external device among the supply currents to the motor; and an output unit that superimposes the additional current generated via the second control unit on the drive current generated via the first control unit and outputs supply power to the motor. A driver comprising the above.

2. The first feedback system of the first control unit further includes a low-pass filter having a first cut-off frequency set based on the rotational speed of the motor. The second feedback system of the second control unit further includes a high-pass filter having a second cut-off frequency set in relation to the power extraction by the extraction unit. The driver according to claim 1.

3. The first control unit is configured to be able to perform feedback control related to the q-axis current and the d-axis current for driving the motor. The second control unit is configured to be able to perform feedback control related to the d-axis current as the additional current for power supply to the external device. The output unit superimposes the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor derived by the first control unit and outputs supply power to the motor. The driver according to claim 1 or claim 2.

4. The d-axis current as the additional current includes an element whose current value varies over time. The driver according to claim 3.

5. The frequency of the varying element included in the d-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed of the motor. The driver according to claim 4.

6. The first control unit is configured to enable feedback control related to the q-axis current and the d-axis current for driving the motor. The second control unit is configured to enable feedback control related to the q-axis current as the additional current for power supply to the external device. The output unit superimposes the q-axis current as the additional current derived by the second control unit on the q-axis current for driving the motor derived by the first control unit, and outputs the power supplied to the motor. The driver according to claim 1 or claim 2.

7. The q-axis current as the additional current includes an element whose current value fluctuates over time. The driver according to claim 6.

8. The frequency of the fluctuating element included in the q-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed of the motor. The driver according to claim 7.

9. The second control unit is further configured to enable feedback control related to the q-axis current as the additional current for power supply to the external device. The output unit superimposes the d-axis current as the additional current derived by the second control unit on the d-axis current for driving the motor derived by the first control unit, and superimposes the q-axis current as the additional current derived by the second control unit on the q-axis current for driving the motor derived by the first control unit, and outputs the power supplied to the motor. The driver according to claim 3.

10. The d-axis current as the additional current includes an element whose current value fluctuates over time. The driver according to claim 9.

11. The frequency of the fluctuating element included in the d-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed of the motor. The driver according to claim 10.

12. The q-axis current as the additional current includes an element whose current value fluctuates over time. The driver according to claim 9.

13. The frequency of the fluctuating element included in the q-axis current as the additional current is higher than the frequency corresponding to the maximum rotational speed of the motor. The driver according to claim 12.

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