driver

Abstract

A driver that supplies driving power to a motor that has an extraction section that extracts a portion of power supplied from the outside and a supply section that supplies the power extracted by the extraction section to an external device, the driver having an output section that superimposes first power supplied to the external device on driving power required for driving the motor and outputs to the motor. The output section adjusts the power superimposed as the first power by controlling a d-axis current value in the driving current of the motor. With this structure, stable power supply to the external device related to the motor is achieved.

Description

Technical Field

[0001] This invention relates to drives. Background Technology

[0002] For motors used to drive loads for various purposes, accurate control requires monitoring the motor's state, typically achieved using detection devices such as encoders. Power is necessary to drive the encoder, and generally, power is supplied via a cable connecting the servo system (e.g., a driver) and the encoder. Alternatively, Patent Document 1 discloses a structure that supplies power to the encoder from a power source different from that of the servo system. That is, it discloses an auxiliary power supply for the encoder that operates even when the power supplied from the system side to the encoder is reduced for certain reasons.

[0003] Furthermore, as another method related to power supply to the encoder, Patent Document 2 discloses a structure for wirelessly supplying power to an encoder that communicates wirelessly with the servo system from an external source. Patent Document 3 discloses a structure for wiredly supplying power to an encoder that communicates wirelessly with the servo system from an external source.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 8-251817

[0007] Patent Document 2: Japanese Patent Application Publication No. 2001-297389

[0008] Patent Document 3: Japanese Patent Application Publication No. 2002-197581 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] Although the power consumed by the encoder installed on the motor is less than that consumed by the motor itself, the status of the driven motor needs to be constantly monitored, thus requiring a stable power supply. Power is typically supplied by connecting the encoder and the motor driver with a wired cable. However, in this case, in addition to the motor's power lines, wiring related to the encoder is also required, potentially increasing the workload of wiring and costs associated with the cables.

[0011] Furthermore, while technologies for wirelessly powering encoders have been proposed in the past, they are not easily implemented in practical scenarios. Typically, the motor is the power source for the drive shaft of the device and is therefore integrated within it. Thus, even if wireless power supply to the encoder were desired, a certain distance would exist between the wireless transmitting device (antenna) and the encoder, significantly reducing the efficiency of power delivery compared to wired methods. Additionally, in cases where the device itself is mobile (such as a robot), obstacles may hinder wireless power transmission, or the device's position or orientation may prevent proper reception, making it difficult to ensure a stable power supply to the encoder. Moreover, various power-dependent devices, such as sensors, are often positioned around the motor.

[0012] The present invention was made in view of the following problem, and its object is to provide a technique for achieving a stable power supply to external devices associated with a motor.

[0013] Methods for solving problems

[0014] One aspect of the present invention discloses a motor that receives power from an external driver via a power line. The motor comprises: an extraction section that extracts a portion of the power supplied to the motor from the driver; and a supply section that supplies the power extracted by the extraction section to an external device. The motor can be a single-phase AC motor or a three-phase AC motor. Furthermore, the wiring configuration of the coils at the motor's winding section can be a delta connection or a star connection (or Y connection). Additionally, the winding configuration of the coils relative to the motor's stator can be distributed winding or concentrated winding. That is, there is no particular intention to limit the specific formation of the winding section in the motor of the present invention. Furthermore, the motor may also include a power input section that inputs power from the driver via the power line to the winding section inside the motor. In this case, the extraction section may also extract a portion of the power from the winding section; alternatively, the extraction section may also extract a portion of the power from the power line.

[0015] Furthermore, in the aforementioned motor, the extraction section can also be configured to form a transformer structure relative to the winding section. This transformer structure is configured such that a portion of the power from the winding section is input to the primary coil of the transformer structure, and a portion of that power is extracted via the transformer structure. In this case, in the aforementioned motor, using the transformer structure configured relative to the motor's winding section, the extraction section extracts a portion of the drive power supplied to the motor via the power line as power for external devices. Here, the transformer structure is formed within the motor such that a portion of the alternating current flowing through the winding section is input to the primary coil side of the transformer structure. The transformer structure can be either a single-winding type transformer or a multi-winding type transformer. Furthermore, in the case of a single-winding type transformer, the secondary coil refers to the coil that shares a portion of the primary coil with the motor. Typically, when a coil is wound on the stator core of the motor, the coil protrudes from the stator core at a certain height at its coil end; therefore, a transformer structure can also be formed for the winding section located at the coil end. Alternatively, a secondary coil of the transformer structure can also be wound together in the space where the coil is wound around the stator core.

[0016] Furthermore, an alternating current corresponding to the alternating current flowing through the primary coil and the turns ratio of the transformer (the ratio of the number of turns in the secondary coil to the number of turns in the primary coil) is extracted from the secondary coil of the transformer. Then, the supply unit rectifies the extracted alternating current and supplies it to an external device. Additionally, the supply unit can transform the rectified voltage to a voltage suitable for driving the external device as needed. Moreover, by storing the rectified power in a secondary battery, the supply unit can provide a more stable power supply to the external device.

[0017] In this way, by employing a structure that extracts a portion of the power supplied to the motor via the power line as power to an external device and supplies it to that device, power can be stably supplied to the external device regardless of the motor's position or orientation, and no cabling is required for supplying power to the external device, thus significantly reducing its workload. Furthermore, the external device can be an encoder mounted on the motor, or alternatively, sensor devices such as temperature sensors or vibration sensors disposed inside or outside the motor.

[0018] Furthermore, regarding the transformer structure in the aforementioned motor, specific embodiments are illustrated. First, the transformer structure may be configured such that the primary coil side of the transformer structure is connected in series with the winding portions of some or all phases included in the winding section, and the secondary coil side of the transformer structure is connected to the supply section. Second, the transformer structure may also be configured such that the primary coil side of the transformer structure is connected in parallel with the winding portions of some or all phases included in the winding section, and the secondary coil side of the transformer structure is connected to the supply section. Third, the transformer structure may also be configured such that the winding portions of some or all phases included in the winding section serve as the primary coil, and its secondary coil is wound together with the winding portions in the motor and connected to the supply section. The transformer structure may also be configured in ways other than those described above.

[0019] Alternatively, in the motor described above, without the aforementioned transformer configuration, the extraction unit can be formed in parallel with a portion or all of the winding portion comprising the winding portion, and connected to the supply unit. That is, in this configuration, the extraction unit does not pass through a transformer configuration; in other words, a portion of the power from the winding portion is directly extracted as power for the encoder. Even in this case, power can be stably supplied to the encoder, thus eliminating the need for cabling to supply power to the encoder and significantly reducing its workload.

[0020] In the aforementioned motor, it is also possible that the motor further includes a signal exchange unit capable of transmitting and receiving predetermined signals between the winding section and the encoder via the transformer structure. That is, the operation of the transformer structure is also used for transmitting and receiving predetermined signals between the encoder and the motor winding section. The motor winding section is connected to an external driver via a power line; therefore, through the transmission and reception of predetermined signals by the signal exchange unit, the encoder and driver can communicate.

[0021] Furthermore, the present invention can be understood from the aspect of a driver that provides drive current to the aforementioned motor. This driver can also be configured to calculate the power supplied by the supply unit, and when the calculated power is lower than a threshold related to the power required to drive the encoder, increase the d-axis current value in the motor's drive current, thereby increasing the power supplied to the motor. In motor drive control, particularly in regions where the motor's drive current is low, the d-axis current is a current that does not contribute to the torque exerted by the motor. Furthermore, in such low-current regions, the power extracted by the extraction unit is also low, potentially insufficient to drive the encoder. Therefore, as described above, when the estimated power supplied to the encoder is lower than a threshold, by increasing the d-axis current value in the motor's drive current, sufficient power can be supplied to the encoder without significantly affecting the motor's operation.

[0022] Furthermore, as another method, the driver of the present invention can also be configured to provide power to the motor in a manner where the d-axis current value varies over time, while the q-axis current value is set to a fixed value required to stop the motor, even when the motor is stopped. According to this configuration, sufficient power can be provided to the encoder even when the motor is stopped or when it is necessary to stop the motor. Moreover, the shift in the d-axis current value in the above-described case can be a sine wave shape, a rectangular wave shape, a triangular wave shape, etc.

[0023] Alternatively, as another method, the driver of the present invention may also include: an inverter circuit connected to the winding section to provide the drive current to the winding section; and a superposition section connected to the winding section in parallel with the inverter circuit to superimpose power onto the drive current flowing in the winding section. With such a structure, AC power suitable for supplying power to external devices can be supplied to the winding section of the motor.

[0024] Furthermore, the present invention can also be understood from the perspective of a driver that provides driving power to a motor, wherein the motor includes: an extraction unit that extracts a portion of the power supplied from the outside; and a supply unit that provides the power extracted by the extraction unit to an external device. Additionally, the technical concept described above can be applied to this motor. Here, the driver may also include an output unit that superimposes a first power supplied to the external device with the driving power required to drive the motor and outputs it to the motor. In this case, the output unit can also adjust the power superimposed as the first power by controlling the d-axis current value in the motor's driving current. Furthermore, the output unit can also generate the first power by controlling both the d-axis current value and the q-axis current value in the motor's driving current. In the present invention, the control of the d-axis current value and the q-axis current value includes the concepts of increase and decrease. Depending on the type of motor (e.g., SPM, IPM, etc.), the superimposed first power can be adjusted by a combination of increasing and decreasing the d-axis current value and the q-axis current value. With this structure in the driver, power can be supplied to external devices via the extraction and supply units, in conjunction with the supply of power to the motor. This helps simplify the structure of the power supply, wiring, etc., required to supply power to external devices.

[0025] Furthermore, in the aforementioned driver, the output unit can also control the d-axis current value within a permissible range of the current output from the driver to the motor to generate the first power. By appropriately utilizing the d-axis current in this way, stable driving of the motor and appropriate power supply to external devices can be achieved simultaneously.

[0026] Here, in the aforementioned driver, the output unit can also control the d-axis current value of the motor's drive current based on the motor's drive speed. The power extraction efficiency of the extraction unit in the motor sometimes depends on the electrical angular frequency of the drive current, which is associated with the motor's drive speed. For example, when the extraction unit achieves power extraction using the aforementioned transformer structure, there is a tendency for a higher electrical angular frequency of the drive current to result in higher extraction efficiency. Therefore, by taking into account such power extraction characteristics, controlling the d-axis current value by the output unit enables the appropriate power supply to external devices.

[0027] For example, the output unit could generate the first power by controlling the d-axis current value in a way that does not change over time when the motor's drive speed is higher than a predetermined threshold, and then superimpose this first power onto the drive power required to drive the motor. The predetermined threshold is the motor's drive speed corresponding to the electrical angle frequency of the drive current, where the power extraction efficiency in the extraction unit is relatively high. Therefore, to ensure the motor's drive speed is higher than the predetermined threshold, it is expected that the power extraction efficiency in the extraction unit will be relatively high; thus, control can be performed in a way that the d-axis current value does not change over time.

[0028] On the other hand, when the output unit cannot expect high-efficiency power extraction from the extraction unit when the motor's drive speed is below a predetermined threshold, the d-axis current value is controlled to generate the first power by varying the d-axis current value over time, and this first power is superimposed on the drive power required to drive the motor. Furthermore, as an example of how the d-axis current value varies over time, the output unit can vary it at a frequency higher than the electrical angular frequency corresponding to the motor's drive speed. Moreover, the variation of the d-axis current value over time can be a sinusoidal wave, a rectangular wave, a triangular wave, or the like.

[0029] Alternatively, in the aforementioned driver, if the power supplied by the supply unit is lower than a threshold related to the power required to drive the external device, the output unit controls the d-axis current value in the drive current of the motor to generate the first power and outputs it to the motor.

[0030] Furthermore, in the aforementioned driver, the output unit can also generate the first power by varying the d-axis current value over time while keeping the q-axis current value fixed, and then output this first power to the motor. According to this structure, power can be appropriately supplied to an external device via the extraction and supply units. In cases where the motor is stopped or must be stopped, it is preferable to generate the first power and output it to the motor based on this structure.

[0031] Furthermore, in the drive described above, the output unit can also perform feedback control on the d-axis current value based on the power extracted by the extraction unit of the motor and the power that should be supplied to the external device. With this structure, the supply of power to the external device via the extraction and supply units of the motor can be more appropriately realized.

[0032] Invention Effects

[0033] It enables a stable power supply to external devices associated with the motor. Attached Figure Description

[0034] Figure 1 It is a diagram showing the general structure of a control system that drives and controls a motor.

[0035] Figure 2 It is a diagram showing the general structure of a motor.

[0036] Figure 3 Figure 1 is a schematic representation of the configuration of the motor winding section and the transformer structure positioned relative to the winding section.

[0037] Figure 4 Figure 2 is a schematic representation of the configuration of the motor winding section and the transformer structure positioned relative to the winding section.

[0038] Figure 5 Figure 3 is a schematic representation of the configuration of the motor winding section and the transformer structure positioned relative to the winding section.

[0039] Figure 6 Figure 4 is a schematic representation of the configuration of the motor winding section and the transformer structure positioned relative to the winding section.

[0040] Figure 7 Figure 5 is a schematic representation of the configuration of the motor winding section and the transformer structure positioned relative to the winding section.

[0041] Figure 8 It is a flowchart illustrating the process by which the driver provides electrical control to the motor.

[0042] Figure 9 It is a graph showing the correlation between the motor's drive speed and the current applied by the driver.

[0043] Figure 10 The first figure shows how the d-axis current value for power supply is increased.

[0044] Figure 11 The second figure shows how the d-axis current value used for power supply is increased.

[0045] Figure 12 This is a diagram showing a variation of the driver.

[0046] Figure 13 It is a diagram showing the schematic structure of the circuit model used to verify the circuit equations of the motor.

[0047] Figure 14 Figure 1 shows the schematic structure of a modified motor.

[0048] Figure 15Figure 2 shows a schematic structure of a modified motor. Detailed Implementation

[0049] <Example 1>

[0050] Figure 1 This is a diagram showing the general structure of a control system for driving and controlling a motor. First, the control system will be described. In the control system, a PLC (Programmable Logic Controller) 5 is connected to network 1 as a higher-level controller. Furthermore, multiple servo drives 4 are connected to network 1, configured to send and receive signals with the PLC 5. Additionally, in… Figure 1 In this document, the functional structure of one servo drive 4 is described in detail, but the other servo drives 4a and 4b also have the same functional structure. Additionally, motor 2 is connected to servo drive 4 via power line 11 and receives drive power. Similarly, motors 2a and 2b receive drive power from servo drives 4a and 4b via power lines 11a and 11b, respectively. The following description of the motor and servo drive construction is based on motor 2 and servo drive 4.

[0051] Here, in order to drive the specified load device, the motor 2 is driven and controlled according to instructions from PLC 5. As an example, various mechanical devices (e.g., the arm of an industrial robot, a handling device) can be exemplified as the load device, and the motor 2 is assembled within the device as an actuator to drive the load device. Alternatively, the motor 2 can be an AC servo motor. As another method, the motor 2 can also be an induction motor or a DC motor. The motor 2 includes: a motor body 21 having a stator and a rotor, the stator including a winding portion formed by coils wound around a stator core, and the rotor being equipped with permanent magnets; and an encoder 22 having a detection disk that rotates in conjunction with the rotation of the rotor, capable of detecting the rotational state of the rotor. The rotation detection of the encoder 22 can be incremental or absolute.

[0052] The detection signal from encoder 22 is wirelessly transmitted to servo driver 4 via communication unit 42, which will be described later. The transmitted detection signal is used for servo control in control unit 41, which will also be described later. The detection signal from encoder 22 may include, for example, position information about the rotational position (angle) of the rotating shaft of motor 2, and information about the rotational speed of the rotating shaft.

[0053] Here, the servo drive 4 includes a control unit 41, a communication unit 42, and a power conversion unit 43. The control unit 41 is a functional unit responsible for the servo control of the motor 2 based on instructions from the PLC 5. The control unit 41 receives motion command signals related to the motion of the motor 2 and detection signals output from the encoder 22 from the PLC 5 via the network 1, and calculates servo control related to the drive of the motor 2, i.e., command values ​​related to the motion of the motor 2. The control unit 41 performs feedback control utilizing a position controller, speed controller, current controller, etc. Furthermore, the control unit 41 is also responsible for control other than the servo control of the motor 2 performed by the servo drive 4.

[0054] The communication unit 42 is a functional unit responsible for wireless communication between the encoder 22 and the servo driver 4. When wireless communication begins, the communication unit 42 of the servo driver 4 determines that the encoder 22 is the target of wireless communication by identifying the encoder that becomes its communication target. Therefore, the communication unit 42 does not perform wireless communication with the encoders of motor 2a and motor 2b. Similarly, the encoders of motor 2a and motor 2b only communicate wirelessly with servo drivers 4a and 4b, respectively. The power conversion unit 43 provides drive power to the motor 2 via the power line 11 based on the command values ​​related to the operation of the motor 2 calculated by the control unit 41. Furthermore, in generating this power supply, AC power is sent to the servo driver 4 from the AC power source 7. In this embodiment, the servo driver 4 is a type that accepts three-phase AC power, but it could also be a type that accepts single-phase AC power. Alternatively, the servo driver 4 could also be a type that accepts direct current.

[0055] Next, based on Figure 2 The general structure of motor 2 will be described. Motor 2 is a three-phase (U-phase, V-phase, W-phase) AC motor, having a motor body 21 and an encoder 22. The motor body 21 includes a rotor 212 and a stator 213. A permanent magnet is assembled on the rotor 212 and supported for rotation. In the stator 213, coils are wound around a stator core formed of electromagnetic steel plates, forming a winding section 25. In this embodiment, the connection method of each phase in the winding section 25 is Y-connection, but it can also be replaced by delta connection. In addition, in this embodiment, the winding method of the coils relative to the stator core can be either distributed winding or concentrated winding. Figure 2 The structure shown is only a schematic one. Regardless of the specific structure of the motor, the technical concept of this invention can be applied.

[0056] The power line 11, which provides drive power from the servo driver 4, is connected to connector 211. Connector 211 corresponds to the power input section of this invention. Connector 211 is connected to each phase of the winding section 25. Furthermore, in the motor 2, a transformer structure is arranged relative to the winding section 25 (see reference). Figures 3-5 (As shown in 53, 63, and 73 (details to follow), this transformer structure includes an extraction section 214 that extracts a portion of the drive power supplied to the coil of the winding section 25 as power for the encoder. Specifically, the extraction section 214 extracts current that can be used as the drive current for the encoder 22 on the secondary coil side by allowing the alternating current flowing through the winding section 25 of the motor body 21 to pass through the primary coil side of the transformer structure. Furthermore, in... Figure 3 as well as Figure 4 In the manner shown, the transformer structure is formed relative to the winding portion 25 located at the coil end of the stator 213. Figure 5 In the manner shown, the transformer structure is formed by winding the primary coil of the transformer structure relative to the stator core together with the coil wound on the winding portion 25 of the stator core. Regarding the transformer structure, methods other than forming it at the ends of the coils can also be used.

[0057] The extraction unit 214 extracts the alternating current output from the secondary coil of the transformer as power for the encoder 22. Therefore, the power is rectified by the supply unit 215, and stepped up or down to a DC voltage suitable for driving the encoder 22 as needed via the DC-DC converter included in the supply unit 215. With the encoder 22 mounted on the motor body 21, the supply unit 215 is electrically connected to the encoder 22, enabling the supply of DC power to the encoder 22 side, particularly to the processing unit 221 that performs the detection processing of the rotor 212's rotation. Alternatively, the supply unit 215 may also include a secondary battery capable of storing the rectified DC power. In this case, power can be supplied to the encoder 22 even when the drive current does not flow through the winding unit 25 or during periods of extremely low drive current.

[0058] Furthermore, in the motor 2 of this embodiment, it is configured to transmit and receive a predetermined signal between the winding section 25 of the motor body 21 and the processing section 221 of the encoder 22 using the extraction processing of the extraction unit 214. This transmission and reception of the predetermined signal is achieved using the transformer structure described above via the signal exchange unit 216. When a predetermined signal is sent from the winding section 25 to the processing section 221, a current superimposed with the predetermined signal flows through the coil of the winding section 25, and this current flows through the primary coil side of the transformer structure. Thus, the extraction unit 214 can generate a current corresponding to the predetermined signal on the secondary coil side of the transformer structure. Furthermore, the extracted corresponding current is transmitted to the processing section 221 via the signal exchange unit 216. In this case, in order to accurately transmit the information contained in 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, if the extracted corresponding current is weak, the signal exchange unit 216 can also perform predetermined amplification processing.

[0059] Furthermore, when a predetermined signal is sent from the processing unit 221 to the winding unit 25, the extraction unit 214 can generate a current corresponding to the predetermined signal on the primary coil side of the transformer structure by causing a current containing the predetermined signal to flow to the secondary coil side of the transformer structure via the signal exchange unit 216, and then direct this current to the coil of the winding unit 25. In this case, the predetermined signal can also be amplified in a predetermined manner via the signal exchange unit 216. The coil of the winding unit 25 is electrically connected to the servo driver 4 via the power line 11, therefore, a predetermined signal can be sent from the encoder 22 to the servo driver 4 using the current corresponding to the predetermined signal output from the processing unit 221. As described above, the encoder 22 and the servo driver 4 are configured to enable wireless communication via the communication unit 42, but the transmission and reception of the predetermined signal via the signal exchange unit 216 is a communication method useful under certain conditions, such as a state prior to the capability of such wireless communication.

[0060] Next, several configurations of the winding section 25 of the motor body 21 and the transformer structure provided relative to the winding section 25 will be illustrated. First, based on... Figure 3 The first method will be explained. The winding section 25 includes winding sections L5, L6, and L7 for the U-phase, V-phase, and W-phase, respectively. The wiring configuration for each phase winding section is Y-connected, and the connection point of each winding section is assumed to be the neutral point. Regarding the U-phase winding section L5, in... Figure 3 In this diagram, the inductance component is represented by 51, and the resistance component by 52. ​​Similarly, for the V-phase winding portion L6, the inductance component is represented by 61, and the resistance component by 62. Furthermore, for the W-phase winding portion L7, the inductance component is represented by 71, and the resistance component by 72.

[0061] Furthermore, each phase is equipped with a transformer structure forming the extraction section 214. Specifically, in phase U, the primary coil 531 of the phase U transformer structure 53 is connected in series with the winding portion L5; in phase V, the primary coil 631 of the phase V transformer structure 63 is connected in series with the winding portion L6; and in phase W, the primary coil 731 of the phase W transformer structure 73 is connected in series with the winding portion L7. Moreover, the secondary coils 532 of phase U transformer structure 53, 632 of phase V transformer structure 63, and 732 of phase W transformer structure 73 are connected to the supply section 215. Furthermore, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange section 216.

[0062] Furthermore, the turns ratio (the ratio of the number of turns in the secondary coil to the number of turns in the primary coil) of the transformers in each phase is basically the same, but it can also be different. Additionally, in Figure 3 In the illustrated configuration, all three phases are equipped with transformer structures, and their secondary coils are connected to the supply unit 215 and the signal exchange unit 216. However, it is also possible to configure transformer structures only for a portion of the three phases, connecting their secondary coils to the supply unit 215 and the signal exchange unit 216. Alternatively, all three phases can be equipped with transformer structures, with the secondary coils of a portion of the transformer structures connected to the supply unit 215, and the secondary coils of the remaining transformer structures 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 transmitting and receiving specified signals with the encoder 22, can be appropriately set according to their respective purposes.

[0063] By employing the winding section 25 and transformer structures 53, 63, and 73 configured in this way, a portion of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction section 214 as drive power for the encoder 22. According to this structure, power is consistently and stably supplied to the encoder 22 even when the motor 2 is being driven. Furthermore, this eliminates the need for wiring for the encoder 22, significantly reducing wiring work and lowering costs. Additionally, in the first embodiment, the transformer structure for each phase is preferably configured using the coil ends of the stator 213.

[0064] Next, based on Figure 4The second method will be described. The structure of the winding section 25 of the motor body 21 is the same as that of the first method described above, so its detailed description is omitted. In the second method, the primary coil 531 of the transformer structure 53 corresponding to U is connected in parallel with respect to the winding sections L5, L6, and L7 of each of the three phases, and the primary coil 631 of the transformer structure 63 corresponding to V is connected in parallel with respect to the primary coil 631 of V and the primary coil 731 of the transformer structure 73 corresponding to W. Specifically, the wire L50 containing the primary coil 531, the wire L60 containing the primary coil 631, and the wire L70 containing the primary coil 731 are Y-connected, and the other ends are connected to the winding section L5 of the U phase, the winding section L6 of the V phase, and the winding section L7 of the W phase, respectively. Furthermore, 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 section 215. Furthermore, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange unit 216.

[0065] Furthermore, in the second method, the turns ratio of the transformers in each phase is basically the same, but it can also be different. Additionally, in Figure 4 In the illustrated configuration, a transformer structure corresponding to all three phases is configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. However, a transformer structure corresponding only to a portion of the three phases can also be configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. Alternatively, a transformer structure corresponding to all three phases can be configured, with the secondary coil of a portion of the transformer structure connected to the supply unit 215, and the secondary coils of the remaining transformer structures 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 transmitting and receiving specified signals with the encoder 22, can be appropriately set according to their respective purposes.

[0066] By employing the winding section 25 and transformer structures 53, 63, and 73 configured in this way, a portion of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction section 214 as drive power for the encoder 22. According to this structure, power is consistently and stably supplied to the encoder 22 even when the motor 2 is being driven. Furthermore, this eliminates the need for wiring for the encoder 22, significantly reducing wiring work and lowering costs. In addition, in the second embodiment, similarly to the first embodiment, the transformer structure for each phase is preferably configured using the coil ends of the stator 213.

[0067] Next, based on Figure 5The third method will be explained. The structure of the winding section 25 of the motor body 21 is the same as that of the first method described above, so its detailed description is omitted. However, in the third method, the coil components 51, 61, and 71 of the winding sections L5, L6, and L7 of each phase are used as the primary coils 531, 631, and 731 of the corresponding transformer structures 53, 63, and 73. Specifically, in phase U, the transformer structure 53 is formed by using coil component 51 as the primary coil 531; in phase V, the transformer structure 63 is formed by using coil component 61 as the primary coil 631; and in phase W, the transformer structure 73 is formed by using coil component 71 as the primary coil 731. Therefore, in the third method, the secondary coils 532, 632, and 732 of the transformer structures 53, 63, and 73 of each phase are wound together with the main coil of the winding section, which is also a primary coil, on the stator core, thereby forming the transformer structures 53, 63, and 73 of each phase. Furthermore, the secondary coil 532 of transformer structure 53, the secondary coil 632 of V-phase transformer structure 63, and the secondary coil 732 of W-phase transformer structure 73 are connected to the supply unit 215. Additionally, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange unit 216.

[0068] Furthermore, in the third method, the turns ratio of the transformers in each phase is basically the same, but it can also be different. Additionally, in Figure 5 In the illustrated configuration, a transformer structure corresponding to all three phases is configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. However, a transformer structure corresponding only to a portion of the three phases can also be configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. Alternatively, a transformer structure corresponding to all three phases can be configured, with the secondary coil of a portion of the transformer structure connected to the supply unit 215, and the secondary coils of the remaining transformer structures 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 transmitting and receiving specified signals with the encoder 22, can be appropriately set according to their respective purposes.

[0069] By employing the winding section 25 and transformer structures 53, 63, and 73 configured in this way, a portion of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction section 214 as drive power for the encoder 22. According to this structure, power is consistently and stably supplied to the encoder 22 even when the motor 2 is being driven. Furthermore, the elimination of wiring for the encoder 22 significantly reduces wiring work and lowers costs. Additionally, in the third embodiment, since the secondary coils of each transformer structure are wound around the stator core, the coil ends of the stator 213 can be compactly formed.

[0070] and, Figures 3 to 5 The transformer structures 53, 63, and 73 shown are multi-winding transformer structures, but as variations, single-winding transformer structures can also be used. For example, in... Figure 5 In the case of a single-winding transformer structure as shown, transformer structures 53, 63, and 73 are formed by setting the winding portion 25 of the motor 2 as the primary coil and setting a portion of the winding portion 25 as the secondary coil. That is, the secondary coil portion in the winding portion 25 is shared by the primary side and the secondary side.

[0071] In addition, based on Figure 6 right Figure 4 A variation of the method shown will be explained. Figure 4 In the illustrated configuration, as described above, transformer configurations 53, 63, and 73 are arranged in parallel with respect to the respective winding portions L5, L6, and L7 of the three phases. Alternatively, power can be extracted from the winding portions L5, L6, and L7 of each phase, and the extracted power can be supplied to a rectifier circuit, a smoothing circuit, and a step-up / step-down circuit based on a DC-DC converter, respectively. In this configuration, the extraction unit 214 extracts power directly from the winding portion 25, rather than from the winding portion 25 via the transformer configuration; however, this also falls within the scope of this invention.

[0072] Next, based on Figure 7 The fourth method will be described. The structure of the winding section 25 of the motor body 21 is the same as in the first method described above, therefore a detailed description is omitted. In the fourth method, the primary coil 531 of the transformer structure 53 is connected between the U and V phases in parallel with the winding sections L5 and L6 of the U and V phases; the primary coil 631 of the transformer structure 63 is connected between the V and W phases in parallel with the winding sections L6 and L7 of the V and W phases; and the primary coil 731 of the transformer structure 73 is connected between the W and U phases in parallel with the winding sections L7 and L5 of the W and U phases. Furthermore, the secondary coils 532 of the transformer structure 53, 632 of the transformer structure 63, and 732 of the transformer structure 73 are connected to the supply section 215. Additionally, each of the secondary coils 532, 632, and 732 is also connected to the signal exchange section 216.

[0073] Furthermore, in the fourth method, the turns ratio of the transformers in each phase is basically the same, but it can also be different. Additionally, in Figure 7In the illustrated configuration, a transformer structure corresponding to all three phases is configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. However, a transformer structure corresponding only to a portion of the three phases can also be configured, with its secondary coil connected to the supply unit 215 and the signal exchange unit 216. Alternatively, a transformer structure corresponding to all three phases can be configured, with the secondary coil of a portion of the transformer structure connected to the supply unit 215, and the secondary coil of the remaining phase transformer structures 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 transmitting and receiving specified signals with the encoder 22, can be appropriately set according to their respective purposes.

[0074] By employing the winding section 25 and transformer structures 53, 63, and 73 configured in this way, a portion of the power supplied to the motor 2 via the power line 11 can be extracted by the extraction section 214 as drive power for the encoder 22. According to this structure, power is consistently and stably supplied to the encoder 22 even when the motor 2 is being driven. Furthermore, the elimination of wiring for the encoder 22 significantly reduces wiring work and lowers costs. In addition, in the fourth embodiment, similar to the first embodiment, the transformer structure for each phase is preferably configured using the coil ends of the stator 213.

[0075] <Power Supply Control>

[0076] By employing a motor 2 with a winding section 25 and a transformer structure as described in the first to third embodiments above, it is possible to extract power for the encoder 22 from the drive power supplied to the motor 2. However, in situations where the drive power supplied to the motor 2 is low, such as when the motor 2 is operating at low speed and light load, it may be difficult to provide sufficient power from the supply section 215 to drive the encoder 22, potentially affecting the operation of the encoder 22. Therefore, to avoid such instability in the power supply to the encoder 22, [further measures are taken]. Figure 8 The power supply control is shown.

[0077] Figure 8 The power supply control shown is a control related to the power supply to the motor 2, which is repeatedly executed by the control unit 41 of the servo drive 4. Furthermore, the power supply to the motor 2 is implemented using known vector control, therefore a detailed description of vector control is omitted. First, in S101, the power supplied by the supply unit 215 to the encoder 22 is calculated. This supplied power is a portion of the power actually supplied to the motor 2 via the power line 11; therefore, specifically, it can be calculated taking into account the voltage applied to each phase, the induced voltage of the motor body 21, impedance, the impedance of the transformer structure, etc.

[0078] Then, in S102, it is determined whether the power supplied calculated in S101 is lower than a threshold associated with the power required to drive the encoder 22. This threshold can be set to the maximum value among the fluctuations in the drive power due to the operation of the encoder 22, but it can also be a value other than this (the minimum value of the fluctuation, an intermediate value). If a positive determination is made in S102, the process proceeds to S103. In S103, the process of increasing the d-axis current value is performed in the vector control used to supply power to the motor 2. The d-axis current value is originally a current that does not contribute to the torque of the motor 2. In addition, even if the current supplied to the motor 2 is low, there is room for the control unit 41 to perform current control. Therefore, even if the d-axis current value is increased through the process of S103, it is difficult to have a significant impact on the drive of the motor 2. Furthermore, the increase in the d-axis current value is adjusted such that the larger the difference between the power supplied calculated in S101 and the aforementioned threshold, the larger the increase in the d-axis current value. In addition, if a negative determination is made in S102, this control ends.

[0079] according to Figure 8 The power supply control shown can provide appropriate power to the encoder 22 regardless of the operating state of the motor 2.

[0080] <Modification 1 of Power Supply Control>

[0081] Here, based on Figures 9-11 The details of providing control using the power derived from the d-axis current value will be explained. In this variation, the servo driver 4 includes an output unit that superimposes the first power required to drive the encoder 22 onto the drive power required to drive the motor 2, and outputs this output to the motor 2. This output unit is equivalent to... Figure 1 The power conversion unit 43 shown, or a functional unit assembled as part of the power conversion unit 43, adjusts the power superimposed on the drive power of the motor 2 as the first power by controlling the d-axis current value in the drive current of the motor 2. Hereinafter, the explanation will focus on the superposition of this first power.

[0082] Figure 9This is a graph showing the correlation between the drive speed of motor 2 and the current applied by servo driver 4. In the low-speed region of motor 2 (e.g., the region where the drive speed is below V0), no d-axis current is applied in its drive control, and its drive current is essentially only the q-axis current. Moreover, in the high-speed region of motor 2 (e.g., the region where the drive speed exceeds V0), the drive current is applied in such a way that the d-axis current value increases with the increase of the drive speed. Therefore, the maximum current that substantially contributes to the torque of motor 2 is represented by line L100, and the upper limit of the current in the low-speed region R2 inside line L100 (including the origin) is approximately constant at the rated current Ir, while the upper limit of the current in the high-speed region R1 decreases with the increase of the drive speed. In addition, the outer side of line L100 is set as region R0 where the application of drive current to motor 2 from servo driver 4 is not allowed or cannot be performed. Therefore, the aforementioned power supply control using the d-axis current value must be performed in regions R1 and R2.

[0083] Here, based on Figure 10 The power supply control for motor 2 is explained in the state represented by point P1 within region R1. In the state of point P1, as follows... Figure 10 As shown in (a), the servo driver 4 outputs drive currents to the motor 2 with a q-axis current value of Iq1 (line L102) and a d-axis current value of Id1 (line L101). In this state, assuming the drive state of the motor 2 does not change, the q-axis current value and the d-axis current value do not change over time. Moreover, when the power required to drive the encoder 22 (the first power) is superimposed with the power required to drive the motor 2 and output to the motor 2, the q-axis current value remains constant at Iq1, and the d-axis current value increases from Id1 with an upper limit of Id1' (line L101'). Figure 10 As shown in (b), when the q-axis current value is Iq1, the d-axis current value Id1' becomes the current output to motor 2. Figure 9 The upper limit of the d-axis current value that can be increased at point P1' on line L100. Figure 10 The circle in (b) is a circle with a radius equal to the rated current Ir.

[0084] Furthermore, when the driving speed of motor 2 is high, i.e., when the driving speed exceeds V0, the electrical angular frequency of the current flowing in the windings of motor 2 becomes relatively high, thus increasing the power extraction efficiency of the transformer structure in the extraction unit 214. Therefore, under such circumstances, as Figure 10As shown in (a), the d-axis current value is increased from Id1 to a maximum of Id1' in a manner that does not change over time. This causes the power required to drive the encoder 22 (the first power) to be superimposed on the drive power of the motor 2, and the power is output from the servo driver 4 to the motor 2. A portion of the output power, that is, the power corresponding to the increase in the d-axis current value, is extracted by the extraction unit 214 and provided to the encoder 22 side.

[0085] Next, based on Figure 11 The power supply control for motor 2, represented by point P2 within region R2, is explained. In the state of point P2, as follows... Figure 11 As shown in (a), the servo driver 4 outputs a drive current to the motor 2 with a q-axis current value of Iq1 (line L102) and a d-axis current value of Id1 (represented by line L101, but Id1 = 0). In this state, assuming that the drive state of the motor 2 does not change, the q-axis current value and the d-axis current value do not change with time.

[0086] Here, when the driving speed of motor 2 is low, i.e., below V0, the electrical angular frequency of the driving current flowing in the windings of motor 2 becomes lower, thus the power extraction efficiency in the aforementioned transformer structure becomes relatively lower. Therefore, when the power required to drive encoder 22 (the first power) is superimposed with the power required to drive motor 2 and output to motor 2, the d-axis current value is increased from Id1 to Id1' while maintaining the q-axis current value at Iq1, but with... Figure 10 The method shown in (a) is different, such as Figure 11 As shown in (a), the d-axis current value is increased to Id1' by varying the d-axis current value along with a specified DC component offset over time. That is, the increased d-axis current value is not a constant value, but rather a value that varies over time with a constant amplitude and a constant frequency. The result is as follows: Figure 11 As shown in (b), if the increased d-axis current value is expressed in terms of effective value, then the current output to motor 2 reaches... Figure 9 Point P2' on line L100. Additionally, if the time-varying d-axis current Id1' is compared with... Figure 11 The superposition of (b) represents the change in amplitude of ΔId.

[0087] Furthermore, regarding the variation of the increased d-axis current value, this variation is preferably in the form of a sinusoidal wave vibrating at a predetermined frequency, for example, a frequency higher than the electrical angular frequency of the drive current associated with the drive speed of motor 2. Alternatively, the increased d-axis current value can also be a variation of a rectangular wave shape or a triangular wave shape. Additionally, the aforementioned offset of the DC component can be appropriately adjusted based on the power that should be supplied to encoder 22.

[0088] Thus, when the motor 2 is in the driving state within region R2, the d-axis current value is increased from dI1 to the maximum dI1' in a manner that the d-axis current value changes over time. This causes the power required to drive the encoder 22 (the first power) to be superimposed on the drive power of the motor 2, and then output from the servo driver 4 to the motor 2. As a result, even when the electrical angle frequency of the drive current of the motor 2 is low, a portion of the output power, that is, the power corresponding to the increase in the d-axis current value, is appropriately extracted by the extraction unit 214 and provided to the encoder 22 side.

[0089] Furthermore, regarding the control of the d-axis current value up to the above, feedback control is preferably performed based on the power actually extracted by the extraction unit 214 of the motor 2 and the power that should be supplied to the encoder 22. In this feedback control, information related to the power actually extracted by the extraction unit 214 and information related to the power that should be supplied to the encoder 22 are transmitted wirelessly from the motor 2 side to the servo drive 4 side. Alternatively, the servo drive 4 may also have predetermined information regarding the power that should be supplied to the encoder 22.

[0090] Based on the above, this modified example illustrates the following method: Based on the efficiency of power extraction in the transformer structure of the extraction unit 214, and the drive speed of the motor 2, the d-axis current required for superimposing the power (first power) for driving the encoder 22 is controlled. Furthermore, in this modified example, the drive speed that will become the boundary between the high-speed and low-speed regions is set to V0. However, this V0 does not necessarily need to coincide with the point of change of the boundary value of the current shown by line L100 (the point where the current begins to decrease as the drive speed increases), and can be appropriately set according to the power extraction efficiency in the transformer structure.

[0091] Furthermore, regarding the generation of the first power superimposed based on the control of the aforementioned d-axis current value, the amount of the first power generated is increased by increasing the d-axis current. However, depending on the type of motor (e.g., SPM, IPM, etc.), the superimposed first power can be adjusted by combining increases and decreases in the d-axis current value and the q-axis current value. Therefore, in addition to controlling the d-axis current value, the q-axis current value can also be controlled, thereby appropriately increasing or decreasing each current value to adjust the amount of the first power generated.

[0092] <Modification 2 of Power Supply Control>

[0093] When motor 2 is stopped (when the rotor 212 of motor 2 is stopped) or when it is necessary to stop motor 2, power is usually not supplied to motor 2. Therefore, it is difficult to supply power to encoder 22. Therefore, in this modified example, when motor 2 is stopped, power is supplied to motor 2 in the following manner: with the q-axis current value set to a constant value required to stop the motor, the d-axis current value is varied over time, for example, the d-axis current value is shifted in a sinusoidal shape. With such power supply, the q-axis current value is a constant value required to stop the motor, so motor 2 is stopped without rotating. Generally, when the external force applied to motor 2 at the time of stop is approximately zero, the q-axis current value is zero; when a certain external force such as an eccentric load is applied, the current value that exerts the torque resisting that external force is set to the q-axis current value.

[0094] Based on this, by flowing a d-axis current that varies over time, it is possible to stop the motor 2 while simultaneously supplying a portion of the power supplied to the motor 2 to the encoder 22 using a transformer structure. In addition to shifting the d-axis current value in a sine wave shape, it is also possible to use a shifting d-axis current in a rectangular wave shape, a shifting d-axis current in a triangular wave shape, etc., and to flow a d-axis current that varies with these other shifts.

[0095] Here, the research is in Figure 3 The circuit equations for motor 2 using a single-phase transformer are shown below. The transformer characteristics are identical for each phase. Furthermore, in the following equations, voltages Vu, Vv, Vw, and currents Iu, Iv, Iw represent the output voltage and current of each phase of driver 4; Lu, Lv, Lw represent the self-inductance of each phase of motor 2; and Muv, Mvw, Mwu represent the mutual inductance between phases of motor 2. Additionally, ωe represents the electrical angular frequency, Φuvw represents the maximum linkage flux of the armature winding, R represents the winding resistance, Ke represents the induced voltage constant, and s is the differential operator. Furthermore, voltages Vux2, Vvx2, Vwx2, and currents Iux2, Ipx2, Iwx2 represent the output voltage and current on the secondary side of the transformer configuration; Lx1, Lx2, and Mx represent the primary inductance, secondary inductance, and mutual inductance of the transformer configuration, respectively; and Rx1 and Rx2 represent the winding resistances on the primary and secondary sides of the transformer configuration. Additionally, θe is the electrical angle.

[0096] The circuit equations for motor 2 are represented by the following equations 1 and 2.

[0097]

[0098]

[0099] Furthermore, by implementing the transformation process from the three phases of UVW to the two phases of dq and the transformation process from the fixed coordinate system to the rotating coordinate system, the circuit equations shown in Equations 3 and 4 are obtained.

[0100]

[0101]

[0102] Here, we verify the appropriateness of Equations 3 and 4 above. Figure 13 The upper section (a) shows a schematic of the circuit model used for this verification. Motor 2 is driven by an inverter (equivalent to driver 4) powered by a DC power supply, which provides drive current via a power line. Figure 13 In the model, a transformer structure (transformer) is arranged between the power line and the motor body, and a load RL (such as a sensor) is installed on its secondary side. The three-phase output of the inverter each contains a transformer structure that acts as a single-phase transformer, and the motor is connected to the next stage. The motor is driven by drive current from the inverter for both current control and speed control. In this current control, parameters related to the motor's characteristics are appropriately fed back to the inverter, which uses these parameters to generate the drive current. Furthermore, Figure 13 The lower section (b) represents the structure of the single-phase transformer and load inside the transformer configuration. The parameters of the motor and transformer configuration in the circuit model are shown in Table 1 and Table 2 below, respectively.

[0103] Table 1 lists the parameters related to the motor.

[0104] [Table 1]

[0105] symbol value unit winding resistance R 2.5 Ω d-axis inductance Ld <![CDATA[2.1×10 -3 ]]> H q-axis inductor Lq <![CDATA[2.1×10 -3 ]]> H Induced voltage constant Ke 0.1386 V / (rad / s) Torque constant Kt 0.1386 Nm / A Electrical angular frequency ωe 523.60 rad / s mechanical angular frequency ωm 104.72 rad / s Extreme logarithm P 5 pole inertia J <![CDATA[0.16×10 -3 ]]> <![CDATA[kg·m 2 ]]> viscosity D <![CDATA[1.3×10 -3 ]]> Nm / (rad / s)

[0106] Table 2 lists the parameters related to the transformer's construction.

[0107] [Table 2]

[0108] symbol value unit First-order self-sensitivity Lx1 <![CDATA[960×10 -6 ]]> H Secondary self-induction Lx2 <![CDATA[960×10 -6 ]]> H Primary winding resistance Rx1 <![CDATA[1.1 4 ]]> Ω Secondary winding resistance Rx2 1.14 Ω Mutual induction Mx <![CDATA[950×10 -6 ]]> H Number of turns ratio N 1 --- Coupling coefficient k 0.99 --- load resistor RL 1 Ω

[0109] Here, Figure 13 In (a), points Pa, Pb, and Pc represent the measurement points for the three-phase voltage and current. In the simulation using the circuit model, the three-phase voltage and current at measurement points Pa, Pb, and Pc are measured, and the voltage and current along the dq axis are calculated based on these measured values. At measurement point Pa, the terminal voltage and current of the motor are calculated; at measurement point Pb, the output voltage and current of the inverter are calculated; and at measurement point Pc, the output voltage and current of the transformer structure are calculated. Furthermore, the d-axis voltage and q-axis voltage at each measurement point calculated according to the aforementioned circuit equations are compared. Additionally, the motor's rotational speed is set to a constant speed during the calculation and comparison.

[0110] The comparison results are shown in Tables 3 to 5 below.

[0111] Table 3 shows the comparison results of the measurement point Pa.

[0112] [Table 3]

[0113]

[0114] Table 4 shows the comparison results of Pb at the measurement points.

[0115] [Table 4]

[0116]

[0117] Table 5 shows the comparison results of the measurement point Pc.

[0118] [Table 5]

[0119]

[0120] Based on the comparison results above, the error between the calculation results based on the circuit equations and the calculation results based on the circuit model converges to within 1%. Therefore, the appropriateness of the circuit equations in Equations 3 and 4 above is confirmed. Furthermore, it is clearly evident that the possibility of incorporating a transformer structure for power extraction into a motor adversely affecting current control and speed control is extremely low. Therefore, it can be said that a motor with a transformer structure can be designed using the above circuit equations.

[0121] Furthermore, Equations 5 and 6 below show that... Figure 3 The circuit equations for motor 2 shown are for motor 2 constructed using a three-phase transformer. These equations are also applicable to motor design.

[0122]

[0123]

[0124] Furthermore, Equations 7 and 8 below show that... Figure 5 The circuit equations for motor 2, which employs a transformer construction, are shown below. These equations are also applicable to motor design.

[0125]

[0126]

[0127] <Variations of Driver 4>

[0128] In the above embodiment, power is supplied to the winding section 25 of the motor 2 via the inverter circuit within the power conversion unit 43 of the driver 4. That is, the drive current generated by the inverter circuit is supplied to the winding section 25 of the motor 2, and a portion of this power is extracted by the extraction unit 214 as power for the encoder 22. On the other hand, in this modified example, as... Figure 12 As shown, power supply can be provided based on the power superposition section 432, which is formed separately from the inverter circuit 431 within the power conversion section 43. Furthermore, Figure 12 The winding section 25 shown is Figure 5 The winding section shown is replaced by the one described above, but for... Figure 3 , Figure 5 The winding section shown can also be applied to this modified example.

[0129] The inverter circuit 431 has a structure in which bridge arms for the U phase, V phase, and W phase are connected in parallel between the positive and negative power lines. The output of each phase bridge arm is connected to the winding portion of each phase of the motor 2 via power lines. Furthermore, a power superposition section 432 is provided within the power conversion unit 43. This power superposition section 432 is connected to the power lines in parallel with the inverter circuit 431, superimposing power onto the drive current of the motor 2 flowing to the winding portion 25 via the power lines. The power superposition section 432 can perform high-frequency power superposition in each of the U, V, and W phases via a transformer structure. With this structure, AC power suitable for supplying power to the encoder 22 can be delivered to the extraction unit 214 separately from the operation of the motor 2. Alternatively, the power superposition section 432 can also be connected in series with the inverter circuit 431.

[0130] <Examples of devices for providing extracted electricity>

[0131] In the above embodiment, the power extracted by the extraction unit 214 is supplied to the encoder 22, but the extracted power can also be supplied to devices other than the encoder 22. For example, power can also be supplied to sensor devices (e.g., temperature sensors, vibration sensors, etc.) disposed inside or outside the motor 2. In this case, a port suitable for power supply, serving as a connection port for cables to the sensors, can also be provided on the motor body 21.

[0132] <Variations on power extraction>

[0133] based on Figure 14 This variation will be explained. Figure 14 This is a diagram showing a schematic structure of motor 2 in this modified example. Furthermore, motor 2 in this embodiment is similar to... Figure 2Similar to the method shown, an extraction section 214 with a transformer structure is provided relative to the winding section 25. The transformer structure of the extraction section 214 can be adopted as... Figure 3 , Figure 4 , Figure 7 The structure shown is essentially the same. Furthermore, in this modified example, an extraction section 214b capable of power extraction is also provided for the power line 11 connected to connector 211. Power extraction by the extraction section 214b is also achieved through... Figure 3 , Figure 4 The transformer structure shown is an electrically identical transformer structure assembled into the power line 11.

[0134] The electricity extracted by the extraction unit 214b can undergo prescribed rectification processes and be used to power devices such as temperature sensors and vibration sensors located externally to the motor 2. Furthermore, by storing the extracted electricity in a secondary battery, a stable power supply can be provided to the temperature sensors, etc. Figure 14 In the motor 2 shown, the power extracted by the extraction unit 214 is supplied to the encoder 22. However, the power extracted by the extraction unit 214b can be used instead, or the power extracted by both the extraction units 214 and 214b can be used to supply the encoder 22. Furthermore, in the motor 2, the extraction unit 214 may not be provided, and the encoder 22 may receive power from a built-in battery or from the servo driver 4.

[0135] Thus, in the motor 2 disclosed herein, power can be extracted not only from its winding section 25, but also from the power line 11 to supply power to the encoder 22, external sensors, etc. Therefore, the wiring load for power supply in the servo system can be greatly reduced.

[0136] <Variations on power supply and signal relay>

[0137] based on Figure 15 This variation will be explained. Figure 15 This is a diagram showing a schematic structure of the motor 2 in this modified example. Furthermore, in this embodiment, Figure 14 The extraction unit 214b shown is also configured to communicate with the processing unit 221 of the encoder 22. Furthermore, the communication with the processing unit 221 is wireless, and the power used for this is extracted from the power line 11 by the extraction unit 214b. Additionally, the power extracted by the extraction unit 214b is supplied to the processing unit 221 of the encoder 22 via the supply unit 215 from the motor body 21 side.

[0138] The extraction unit 214b of this method includes a first communication unit 2141 and a second communication unit 2142. The first communication unit 2141 can wirelessly communicate with the processing unit 221. The detection signal from the encoder 22 is input via wireless communication, and signals can also be transmitted from the first communication unit 2141 to the encoder 22. The wireless communication method of the first communication unit 2141 is not limited to a specific method. Moreover, as described above, the extraction unit 214b has a transformer structure for extracting power, and the second communication unit 2142 functions as an interface for communicating with the servo driver 4 using the transformer structure. For example, the second communication unit 2142 can superimpose the detection signal from the encoder 22 received via the first communication unit 2141 with the current flowing through the power line 11. That is, when the second communication unit 2142 superimposes a signal onto the power line 11, it sends a signal to the secondary coil side in the transformer structure, thereby superimposing the output of the primary coil side with the current flowing through the power line 11. Thus, the system is configured to transmit and receive signals between the power line 11 and the processing unit 221 of the encoder 22 via the second communication unit 2142, and send the signal to the servo driver 4 via the power line 11.

[0139] Furthermore, the second communication unit 2142 can also receive a specified signal from the servo driver 4 via the aforementioned transformer structure and transmit it to the first communication unit 2141, which then transmits it wirelessly to the processing unit 221 of the encoder 22. That is, the extraction unit 214b and the processing unit 221 can communicate with each other.

[0140] With this structure, the power to the encoder 22 mounted on the motor 2 is supplied by a portion of the power from the power line 11, and the motor 2 also functions as a relay device for information between the servo drive 4 and the encoder 22. The extraction unit 214b can be positioned in the power line 11 at a location capable of wireless communication with the encoder 22. Generally, both the encoder 22 and the power line 11 are located near the motor body 21, thus facilitating the installation of the extraction unit 214b. Furthermore, in Figure 15 In the manner shown, there is no need for wiring to supply power to the encoder 22 or to transmit signals, thus greatly reducing the workload required to configure the servo system.

[0141] Furthermore, as another variation, the extraction unit 214b can also be configured to receive detection signals from temperature sensors, vibration sensors, etc., which are power supply destinations, via wireless communication using the first communication unit 2141, and then superimpose them onto the power line 11 via the second communication unit 2142 before transmitting them to the servo driver 4. Moreover, the extraction unit 214b can also be configured to relay the detection signals of both the aforementioned sensors and the encoder 22 to the servo driver 4. Additionally, the first communication unit 2141 can also perform wired communication with the encoder 22, sensors, etc.

[0142] <Postscript 1>

[0143] A driver (4) provides drive power to a motor (2), the motor (2) comprising: an extraction unit (214) for extracting a portion of power supplied from the outside; and a supply unit (215) for supplying the power extracted by the extraction unit (214) to an external device, the driver comprising an output unit that superimposes a first power supplied to the external device with drive power required for driving the motor (2) and outputs it to the motor, the output unit adjusting the power superimposed as the first power by controlling the d-axis current value in the drive current of the motor (2).

[0144] Label Explanation

[0145] 2: Motor; 4: Servo driver; 22: Encoder; 25: Winding section; 53, 63, 73: Transformer structure; 211: Connector (power input section); 214: Extraction section; 251: Supply section.

Claims

1. A driver that provides driving power to a motor, the motor comprising: an extraction section for extracting a portion of power supplied from an external source; and a supply section for supplying the power extracted by the extraction section to an external device, wherein, The driver includes an output section that superimposes a first power supplied to the external device with the drive power required to drive the motor, and outputs the superimposed power to the motor. The output unit adjusts the power superimposed as the first power by controlling the d-axis current value in the drive current of the motor.

2. The driver according to claim 1, wherein, The output unit generates the first power by controlling the d-axis current value within the allowable current range that can be output from the driver to the motor.

3. The driver according to claim 2, wherein, The output unit controls the d-axis current value in the motor's drive current based on the motor's drive speed.

4. The driver according to claim 3, wherein, When the drive speed of the motor is higher than a predetermined threshold, the output unit controls the d-axis current value in a way that prevents the d-axis current value from changing over time to generate the first power, which is then superimposed on the drive power required for the motor's drive.

5. The driver according to claim 3, wherein, When the drive speed of the motor is below a predetermined threshold, the output unit controls the d-axis current value in a manner that changes the d-axis current value over time to generate the first power, which is then superimposed on the drive power required for the motor's drive.

6. The driver according to claim 5, wherein, The output unit controls the d-axis current value in such a way that the d-axis current value changes over time at a frequency higher than the electrical angular frequency corresponding to the driving speed of the motor.

7. The driver according to claim 1, wherein, When the power supplied by the supply unit is lower than a threshold related to the power required to drive the external device, the output unit controls the d-axis current value in the drive current of the motor to generate the first power and outputs it to the motor.

8. The driver according to claim 2, wherein, In addition to controlling the d-axis current value, the output unit also controls the q-axis current value in the motor's drive current to generate the first power.

9. The driver according to claim 1, wherein, The output unit generates the first power by changing the d-axis current value over time while setting the q-axis current value to a fixed value, and then outputs it to the motor.

10. The driver according to claim 9, wherein, When the motor stops, the output unit generates the first power and outputs it to the motor.

11. The driver according to any one of claims 1 to 10, wherein, The output unit performs feedback control on the d-axis current value based on the power extracted by the extraction unit of the motor and the power that should be supplied to the external device.

Images