motor control device

Abstract

The present invention provides an electric motor control device comprising an electric motor drive unit for driving and controlling an electric motor, a discharge control unit for controlling the consumption of regenerative power from the electric motor through a regenerative power discharge resistor, and a housing for housing the electric motor drive unit and the discharge control unit, wherein at least a portion of the housing is configured as a regenerative power discharge resistor.

Description

Technical Field

[0001] This invention relates to an electric motor control device. Background Technology

[0002] Traditionally, electric motors are installed in machine tools, industrial machinery, and the like, and electric motor control devices are used to control these motors. These electric motor control devices include a regenerative discharge resistor for dissipating the electricity regenerated when the motor is decelerated or stopped. Japanese Patent Application Publication No. 05-276774 discloses a servo control device in which an internal regenerative discharge resistor and an external regenerative discharge resistor are connected in series or parallel. Summary of the Invention

[0003] The regenerative discharge resistor can be mounted outside the housing of the motor control device or disposed inside the housing, which is a typical configuration. In this case, dedicated space must be ensured both outside and inside the housing for the regenerative discharge resistor.

[0004] One aspect of this disclosure is an electric motor control device comprising an electric motor drive unit for driving and controlling an electric motor, a discharge control unit for controlling the consumption of regenerative power from the electric motor through a regenerative power discharge resistor, and a housing for housing the electric motor drive unit and the discharge control unit, wherein at least a portion of the housing is configured as the regenerative power discharge resistor. Attached Figure Description

[0005] The objects, features, and advantages of the present invention will become more apparent from the following description of embodiments in conjunction with the accompanying drawings. In these drawings,

[0006] Figure 1 This is a perspective view showing the external structure of a motor control device according to one embodiment.

[0007] Figure 2 This is a three-dimensional diagram showing the internal structure of the electric motor control device.

[0008] Figure 3 This is a block diagram illustrating an example of the circuit structure of the motor drive unit in a motor control device.

[0009] Figure 4 This diagram illustrates a first structural example where the housing is configured as a regenerative power discharge resistor.

[0010] Figure 5 This diagram illustrates a second structural example where the housing is configured as a regenerative electrical discharge resistor.

[0011] Figure 6A This is a cross-sectional view showing an example of the internal structure of a wall within a housing that is configured as a regenerative electrical discharge resistor.

[0012] Figure 6B This is a cross-sectional view showing another example of the internal structure of the wall within the housing, which is configured as a regenerative electrical discharge resistor. Detailed Implementation

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Throughout the drawings, corresponding structural elements are labeled with the same reference numerals. For ease of understanding, the scale of these drawings has been appropriately altered. Furthermore, the embodiments shown in the drawings are merely examples for implementing the invention, and the invention is not limited to the illustrated embodiments.

[0014] Figure 1 This is a perspective view showing the external structure of an electric motor control device 10 according to one embodiment. The electric motor control device 10 is a device for driving and controlling an electric motor 11. Inside the housing 1, a printed circuit board (see reference 1) houses the circuitry of the electric motor control unit 12 and the electric motor drive unit 3. Figure 3 Various connector types, including connectors for connecting to the motor 11, are disposed on the front side wall 1a of the housing 1. The motor 11 is connected to the motor control device 10 via the connectors disposed on the front side wall 1a. The housing 1 includes a front side wall 1a, a left side wall 1b, a right side wall 1c, an upper side wall 1d, a lower side wall 1e, and a rear side wall 1f. In addition, the rear side wall 1f of the housing 1 is configured as a mounting plate for mounting the motor control device 10 to the control panel 2.

[0015] Figure 2 This is a perspective view showing the internal structure of the motor control device 10. Additionally, in Figure 2 In order to show the internal structure, only the rear side wall 1f and the left side wall 1b of the walls constituting the shell 1 are shown in the diagram. Figure 2 As shown, printed circuit boards 21 and 22, which house various circuit components for driving the electric motor, are housed inside the motor control device 10. Circuit components constituting the motor control unit 12 are mounted on the printed circuit board 21, and circuit components constituting the motor drive unit 3 are mounted on the printed circuit board 22 (see reference). Figure 3 ).

[0016] Figure 3 It means Figure 1 A block diagram illustrating an example of the circuit structure of the motor drive unit 3 in the motor control device 10 shown. (See diagram for example.) Figure 3 As shown, the motor drive unit 3 drives and controls the motor 11 based on the control signal from the motor control unit 12, and includes a control coil 31, an electromagnetic contactor 32, a reactor (three-phase reactor) 33, an AC / DC converter 34, a charging control unit 35, a discharging control unit 36, a DC link capacitor 37, and a DC / AC converter 38.

[0017] The control coil 31 controls the connection (on) / disconnection (off) of the electromagnetic contactor 32 based on the electromagnetic contactor opening / closing command from the motor control unit 12. AC voltage from an AC power source (e.g., a three-phase AC power source) is applied to the AC / DC converter 34 via the connected electromagnetic contactor 32 and a reactor (three-phase reactor) 33, converting it into DC (pulsating current) voltage. Here, the three-phase reactor 33 is located on the primary side (AC power supply side) of the motor drive unit (inverter) 3 to improve the power factor (to address high-order harmonics) or reduce power surges. The AC / DC converter 34 has rectifier diodes 341, 342, 343, 344, and 345, 346 respectively, for the three phases (R-phase, S-phase, and T-phase) input via the three-phase reactor 33.

[0018] The DC voltage, after AC / DC conversion by AC / DC converter 34, is smoothed by DC link capacitor 37 via charging control unit 35. The smoothed DC voltage is then converted into AC voltage (e.g., three-phase AC voltage) for driving motor 11 by DC / AC converter 38. Here, discharge control unit 36 ​​is provided in parallel across DC link capacitor 37. Furthermore, DC link capacitor 37 is also connected to motor control unit 12, allowing the motor control unit 12 to detect the voltage (DC link voltage) across DC link capacitor 37.

[0019] The charging control unit 35 includes a charging resistor 352 and a switch 351 connected in parallel with the charging resistor 352. The switch 351 is turned on / off based on a short-circuit command from the motor control unit 12. For example, during charging after the DC link capacitor 37 has been fully discharged, the charging control unit 35 opens the switch 351 and inserts the charging resistor 352 in series to suppress the flow of large current.

[0020] The discharge control unit 36 ​​includes a regenerative discharge resistor 362 and a switch 361 connected in series with the regenerative discharge resistor 362. Furthermore, as described later, in this embodiment, at least a portion of the housing 1 is configured as the regenerative discharge resistor 362. The switch 361 is switched on / off controlled based on a discharge command from the motor control unit 12. The discharge control unit 36 ​​may also include a temperature detector 363 that detects the temperature of the regenerative discharge resistor 362. In this case, the motor control unit 12 can be configured to monitor the temperature (resistance temperature) of the regenerative discharge resistor 362 detected by the temperature detector 363.

[0021] The motor control unit 12 can, for example, calculate the time (resistance regeneration time) during which regenerated power is consumed by the regenerated power discharge resistor 362 and the amount of regenerated power consumed by the regenerated power discharge resistor 362 (resistance regeneration amount) based on the discharge command (timing of switching 361 on / off control) that controls the switch 361 of the discharge control unit 36 ​​and the detected changes in the DC link voltage.

[0022] Furthermore, based on the resistor regeneration start voltage set in the motor control unit 12, the switch 361 of the discharge control unit 36 ​​is turned on (connected) to apply the DC link voltage to the regenerative power discharge resistor 362, through which regenerative power is consumed. Conversely, based on the resistor regeneration stop voltage, the switch 361 of the discharge control unit 36 ​​is turned off (disconnected) to disconnect the regenerative power discharge resistor 362. In other words, the resistor regeneration start voltage and resistor regeneration stop voltage control the start and stop of discharge of the regenerative power discharge resistor 362, which is connected in parallel with the DC link capacitor 37.

[0023] Specifically, if the DC link voltage is higher than the resistor regeneration start voltage, the switch 361 of the discharge control unit 36 ​​is turned on to start regeneration based on the regenerative power discharge resistor 362 (resistive regeneration). If the DC link voltage is lower than the resistor regeneration stop voltage, the switch 361 of the discharge control unit 36 ​​is turned off to stop regeneration based on the regenerative power discharge resistor 362. This, for example, prevents damage to the DC link capacitor 37, the AC / DC converter 34, and the DC / AC converter 38.

[0024] That is, for example, in Figure 3 In the illustrated structure, when the motor 11 decelerates, regenerative power is generated, and the DC link voltage (the voltage of the DC link capacitor 37) rises. If the DC link voltage rises excessively, for example, the motor control unit 12, which detects the DC link voltage, outputs a DC link overvoltage alarm. This is because overvoltage damage occurs due to exceeding the withstand voltage of the motor drive unit 3 (DC link capacitor 37, AC / DC converter 34, and DC / AC converter 38, etc.), causing the system to stop. Therefore, to prevent the system from stopping, regenerative power is dissipated through the regenerative power discharge resistor 362 to prevent the DC link voltage from rising excessively.

[0025] The electric motor control device 10 according to this embodiment achieves space saving by configuring a part or the whole of the housing 1 as a regenerative power discharge resistor 362.

[0026] Figure 4 This represents a first structural example in which the housing 1 is configured as a regenerative power discharge resistor 362. Figure 4A structural example is the four walls forming a square cylindrical circumference in a box-shaped shell 1 (in... Figure 4 The example shown is where the left side wall 1b, right side wall 1c, front side wall 1a, and rear side wall 1f are configured as a regenerative discharge resistor 362. In this structural example, the resistor forming the regenerative discharge resistor 362 is integrally configured with the four walls of the housing in a cylindrical shape. The two ends 362a and 362b of the resistor forming the regenerative discharge resistor 362 are connected to the discharge control unit 36 ​​on the printed circuit board 22 via connecting cables (not shown). The resistor forming the regenerative discharge resistor 362 is integral with each wall, for example, by being constructed to be embedded in each wall.

[0027] Figure 5 This represents a second structural example in which the housing 1 is configured as a regenerative power discharge resistor 362. Figure 5 A structural example is that one of the walls constituting the shell 1 (in) Figure 5 The example shown is where the left side wall portion 1b is configured as a regenerative discharge resistor 362. In this structural example, the resistor constituting the regenerative discharge resistor 362 is arranged in a zigzag pattern on the left side wall portion 1b. The two ends 362c and 362d of the resistor forming the regenerative discharge resistor 362 are connected to the discharge control unit 36 ​​on the printed circuit board 22 via connecting cables (not shown). The resistor forming the regenerative discharge resistor 362 is integral with each side wall, for example, by being constructed to be embedded in the left side wall portion 1b.

[0028] Figure 4 and Figure 5 The example shown of the regenerative power discharge resistor 362 is illustrative, and it is possible to arrange the regenerative power discharge resistor 362 on a portion or all of the wall surface of the housing 1. For example, the rear side wall portion 1f, which is configured as a mounting plate, can also be... Figure 5 The structure shown is configured as a regenerative electrical discharge resistor 362. Alternatively, all six walls constituting the housing may be configured as regenerative electrical discharge resistors 362.

[0029] Figure 6A and Figure 6B This is a cross-sectional view showing an example of the internal structure of the wall in the housing 1 that is configured as a regenerative power discharge resistor 362. Figure 6A and Figure 6B express Figure 5 The cross-sectional structure of the left side wall 1b along line AA. Figure 6AIn the example of the cross-sectional structure shown, the structure consists of an outer layer 101 forming the outer surface of the housing 1 in the left side wall portion 1b and an inner layer 102 forming the inner surface of the housing 1, sandwiching a resistive element constituting the regenerative power discharge resistor 362. In this structural example, the outer layer 101 and the inner layer 102 are respectively made of insulating materials, resin, ceramic, etc.

[0030] When the outer layer 101 and the inner layer 102 are made of metal components, such as Figure 6B As shown in the structural example, an insulating layer 103 and 104 with insulating properties are respectively sandwiched between the outer layer 101 and the resistor, and between the inner layer 102 and the resistor. The insulating layers 103 and 104 can be formed using mica, for example. Furthermore, in... Figure 6B In the structural example, when a metal component is used as the outer layer 101, the inner layer 102 can also be formed of other components (resin, ceramic, etc.). Alternatively, in this case, the inner layer 102 can be omitted. By forming the outer layer 101 with at least a metal component, a portion or all of the housing 1 can function as a regenerative power discharge resistor and a heat sink for internal heat sources.

[0031] The rear side wall portion 1f in the housing 1 is located on the rear side of the motor control device 10 and functions as a mounting plate, making it relatively easy to adopt a design that integrates the heat sink. Therefore, by integrating the heat sink onto the rear side wall portion 1f, and configuring the rear side wall portion 1f or multiple wall surfaces including the rear side wall portion 1f as a regenerative power discharge resistor 362, a structure that facilitates heat dissipation can be achieved.

[0032] Thus, in this embodiment, by configuring at least a portion of the housing as a regenerative discharge resistor, space-saving can be achieved as a motor control device. Furthermore, by configuring at least a portion of the housing as a regenerative discharge resistor, the design freedom of the length, volume, and other regenerative discharge resistors 362 is increased. According to this embodiment, a larger length and volume of the regenerative discharge resistor can be ensured, thereby increasing energy consumption as a regenerative discharge resistor.

[0033] The embodiments of this disclosure have been described above, but those skilled in the art should understand that various modifications and alterations can be made without departing from the scope of the disclosure as described below.

[0034] In the above embodiment, the motor control device has a housing formed in a box shape, but this shape is just one example, and the housing can be formed in various shapes. In this case, at least a portion of the housing can be configured as a regenerative power discharge resistor, achieving the same effect as in the above embodiment.

Claims

1. An electric motor control device characterized by comprising: Possessing: a motor drive section that performs drive control on a motor; a discharge control section that performs control to consume regenerative power from the motor by a regenerative power discharge resistor; a printed board that mounts a circuit of the motor drive section; and a case that houses the motor drive section, the discharge control section, and the printed board, at least a portion of the case is configured as the regenerative power discharge resistor, the case is formed in a box shape, a resistor body that forms the regenerative power discharge resistor is arranged integrally with four wall surfaces along which the case is formed in a square tube shape, the printed board and the end portion of the resistor body are connected by a connection cable.

2. An electric motor control device characterized by comprising: Possessing: a motor drive section that performs drive control on a motor; a discharge control section that performs control to consume regenerative power from the motor by a regenerative power discharge resistor; a printed board that mounts a circuit of the motor drive section; and a case that houses the motor drive section, the discharge control section, and the printed board, at least one of the wall surfaces that configures the case is configured as the regenerative power discharge resistor, the regenerative power discharge resistor is arranged integrally with the at least one wall surface in a pattern shape after being bent in a meandering shape, the printed board and the end portion of the regenerative power discharge resistor are connected by a connection cable.

3. An electric motor control device characterized by comprising: Possessing: a motor drive section that performs drive control on a motor; a discharge control section that performs control to consume regenerative power from the motor by a regenerative power discharge resistor; a printed board that mounts a circuit of the motor drive section; and a case that houses the motor drive section, the discharge control section, and the printed board, all of the wall surfaces that configures the case are configured as the regenerative power discharge resistor, the printed board and the end portion of the regenerative power discharge resistor are connected by a connection cable.

4. The motor control device according to any one of claims 1 to 3, wherein the wall surface of the case that is configured as the regenerative power discharge resistor has an outer layer portion that forms an outer surface of the case and an inner layer portion that forms an inner surface of the case, the resistor body that forms the regenerative power discharge resistor is arranged between the outer layer portion and the inner layer portion.

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