Motor drive device with power storage device

Abstract

The present invention provides a motor drive device having a power storage device. The motor drive device includes: a converter that converts power between AC power from an AC power source and DC power in a DC link; a drive inverter that converts power between DC power in the DC link and AC power serving as drive power or regenerative power for a drive servo motor; a power storage device that supplies DC power to the DC link or stores DC power from the DC link; a power consumption estimation unit that obtains an estimated power consumption value, which is an estimated value of total power consumption obtained as the sum of the output of the drive servo motor, coil loss in the drive servo motor, loss in the converter, and loss in the drive inverter, at a predetermined time earlier than the current value; and a power storage device control unit that controls power supply and storage in the power storage device in accordance with the estimated power consumption value.

Description

Technical Field

[0001] The present invention relates to a motor drive device having a power storage device. Background Art

[0002] In a motor drive device that controls the rotation of a servo motor (hereinafter referred to as a "driving servo motor") that drives a drive shaft installed in a machine, such as a machine tool or robot, a converter converts AC power supplied from an AC power source into DC power and outputs it to a DC link. Furthermore, an inverter converts the DC power in the DC link back into AC power, which is then used as driving power for the driving servo motor. The machine includes machine tools, robots, and the like. The term "DC link" refers to the circuit portion that electrically connects the DC output side of the converter with the DC input side of the inverter. It is sometimes also referred to as a "DC link unit," "DC link," "DC link unit," or "DC intermediate circuit." Generally, to reduce the cost and space requirements of a motor drive device, a single converter is often used for multiple inverters. Specifically, the converter that converts AC power supplied from the AC power source into DC power serves as a common power source, and multiple driving inverters use the DC power output from this power source to generate AC power for driving the driving servo motors.

[0003] When a motor drive device accelerates or decelerates a servo motor, a large amount of AC power is required to be output or regenerated from the AC power supply, generating a peak power level. In particular, in motor drive devices that connect multiple drive inverters to a single converter, this peak power level can be higher than the intended peak power level. Larger peak power levels increase power supply capacity and motor drive device operating costs, and can also cause power outages or flickering on the AC power supply side. Therefore, it is desirable to reduce peak power levels.

[0004] To reduce peak power, the following method has been used: a storage device capable of storing DC power is provided in the DC link connecting the converter of the motor drive device and the drive inverter, and the energy consumed or regenerated by the drive servo motor is appropriately exchanged via the DC link. According to this method, the peak power can be reduced because the regenerative power generated by the drive servo motor when the drive servo motor decelerates can be stored in the storage device, or the stored power can be reused when the drive servo motor accelerates. In other words, by using a storage device that inputs and outputs power to and from the DC link, it is possible to cope with the operation (acceleration and deceleration) of the drive servo motor that consumes more power than the maximum power supply of the converter. Examples of storage devices include capacitor-type and flywheel-type storage devices.

[0005] For example, a stamping press generates extremely high peak power consumption during a stamping operation, posing a problem of insufficient power supply capacity. Therefore, a flywheel-type power storage device is installed in the DC link of the press's motor drive. When the press consumes high power, power is supplied from the power storage device. This allows the press to be driven using a relatively small power supply. For example, when the power consumption of the driving servo motor is low, a buffer servo motor coupled to the flywheel rotates at a fixed speed. When power consumption increases due to acceleration or deceleration of the driving servo motor, the speed of the buffer servo motor is reduced, and power is regenerated via a buffer inverter, supplying DC power to the DC link to drive the driving servo motor. This allows the press to be driven using regenerated power from the buffer servo motor coupled to the flywheel, even during acceleration or deceleration operations involving power consumption exceeding the maximum power that the converter can convert, or the maximum convertible power.

[0006] For example, as described in Japanese Patent Application Laid-Open No. 2013-009524, there is known a motor drive device characterized by comprising: an AC-DC converter that converts AC power from an AC power source into DC power; a DC-AC converter that converts DC power into AC power for driving a motor or converts AC power regenerated from the motor into DC power; a DC link unit that connects the DC side of the AC-DC converter to the DC side of the DC-AC converter to exchange DC power; an energy storage unit having at least one capacitor storage unit and at least one flywheel storage unit, connected to the DC link unit to store DC power from the DC link unit or to supply DC power to the DC link unit; a motor control unit that controls the DC-AC inverter to output a desired AC power in accordance with a motor operation command that instructs the motor to operate; and an energy control unit that controls the energy storage unit to store DC power from the DC link unit or to supply DC power to the DC link unit.

[0007] For example, as described in Japanese Patent Application Laid-Open No. 2016-046833, there is known a servo motor control system for driving an axis of industrial machinery or a machine tool. The control system comprises: a plurality of first servo motors for driving the axis; a plurality of converters for converting AC voltage into DC voltage; a plurality of first inverters for receiving DC voltage from the converters and converting the DC voltage into AC voltage for driving the plurality of first servo motors, or for converting AC power regenerated from the first servo motors into DC power; a second servo motor for inertia rotation; a plurality of second inverters for receiving DC voltage from the converters and converting the DC voltage into AC voltage for driving the second servo motors, or for converting AC power regenerated from the second servo motors into DC power; and a servo motor control device for controlling the plurality of first servo motors and the second servo motors, wherein the number of the second servo motors is smaller than the number of the plurality of second inverters, at least one of the second servo motors has a plurality of independent coils, and at least some of the plurality of second inverters are connected to the plurality of independent coils provided in one of the second servo motors.

[0008] In a motor drive device equipped with a power storage device in a DC link connected between a converter and a drive inverter to reduce peak power consumption in the power supply equipment, commands are issued to the power storage device to supply or store power in response to increases or decreases in the "total power consumption," which is the sum of the power consumed by the drive servo motor, the drive inverter, and the converter. However, the power storage device has poor responsiveness to discharge or storage commands. Specifically, there is a time delay between when a power supply or storage command is issued to the power storage device and when the power storage device actually starts supplying power or stops storing power in response to the command. Historically, this delay in the power storage device's response has sometimes prevented peak power from being reduced. If peak power cannot be reduced as expected, the motor drive device and the machine tool incorporating the motor drive device may suddenly stop with an alarm, or damage the converter may occur.

[0009] For example, if an unexpectedly high load is applied to a driving servo motor, the servo motor may consume more power than usual. Sometimes, due to a response delay in the power storage device, the power storage device cannot supply enough power to compensate for the total power consumption exceeding the maximum power supply of the inverter. In such cases, insufficient AC power to drive the servo motor can cause the motor drive device and the machine tool incorporating the motor drive device to stop alarming. Alternatively, energy exceeding the maximum convertible power of the inverter can flow from the AC power source into the inverter, potentially damaging the inverter.

[0010] For example, when the regenerative energy generated by the driving servo motor is braked, if the energy recovery (storage) of the energy storage device is delayed, energy exceeding the maximum convertible power of the converter may flow into the converter from the DC link side, potentially damaging the converter. Summary of the Invention

[0011] Therefore, there is a need for a technology that can reliably reduce the peak power level in a motor drive device including a power storage device provided to reduce the peak power level of a power supply device.

[0012] According to one embodiment of the present disclosure, a motor drive device includes: a converter that converts power between AC power on the AC power source side and DC power in a DC link; a drive inverter that converts power between DC power in the DC link and AC power serving as drive power or regenerative power for a drive servo motor; a drive motor control unit that controls the drive servo motor connected to the drive inverter; a power storage device that supplies DC power to the DC link or stores DC power from the DC link; a power consumption estimating unit that obtains an estimated power consumption value, which is an estimated value of total power consumption obtained as the sum of the output of the drive servo motor, coil loss in the drive servo motor, loss in the converter, and loss in the drive inverter, that is, a value that is a predetermined time earlier than a current value, wherein the total power consumption is obtained as the sum of the output of the drive servo motor, coil loss in the drive servo motor, loss in the converter, and loss in the drive inverter; and a power storage device control unit that controls power supply and storage in the power storage device in accordance with the estimated power consumption value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention can be further clearly understood by referring to the following drawings.

[0014] Figure 1 This is a block diagram of a motor drive device according to one embodiment of the present disclosure.

[0015] Figure 2 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a flywheel-type power storage device.

[0016] Figure 3 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a capacitor-type power storage device.

[0017] Figure 4 This is a flowchart showing the operation flow of the motor drive device according to one embodiment of the present disclosure.

[0018] Figure 5 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including the power consumption estimating unit according to the first aspect.

[0019] Figure 6AThis is a diagram explaining an approximate straight line used for calculating an estimated value, and shows a case where the least squares method is used.

[0020] Figure 6B This is a diagram explaining an approximate straight line for calculating an estimated value, and shows a case where straight line approximation is used.

[0021] Figure 7 This is a diagram for explaining calculation of an estimated power consumption value by a power consumption estimating unit and control of a power storage device by a power storage device control unit.

[0022] Figure 8 This is a diagram illustrating the relationship between an estimated power consumption value, a power supply threshold value, and a power storage threshold value in the motor drive device according to one embodiment of the present disclosure.

[0023] Figures 9A to 9C 1 and 2 are diagrams showing an example of the operations of the power consumption estimating unit and the power storage device control unit before and after the estimated power consumption value exceeds the power supply threshold value in the motor drive device according to the embodiment of the present disclosure.

[0024] Figures 10A to 10C 1 is a diagram showing an example of the operations of the power consumption estimating unit and the power storage device control unit before and after the estimated power consumption value falls below the power storage threshold value in the motor drive device according to the embodiment of the present disclosure.

[0025] Figure 11 This is a diagram illustrating the relationship between the total power consumption and the operation of the flywheel type power storage device in the motor drive device according to one embodiment of the present disclosure.

[0026] Figure 12 This is a diagram illustrating the relationship between the total power consumption and the operation of a flywheel-type power storage device in a conventional motor drive device without considering the response delay of the power storage device.

[0027] Figure 13 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a measuring unit that measures a response delay time of a power storage device.

[0028] Figure 14 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a power consumption estimating unit according to the second aspect.

[0029] Figure 15 This is a diagram illustrating changes in torque of a driving servo motor.

[0030] Figures 16A to 16C Yes Figure 15 Calculation of the estimated torque value of the driving servo motor in the vicinity of region C is explained.

[0031] Figure 17 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a power consumption estimating unit according to a third aspect.

[0032] Figure 18 This is a diagram illustrating a change in speed of a driving servo motor.

[0033] Figures 19A to 19C Yes Figure 18 Calculation of the estimated speed value of the driving servo motor in the vicinity of region D is explained.

[0034] Figure 20 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including a power consumption estimating unit according to a fourth aspect. DETAILED DESCRIPTION

[0035] The following drawings describe a motor drive device with a power storage device. Identical components are denoted by the same reference numerals in the drawings. For ease of understanding, the scale of the drawings may be modified as appropriate. The embodiments shown in the drawings are examples for implementation and are not limited to the embodiments shown. The term "output of the driving servo motor" includes "power consumption of the driving servo motor" and "regenerated power of the driving servo motor," and the term "output of the buffering servo motor" includes "power consumption of the buffering servo motor" and "regenerated power of the buffering servo motor." Power consumption is expressed as positive, while power regeneration is expressed as negative. The rotational angular velocity of the driving servo motor and the buffering servo motor is simply referred to as "speed." The term "power value" refers to "power per unit time," or "work done by the current," and is expressed in W (watts). The term "energy value" refers to "electrical energy," or "work done by the current," and is expressed in J (joules). Therefore, the relationship "energy value [J] = power value [W] × time [s]" holds.

[0036] Figure 11 is a block diagram of a motor drive device according to an embodiment of the present disclosure. Here, as an example, a case where two drive servo motors 3 driving a drive shaft in a machine including a machine tool or a robot are controlled by a motor drive device 1 is described. The number of drive servo motors 3 is not particularly limited to this embodiment and may be one or more than three. Furthermore, the number of phases of the AC power supply 2 and the drive servo motors 3 is not particularly limited to this embodiment and may be, for example, three-phase AC or single-phase AC. Furthermore, the type of drive servo motor 3 is not particularly limited to this embodiment and may be, for example, an induction motor or a synchronous motor. In addition to machine tools or robots, machines equipped with drive servo motors 3 include forging machines, injection molding machines, industrial machinery, various electrical appliances, trains, automobiles, airplanes, and the like. Examples of the AC power supply 2 include a three-phase 400V AC power supply, a three-phase 200V AC power supply, a three-phase 600V AC power supply, and a single-phase 100V AC power supply.

[0037] First, each circuit component of the motor drive device 1 will be described.

[0038] like Figure 1 As shown, a motor drive device 1 according to one embodiment of the present disclosure includes a converter 11, a drive inverter 12, a drive motor control unit 13, a power storage device 14, a power consumption estimation unit 15, and a power storage device control unit 16. For example, the drive motor control unit 13, the power consumption estimation unit 15, and the power storage device control unit 16 are provided in a numerical controller for a machine tool. Alternatively, the drive motor control unit 13, the power consumption estimation unit 15, and the power storage device control unit 16 may be provided in a processing unit other than the numerical controller.

[0039] Converter 11 is a forward converter (rectifier) ​​that converts power between AC power from AC power source 2 and DC power from DC link 4. Converter 11 is configured as a three-phase bridge circuit when three-phase AC is supplied from AC power source 2, and as a single-phase bridge circuit when single-phase AC is supplied from power source 2. Converter 11 can be implemented as a power converter capable of bidirectional AC / DC conversion, such as a 120-degree conduction rectifier circuit or a PWM switching control rectifier circuit. This circuit converts AC power input from AC power source 2 into DC power and outputs it to the DC side. When power is regenerated, it converts DC power from DC link 4 into AC power and outputs it to AC power source 2. For example, if converter 11 is a PWM switching control rectifier circuit, it consists of a bridge circuit consisting of switching elements and diodes connected in antiparallel thereto. Each switching element is controlled to open and close based on drive commands received from a higher-level control device (not shown), thereby performing bidirectional AC / DC power conversion. Examples of the switching element include unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, GTOs, and the like. The type of the switching element itself is not limited to the present embodiment, and other switching elements may be used.

[0040] Furthermore, the converter 11 is specified with a "maximum supplyable power" as the maximum amount of electricity that can be supplied to the DC link 4 by converting AC power to DC power. The converter 11 is also specified with a "maximum regenerative power" as the maximum amount of electricity that can be regenerated by converting DC power from the DC link 4 to AC power. The maximum supplyable power and maximum regenerative power are generally specified as various raw data related to the converter 11's conversion capacity, for example, as described in the converter 11's specification sheet or operating manual. Hereinafter, in this specification, the converter 11's maximum supplyable power and maximum regenerative power are collectively referred to as the "maximum convertible power."

[0041] Converter 11 is connected to drive inverter 12 via DC link 4. A DC link capacitor (also called a smoothing capacitor) is provided in DC link 4, though not shown. The DC link capacitor has the function of storing DC power in DC link 4 and suppressing pulsating components in the DC output of converter 11.

[0042] The drive inverter 12 is a servo amplifier that converts the DC power of the DC link 4 into AC power to drive the drive servo motor 3. The drive inverter 12 converts the DC power of the DC link 4 into AC power and supplies it to the drive servo motor 3 as drive power. The drive inverter 12 performs power conversion between the DC power of the DC link 4 and the AC power that serves as drive power or regenerative power for the drive servo motor 3. Generally, the drive servo motor 3 is provided with one or more coils. In order to drive the drive servo motor 3, a drive inverter 12 is required for each coil in the drive servo motor 3. Figure 1In the embodiment, the driving servo motors 3 are single-coil type as an example, and therefore each driving servo motor 3 is connected to one driving inverter 12 .

[0043] The drive inverter 12 is composed of a bridge circuit consisting of switching elements and diodes connected in antiparallel thereto. Each switching element is controlled by, for example, PWM switching control using a triangular wave comparison method. The drive inverter 12 is composed of a three-phase bridge circuit when the drive servo motor 3 is a three-phase motor, and a single-phase bridge circuit when the drive servo motor 3 is a single-phase motor. Examples of switching elements include unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, GTOs, and the like. However, the type of switching element itself is not limited to this embodiment and other switching elements may be used.

[0044] The drive inverter 12 controls the opening and closing of each switching element based on drive commands received from the drive motor control unit 13 (described later), thereby converting power between the DC power of the DC link 4 and the AC power serving as driving power or regenerative power for the drive servo motor 3. More specifically, the drive inverter 12 switches its internal switching elements based on the drive commands received from the drive motor control unit 13, converting the DC power supplied from the converter 11 via the DC link 4 into AC power having the desired voltage and frequency for driving the drive servo motor 3 (reverse conversion). This rotationally drives the drive servo motor 3. Furthermore, regenerative power may be generated during deceleration of the drive servo motor 3. In response to the drive commands received from the drive motor control unit 13, the internal switching elements are switched to convert the AC regenerative power generated by the drive servo motor 3 into DC power and return it to the DC link 4 (forward conversion).

[0045] The drive motor control unit 13 controls the drive servo motor 3 connected to the drive inverter 12 so that it operates (i.e., rotates) in a predetermined operating mode. The operating mode of the drive servo motor 3 is formed by appropriately combining acceleration, deceleration, constant speed, and stop, depending on the operating content of the machine in which the drive servo motor 3 is installed. The operating mode of the drive servo motor 3 is defined by an operating program for the drive servo motor 3. For example, if the drive servo motor 3 is installed in a machine tool, the operating program for the drive servo motor 3 is defined as part of the machining program for the machine tool.

[0046] In this way, the speed, torque, or rotor position of the drive servo motor 3 is controlled based on, for example, the variable voltage and variable frequency AC power supplied from the drive inverter 12. Consequently, the control of the drive servo motor 3 by the drive motor control unit 13 is achieved by controlling the power conversion operation of the drive inverter 12. Specifically, the drive motor control unit 13 controls the power conversion within the drive inverter 12 according to a predetermined operation program, thereby causing the drive servo motor 3 to operate according to a predetermined operation mode. More specifically, as follows: The drive motor control unit 13 generates drive commands for controlling the speed, torque, or rotor position of the drive servo motor 3 based on the speed of the drive servo motor 3 detected by the speed detector 52 (speed feedback), the current flowing through the coils of the drive servo motor 3 (current feedback), a predetermined torque command, and the operation program of the drive servo motor 3. The power conversion operation of the drive inverter 12 is controlled based on the drive commands generated by the drive motor control unit 13. The configuration of the drive motor control unit 13 defined here is merely an example, and the configuration of the drive motor control unit 13 may be defined by including terms such as a position instruction generating unit, a torque instruction generating unit, and a switching instruction generating unit.

[0047] In order to drive the driving servo motor 3 with an output exceeding the maximum convertible power of the inverter 11 , the motor drive device 1 is provided with a power storage device 14 .

[0048] The power storage device 14 supplies DC power to the DC link 4 (power supply) and accumulates DC power from the DC link 4 (power storage). The power supply and power storage operations of the power storage device 14 are controlled by the power storage device control unit 16. A reference energy reserve is specified as a reference value (target value) of energy that the power storage device 14 should hold. Under the control of the power storage device control unit 16, the power storage device 14 stores power so that the energy reserve reaches the target value, i.e., the reference energy reserve. For example, during a period when the driving servo motor 3 is not operating and power input or output from the power storage device 14 is not particularly required, the energy reserve of the power storage device 14 is maintained at the reference energy reserve. When the power storage device 14 is powering, the energy reserve of the power storage device 14 decreases to a value less than the reference energy reserve. When the power storage device 14 is storing power, the energy reserve of the power storage device 14 increases, returning the reference energy reserve to the target value.

[0049] The power storage device 14 has, for example, Figure 2 The flywheel type shown is Figure 3 Capacitor type as shown.

[0050] Figure 2This is a block diagram of a motor drive device according to an embodiment of the present disclosure having a flywheel-type power storage device. The flywheel-type power storage device 14 includes a flywheel 41 , a buffer servo motor 42 , and a buffer inverter 43 .

[0051] The flywheel 41 can store rotational energy, also known as inertia.

[0052] The buffer servo motor 42 is an electric motor for rotating the flywheel 41. The flywheel 41 is connected to the rotating shaft of the buffer servo motor 42. Rotating the buffer servo motor 42 allows the flywheel 41 to accumulate rotational energy. The number of phases of the buffer servo motor 42 is not particularly limited to this embodiment; for example, it can be three-phase or single-phase. The buffer servo motor 42 is provided with a speed detector 52. The speed (rotor) of the buffer servo motor 42 detected by the speed detector 52 is used to control the power storage device 14 by the power storage device control unit 16.

[0053] The buffer inverter 43 controls the opening and closing of each switching element based on the power storage command and power supply command received from the power storage device control unit 16, thereby converting the DC power of the DC link 4 into the AC power serving as the drive power or regenerative power for the buffer servo motor 42. The buffer inverter 43 is composed of a bridge circuit of switching elements and diodes connected in antiparallel thereto. If the buffer servo motor 42 is a three-phase motor, the buffer inverter 43 is composed of a three-phase bridge circuit; if the buffer servo motor 42 is a single-phase motor, the buffer inverter 43 is composed of a single-phase bridge circuit. Examples of switching elements include unipolar transistors such as FETs, bipolar transistors, IGBTs, thyristors, GTOs, etc. The type of switching element itself is not limited to this embodiment and may be other switching elements. For example, the switching elements within the buffer inverter 43 are controlled to open and close based on a PWM switching signal obtained by comparing the received drive command with a triangular wave carrier.

[0054] The power storage device control unit 16 controls the power conversion of the buffer inverter 43, thereby causing the buffer servo motor 42 connected to the flywheel 41 to rotate while accelerating or decelerating, or to rotate at a constant speed. As a result, the DC power to be stored or supplied to the power storage device 14 (the DC power input and output from the power storage device 14 to the DC link 4) is adjusted. More details are as follows.

[0055] While the power storage device 14 is storing energy, the buffer inverter 43 performs reverse conversion, converting the DC power from the DC link 4 into AC power, based on a power storage command received from the power storage device control unit 16. This process draws electrical energy from the DC link 4 into the buffer servo motor 42, which is then connected to the flywheel 41 and rotates. Thus, in the flywheel-type power storage device 14, the electrical energy flowing from the DC link 4 is converted into rotational energy for the flywheel 41 and stored.

[0056] Furthermore, when the power storage device 14 is supplying power, the buffer inverter 43, in response to a power supply command received from the power storage device control unit 16, decelerates the buffer servo motor 42 connected to the flywheel 41 to generate AC regenerative power, and then performs a forward conversion operation (rectification) to convert this AC power into DC power. This converts the rotational energy stored in the flywheel 41 into electrical energy, which is then supplied to the DC link 4.

[0057] Figure 3 This is a block diagram of a motor drive device according to one embodiment of the present disclosure having a capacitor-type power storage device. The capacitor-type power storage device 14 includes a capacitor 44 and a DC-DC converter 45 that converts DC power from the DC link 4 to the DC power stored in the capacitor 44 .

[0058] The DC-DC converter 45 includes, for example, a step-up / step-down DC chopper circuit. The power storage device control unit 16 controls the step-up and step-down operations of the DC-CDC converter 45, thereby adjusting the DC power to be stored or supplied by the power storage device 14 (the DC power outputted by the power storage device 14 to the DC link 4). This is described in more detail below.

[0059] When the power storage device 14 is storing electricity, the DC-DC converter 45 is controlled by the power storage device control unit 16 based on a power storage command received from the power storage device control unit 16 so that the DC voltage on the capacitor 44 side is lower than the DC voltage on the DC link 4 side. As a result, electric energy from the DC link 4 flows into the capacitor 44, and the power storage device 14 stores electricity.

[0060] Furthermore, when the power storage device 14 is supplying power, the DC-DC converter 45 is controlled by the power storage device control unit 16 in accordance with a power supply command received from the power storage device control unit 16 so that the DC voltage on the capacitor 44 side is higher than the DC voltage on the DC link 4 side. As a result, the electric energy from the capacitor 44 flows into the DC link 4, and the power storage device 14 is supplied with power.

[0061] The motor drive device 1 includes a power storage device 14 that performs the above-described operation. Consequently, when accelerating the drive servo motor 3, in addition to the energy supplied from the inverter 11, the energy stored in the power storage device 14 is also supplied to the drive servo motor 3, serving as the motive force for accelerating the drive servo motor 3. Furthermore, when decelerating the drive servo motor 3, the energy regenerated from the drive servo motor 3 is stored in the power storage device 14. The energy stored in the power storage device 14 is used together with the power supplied by the inverter 11 to drive the drive servo motor 3. This allows the drive servo motor 3 to be driven with an output exceeding the maximum convertible power of the inverter 11, thereby reducing peak power. This reduction in peak power reduces the power supply capacity and operating costs of the motor drive device 1, and also prevents power outages and flickering on the AC power source 2 side.

[0062] The power storage device 14 performs power supply and power storage operations according to the instructions from the power storage device control unit 16. The power storage device 14 has poor responsiveness to the discharge instruction or power storage instruction. When the power storage device 14 is instructed to supply power or store power, there is a time delay from the time when the power storage device 14 responds to the instruction to supply power or store power until the power storage device 14 actually starts power supply or stores power. For example, the power storage device 14 is Figure 2 In the case of the flywheel type shown, due to the inertia of the buffer servo motor 42 or the control performance of the buffer inverter 43, there is a time delay from the start of the instruction to accelerate or decelerate the buffer servo motor 42, and the buffer servo motor 42 starts to accelerate or decelerate. Figure 3In the case of the capacitor type shown, there is a time delay from the start of the charge or discharge command for capacitor 44 due to the charge and discharge characteristics of capacitor 44 and the control performance of the DC-DC converter 45 connected to the capacitor. Capacitor 44 is charged to the desired voltage or discharged. When the "total power consumption at the current time," which is the sum of the output of the drive servo motor 3, the coil loss in the drive servo motor 3, the loss in converter 11, and the loss in the drive inverter 12, exceeds the maximum power supply of converter 11, even if power storage device 14 is instructed to supply power, there is a time delay from the start of the power supply command until the power storage device 14 actually starts supplying power. Therefore, the total power consumption exceeds the maximum power supply of converter 11, and the peak power reduction is not possible. Similarly, the power storage device 14 stores power; there is a time delay from the start of the power storage command until the power storage device 14 actually starts storing power. Therefore, the total power consumption exceeds the maximum regenerative power of converter 11, and the peak power reduction is not possible. Therefore, in this embodiment, an estimated power consumption value is calculated, i.e., an estimated value of total power consumption obtained as the sum of the output of the drive servo motor 3, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12, and is estimated a predetermined time prior to the current time. The power supply and storage of power by the power storage device 14 are controlled in accordance with this estimated power consumption value. Specifically, in this embodiment, the total power consumption at a time prior to the current time by a time corresponding to the response delay time is estimated based on known data on total power consumption prior to the current time. Based on the result of comparing this estimated value with the power supply and storage thresholds, the power storage device control unit 16 controls the power supply and storage of power by the power storage device 14. The response delay time from when the power storage device control unit 16 instructs the power storage device 14 to supply or store electricity until the power storage device 14 actually starts supplying or storing electricity can be measured in advance, or, as described later, a measurement unit can be provided to measure it in real time. The following describes a case where the "predetermined time" is set to the same length as the response delay time of the power storage device 14.

[0063] The power consumption estimation unit 15 obtains an estimated power consumption value, which is an estimated value of total power consumption obtained as the sum of the output of the drive servo motor 3, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12, at a predetermined time earlier than the current value. The estimated value acquisition process by the power consumption estimation unit 15 is executed at a predetermined control cycle. Furthermore, the estimated value acquisition process by the power consumption estimation unit 15 is executed before the power storage device control process performed by the power storage device control unit 16, which will be described later. Details of the estimated value acquisition process performed by the power consumption estimation unit 15 will be described later.

[0064] The power storage device control unit 16 controls the power supply and storage of the power storage device according to the estimated power consumption value. In one control cycle, the power consumption estimation unit 15 calculates the estimated power consumption value, and the power storage device control unit 16 uses this estimated power consumption value to execute the command generation process. More details are as follows.

[0065] The power storage device control unit 16 compares the estimated power consumption value with the power supply threshold value at each control cycle. If the comparison results in a determination that the estimated power consumption value is higher than the power supply threshold value, the power storage device control unit 16 instructs the power storage device 14 to supply power, thereby controlling the power storage device 14 to supply DC power to the DC link 4. Furthermore, while controlling the power storage device 14 to perform power supply operations, the power storage device control unit 16 compares the estimated power consumption value with the power supply threshold value at each control cycle. If the comparison results in a determination that the estimated power consumption value is lower than the power supply threshold value, the power storage device control unit 16 stops generating power supply commands to the power storage device 14 and terminates the DC power supply operation to the DC link 4.

[0066] The supply threshold value can be set based on the maximum convertible power, or the maximum supplyable power, associated with the forward conversion operation of converter 11. For example, if the difference between converter 11's maximum supplyable power and the estimated power consumption value calculated by power consumption estimation unit 15 is negative, the estimated power consumption value exceeds converter 11's maximum supplyable power during forward conversion. Therefore, the energy converter 11 receives from AC power source 2 to DC link 4 may not fully cover the actual total power consumption. This shortfall should be compensated by DC power supplied from power storage device 14 to DC link 4. The supply threshold value is set as a reference value for determining whether a situation exists in which DC power should be supplied from power storage device 14 to DC link 4 because the estimated power consumption value exceeds converter 11's maximum supplyable power during forward conversion.

[0067] Furthermore, the power storage device control unit 16 compares the estimated power consumption value with the power storage threshold value at each control cycle. If the result of this comparison indicates that the estimated power consumption value is lower than the power storage threshold value, the power storage device 14 is instructed to store power, thereby controlling the power storage device 14 to store DC power from the DC link 4. Furthermore, while the power storage device control unit 16 is controlling the power storage device 14 to perform power storage, the estimated power consumption value is compared with the power storage threshold value at each control cycle. If the result of this comparison indicates that the estimated power consumption value is higher than the power storage threshold value, the power storage device 16 stops generating power storage commands to the power storage device 14, thereby terminating the DC power storage operation from the DC link 4.

[0068] The power storage threshold value may be set based on the maximum convertible power related to the reverse conversion operation of converter 11, i.e., the maximum regenerative power. For example, if the difference between the absolute value of converter 11's maximum regenerative power and the absolute value of the estimated regenerative power consumption calculated by power consumption estimation unit 15 is negative, the actual total power consumption may exceed the maximum regenerative power available during reverse conversion of converter 11. Therefore, the excess power should be stored in power storage device 14. The power storage threshold value is set as a reference value for determining whether the estimated regenerative power consumption exceeds the maximum regenerative power available for converter 11, and therefore DC power from DC link 4 should be stored in power storage device 14.

[0069] Figure 4 This is a flowchart showing the operation flow of the motor drive device according to one embodiment of the present disclosure. The processes of steps S101 to S112 are executed in a predetermined control cycle.

[0070] In step S101, the drive motor control unit 13 generates a drive command for controlling the speed, torque, or rotor position of the drive servo motor 3 based on the speed of the drive servo motor 3 detected by the speed detector 52 (speed feedback), the current flowing through the coils of the drive servo motor 3 (current feedback), a predetermined torque command, and the operating program of the drive servo motor 3. The drive command generated by the drive motor control unit 13 controls the power conversion operation performed by the drive inverter 12. To drive the drive servo motor 3, the drive inverter 12 converts the DC power of the DC link 4 into AC power and supplies it to the drive servo motor 3 as drive power. Alternatively, it converts the AC regenerative power generated by the drive servo motor 3 during braking into DC power and returns it to the DC link 4.

[0071] In step S102, the power consumption estimating unit 15 obtains a total power consumption value obtained as the sum of the output of the driving servo motor 3, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12, which is an estimated power consumption value that is a predetermined time earlier than the current value.

[0072] In step S103, the power storage device control unit 16 compares the estimated power consumption value with the power supply threshold value to determine whether the estimated power consumption value exceeds the power supply threshold value. If the power storage device control unit 16 determines that the estimated power consumption value exceeds the power supply threshold value, the process proceeds to step S104; otherwise, the process proceeds to step S108.

[0073] In step S104 , the power storage device control unit 16 instructs the power storage device 14 to supply power, thereby controlling the power storage device 14 to supply DC power to the DC link 4 .

[0074] In step S105, the power consumption estimating unit 15 obtains a total power consumption value obtained as the sum of the output of the driving servo motor 3, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12, which is an estimated power consumption value that is a predetermined time earlier than the current value.

[0075] In step S106, the power storage device control unit 16 compares the estimated power consumption value with the power supply threshold value to determine whether the estimated power consumption value is higher than the power supply threshold value. If the power storage device control unit 16 determines that the estimated power consumption value is lower than the power supply threshold value, the process proceeds to step S107; otherwise, the process returns to step S104.

[0076] In step S107, the power storage device control unit 16 stops generating the power supply command to the power storage device 14 and ends the operation of supplying DC power to the DC link 4. After step S107, the process returns to step S102.

[0077] If the power storage device control unit 16 does not determine in step S103 that the estimated power consumption value is higher than the power supply threshold, then in step 108, the power storage device control unit 16 compares the estimated power consumption value with the power storage threshold to determine whether the estimated power consumption value is lower than the power storage threshold. If the power storage device control unit 16 determines that the estimated power consumption value is lower than the power storage threshold, the process proceeds to step S109; otherwise, the process returns to step S102.

[0078] In step S109 , the power storage device control unit 16 instructs the power storage device 14 to store electricity, thereby controlling the power storage device 14 to store DC power from the DC link 4 .

[0079] In step S110, the power consumption estimating unit 15 obtains a total power consumption value obtained as the sum of the output of the driving servo motor 3, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12, which is an estimated power consumption value that is a predetermined time earlier than the current value.

[0080] In step S111, the power storage device control unit 16 compares the estimated power consumption value with the power storage threshold value to determine whether the estimated power consumption value exceeds the power storage threshold value. If the power storage device control unit 16 determines that the estimated power consumption value exceeds the power supply threshold value, the process proceeds to step S112; otherwise, the process returns to step S109.

[0081] In step S112, the power storage device control unit 16 stops generating the power storage command to the power storage device 14, and ends the operation of storing DC power from the DC link 4. After step S112, the process returns to step S102.

[0082] Thus, the estimated value acquisition process (steps S102, S105, and S110) by the power consumption estimation unit 15 must be executed before the power storage device control process (steps S103 and S104, steps S106 and S107, steps S108 and S109, and steps S111 and S112) by the power storage device control unit 16. Since the power storage device control process by the power storage device control unit 16 is executed at a predetermined control cycle, the estimated value acquisition process by the power consumption estimation unit 15 must also be executed once within that control cycle.

[0083] The processing of step S103 and steps S104 to S107 following step S103, and the processing of step S108 and steps S109 to S112 following step S108, may be performed in an alternate order. Specifically, the power storage device control unit 16 may compare the estimated power consumption value with the power storage threshold value to determine whether the estimated power consumption value is lower than the power storage threshold value. If the estimated power consumption value is not lower than the power storage threshold value, the power storage device control unit 16 may continue to compare the estimated power consumption value with the power supply threshold value to determine whether the estimated power consumption value is higher than the power supply threshold value.

[0084] Next, several aspects of the power consumption estimating unit 15 of the motor drive device 1 according to one embodiment of the present disclosure will be listed.

[0085] The power consumption estimating unit 15 according to the first embodiment calculates the total power consumption obtained as the sum of the output of the driving servo motor 3, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12 at the current time, and obtains an estimated power consumption value that is an estimated value that is a predetermined time ahead of the total power consumption value at the current time.

[0086] Figure 5 This is a block diagram of a motor drive device according to one embodiment of the present disclosure including the power consumption estimating unit according to the first aspect.

[0087] The power consumption estimating unit 15 includes a power consumption calculating unit 21 , a power consumption storing unit 22 , and a power consumption estimated value calculating unit 23 .

[0088] The power consumption calculation unit 21 calculates the total power consumption, which is the sum of the output of the drive servo motor 3 at the current time, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12. The losses of the converter 11 and the drive inverter 12 include switching losses and resistance losses in each main circuit, and can be measured using known methods. Furthermore, the output of the drive servo motor 3 at the current time is obtained by multiplying the rotational speed of the drive servo motor 3 detected by the speed detector 52 by the torque of the drive servo motor 3. When the drive servo motor 3 accelerates, the drive servo motor 3 consumes the AC power supplied by the drive inverter 12. The output of the drive servo motor 3 during this power consumption is considered "positive." Therefore, when the drive servo motor 3 decelerates and regenerates power, the output of the drive servo motor 3 is "negative." Normally, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12 are smaller than the absolute value of the output of the drive servo motor 3. Therefore, the influence of the output of the drive servo motor 3 dominates the total power consumption. Therefore, the positive and negative output of the drive servo motor 3 (consumption or regeneration) roughly corresponds to the positive and negative total power consumption. Figure 1 As illustrated, when there are multiple drive inverters 12 and multiple drive servo motors 3, the power consumption calculation unit 21 calculates the total power consumption as the sum of the outputs of the multiple drive servo motors 3, the coil losses in the multiple drive servo motors 3, the losses in the converter 11, and the losses in the multiple drive inverters 12.

[0089] The buffer inverter 43 and DC-DC converter 45 within the power storage device 14 also have losses. Therefore, the power consumption calculation unit 21 can calculate the total power consumption by adding the losses of the buffer inverter 43 (for a flywheel type) or the DC-DC converter 45 (for a capacitor type) to the sum of the output of the drive servo motor 3, the coil losses in the drive servo motor 3, the losses in the converter 11, and the losses in the drive inverter 12. The losses of the buffer inverter 43 and the DC-DC converter 45 include switching losses and resistance losses in each main circuit and can be measured using known methods. Furthermore, if there are multiple buffer inverters 43 or multiple DC-DC converters 45, the power consumption calculation unit 21 can calculate the total power consumption by adding the sum of the losses of the multiple buffer inverters 43 or multiple DC-DC converters 45 to the sum of the output of the drive servo motor 3, the coil losses in the drive servo motor 3, the losses in the converter 11, and the losses in the drive inverter 12.

[0090] The power consumption storage unit 22 stores the total power consumption value calculated by the power consumption calculation unit. The power consumption storage unit 22 is composed of, for example, a nonvolatile memory that can be electrically erased and recorded, such as EEPROM (registered trademark), or a random access memory that can read and write at high speed, such as DRAM or SRAM.

[0091] The estimated power consumption value calculation unit 23 calculates an estimated power consumption value, which is an estimated value that precedes the current value by a predetermined time, based on at least two total power consumption values ​​prior to the current time stored in the power consumption storage unit 22. For example, the estimated power consumption value is estimated by calculating an approximate straight line using the at least two total power consumption values ​​prior to the current time stored in the power consumption storage unit 22. The estimated power consumption value is then output as the estimated power consumption value. The "predetermined time" used by the estimated power consumption value calculation unit 23 in calculating the estimated power consumption value is the "response delay time from the time the power storage device control unit 16 instructs the power storage device 14 to supply or store power until the power storage device 14 actually starts supplying or storing power."

[0092] Figure 6A This is a diagram explaining an approximate straight line used for calculating an estimated value, and shows a case where the least squares method is used. Figure 6B This diagram explains the approximate straight line used to calculate the estimated value, showing the case where first-order approximation is used. When the estimated power consumption value at time t is P, the approximate straight line used to calculate the estimated value is expressed by the following mathematical formula 1.

[0093] P=αt+β(1)

[0094] For example, when the slope α and intercept β of the approximate straight line represented by Mathematical Formula 1 are calculated using the least squares method, the three total power consumption values ​​before the current time point stored in the power consumption storage unit 22 are used. The three total power consumption values ​​"before" the current time point used to calculate the approximate straight line may or may not include the total power consumption value at the current time point. Figure 6A For example, the current time is t3. The total power consumption calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 at time t3, which is the sum of the output of the drive servo motor 3, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12, is P3. The total power consumption calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 at time t2, which is earlier than time t3, is P2. The total power consumption calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 at time t1, which is earlier than time t2, is P1. The slope α of the approximate straight line represented by Mathematical Formula 1 for calculating the estimated value of the total power consumption based on the least squares method can be obtained using the following Mathematical Formula 2, and the intercept β can be obtained using the following Mathematical Formula 3.

[0095]

[0096]

[0097] For another example, when the slope α and intercept β of the approximate straight line represented by the mathematical formula 1 are calculated using the first-order approximation (linear approximation), the two total power consumption values ​​before the current time point stored in the power consumption storage unit 22 are used. The two total power consumption values ​​"before" the current time point used to calculate the approximate straight line may or may not include the total power consumption value at the current time point. Figure 6B For example, the current time is set to t2. The total power consumption calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 at time t2, which is the sum of the output of the drive servo motor 3, the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12, is set to P2. The total power consumption calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 at time t1, which is earlier than time t2, is set to P1. The slope α of the approximate straight line represented by Mathematical Formula 1 for calculating the estimated value of the total power consumption based on the first-order approximation can be obtained using the following Mathematical Formula 4, and the intercept β can be obtained using the following Mathematical Formula 5.

[0098]

[0099]

[0100] Substituting a time point a predetermined time prior to the current time point into the approximate line represented by Formula 1 calculated as described above, the estimated power consumption value for the time point a predetermined time prior can be calculated. Estimated power consumption value calculation unit 23 within power consumption estimation unit 15 calculates the estimated power consumption value for each control cycle according to the above series of processes. In addition to using the total power consumption at the current time point to calculate the estimated power consumption value as described above, the output of drive servo motor 3 at the current time point or the speed of drive servo motor 3 at the current time point can also be used for calculation. These methods will be described later as second to fourth methods.

[0101] The power storage device control unit 16 generates a power supply command or a power storage command according to the power consumption estimated value estimated by the power consumption estimating unit 15 , and controls power supply or power storage of the power storage device 14 . Figure 7 This is a diagram illustrating the calculation of the power consumption estimate value by the power consumption estimate unit and the control of the power storage device by the power storage device control unit. For example, the current time point is set to t3. The approximate straight line represented by the mathematical formula 1 calculated as described above is represented by a dotted line. In addition, the straight line connecting the power consumption estimate values ​​estimated by the power consumption estimate unit 15 before the time t3 is represented by a single-point chain line. At the time t3 of the current time point, the power consumption estimation processing by the power consumption estimate unit 15 and the instruction generation processing for the power storage device 14 by the power storage device control unit 16 are executed. That is, the power consumption estimate unit 15 calculates the slope α and the intercept β in the mathematical formula 1, and sets the time t3 of the current time point to a predetermined time T earlier than the time t3 of the current time point. x Time t3+T x Substituting into the variable t in the mathematical formula 1, the power consumption estimate value P4' is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value estimated at the current time t3 with the power supply threshold value and the power storage threshold value. Figure 7 In the illustrated example, the estimated power consumption value is higher than the power supply threshold value, so the power storage device control unit 16 instructs the power storage device 14 to supply power, thereby controlling the power storage device 14 to supply DC power to the DC link 4 .

[0102] Figure 8 : is a diagram illustrating the relationship between the power consumption estimated value, the power supply threshold value, and the power storage threshold value in the motor drive device according to one embodiment of the present disclosure. As an example, the power consumption estimated value calculated by the power consumption estimating unit 15 is as follows: Figure 8The control performed by the power storage device control unit 16 during the transition shown will be described. When the power storage device control unit 16 determines that the estimated power consumption value is higher than the power supply threshold, it instructs the power storage device 14 to supply power, thereby controlling the power storage device 14 to supply DC power to the DC link 4. Thereafter, when the power storage device control unit 16 determines that the estimated power consumption value is lower than the power supply threshold, it stops generating the power supply instruction to the power storage device 14 and ends the power supply operation of DC power to the DC link 4. Thereafter, when the power storage device control unit 16 determines that the estimated power consumption value is lower than the power storage threshold, it instructs the power storage device 14 to store power, thereby controlling the power storage device 14 to store DC power from the DC link 4. Thereafter, when the power storage device control unit 16 determines that the estimated power consumption value is higher than the power storage threshold, it stops generating the power storage instruction to the power storage device 14 and ends the power storage operation of DC power from the DC link 4. Use Figures 9A to 9C as well as Figures 10A to 10C right Figure 8 The operation examples of the power consumption estimating unit 15 and the power storage device control unit 16 in the region A where the estimated power consumption value exceeds the power supply threshold and the region B where the estimated power consumption value falls below the power storage threshold will be described in more detail.

[0103] Figures 9A to 9C 1 and 2 are diagrams showing an example of the operations of the power consumption estimating unit and the power storage device control unit before and after the estimated power consumption value exceeds the power supply threshold value in the motor drive device according to the embodiment of the present disclosure.

[0104] like Figure 9A The current moment is t 12 At time t 12 The total power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 is used to calculate the slope α and intercept β in the mathematical formula 1, and the current time point t is changed to 12 Early stipulated time T x Time t 12 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power supply threshold value. Figure 9A As shown at time t 12 Since the estimated power consumption value is not higher than the power supply threshold value, the power storage device control unit 16 does not generate a power supply instruction and does not perform power supply control for the power storage device 14 .

[0105] Then time goes on, such as Figure 9B The current time is t 13 At time t 13The total power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 is used to calculate the slope α and intercept β in the mathematical formula 1, and the current time point t is changed to 13 Early stipulated time T x Time t 13 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power supply threshold value. Figure 9B As shown, at time t 13 Since the estimated power consumption value is higher than the power supply threshold value, the power storage device control unit 16 instructs the power storage device 14 to supply power.

[0106] Then time goes on, such as Figure 9C The current time is t 14 At time t 14 The total power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 14 Early stipulated time T x Time t 14 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power supply threshold value. Figure 9C As shown, at time t 14 The estimated power consumption value is still higher than the power supply threshold value, so the power storage device control unit 16 instructs the power storage device 14 to supply power.

[0107] Figures 10A to 10C 1 is a diagram showing an example of the operations of the power consumption estimating unit and the power storage device control unit before and after the estimated power consumption value falls below the power storage threshold value in the motor drive device according to the embodiment of the present disclosure.

[0108] like Figure 10A As shown, at the current time t 12 At time t 12 The slope α and intercept β of the mathematical formula 1 are calculated based on the power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22, and the current time point t is changed to 12 Early stipulated time T x Time t 12 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power storage threshold value. Figure 10A As shown, at time t12 Since the estimated power consumption value is not lower than the power storage threshold value, the power storage device control unit 16 does not generate a power storage command and does not perform power storage control on the power storage device 14 .

[0109] Then time goes on, such as Figure 10B As shown, at the current time t 13 At time t 13 The total power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 13 Early stipulated time T x Time t 13 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power storage threshold value. Figure 10B As shown, at time t 13 Since the estimated power consumption value is lower than the power storage threshold value, the power storage device control unit 16 instructs the power storage device 14 to store power.

[0110] Then time goes on, such as Figure 10C As shown, the current time is t 14 At time t 14 The total power consumption previously calculated by the power consumption calculation unit 21 and stored in the power consumption storage unit 22 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 14 Early stipulated time T x Time t 14 +T x Substituting into the variable t of Mathematical Formula 1, the power consumption estimate value is calculated. Then, the power storage device control unit 16 compares the power consumption estimate value with the power storage threshold value. Figure 10C As shown, at time t 14 Since the estimated power consumption value is still lower than the power storage threshold value, the power storage device control unit 16 instructs the power storage device 14 to store power.

[0111] Figure 11 This is a diagram illustrating the relationship between the total power consumption of the motor drive device and the operation of the flywheel type power storage device according to one embodiment of the present disclosure. Figure 11The upper section represents the total power consumption obtained as the sum of the output of the driving servo motor 3, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12, and the lower section represents the power of the flywheel-type power storage device 14. The lower section also represents the torque command for the buffer servo motor 42 and the actual torque of the buffer servo motor 42, and the lower section also represents the speed of the buffer servo motor 42.

[0112] Here, as an example, consider a case where the motor drive device 1 including the flywheel type power storage device 14 accelerates the driving servo motor 3 and decelerates the driving servo motor 3 at time t2 , thereby changing the total power consumption.

[0113] As described above, in this embodiment, the response delay time from when the power storage device control unit 16 instructs the power storage device 14 to supply or store power to when the power storage device 14 actually starts supplying or storing power is taken into account, and based on the known data of the total power consumption before the current time point, it is estimated that the time T that is "equivalent to the response delay time" before the current time point is x The power storage device control unit 16 controls the power supply and storage of the power storage device 14 based on the result of comparison of the estimated value with the power supply threshold value and the power storage threshold value. Figure 11 In the process, the driving servo motor 3 is gradually accelerated. For example, when the total power consumption exceeds the power supply threshold at time t1, the power consumption estimating unit 15 starts the power supply at a predetermined time T before time t1. x At the time point t1", the total power consumption at the time t1 is estimated and output as the "estimated power consumption value". At the time t1", the power storage device control unit 16 compares the estimated power consumption value with the power supply threshold value. Since the estimated power consumption value is higher than the power supply threshold value, the power storage device control unit 16 instructs the power storage device 14 to supply power. Based on the power supply instruction, a torque instruction is generated for the buffer servo motor 42. The power storage device control unit 16 delays the power storage device 14 from supplying power after the power storage device control unit 16 instructs the power storage device 14 to supply power. x The power storage device 1 actually starts to supply power, so the actual torque of the buffer servo motor 42 is delayed by a predetermined time T relative to the torque command. x That is, the power storage device 14 is set to follow the power supply instruction at a time t1" later than the time when the power storage device control unit 16 outputs the power supply instruction. x At time t1, DC power starts to be supplied to the DC link 4. As a result, after time t1, the amount of power exceeding the power supply threshold in the total power consumption is compensated by the DC power supplied from the power storage device 14 to the DC link 4, and the power peak of the AC power supply 2 is reduced.

[0114] When the driving servo motor 3 is decelerated at time t2 and the total power consumption falls below the power storage threshold, the power consumption estimating unit 15 starts the predetermined time T before time t2. x At the time point t2", the total power consumption at the time t2 is estimated and output as the "estimated power consumption value". At the time t2", the power storage device control unit 16 compares the estimated power consumption value with the power storage threshold value. Since the estimated power consumption value is lower than the power storage threshold value, the power storage device control unit 16 instructs the power storage device 14 to store power. Based on the power storage instruction, a torque instruction is generated for the buffer servo motor 42. A predetermined time T is delayed from the time when the power storage device control unit 16 instructs the power storage device 14 to store power. x The power storage device 14 actually starts to store electricity, so the actual torque of the buffer servo motor 42 is delayed by a predetermined time T relative to the torque command. x That is, the power storage device 14 is set to follow the power storage device 16 at a time t2" later than the time when the power storage device control unit 16 outputs the power storage instruction. x At time t2, DC power storage starts from the DC link 4. As a result, the difference between the total power consumption (regenerated by the drive servo motor 3 and represented as a negative value) and the power storage threshold value after time t2 is stored from the DC link 4 in the power storage device 14, reducing the power peak of the AC power supply 2.

[0115] Figure 12 This is a diagram illustrating the relationship between the total power consumption of a conventional motor drive device and the operation of a flywheel-type power storage device without considering the response delay of the power storage device. Figure 12 The upper section represents the total power consumption obtained as the sum of the output of the driving servo motor, the coil loss in the driving servo motor, the loss in the converter, and the loss in the driving inverter. The lower section represents the power of the flywheel-type power storage device, and the lower section also represents the torque command for the buffer servo motor and the actual torque of the buffer servo motor, and the lower section also represents the speed of the buffer servo motor.

[0116] Figure 12 As an example, the following example is considered: without considering the response delay of the power storage device Figure 11 In the same operation pattern as in the case of , the driving servo motor is accelerated by the conventional motor driving device, and the driving servo motor 3 is decelerated at time t2, thereby changing the total power consumption.

[0117] exist Figure 12In the example, when the total power consumption exceeds the power supply threshold at time t1, the power storage device control unit instructs the power storage device to supply power at time t1. Based on this power supply instruction, a torque instruction is generated for the buffer servo motor. The power storage device responds with a delay time T from the time the power storage device receives the power supply instruction. x Therefore, the actual torque of the buffer servo motor will be delayed by the response delay time T relative to the torque command. x That is, the power storage device is set to follow the power supply command at a time T later than the time t1 at which the power storage device control unit outputs the power supply command. x At time t1', DC power supply to the DC link begins. As a result, after time t1', the amount of total power consumption exceeding the power supply threshold is compensated by the DC power supplied from the power storage device to the DC link, reducing the peak power of the AC power supply. However, at time t1, regardless of whether the total power consumption exceeds the power supply threshold, the start of power supply is delayed due to the response delay of the power storage device. Therefore, the total power consumption exceeding the power supply threshold cannot be reduced from time t1 to time t1'.

[0118] exist Figure 12 At time t2, the driving servo motor is decelerated. When the total power consumption falls below the storage threshold, the storage device control unit instructs the storage device to store power. Based on this storage command, a torque command is generated for the buffer servo motor. The response delay time T is delayed from the time the storage device receives the storage command. x Therefore, the actual torque of the buffer servo motor will be delayed by a predetermined time T relative to the torque command. x That is, the power storage device is set to follow the power storage device at a time T later than the time t2 at which the power storage device control unit outputs the power storage instruction. x At time t2', DC power from the DC link begins to be stored. Consequently, after time t2', the difference between the total power consumption (negative due to the regenerative power of the drive servo motor) and the power storage threshold is stored from the DC link in the power storage device, reducing the peak power of the power supply. However, regardless of whether the total power consumption falls below the power storage threshold at time t2, the start of power storage is delayed due to the response delay of the power storage device. Therefore, from time t2 to time t3, when the total power consumption exceeds the power storage threshold, the total power consumption difference between the total power consumption and the power storage threshold cannot be reduced. The operation after time t5 is identical to that up to time t4, so the description is omitted.

[0119] As reference Figure 12 As described above, conventionally, there has been a case where a power peak cannot be reduced due to a response delay from when a power supply or power storage instruction is issued to a power storage device until the power storage device actually starts power supply or power storage.

[0120] In contrast, according to the embodiment of the present disclosure, the response delay time from the time when the storage device control unit 16 instructs the storage device 14 to supply power or store power to the time when the storage device 14 actually starts supplying power or storing power is taken into account. Based on the known data of the total power consumption before the current time point, the total power consumption at a time point earlier than the current time point by "a time equivalent to the response delay time" is estimated. Based on the comparison result of the estimated value with the power supply threshold value and the power storage threshold value, the storage device control unit 16 controls the power supply and storage of the storage device 14, thereby reliably reducing the power peak.

[0121] As described above, the "predetermined time" used by the power consumption estimating unit 15 to calculate the estimated power consumption value is set as the "predetermined time." The response delay time from the time the power storage device control unit 16 instructs the power storage device 14 to supply or store power to the time the power storage device 14 actually starts supplying or storing power is set. The response delay time from the time the power storage device control unit 16 instructs the power storage device 14 to supply or store power to the time the power storage device 14 actually starts supplying or storing power can be measured in advance or in real time by providing a measurement unit. Figure 13 This is a block diagram of a motor drive device according to one embodiment of the present disclosure, including a measurement unit that measures the response delay time of a power storage device. The power storage device control unit 16 includes a measurement unit 38 that measures the response delay time from the time the power storage device 14 is instructed to supply or store power until the time the power storage device 14 begins supplying or storing power. The power consumption estimation unit 15, based on known data on total power consumption prior to the current time, estimates the total power consumption at a time prior to the current time by at least "a time corresponding to the response delay time" measured by the measurement unit 38, and outputs this estimated value as the estimated power consumption value.

[0122] Next, the power consumption estimating unit 15 according to the second to fourth embodiments will be described. The power consumption estimating unit 15 according to the second to fourth embodiments calculates an estimated driving servo motor output value, which is an estimated value that precedes the current output value of the driving servo motor 3 by a predetermined time, and calculates an estimated power consumption value that includes the estimated driving servo motor output value.

[0123] Figure 14 This is a block diagram of a motor drive device according to an embodiment of the present disclosure including a power consumption estimating unit according to a second aspect.

[0124] The power consumption estimating unit 15 of the second embodiment includes an output estimating unit 24 for obtaining an estimated driving servo motor output value, which is an estimated value that is a predetermined time earlier than the current output value of the driving servo motor 3; and an estimated power consumption value calculating unit 25 for calculating an estimated power consumption value including at least the estimated driving servo motor output value.

[0125] In the second embodiment, the output estimation unit 24 includes a torque acquisition unit 31 , a torque storage unit 32 , a torque estimated value calculation unit 33 , a speed acquisition unit 34 , and an output estimated value calculation unit 37 .

[0126] The torque acquisition unit 31 acquires the torque value of the driving servo motor 3 from the driving motor control unit 13 .

[0127] The torque storage unit 32 stores the torque value acquired by the torque acquisition unit 31. The torque storage unit 32 is composed of, for example, an electrically erasable and recordable nonvolatile memory such as EEPROM (registered trademark) or a high-speed readable and writable random access memory such as DRAM or SRAM.

[0128] The speed acquisition unit 34 acquires the speed value of the driving servo motor 3 from the speed detector 52 .

[0129] The estimated torque value calculation unit 33 calculates an estimated torque value that is a predetermined time prior to the torque value at the current time point, based on at least two torque values ​​stored in the torque storage unit 32 before the current time point. For example, the estimated torque value is calculated by using an approximate straight line using the at least two torque values ​​stored in the torque storage unit 32 before the current time point to estimate the torque at a predetermined time prior to the current time point.

[0130] Figure 15 : is a diagram illustrating the change in torque of the driving servo motor. Figures 16A to 16C Yes Figure 15 Calculation of the estimated torque value of the driving servo motor in the vicinity of region C is explained.

[0131] The torque estimation value can be calculated using the approximate straight line represented by Mathematical Formula 1, which is used to calculate the reference value. Figure 6A as well as Figure 6B For example, in the case of Figure 6A When the least square method is used to calculate the torque estimate value as described above, the slope α of the approximate straight line represented by the mathematical formula 1 for calculating the torque estimate value based on the least square method can be obtained using the mathematical formula 2 based on the three torque values ​​before the current time point stored in the torque storage unit 32, and the intercept β can be obtained using the mathematical formula 3. Figure 6BWhen first-order approximation is used to calculate the torque estimate as described above, the slope α of the approximate line represented by Mathematical Formula 1, used to calculate the torque estimate based on the first-order approximation, can be calculated using Mathematical Formula 4, and the intercept β can be calculated using Mathematical Formula 5, based on the two torque values ​​stored before the current time point in the torque storage unit 32. Substituting a time point a predetermined time prior to the current time point into the approximate line represented by Mathematical Formula 1 calculated as described above, the torque estimate at the predetermined time point can be calculated. The torque estimate calculation unit 33 within the output estimation unit 24 calculates the torque estimate for each control cycle according to the above series of processes.

[0132] For example, Figure 16A The current time is t 12 At time t 12 The torque value previously acquired by the torque acquisition unit 31 and stored in the torque storage unit 32 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 12 Early stipulated time T x Time t 12 +T x Substitute into the variable t in Mathematical Formula 1 to calculate the torque estimate. As time progresses, Figure 16B The current time is t 13 At time t 13 The torque value previously acquired by the torque acquisition unit 31 and stored in the torque storage unit 32 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 13 Early stipulated time T x Time t 13 +T x Substitute the variable t into the mathematical formula 1 to calculate the torque estimate. As time progresses, Figure 16C The current time is t 14 At time t 14 The torque value previously acquired by the torque acquisition unit 31 and stored in the torque storage unit 32 is used to calculate the slope α and intercept β of the mathematical formula 1, and the current time point t is changed to 14 Early stipulated time T x Time t 14 +T x Substitute the variable t into the mathematical formula 1 to calculate the torque estimation value.

[0133] The output estimated value calculation unit 37 calculates the estimated output value of the driving servo motor by multiplying the torque estimated value calculated by the torque estimated value calculation unit 33 as described above by the speed value at the current time point acquired by the speed acquisition unit 34 .

[0134] The estimated power consumption value calculation unit 25 calculates an estimated power consumption value that includes at least the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37. Specifically, the estimated power consumption value calculation unit 25 calculates the estimated power consumption value by adding the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12.

[0135] Figure 17 This is a block diagram of a motor drive device according to an embodiment of the present disclosure including a power consumption estimating unit according to a third aspect.

[0136] The power consumption estimating unit 15 of the third embodiment includes an output estimating unit 24 for obtaining an estimated driving servo motor output value, which is an estimated value that is a predetermined time earlier than the output value of the driving servo motor 3 at the current time point; and an estimated power consumption value calculating unit 25 for calculating an estimated power consumption value including at least the estimated driving servo motor output value.

[0137] In the third embodiment, the output estimating unit 24 includes a torque acquiring unit 31 , a speed acquiring unit 34 , a speed storage unit 35 , a speed estimated value calculating unit 36 ​​, and an output estimated value calculating unit 37 .

[0138] The torque acquisition unit 31 acquires the torque value of the driving servo motor 3 from the driving motor control unit 13 .

[0139] The speed acquisition unit 34 acquires the speed value of the driving servo motor 3 from the speed detector 52 .

[0140] The speed storage unit 35 stores the speed value of the driving servo motor 3 acquired by the speed acquisition unit 34. The speed storage unit 35 is composed of, for example, a nonvolatile memory capable of electrically erasing and recording, such as EEPROM (registered trademark), or a random access memory capable of high-speed reading and writing, such as DRAM or SRAM.

[0141] The estimated speed value calculation unit 36 ​​calculates an estimated speed value that is a predetermined time prior to the current speed value based on at least two speed values ​​stored in the speed storage unit 35. For example, the estimated speed value is calculated by using an approximate straight line using the at least two speed values ​​stored in the speed storage unit 35 to estimate the speed at a predetermined time prior to the current speed value.

[0142] Figure 18 : is a diagram illustrating the change in the speed of the driving servo motor. Figures 19A to 19C Yes Figure 18Calculation of the estimated speed value of the driving servo motor in the vicinity of region D is explained.

[0143] The speed estimation value can be calculated using the approximate straight line represented by Mathematical Formula 1, which is used to calculate the reference Figure 6A as well as Figure 6B For example, in the case of Figure 6A When the least square method is used to calculate the speed estimate value as described above, the slope α of the approximate straight line represented by the mathematical formula 1 for calculating the speed estimate value based on the least square method can be obtained using the mathematical formula 2 based on the three speed values ​​before the current time point stored in the speed storage unit 35, and the intercept β can be obtained using the mathematical formula 3. Figure 6B When first-order approximation is used to calculate the speed command value as described above, the slope α of the approximate line represented by Mathematical Formula 1, which calculates the speed estimate value based on the first-order approximation, can be calculated using Mathematical Formula 4, based on two speed values ​​before the current time point stored in the speed storage unit 35. The intercept β can be calculated using Mathematical Formula 5. Substituting a time point a predetermined time prior to the current time point into the approximate line represented by Mathematical Formula 1 calculated as described above, the speed estimate value at the predetermined time point can be calculated. The speed estimate value calculation unit 36 ​​within the output estimation unit 24 calculates the speed estimate value for each control cycle according to the above series of processes.

[0144] For example, Figure 19A The current time is t 12 At time t 12 The slope α and intercept β of the mathematical formula 1 are calculated by using the speed value previously acquired by the speed acquisition unit 34 and stored in the speed storage unit 35, and the current time point t is changed to 12 Early stipulated time T x Time t 12 +T x Substitute the variable t into the mathematical formula 1 to calculate the speed estimate. Then, as time progresses, Figure 19B The current time is t 13 At time t 13 The slope α and intercept β of the mathematical formula 1 are calculated by using the speed value previously acquired by the speed acquisition unit 34 and stored in the speed storage unit 35, and the current time point t is changed to 13 Early stipulated time T x Time t 13 +T x Substitute the variable t into the mathematical formula 1 to calculate the speed estimate. Then, as time progresses, Figure 19C The current time is t 14 At time t 14The slope α and intercept β of the mathematical formula 1 are calculated by using the speed value previously acquired by the speed acquisition unit 34 and stored in the speed storage unit 35, and the current time point t is changed to 14 Early stipulated time T x Time t 14 +T x Substitute this into the variable t in Mathematical Formula 1 to calculate the estimated speed value.

[0145] The output estimated value calculation unit 37 calculates the estimated output value of the driving servo motor by multiplying the torque value acquired by the torque acquisition unit 31 by the speed estimated value calculated by the speed estimated value calculation unit 36 ​​as described above.

[0146] The estimated power consumption value calculation unit 25 calculates an estimated power consumption value that includes at least the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37. Specifically, the estimated power consumption value calculation unit 25 calculates the estimated power consumption value by adding the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12.

[0147] Figure 20 This is a block diagram of a motor drive device according to an embodiment of the present disclosure including a fourth aspect of the power consumption estimating unit.

[0148] The power consumption estimating unit 15 of the fourth embodiment includes an output estimating unit 24 for obtaining an estimated driving servo motor output value, which is an estimated value that is a predetermined time earlier than the current output value of the driving servo motor 3; and an estimated power consumption value calculating unit 25 for calculating an estimated power consumption value including at least the estimated driving servo motor output value.

[0149] In the fourth embodiment, the output estimation unit 24 includes a torque acquisition unit 31 , a torque storage unit 32 , a torque estimated value calculation unit 33 , a speed acquisition unit 34 , a speed storage unit 35 , a speed estimated value calculation unit 36 ​​, and an output estimated value calculation unit 37 .

[0150] The torque acquisition unit 31 acquires the torque value of the driving servo motor 3 from the driving motor control unit 13 .

[0151] The torque storage unit 32 stores the torque value acquired by the torque acquisition unit 31. The torque storage unit 32 is composed of, for example, an electrically erasable and recordable nonvolatile memory such as EEPROM (registered trademark) or a high-speed readable and writable random access memory such as DRAM or SRAM.

[0152] The torque estimated value calculation unit 33 calculates an estimated value of the torque at a predetermined time prior to the torque value at the current time point based on at least two torque values ​​before the current time point stored in the torque storage unit 32. The torque estimated value is calculated by, for example, calculating an approximate straight line using at least two torque values ​​before the current time point stored in the torque storage unit 32 to estimate the torque at a predetermined time prior to the current time point. The calculation method of the torque estimated value is described in relation to the second embodiment. Figure 15 as well as Figures 16A to 16C As described.

[0153] The speed acquisition unit 34 acquires the speed value of the driving servo motor 3 from the speed detector 52 .

[0154] The speed storage unit 35 stores the speed value of the driving servo motor 3 acquired by the speed acquisition unit 34. The speed storage unit 35 is composed of, for example, a nonvolatile memory capable of electrically erasing and recording, such as EEPROM (registered trademark), or a random access memory capable of high-speed reading and writing, such as DRAM or SRAM.

[0155] The speed estimation value calculation unit 36 ​​calculates a speed estimation value that is an estimated value at a predetermined time before the speed value at the current time point based on at least two speed values ​​before the current time point stored in the speed storage unit 35. For example, the speed estimation value is calculated by using an approximate straight line using at least two speed values ​​before the current time point stored in the speed storage unit 35 to estimate the speed at a predetermined time before the current time point. The calculation method of the speed estimation value is as described in relation to the third embodiment. Figure 18 as well as Figures 19A to 19C As described.

[0156] The output estimated value calculation unit 37 calculates the estimated output value of the driving servo motor by multiplying the torque estimated value obtained by the torque estimated value calculation unit 33 by the speed estimated value calculated by the speed estimated value calculation unit 36 ​​as described above.

[0157] The estimated power consumption value calculation unit 25 calculates an estimated power consumption value that includes at least the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37. Specifically, the estimated power consumption value calculation unit 25 calculates the estimated power consumption value by adding the estimated output value of the driving servo motor calculated by the estimated output value calculation unit 37, the coil loss in the driving servo motor 3, the loss in the converter 11, and the loss in the driving inverter 12.

[0158] Furthermore, the output of the drive servo motor 3 has a dominant influence on the total power consumption. Therefore, the power consumption estimating unit 15 in the second to fourth embodiments calculates an estimated output value of the drive servo motor 3. As a modified example, estimated values ​​may be calculated for the coil loss in the drive servo motor 3, the loss in the converter 11, and the loss in the drive inverter 12, and the power consumption estimated value may be calculated incorporating these estimated values.

[0159] The drive motor control unit 13, power consumption estimation unit 15, and power storage device control unit 16 described above can be implemented, for example, as software programs, or as a combination of various electronic circuits and software programs. In this case, the functions of each unit can be implemented by executing the software programs on a processing unit such as a CPU, MPU, or DSP. Alternatively, they can be implemented as a semiconductor integrated circuit, on which the software programs implementing the functions of the drive motor control unit 13, power consumption estimation unit 15, and power storage device control unit 16 are written.

[0160] Furthermore, the drive motor control unit 13, the power consumption estimation unit 15, and the power storage device control unit 16 are, for example, provided within a main control unit (not shown) of the motor drive device 1. For example, when the motor drive device 1 controls the drive servo motor 3 installed in a machine tool, these drive motor control unit 13, the power consumption estimation unit 15, and the power storage device control unit 16 can be provided within the numerical controller of the machine tool. If the drive motor control unit 13, the power consumption estimation unit 15, and the power storage device control unit 16 are implemented as software programs, the functions of these units can be implemented by having the arithmetic processing unit within the numerical controller execute the software programs.

[0161] According to one aspect of the present disclosure, in a motor drive device including a power storage device provided to reduce a power peak of a power supply device, it is possible to reliably reduce the power peak.

Claims

1. A motor drive device, characterized in that: have: a converter that converts AC power from the AC power source to DC power in the DC link; a driving inverter that converts DC power in the DC link into AC power serving as driving power or regenerative power for a driving servo motor; a driving motor control unit that controls the driving servo motor connected to the driving inverter; a power storage device that supplies DC power to the DC link or stores DC power from the DC link; a power consumption estimating unit configured to obtain an estimated power consumption value, which is an estimated value of total power consumption obtained as a sum of an output of the driving servo motor, a coil loss in the driving servo motor, a loss in the converter, and a loss in the driving inverter, that is, a value that is estimated a predetermined time earlier than a value at a current time point; and a power storage device control unit configured to control power supply and power storage of the power storage device in accordance with the estimated power consumption value; The power storage device control unit compares the estimated power consumption value with a predetermined power supply threshold value and a power storage threshold value. When it is determined as a result of the comparison that the estimated power consumption value is higher than the power supply threshold value, controlling the power storage device so that the power storage device supplies DC power to the DC link; When it is determined as a result of the comparison that the estimated power consumption value is lower than the power storage threshold value, the power storage device is controlled so that the power storage device stores DC power from the DC link.

2. A motor drive device, characterized in that: have: a converter that converts AC power from the AC power source to DC power in the DC link; a driving inverter that converts DC power in the DC link into AC power serving as driving power or regenerative power for a driving servo motor; a driving motor control unit that controls the driving servo motor connected to the driving inverter; a power storage device that supplies DC power to the DC link or stores DC power from the DC link; a power consumption estimating unit configured to obtain an estimated power consumption value, which is an estimated value of total power consumption obtained as a sum of an output of the driving servo motor, a coil loss in the driving servo motor, a loss in the converter, and a loss in the driving inverter, that is, a value that is estimated a predetermined time earlier than a value at a current time point; and a power storage device control unit configured to control power supply and power storage of the power storage device in accordance with the estimated power consumption value; The power consumption estimating unit includes: a power consumption calculation unit that calculates the total power consumption; a power consumption storage unit that stores the total power consumption value calculated by the power consumption calculation unit; and The estimated power consumption value calculation unit calculates the estimated power consumption value based on at least two values ​​of the total power consumption before a current time point stored in the power consumption storage unit.

3. A motor drive device, characterized in that: have: a converter that converts AC power from the AC power source to DC power in the DC link; a driving inverter that converts DC power in the DC link into AC power serving as driving power or regenerative power for a driving servo motor; a driving motor control unit that controls the driving servo motor connected to the driving inverter; a power storage device that supplies DC power to the DC link or stores DC power from the DC link; a power consumption estimating unit configured to obtain an estimated power consumption value, which is an estimated value of total power consumption obtained as a sum of an output of the driving servo motor, a coil loss in the driving servo motor, a loss in the converter, and a loss in the driving inverter, that is, a value that is estimated a predetermined time earlier than a value at a current time point; and a power storage device control unit configured to control power supply and power storage of the power storage device in accordance with the estimated power consumption value; The power consumption estimating unit includes: an output estimating unit that obtains an estimated driving servo motor output value that is an estimated value earlier than the current output value of the driving servo motor by the predetermined time; and The power consumption estimated value calculation unit calculates the power consumption estimated value including at least the output estimated value of the driving servo motor.

4. The motor drive device according to claim 3, wherein: The output estimation unit includes: a torque acquisition unit that acquires a torque value of the driving servo motor; a torque storage unit that stores the torque value acquired by the torque acquisition unit; a torque estimated value calculation unit for calculating a torque estimated value that is an estimated value earlier than the torque value at the current time by the predetermined time based on at least two torque values ​​before the current time stored in the torque storage unit; a speed acquisition unit that acquires a speed value of the driving servo motor; as well as An output estimated value calculation unit calculates an estimated output value of the driving servo motor based on the torque estimated value and the speed value at a current time point.

5. The motor drive device according to claim 3, wherein: The output estimation unit includes: a torque acquisition unit that acquires a torque value of the driving servo motor; a speed acquisition unit that acquires a speed value of the driving servo motor; a speed storage unit that stores the speed value acquired by the speed acquisition unit; a speed estimated value calculation unit for calculating a speed estimated value that is an estimated value earlier than the speed value at the current time by the predetermined time based on at least two speed values ​​before the current time stored in the speed storage unit; as well as An output estimated value calculation unit calculates an estimated output value of the driving servo motor based on the speed estimated value and the torque value at a current time point.

6. The motor drive device according to claim 3, wherein: The output estimation unit includes: a torque acquisition unit that acquires a torque value of the driving servo motor; a torque storage unit that stores the torque value acquired by the torque acquisition unit; a torque estimated value calculation unit for calculating a torque estimated value that is an estimated value earlier than the torque value at the current time by the predetermined time based on at least two torque values ​​before the current time acquired by the torque acquisition unit; a speed acquisition unit that acquires a speed value of the driving servo motor; a speed storage unit that stores the speed value acquired by the speed acquisition unit; a speed estimated value calculation unit for calculating a speed estimated value that is an estimated value earlier than the speed value at the current time by the predetermined time based on at least two speed values ​​before the current time acquired by the speed acquisition unit; as well as An output estimated value calculation unit calculates an estimated output value of the driving servo motor based on the estimated torque value and the estimated speed value.

7. The motor drive device according to any one of claims 1 to 6, characterized in that: The power storage device control unit further includes a measuring unit that measures a response delay time from when the power storage device is instructed to supply power or store power to when the power storage device starts supplying power or storing power. The predetermined time includes at least the response delay time.

8. The motor drive device according to any one of claims 1 to 6, wherein: The power storage device comprises: a flywheel, which is capable of storing rotational energy; a buffer servo motor having a rotating shaft coupled to the flywheel; and The buffer inverter converts between direct current in the DC link and alternating current serving as driving power or regenerative power for the buffer servo motor.

9. The motor drive device according to any one of claims 1 to 6, wherein: The power storage device comprises: capacitors; and The DC-DC converter performs power conversion between the DC power in the DC link and the DC power stored in the capacitor.

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