JPWO2020217272A1 - Motor drive system and motor drive - Google Patents

Abstract

The motor drive system (300) includes a motor drive device (200a, 200b) and a controller (125). The motor drive device (200a) drives the motors (100a, 124) based on the drive command generated by the control unit (23). The motor drive device (200b) drives the motors (100b, 124) based on the drive command generated by the control unit (23). The controller (125) generates a motor control valid command and controls the operation of the motor drive devices (200a, 200b) based on the motor control valid command. The controller (125) outputs a motor control valid command to any one of the motor drive devices (200a, 200b), and each control unit (23) drives the motor during the period when the motor control valid command is not received. Stop the output of the command.

Description

The present invention relates to a motor drive system and a motor drive device for driving a motor.

The motor drive device includes an inverter circuit that supplies AC power to the motor. The inverter circuit is configured to include two or more legs in which an upper arm switching element and a lower arm switching element are connected in series. The upper arm points to the high potential side, and the lower arm points to the low potential side.

In order to control each switching element provided in the inverter circuit, a gate drive circuit for applying a gate drive voltage to each switching element is required. Further, in order to operate the gate drive circuit, a gate power supply is required. Patent Document 1 below discloses a configuration of a gate drive circuit including an individual gate power supply (hereinafter referred to as "individual power supply") in order to individually control each switching element of the inverter circuit.

There is also a common power supply type gate drive circuit that has a charge pump circuit and a single upper arm gate power supply for driving a plurality of upper arm switching elements, as opposed to a gate drive circuit having an individual power supply. .. In the case of the common power supply system, the charge pump circuit is provided for each upper arm switching element. Then, as the gate drive voltage for driving each upper arm switching element, the charge voltage charged in the charge pump circuit is used. The charge pump circuit is charged by operating the corresponding lower arm switching element.

In the common power supply system, when driving the upper arm switching element, it is necessary to operate the corresponding lower arm switching element immediately before that to complete charging of the charge pump circuit. It takes some time to charge the charge pump circuit. Therefore, the time during which the drive command is actually turned on or off after the drive command is issued varies between the upper arm switching element and the lower arm switching element. Further, since the charging time of the charge pump circuit also varies, the time of the ON operation or the OFF operation also varies among the upper arm switching elements. Therefore, in an application in which the timing at which each switching element operates becomes a problem, an individual power supply method is often used instead of the common power supply method.

Further, the motors driven by the inverter circuit are roughly classified into a rotary motor in which a rotor rotates around a rotating shaft and a linear motor having no rotating shaft and performing linear motion. A general linear motor configuration is a method in which a magnet pair as a fixed portion is arranged on the ground side and a coil is arranged on the movable portion side. In this method, the coil of the movable part is driven by the current supplied from the motor drive device.

However, in the method in which the coil is located in the movable portion, a mechanism is required in which the power cable for applying the power supply voltage to the movable portion is run in parallel following the operation of the coil in the movable portion. Alternatively, a mechanism for applying a power supply voltage to the moving part is required by adding a non-contact power supply device or the like. When the power cable runs in parallel following the operation of the coil of the moving part, there are restrictions such as cable length and cable twist in the case of a circular operation path. Further, when adding a non-contact power supply device, there is a problem that a large amount of cost is required.

In response to the above problems, there is also a method in which the configuration is opposite to that of a general linear motor, that is, a method in which a coil is arranged on the ground side as a fixed portion and a magnet is arranged in a movable portion. This method is called "moving magnet method" or "moving magnet control". In the case of the moving magnet method, since the moving part is a magnet, it is not necessary to supply power to the moving part. Therefore, the restrictions such as the cable length and the cable twist, which have been problems in the linear motor in which the coil is arranged in the movable portion, do not occur. Further, in the case of this moving magnet method, it is not necessary to add a non-contact power feeding device.

Japanese Unexamined Patent Publication No. 2012-120304

However, the moving magnet method also has a problem. For example, if the stroke, which is the operating range of the movable part, becomes longer than a certain amount, the stroke cannot be secured by one set of coils and one motor drive device, and it is necessary to prepare a plurality of sets of coils and motor drive devices. .. Then, among the plurality of prepared coils, when switching the coil to be excited, there is a need for a technique for ensuring the continuity of control and smoothly switching between the coils.

As described above, in the case of the gate drive circuit of the individual power supply system as in Patent Document 1, the variation in the operation timing of each switching element can be reduced as compared with the common power supply system. However, the problem of smoothly switching between a plurality of coils in the moving magnet system described above cannot be solved only by using the gate drive circuit of the individual power supply system.

The present invention has been made in view of the above, and an object of the present invention is to obtain a motor drive system capable of smoothly switching between coils when switching coils to be excited.

In order to solve the above-mentioned problems and achieve the object, the motor drive system according to the present invention includes first and second motor drive devices and a higher-level control device. The first motor drive device includes a first control unit, and drives the first motor based on a drive command generated by the first control unit. The second motor drive device includes a second control unit, and drives the second motor based on a drive command generated by the second control unit. The host control device generates a motor control valid command and controls the operation of the first and second motor drive devices based on the motor control valid command. The host control device outputs a motor control valid command to any one of the first and second motor drive devices, and the first and second control units do not receive the motor control valid command during the period. Stop the output of the drive command.

According to the motor drive system according to the present invention, when switching the coils to be excited, there is an effect that the switching between the coils can be smoothly performed.

A block diagram showing a configuration of a motor drive device used in the motor drive system according to the first embodiment. A circuit diagram showing a detailed configuration of the inverter circuit shown in FIG. A circuit diagram used for explaining the configuration of the gate drive circuit according to the first embodiment. System configuration diagram of the motor drive system according to the first embodiment using the motor drive device shown in FIG. FIG. 4 shows an operating state immediately before switching from the first coil to the second coil. FIG. 4 shows an operating state immediately after switching to the second coil. Time chart for explaining the operation of the motor drive system shown in FIG. Block diagram showing a configuration example of the motor drive system according to the second embodiment Time chart for explaining the operation of the motor drive system shown in FIG. A time chart provided for explaining the operation of the motor drive system according to the third embodiment.

Hereinafter, the motor drive system and the motor drive device according to the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments.

Embodiment 1.
FIG. 1 is a block diagram showing a configuration of a motor drive device 200 used in the motor drive system according to the first embodiment. As shown in FIG. 1, the motor drive device 200 is a drive device that drives the motor 150, which is a load, by using the electric power supplied from the AC power supply 26. The motor drive device 200 includes a converter circuit 18, an inverter circuit 20, a smoothing capacitor 22, a control unit 23, and a gate drive circuit 24.

The converter circuit 18 rectifies the AC voltage applied from the AC power supply 26 and converts it into a DC voltage. An example of the converter circuit 18 is a full-wave rectifier circuit composed of a diode bridge. An inverter circuit 20 is connected to the output end of the converter circuit 18. The converter circuit 18 and the inverter circuit 20 are connected by a DC bus 27 on the high potential side and a DC bus 28 on the low potential side. A smoothing capacitor 22 is arranged between the DC bus 27 and the DC bus 28. The voltage between the DC bus 27 and the DC bus 28 is called the "bus voltage". The smoothing capacitor 22 serves to smooth the bus voltage and stabilize the bus voltage.

The inverter circuit 20 converts the DC voltage smoothed by the smoothing capacitor 22 into an AC voltage and applies it to the motor 150. The motor 150 is driven by AC power supplied from the inverter circuit 20. The motor 150 is provided with a position sensor 130. The position sensor 130 detects the rotational position of the rotor in the motor 150 (not shown). The position sensor signal 132 detected by the position sensor 130 is input to the control unit 23.

The control unit 23 includes a processor 23a and a memory 23b. The processor 23a generates a drive command 30 for controlling the switching element 21 of the inverter circuit 20 based on the position sensor signal 132. The gate drive circuit 24 generates a drive voltage 32 based on the drive command 30. The drive voltage 32 is a gate drive voltage for driving the switching element 21 of the inverter circuit 20.

The processor 23a may be referred to as a microprocessor, a microcomputer, a microcomputer, a CPU (Central Processing Unit), or a DSP (Digital Signal Processor).

The memory 23b stores a program read by the processor 23a, parameters referenced by the processor 23a, data obtained by processing by the processor 23a, and the like. The memory 23b is also used as a work area when the processor 23a performs arithmetic processing. The memory 23b is generally a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a flash memory, an EPROM (Erasable Programmable ROM), or an EEPROM (registered trademark) (Electrically EPROM).

In FIG. 1, the AC power supply 26 is a three-phase power supply, but the present invention is not limited to this. The AC power supply 26 may be a single-phase power supply. When the AC power supply 26 is a single-phase power supply, the converter circuit 18 is configured to match the single-phase power supply. An example of the motor 150 is a three-phase motor. When the motor 150 is a three-phase motor, the inverter circuit 20 also has a three-phase circuit configuration.

FIG. 2 is a circuit diagram showing a detailed configuration of the inverter circuit 20 shown in FIG. The inverter circuit 20 has legs 21A, legs 21B and legs 21C, as shown in FIG. The legs 21A, 21B and 21C are connected in parallel to each other between the DC bus 27 and the DC bus 28. The leg 21A is a circuit unit in which a U-phase upper arm switching element 21UP and a lower arm switching element 21UN are connected in series. The leg 21B is a circuit unit in which a V-phase upper arm switching element 21VP and a lower arm switching element 21VN are connected in series. The leg 21C is a circuit unit in which a W-phase upper arm switching element 21WP and a lower arm switching element 21WN are connected in series.

Note that FIG. 2 illustrates a case where the upper arm switching elements 21UP, 21VP, 21WP and the lower arm switching elements 21UN, 21VN, 21WN are metal oxide semiconductor field effect transistors (MOSFETs). However, it is not limited to this. Instead of the MOSFET, an insulated gate bipolar transistor (IGBT) may be used.

Further, each switching element may be provided with a diode connected in antiparallel. When the switching element is a MOSFET, a parasitic diode contained in the MOSFET itself may be used. Parasitic diodes are also called body diodes.

FIG. 3 is a circuit diagram used for explaining the configuration of the gate drive circuit 24 in the first embodiment. FIG. 3 shows a detailed connection relationship of the gate drive circuit 24 arranged between the processor 23a shown in FIG. 1 and the inverter circuit 20. The gate drive circuit 24 in the first embodiment is an individual power supply type gate drive circuit.

The gate drive circuit 24 in the first embodiment has gate power supply circuits 24a, 24b, 24c, 24d as shown in FIG. The gate power supply circuits 24a, 24b, and 24c are gate power supply circuits for the upper arm switching element. The gate power supply circuit 24a includes a resistor 241, a photocoupler 242 which is a signal transmission means and an insulating means, and a DC power supply 243. The gate power supply circuits 24b and 24c are also configured in the same manner as the gate power supply circuits 24a.

Further, the gate power supply circuit 24d is a gate power supply circuit for the lower arm switching element. The configuration in which the resistor 241 and the photocoupler 242 are individually provided for each lower arm switching element is the same as that of the gate power supply circuits 24a, 24b, 24c for the upper arm switching element.

Further, the gate power supply circuit 24d shown in FIG. 3 has a configuration in which the lower arm gate power supply is shared and includes one DC power supply 244. This is because in the inverter circuit 20, the source terminals of the lower arm switching elements are connected to each other and have the same potential, and this potential can be used as the reference potential of the gate power supply circuit 24d. Therefore, whether the gate drive circuit is an individual power supply system or a common power supply system is determined by whether or not the upper arm gate power supply is shared. Needless to say, the lower arm gate power supply may not be shared and may be configured by using three DC power supplies.

When the drive command 30 is issued from the processor 23a, the photocoupler 242 becomes conductive by the drive command 30. For example, when the drive command 30 is a drive command for turning on the U-phase upper arm switching element 21UP, the photocoupler 242 of the gate power supply circuit 24a conducts, and the drive voltage 32 is applied to the upper arm switching element 21UP. As a result, the upper arm switching element 21UP is turned on. Other switching elements are driven in the same way. Further, when the continuity of the photocoupler 242 is cut off, the switching element is turned off.

As described above, the gate drive circuit 24 of the individual power supply system can reduce the variation in the time when the switching element is actually turned ON or OFF after the drive command 30 is issued. Thereby, it can be suitably used for the application example of the first embodiment described below.

Next, an application example of the motor drive device 200 described above will be described. FIG. 4 is a diagram showing a configuration example of the motor drive system 300 according to the first embodiment using the motor drive device 200 shown in FIG. The drive target of the motor drive system 300 shown in FIG. 4 is a moving magnet type linear motor. In a moving magnet type linear motor, a plurality of coils are arranged in a fixed portion formed on the ground side, and a plurality of magnet pairs are arranged in a movable portion.

In FIG. 4, three coils 100a, 100b, and 100c are arranged in this order on the ground side along the positive direction of x1, which is the first direction, as an example of the plurality of coils. Further, the movable carriage 124 constituting the movable portion is equipped with three magnet pairs 120 as an example of the plurality of magnet pairs. A linear motor is composed of coils 100a, 100b, 100c and three magnet pairs 120 mounted on a movable carriage 124.

The magnetic pole direction of the magnet pair 120 is the direction of y1, which is the second direction. y1 is a direction orthogonal to x1. The three magnet pairs 120 are connected, and the NS of the magnetic poles of the adjacent magnet pairs is reversed by 180 °. As a result, when the movable carriage 124 moves in the first direction, the north pole and the south pole of the magnet pair 120 referred to from the coil side appear alternately.

Let L1 be the length of one coil in the x1 direction, and let L2 be the length of the entire three magnet pairs 120 in the x1 direction. In the case of the example of FIG. 4, there is a relationship of L1 <L2 <2 × L1 between these L1 and L2. The relationship of L1 <L2 <2 × L1 is a state in which three magnet pairs 120 straddle two coils and straddle three or more coils except at both ends of a coil group composed of a plurality of coils. Means that it does not exist. Depending on the specifications of the system, a state of straddling three or more coils may be allowed. Further, depending on the specifications of the system, L1> L2 may be satisfied.

Motor drive devices 200a, 200b, and 200c are mounted on the ground side. Each of the motor drive devices 200a, 200b, 200c and each of the coils 100a, 100b, 100c are connected on a one-to-one basis. The coil 100a is excited by the current output by the motor drive device 200a. As a result, the coil 100a becomes an electromagnet, an attractive force or a repulsive force is generated between the coil 100a and the magnet pair 120 arranged on the movable carriage 124, and the movable carriage 124 advances in the positive direction of x1.

Further, sensors 130a, 130b, 130c are arranged in each of the coils 100a, 100b, and 100c, respectively. An example of the sensors 130a, 130b, 130c is an optical sensor, and a specific example of the optical sensor is a barcode reader. A barcode 123 as a position identifier is readablely attached to the movable carriage 124 by sensors 130a, 130b, 130c, which are barcode readers. In FIG. 4, the coils 100a, 100b, and 100c are shown in part, and the number of coils is determined by the scale of the system. Further, in FIG. 4, each coil is arranged without a gap, but each coil may be arranged with a gap. Further, the sensors 130a, 130b and 130c may be magnetic sensors.

The motor drive device 200a is connected to the motor drive device 200b by a communication line 106, and the motor drive device 200b is connected to the motor drive device 200c by a communication line 106. That is, the motor drive devices 200a, 200b, and 200c are connected to the series by the communication line 106. The motor drive device 200a is further connected to the controller 125, which is a higher-level control device, by a communication line 106.

The controller 125 generates the control command 140. The control command 140 is transmitted to the motor drive device 200a through the communication line 106. The control command 140 includes an operation command, a position command, a speed command, and a motor control effective command. The operation command is a command value or a command signal for determining whether to operate or stop the movable carriage 124, which is a movable portion. The position command is a command value or a command signal for instructing the position of the movable carriage 124. The speed command is a command value or a command signal for instructing the speed of the movable carriage 124. The motor control effective command will be described later.

The motor drive device 200a transmits the received control command 140 to the motor drive device 200b. The motor drive device 200b transmits the received control command 140 to the motor drive device 200c. The connection example of FIG. 4 is an example, and is not limited to this example. Any connection form may be used as long as the control command 140 generated by the controller 125 can be transmitted to the motor drive devices 200a, 200b, 200c. Further, although it is connected by wire in FIG. 4, it may be connected wirelessly.

Next, the operation of the motor drive system 300 shown in FIG. 4 will be described with reference to the drawings of FIGS. 5 to 7 in addition to FIG. FIG. 5 is a diagram showing an operating state immediately before the coil for which motor control is enabled is switched from the first coil to the second coil. FIG. 6 is a diagram showing an operating state immediately after the coil for which motor control is enabled is switched to the second coil. FIG. 7 is a time chart provided for explaining the operation of the motor drive system 300 shown in FIG. As a supplement to the drawings, FIG. 4 shows a state of operation when the coil for which motor control is enabled is the first coil. Further, FIG. 7 shows an operation when the coil for which motor control is enabled is switched from the first coil to the second coil.

In FIG. 7, first, at time t1, the controller 125 outputs a position command to the motor drive device 200a (see FIG. 7D), and outputs a motor control valid command to the motor drive device 200a. (See FIG. 7 (f)). In FIGS. 7 (f) and 7 (g), the state in which the motor control valid command is received and the motor control is valid is represented by “ON”, the motor control valid command is not received, and the motor control is not valid. The state is represented by "OFF". The operating state of the motor drive device 200a is switched from OFF to ON, and the operation is started. When the motor drive device 200a is in the ON state, the motor drive device 200a excites the coil 100a, so that the movable carriage 124 is driven and moves, and the position of the movable carriage 124 changes (see FIG. 7A). FIG. 7B shows the position information of the movable carriage 124 detected by the sensor 130a. The position information is transmitted to the controller 125 via the motor drive device 200a. In FIG. 7, the position of the movable carriage 124 changes at the same time t1 when the position command is output to the motor drive device 200a, but in reality, the position of the movable carriage 124 is changed due to the control time lag. It goes without saying that the change occurs later than the change in the position command.

On the other hand, at time t1, the motor control valid command is not output to the motor drive device 200b, and the operating state of the motor drive device 200b remains OFF (see FIG. 7 (g)). Here, the motor control effective command is supplemented. As described above, the motor control effective command is one of the control commands 140 output from the controller 125. The controller 125 designates one motor driving device that enables motor control when outputting a motor control valid command. It should be noted that a plurality of motor drive devices are not designated for one movable carriage 124 at the same time.

Returning to the description of FIG. 7, the position command for the motor drive device 200a is continued until the time t12 beyond the time t3, and the position command for the motor drive device 200b is started from the time t11 before the time t3. That is, the position commands for the motor drive devices 200a and 200b overlap between the times t11 and t12. On the other hand, the motor control valid command for the motor drive device 200a and the motor control valid command for the motor drive device 200b are switched at time t3 so as not to overlap (see FIGS. 7 (f) and 7 (g)). FIG. 5 shows the state at time t11, and FIG. 6 shows the state at time t12.

In the case of FIGS. 5 and 6, since both the sensors 130a and 130b have a readable positional relationship with respect to the barcode 123, both the sensors 130a and 130b detect the position information (FIG. 7 (b). ), (C)). Although not shown, the time t2 is the time when the right end of the barcode 123 reaches the sensor 130b, and the time t4 is the time when the left end of the barcode 123 passes through the sensor 130a.

In the case of a moving magnet type linear motor, the magnet pair 120 mounted on the movable carriage 124 has a finite length, and the movable carriage 124 cannot be operated in the entire area with only one coil. Therefore, as shown in FIGS. 5 and 6, the movable carriage 124 advances to some extent, and the length facing the magnet pair 120 of the coil 100b, which is the second coil, is larger than that of the coil 100a, which is the first coil. The validity of the motor control is switched at the timing when the length becomes longer. Switching from the coil 100b to the coil 100c can be performed in the same manner. When switching from the coil 100b to the coil 100c, the coil 100b becomes the first coil and the coil 100c becomes the second coil. Further, when the motor drive device that excites the first coil is the first motor drive device and the motor drive device that excites the second coil is the second motor drive device, the motor drive device that drives the coil 100b is used. The 200b serves as the first motor drive device, and the motor drive device 200c that drives the coil 100c serves as the second motor drive device.

In the above description, the case where the number of movable carriages 124 to be operated is one has been described, but the present invention is not limited to this. The number of movable carriages 124 to be operated may be plural. When the number of movable carriages 124 to be operated is a plurality, the first motor driving device is designated for each of the movable carriages 124. In addition, the coil and motor drive device described above are switched for each movable carriage 124.

Further, in the examples of FIGS. 4 to 6, the movable carriage 124 has been described as traveling in the positive direction of x1, but the movable carriage 124 can also travel in the negative direction of x1. When the movable carriage 124 advances in the negative direction of x1, the coil 100b is switched to the coil 100a. In this case, the first coil switches from the coil 100c to the coil 100b, and the second coil switches from the coil 100b to the coil 100a. Further, the first motor drive device switches from the motor drive device 200c to the motor drive device 200b, and the second motor drive device switches from the motor drive device 200b to the motor drive device 200a.

Further, in the examples of FIGS. 5 and 6, an example of switching the effectiveness of the motor control based on the length of the magnet pair 120 facing the magnet pair 120 has been described, but the present invention is not limited to this example. There are various methods for switching the coil, and other methods may be used. As an example, it is conceivable to switch the validity of the motor control based on the detection level of the position sensor signal 132.

In the case of a gate drive circuit composed of a charge pump circuit, it is necessary to continue switching of the lower arm switching element in order to secure the upper arm gate power supply even when motor control is not required. If the switching of the lower arm switching element is continued, a braking current may flow due to the dynamic braking, a braking force may be generated in the motor, and the motor may decelerate. On the other hand, in the first embodiment, since the gate drive circuit of the individual power supply system is used, control for securing the upper arm gate power supply is unnecessary. As a result, the occurrence of dynamic braking when securing the upper arm gate power supply can be suppressed, so that efficient motor control becomes possible.

Further, in the case of a moving magnet type linear motor, as shown in FIG. 4, both the first coil and the second coil are magnet pairs in the process of switching the magnet pair 120 from the first coil to the second coil. There are cases where it overlaps with. On the other hand, in the method of the first embodiment, when the motor control is not effective, the switching element is not controlled to be ON. Therefore, it is possible to suppress the generation of disturbance or impact due to the dynamic brake, and it is possible to smoothly switch between the coils at the joints between the coils.

Further, in the method of the first embodiment, the position commands for the first and second motor drive devices are output in an overlapping manner. Therefore, in the process of switching from the first coil to the second coil, the control operations for driving the first and second coils are performed in parallel. Therefore, the second coil can be quickly excited even immediately after the switching. As a result, switching between the coils can be quickly performed at the connection between the coils. Further, by overlapping the position commands, switching between a plurality of coils is performed after the integration terms of the control model in the control system (not shown) are accumulated. As a result, when switching the coils to be excited, the switching between the coils can be performed smoothly.

As described above, according to the motor drive system according to the first embodiment, the host control device outputs a motor control effective command to any one of the first and second motor drive devices, and the first and second motor drive devices are output. The second control unit stops the output of the drive command during the period during which the motor control valid command is not received. Thereby, when switching between the first coil excited by the first motor driving device and the second coil excited by the second motor driving device, the switching between the coils can be smoothly performed. ..

Further, in the motor drive system according to the first embodiment, the first motor is configured to be movable to the positive side and the negative side in the first direction with the first coil arranged in the fixed portion. A second motor is composed of a plurality of magnet pairs arranged in a fixed portion, and a second coil arranged on a fixed portion and adjacent to a first coil on the positive side in the first direction and a plurality of the magnet pairs. It can be applied to a linear motor composed of. At that time, the first coil excited by the first motor driving device and the second coil excited by the second motor driving device are on the positive side in the first direction as the moving portion moves. Alternatively, the coil is sequentially switched to the coil adjacent to the negative side. Then, the host control device outputs a motor control valid command to any one of the first and second motor drive devices, and the first and second control units do not receive the motor control valid command during the period. Stops the output of the drive command. As a result, both the first and second coils are not excited at the same time even if there is a period in which both the first and second coils overlap with the magnet pair. As a result, the occurrence of dynamic braking can be suppressed. Further, when switching between the first coil excited by the first motor driving device and the second coil excited by the second motor driving device, the switching between the coils can be smoothly performed.

Further, in order to instantly determine whether or not the motor control is effective, the information of the motor control effective command transmitted from the host control device may be stored in the memory 23b as a parameter. In this way, the existing functions and the new functions can easily coexist, and the cost of system construction can be reduced. An example of how to use the parameters is shown below.

(1) For normal motor control-Set the parameter to "0".
-When the parameter is "0", the alarm is always enabled regardless of the presence or absence of the motor control valid command.
(2) For moving magnet control-Set the parameter to "1".
-When the parameter is "1", the alarm is enabled only when the motor control valid command is output.

Embodiment 2.
In the second embodiment, a motor drive system for switching a plurality of sets of a general rotary motor and a motor drive device for each set will be described. One of the application examples of the motor drive system of the second embodiment is a combination of a motor drive device for driving a spindle in a machine tool and a motor. When driving tools such as drills and end mills at high speed and with high torque, such as the spindle of a machine tool, one motor can achieve both high speed and high torque due to the structure of the motor winding. Can be difficult. In such a case, the motor drive system according to the second embodiment is useful.

FIG. 8 is a block diagram showing a configuration example of the motor drive system 300A according to the second embodiment. As shown in FIG. 8, the motor drive system 300A according to the second embodiment includes motor drive devices 200a and 200b, motors 150a and 150b, a controller 125, and a switch 126.

In FIG. 8, the motor 150a, which is the first motor, is a motor that mainly operates in a low speed region. The second motor, the motor 150b, is a motor that mainly operates in a high-speed region. Hereinafter, for convenience, a motor operating in a low speed region is referred to as a "low speed motor", and a motor operating in a high speed region is referred to as a "high speed motor".

The shaft end of the rotating shaft 152 of the motor 150a and the shaft end of the rotating shaft 153 of the motor 150b are connected by a coupler 155. The motor drive device 200a drives the motor 150a, and the motor drive device 200b drives the motor 150b. The switch 126 is arranged between the motor 150a and the motor driving device 200a. The switch 126 opens and closes the electrical connection between the motor 150a and the motor drive device 200a.

The motor drive device 200a and the motor drive device 200b are connected by a communication line 106. The motor drive device 200a is further connected to the controller 125, which is a higher-level control device, by a communication line 106. The controller 125 generates a control command 140, and transmits the generated control command 140 to the motor drive device 200a through the communication line 106. The control command 140 includes an operation command, a position command, a speed command, and a motor control effective command.

Next, the operation of the motor drive system 300A according to the second embodiment will be described with reference to the drawings of FIG. 9 in addition to FIG. FIG. 9 is a time chart provided for explaining the operation of the motor drive system 300A shown in FIG.

In FIG. 9, at time t41, the controller 125 outputs a speed command to the motor drive device 200a (see FIG. 9B), and outputs a motor control valid command to the motor drive device 200a (FIG. 9). 9 (e)). In FIGS. 9 (e) and 9 (f), the state in which the motor control valid command is received and the motor control is valid is represented by “ON”, the motor control valid command is not output, and the motor control is not valid. The state is represented by "OFF". The operating state of the motor drive device 200a is switched from OFF to ON, and the operation is started. When the motor driving device 200a is in the ON state, the motor driving device 200a drives the motor 150a, so that the motor 150a rotates and the spindle speed, which is the speed of the rotating shaft 152, increases (see FIG. 9A). .. In FIG. 9, the spindle speed changes at the same time t41 when the speed command is output to the motor drive device 200a, but in reality, the change in the spindle speed changes due to the control time lag. It goes without saying that it will occur later than.

On the other hand, at time t41, the motor control valid command is not output to the motor drive device 200b, and the operating state of the motor drive device 200b remains OFF (see FIG. 9F). The controller 125 designates one motor driving device that enables motor control when outputting a motor control valid command. It should be noted that a plurality of motor drive devices are not specified at the same time.

The speed command for the motor drive device 200a is continued beyond the time t43 until the time t44, and the speed command for the motor drive device 200b is started at the time t42 before the time t43. That is, the speed commands for the motor drive devices 200a and 200b overlap between the times t42 and t44. On the other hand, the motor control valid command for the motor drive device 200a and the motor control valid command for the motor drive device 200b are switched at time t43 so as not to overlap (see FIGS. 9 (e) and 9 (f)).

Further, at time t43, the switch 126 is controlled to be OFF to open the electrical connection between the motor 150a and the motor driving device 200a. The reason for this will be described later.

The above-mentioned operation was an operation when accelerating the spindle speed, but the same operation is performed when decelerating the spindle speed. Specifically, it is as follows.

When decelerating the spindle speed, first, at time t45, the controller 125 outputs a speed command to the motor drive device 200a (see FIG. 9B). At this time, the motor control valid command is not output (see FIG. 9E), and the switch 126 is also OFF, that is, in the “open” state. At time t46, the motor control valid command is output to the motor drive device 200a (see FIG. 9E), and the motor control valid command output to the motor drive device 200b is stopped (FIG. 9 (FIG. 9). f) See). Further, the speed command output to the motor drive device 200a is stopped at time t47 (see FIG. 9C).

As described above, when a braking current flows by the dynamic brake, a braking force is generated in the motor and the motor decelerates. On the other hand, in the method of the second embodiment, when the motor control for the motor 150a, which is a low-speed motor, is switched from valid to invalid, the switch 126 is opened and the electric connection between the motor 150a and the motor driving device 200a is performed. To open. As a result, the generation of the dynamic brake is suppressed, so that the generation of disturbance or impact due to the dynamic brake can be suppressed. Further, since the occurrence of the dynamic brake is suppressed, the motor can be switched smoothly.

Further, in the configuration of the second embodiment, when the motor control for the motor 150a which is a low speed motor is not effective and the motor control for the motor 150b which is a high speed motor is effective, the rotation speed of the motor 150a which is a low speed motor. Is higher than the number of revolutions that can be controlled independently. As a result, it is assumed that the induced voltage of the motor 150a, which is a low-speed motor, becomes higher than the bus voltage of the motor driving device 200a. Therefore, a switch 126 is provided as a mechanism for blocking the current from the induced voltage of the motor 150a to the motor driving device 200a. In the motor 150b, which is a high-speed motor, the induced voltage of the motor 150b does not become higher than the bus voltage of the motor drive device 200b, so that it is not necessary to install a switch.

As described above, according to the motor drive system according to the second embodiment, the rotation shafts of the first motor and the second motor capable of operating at a higher speed than the first motor are couplers. A switch for opening and closing an electrical connection is arranged between the first motor and the first motor drive device. Then, when the motor control for the first motor, which is a low-speed motor, is switched from valid to invalid, the switch is opened to open the electrical connection between the first motor and the motor drive device. As a result, it is possible to suppress the generation of disturbance or impact due to the dynamic brake, and the motor can be switched smoothly.

Further, according to the motor drive system according to the second embodiment, the speed commands for the first and second motor drive devices are output in an overlapping manner. By overlapping the speed commands, switching between the first motor and the second motor is performed after accumulating the integral terms of the control model in the control system (not shown). As a result, switching between motors can be performed smoothly.

In the second embodiment, from the viewpoint of ease of understanding, the case where the shaft end of the rotating shaft of the first motor and the shaft end of the rotating shaft of the second motor are connected by a coupler is used. Although described by way of example, the present invention is not limited to this. The method of the second embodiment can be applied as long as it is a motor drive system in which the pair of the motor drive device and the motor is sequentially switched, and the effect according to the second embodiment described above can be obtained.

Embodiment 3.
In the configuration of the system in which the control target is switched while the motor is operating as in the first embodiment and the second embodiment, it is necessary to start the motor control for the motor rotating at high speed, for example. Such a situation is not assumed in the conventional motor drive device. Therefore, in the conventional protection function, although it is not an abnormality, an alarm such as a position deviation abnormality, a speed detection abnormality, a position detection abnormality, or a speed command abnormality is issued. Therefore, in the third embodiment, a control method for suppressing false detection of an alarm is proposed by using the motor control effective command described in the first embodiment and the second embodiment.

FIG. 10 is a time chart provided for explaining the operation of the motor drive system according to the third embodiment. In FIG. 10, the waveforms (a) to (g) are the same as those shown in FIG. In the third embodiment, a period during which the alarm detection is valid is set in order to suppress false detection of the alarm (see FIGS. 10 (h) and 10 (i)). Specifically, between the time t21 and the time t22, the alarm detection valid period is set for the motor drive device 200a. This alarm detection valid period is set by the controller 125. Although the alarm detection valid period is shorter than the period in which the motor control valid command is output in FIG. 10, it may be the same period as the period in which the motor control valid command is output. If the same period is used, time management becomes easy and control becomes easy.

According to the motor drive system according to the third embodiment, the alarm detection valid period is set based on the motor control valid command, so that an alarm is issued by an unintended operation performed during the period when the motor control is not valid. Can be deterred.

Further, according to the motor drive system according to the third embodiment, the alarm detection effective period is set shorter than the period in which the motor control is effective, so that the possibility that an alarm is issued due to an erroneous detection is reduced. Can be done.

The configuration shown in the above-described embodiment shows an example of the content of the present invention, can be combined with another known technique, and is configured without departing from the gist of the present invention. It is also possible to omit or change a part of.

18 converter circuit, 20 inverter circuit, 21 switching element, 21UP, 21VP, 21WP upper arm switching element, 21UN, 21VN, 21WN lower arm switching element, 21A, 21B, 21C leg, 22 smoothing capacitor, 23 control unit, 23a processor, 23b memory, 24 gate drive circuit, 24a, 24b, 24c, 24d gate power supply circuit, 26 AC power supply, 27, 28 DC bus, 30 drive command, 32 drive voltage, 100a, 100b, 100c coil, 106 communication line, 120 magnets Pair, 123 bar code, 124 movable carriage, 125 controller, 126 switch, 130 position sensor, 130a, 130b, 130c sensor, 132 position sensor signal, 140 control command, 150, 150a, 150b motor, 152, 153 rotation shaft, 155 capacitors, 200, 200a, 200b, 200c motor drive, 241 resistors, 242 optocouplers, 243,244 DC power supplies, 300, 300A motor drive systems.

Claims (9)

A first motor drive device including a first control unit and driving the first motor based on a drive command generated by the first control unit.
A second motor drive device including a second control unit and driving the second motor based on a drive command generated by the second control unit.
A higher-level control device that generates a motor control valid command and controls the operation of the first and second motor drive devices based on the motor control valid command.
With
The higher-level control device outputs the motor control valid command to any one of the first and second motor drive devices.
The first and second control units are a motor drive system, characterized in that the output of the drive command is stopped during a period during which the motor control valid command is not received. The first and second motor drive devices include an inverter circuit.
The motor drive system according to claim 1, wherein the upper arm switching element of the inverter circuit is driven by a gate drive circuit including an individual power supply. The motor according to claim 1 or 2, wherein the first and second control units issue an alarm when an abnormality of the motor to be driven is detected within the reception period of the motor control valid command. Drive system. The first motor is composed of a first coil arranged in a fixed portion and a plurality of magnet pairs arranged in a movable portion configured to be movable on the positive side and the negative side in the first direction. ,
The second motor is arranged in the fixed portion, and is composed of a second coil on the positive side in the first direction and adjacent to the first coil, and a plurality of the magnet pairs.
Any one of claims 1 to 3, wherein the first and second coils are sequentially switched to coils adjacent to the positive side or the negative side in the first direction as the movable portion moves. The motor drive system described in the section. The upper control device generates a position command for instructing the position of the movable portion of the first and second motors, and outputs the position command to each of the first and second motor drive devices.
The position command for each motor drive device is output before the respective motor control valid command is valid, and the output is stopped after the respective motor control valid command is invalidated. The motor drive system according to claim 4. The second motor is a motor capable of operating at a higher speed than the first motor.
In the first and second motors, their respective rotating shafts are connected via a coupler, and the respective rotating shafts are connected via a coupler.
The invention according to any one of claims 1 to 3, wherein a switch for opening and closing an electrical connection is arranged between the first motor and the first motor driving device. Motor drive system. The upper control device generates a speed command for instructing the speed of the rotation shafts of the first and second motors, and outputs the speed command to each of the first and second motor drive devices.
The speed command for each motor drive device is output before the respective motor control valid command is valid, and the output is stopped after the respective motor control valid command is invalidated. The motor drive system according to claim 6. The first and second control units have a memory and have a memory.
Information of the motor control valid command output from the higher-level control device is written as a parameter in the memory.
Based on the parameters, the first and second control units always enable the alarm regardless of the presence or absence of the motor control valid command, or enable the alarm only when the motor control valid command is output. The motor drive system according to any one of claims 1 to 7, wherein the motor drive system is determined. A motor drive device used in the motor drive system according to any one of claims 1 to 8.

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