Linear motor drive device

Abstract

A linear motor drive device (1000) comprises: a plurality of stator units (1) in which a plurality of stators (11) are housed; a plurality of motor drive units (2) which respectively correspond to the plurality of stator units (1) and are each provided with an inverter circuit (23) for supplying power to the stators (11); and a host device (3) which supplies a synchronization signal to the motor drive units (2). The motor drive units (2) generate a carrier on the basis of preset carrier phase information and the synchronization signal, and PWM-control the inverter circuits (23) on the basis of the carrier. The motor drive units (2) are each synchronously controlled, and at least one of the motor drive units (2) uses a carrier phase different from that of the other motor drive units (2).

Description

Linear motor drive device

[0001] The present disclosure relates to a linear motor drive device.

[0002] A linear motor drive device is a system that moves a mover equipped with permanent magnets by supplying power to a plurality of stators arranged along the rail shape to generate electromagnetic force. A rail for guiding the movement of the mover and a plurality of stators arranged accordingly are constructed in unit units of an appropriate length, and a system of any length and shape is constructed by combining a plurality of units. Each unit is composed of a stator unit that stores a plurality of stators in the same housing, and a motor drive unit that includes an inverter circuit and a control circuit that supply power to each stator. In such a linear motor drive device, a very large number of inverter circuits are required within each unit and the entire system.

[0003] Inverter circuits are known to be sources of electromagnetic noise, and due to the nature of a linear motor drive device that includes a very large number of inverter circuits, there are concerns about the problem of electromagnetic compatibility (EMC). For example, electromagnetic noise generated from the inverter circuit may cause problems to other electronic devices that share power with the linear motor drive device through power lines or the like. To address such problems, a technique for suppressing electromagnetic noise generated from the inverter circuit is known by utilizing the feature that a plurality of inverter circuits are implemented.

[0004] To further improve this problem, within one linear motor drive unit, a plurality of inverter circuits that supply power to the stator are divided into two groups, and two carrier generation circuits and two phase control circuits used for PWM control of the inverter are provided within each motor drive unit, and a linear motor drive device is disclosed in which the generation timing of the carriers supplied to the two inverter circuit groups is shifted by half the time of the carrier period (T).

[0005] Japanese Patent No. 7570568

[0006] However, while Patent Document 1 makes it possible to cancel out electromagnetic noise generated from multiple inverter circuits, stators belonging to different groups must be electrically isolated. Therefore, electrically isolating a portion of the stator windings may worsen the controllability of the inverter circuit and increase manufacturing costs. In addition, since two carrier generation circuits and a phase control circuit are required within a single motor drive unit, there is a problem of increased circuit size.

[0007] This disclosure provides technology to solve the above-mentioned problems, and aims to provide a linear motor drive device that can improve the controllability of the inverter circuit, suppress increases in manufacturing costs and circuit size, and reduce electromagnetic noise generated from the inverter circuit.

[0008] The linear motor drive system of the present disclosure comprises a plurality of stator units each housing a plurality of stators, a plurality of motor drive units each corresponding to the plurality of stator units and equipped with an inverter circuit for supplying power to the stators, and a higher-level device for supplying synchronization signals to the motor drive units, wherein each motor drive unit comprises a phase control circuit that generates timing pulses based on preset carrier phase information and the synchronization signal from the higher-level device, and a carrier generation circuit that generates carriers from the timing pulses, the inverter circuit is PWM controlled based on the carriers, each of the motor drive units is synchronously controlled, and at least one of the motor drive units uses a different carrier phase than the other motor drive units.

[0009] According to the linear motor drive device of this disclosure, a linear motor drive device is obtained that can improve the controllability of the inverter circuit, suppress increases in manufacturing costs and circuit size, and suppress electromagnetic noise generated from the inverter circuit.

[0010] This is an overall configuration diagram of the linear motor drive device according to Embodiment 1. This is a conceptual diagram of the stator unit of the linear motor drive device according to Embodiment 1. This is a circuit block diagram of the motor drive unit of the linear motor drive device according to Embodiment 1. This is a functional explanatory diagram of the phase control circuit and carrier generation circuit of the linear motor drive device according to Embodiment 1. This is a functional explanatory diagram of the phase control circuit and carrier generation circuit of the linear motor drive device according to Embodiment 1. This is an explanatory diagram of the principle of noise suppression of the linear motor drive device according to Embodiment 1. This is an overall configuration diagram of the linear motor drive device according to Embodiment 2. This is a connection diagram of the stator and inverter circuit of the linear motor drive device according to Embodiment 4. This is a connection diagram of the stator and inverter circuit of the linear motor drive device according to Embodiment 5. This is an example of the hardware configuration of the control unit.

[0011] Embodiment 1. Embodiment 1 relates to a linear motor drive system comprising a plurality of stator units each housing a plurality of stators, a plurality of motor drive units each equipped with an inverter circuit for supplying power to the stators, a higher-level device for supplying synchronization signals to the motor drive units, a motor drive unit comprising a phase control circuit that generates timing pulses based on preset carrier phase information and synchronization signals from the higher-level device, a carrier generation circuit that generates carriers from the timing pulses, and a PWM control of the inverter circuit based on the carrier, thereby synchronously controlling each motor drive unit, and at least one motor drive unit using a different carrier phase from the other motor drive units.

[0012] The linear motor drive device according to Embodiment 1 will be described below based on Figure 1, which is an overall configuration diagram of the linear motor drive device; Figure 2, which is a conceptual diagram of the stator unit; Figure 3, which is a circuit block diagram of the motor drive unit; Figures 4 and 5, which are functional explanatory diagrams of the phase control circuit and carrier generation circuit; and Figure 6, which is an explanatory diagram of the noise suppression principle. In each figure, the same or corresponding parts are indicated by the same reference numerals.

[0013] The overall configuration of the linear motor drive unit 1000 of Embodiment 1 will be described with reference to Figure 1. The linear motor drive unit 1000 comprises, as its main components, a stator unit 1, a motor drive unit 2 corresponding to the stator unit 1, a higher-level device 3, a noise filter 4 for the power supply system, a rectifier 5, a guide rail 6, and a movable element 7. Furthermore, the linear motor drive unit 1000 includes a power cable 8 and a communication cable 9. The function and configuration of each component will be described in order.

[0014] First, let's describe the stator unit 1. The linear motor drive unit 1000 comprises stator units 1-1, 1-2, 1-3, 1-4, ..., and 1-N. Here, N is any natural number. Note that when there is no need to distinguish between the stator units and they are described collectively, they are referred to as stator unit 1.

[0015] Next, we will describe the motor drive unit 2. Motor drive units 2-1, 2-2, 2-3, 2-4, ..., 2-N are connected to each of the stator units 1-1, 1-2, 1-3, 1-4, ..., 1-N. When there is no need to distinguish between the motor drive units and they are described collectively, they are referred to as motor drive unit 2.

[0016] The stator unit 1 is equipped with guide rails 6 divided into predetermined lengths. The guide rails 6 play a role in guiding the multiple movable elements 7 to prevent them from deviating from the track. By preparing several types of curved tracks for the guide rails 6, such as straight lines, perfect circles, and clothoid curves, it is possible to construct a track of any shape and length. This track may be an open path (where the start and end points are different) as shown in Figure 1, or it may be a closed loop path (where the start and end points coincide).

[0017] The higher-level device 3 controls the movement of the movable element 7 throughout the entire device. The higher-level device 3 communicates synchronization signals and other signals to each of the motor drive units 2-1, 2-2, ..., 2-N via communication cables 9a and 9b. In Figure 1, the communication cable for daisy-chain connection is referred to as communication cable 9b, distinguishing it from the communication cable 9a from the higher-level device 3 to the motor drive unit 2-1. When referring to the communication cables collectively, they are referred to as communication cable 9.

[0018] This communication can be carried out using electrical signals or optical communication. In Figure 1, the communication cables between motor drive units 2-1, 2-2, ..., 2-N are connected in a daisy-chain configuration. However, this is for the purpose of reducing wiring, and the communication cables 9a may also be directly connected from the host device 3 to all motor drive units 2-1, 2-2, ..., 2-N. Furthermore, the host device 3 does not need to be a single device; multiple devices with similar functions may be interconnected and used.

[0019] A DC power supply, rectified from the grid power supply via a noise filter 4 and a rectifier 5, is supplied to each motor drive unit 2-1, 2-2, ..., 2-N via power cables 8a and 8b. These power cables 8a and 8b include not only power supply wires but also ground wires, etc. In Figure 1, the power cable for daisy-chain connection is referred to as power cable 8b, distinguishing it from power cable 8a which goes from the rectifier 5 to motor drive unit 2-1. When referring to power cables collectively, they are referred to as power cable 8.

[0020] In Figure 1, wiring is simplified by using a daisy-chain connection, directly connecting each motor drive unit 2 with a power cable 8b. However, a daisy-chain connection is not necessarily required; the output of the rectifier 5 may be supplied directly to each motor drive unit 2-1, 2-2, ..., 2-N.

[0021] Next, the internal configuration and connection method of the stator unit 1 and the motor drive unit 2 will be explained based on Figure 2. The stator unit 1 contains multiple stators 11-1, 11-2, 11-3, 11-4, ..., 11-k housed in a support housing 10. Here, k is a natural number and may be different from the natural number N mentioned above. When there is no need to distinguish each stator and they are described collectively, they will be referred to as stator 11. Each stator 11 is equipped with a stator winding 11A and a winding terminal 11B.

[0022] The support housing 10 is fitted with guide rails 6. The winding terminals 11B of each stator 11-1, 11-2, ..., 11-k are connected to the motor drive unit 2 via power cables. Power supplied from the motor drive unit 2 generates an electromagnetic force in the stator 11, and the electromagnetic force acting between the stator 11 and the movable element 7, which is equipped with a permanent magnet (not shown), drives the movable element 7.

[0023] Next, the circuit configuration of the motor drive unit 2 will be explained based on Figure 3, a circuit block diagram showing the internal configuration of the motor drive unit 2. The motor drive unit 2 comprises a control unit 21, a PWM control circuit 22, an inverter circuit 23, a phase control circuit 24, and a carrier generation circuit 25. In order to reduce the circuit size, only one phase control circuit 24 and one carrier generation circuit 25 are provided in each motor drive unit 2. Furthermore, the PWM control circuit 22 is specifically described as comparator 22-1, comparator 22-2, ..., comparator 22-n. Here, n is a natural number and may be different from the natural numbers N and k mentioned above.

[0024] The motor drive unit 2 is equipped with multiple inverter circuits 23-1, 23-2, ..., 23-n, and each inverter circuit 23-1, 23-2, ..., 23-n is connected to the winding terminals 11B of the stators 11-1, 11-2, ..., 11-k. When describing each inverter circuit collectively, it is referred to as inverter circuit 23.

[0025] When using the single-phase inverter circuits described in Embodiment 4 as inverter circuits 23-1, 23-2, ..., 23-n, there is a one-to-one relationship between the inverter circuit 23 and the stator 11, so n is the same as k. Also, when using a circuit configuration other than a single-phase inverter circuit, as described in Embodiment 5, n and k are different.

[0026] Furthermore, the switching elements used in the inverter circuit 23 are typically IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors).

[0027] Since the inverter circuit 23 is controlled by the PWM (Pulse Width Modulation) method, a PWM control circuit 22 is provided. Comparators 22-1, 22-2, ..., 22-n are provided corresponding to inverter circuits 23-1, 23-2, ..., 23-n.

[0028] A PWM waveform is generated based on the carrier (Cw) supplied from the carrier generation circuit 25 and the voltage commands V1, V2, ..., Vn output from the control unit 21. In Figure 3, this PWM waveform is labeled as PWM control. At this time, only one carrier generation circuit 25 is provided in each motor drive unit 2, and the generated carrier (Cw) is shared by each comparator 22-1, 22-2, ..., 22-n.

[0029] Here, the functions and operation of the control unit 21 will be explained. The control unit 21 receives operating information of the movable element 7 from the encoder (not shown). The control unit 21 also receives control information and synchronization signals from the host device 3. Based on the synchronization signals received from the host device 3, the control unit 21 synchronously controls each motor drive unit 2-1, 2-2, ..., 2-N. The synchronization signal is a periodic signal with a predetermined period (T), and at the stage of transmission from the host device 3 to each motor drive unit 2-1, 2-2, ..., 2-N, it may be an optical signal or an electrical signal. In the case of optical communication, it is converted to an electrical signal within the motor drive unit 2.

[0030] The control unit 21 calculates the current value to be supplied to each stator 11 based on the actual motion information (position and velocity) of the movable element 7 obtained from the encoder and the motion commands for the movable element (target position of the movable element, etc.) transmitted from the host device 3. The phase control circuit 24 generates a timing pulse (Tm) based on the synchronization signal received from the host device 3 and preset phase information (described later). One of these phase control circuits 24 is sufficient for each motor drive unit 2.

[0031] Here, the functions of the phase control circuit 24 and the carrier generation circuit 25 will be explained based on Figures 4 and 5, which are explanatory diagrams of the functions of the phase control circuit and the carrier generation circuit. Figures 4 and 5 illustrate the relationship between the synchronization signal from the higher-level device 3, the timing pulse (Tm) generated by the phase control circuit 24, and the carrier (Cw) generated by the carrier generation circuit 25 from this timing pulse (Tm). Figure 5 also shows the signal obtained by dividing the synchronization signal.

[0032] First, Figure 4 illustrates the case where the timing pulse (Tm) is directly generated using the synchronization signal from the higher-level device 3. The synchronization signal from the higher-level device 3 is supplied to the phase control circuit 24, which generates the timing pulse (Tm). The carrier generation circuit 25 generates a carrier (Cw) from the timing pulse (Tm) from the phase control circuit 24. In this case, the carrier frequency and the frequency of the synchronization signal are the same.

[0033] Next, Figure 5 illustrates the case where a timing pulse (Tm) is generated by dividing the frequency of the synchronization signal from the higher-level device 3. By providing a frequency division function within the phase control circuit 24 to divide the frequency of the synchronization signal, the carrier frequency is lowered to a frequency lower than that of the synchronization signal. As a result, for example, even if the frequency of the synchronization signal is 1 MHz, a carrier frequency of 1 kHz can be set by dividing the frequency of the synchronization signal by 1 / 1000. This division ratio can be set arbitrarily. For example, information regarding the division ratio may be stored within the higher-level device 3, and this information may be transmitted to each motor drive unit 2-1, 2-2, ..., 2-N when the power is turned on. However, the division ratio must be set to the same value for all motor drive units 2-1, 2-2, ..., 2-N.

[0034] The phase control circuit 24 outputs a timing pulse (Tm) at a timing shift of an arbitrary time (α) from the rising and falling edges of the synchronization signal from the host device 3, or the signal waveform obtained by dividing the synchronization signal. The timing pulse (Tm) can be any type of repeating signal, as long as it has a pulse width that is sufficiently short compared to the pulse width of the synchronization signal or the signal obtained by dividing the synchronization signal. For example, the sign of the timing pulse can be reversed for the rising and falling edges of the synchronization signal or the signal obtained by dividing the synchronization signal, and the pulse width can be made to be approximately the same as the rising and falling edges of the synchronization signal or the signal obtained by dividing the synchronization signal.

[0035] This arbitrary time (α) will be called phase information (α). This phase information (α) may be stored in the host device 3 and transmitted from the host device 3 when the linear motor drive unit 1000 is powered on. Alternatively, it may be stored in advance in each motor drive unit 2 and read when the power is turned on. With respect to this phase information (α), if at least one motor drive unit 2-1, 2-2, ..., 2-N has different phase information (α), there will be an effect of suppressing electromagnetic noise.

[0036] The carrier generation circuit 25 switches between counting up and down the carrier based on the sign of the timing pulse (Tm) received from the phase control circuit 24, generating a triangular wave carrier (Cw) with the same period as the timing pulse (Tm). The phase control circuit 24 and the carrier generation circuit 25 may be constructed using an IC (Integrated Circuit), or they may be constructed inside an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit).

[0037] Next, the provision of a phase control circuit 24 enables noise suppression in the linear motor drive device 1000 of Embodiment 1, and this will be explained based on Figure 6, a diagram illustrating the principle of noise suppression. The main electromagnetic noise is generated by potential fluctuations due to the switching of the inverter circuit 23 in the motor drive unit 2. As an example, Figure 6 shows adjacent stator units 1-1 and 1-2, and motor drive units 2-1 and 2-2, rather than those of the same stator unit 1 and motor drive unit 2. In Figure 6, for explanatory purposes, grounding relationships are labeled as ground 100 and ground wire 102, and noise relationships are labeled as power line noise 103a, 103b and ground wire noise 104a, 104b. As shown in Figure 6, a stray capacitance 105 inevitably occurs between the stator winding 11A of stator 11-1 and its support housing 10. The potential fluctuations due to the switching of the inverter circuit 23 charge and discharge this stray capacitance 105, generating noise current.

[0038] When the inverter circuit 23 switches, the currents of the power line noise 103a and 103b superimposed on the power cable 101 flow from the support housing 10 through the earth wire 102 to the ground 100, which is the reference potential of the stator unit 1. As a result, earth wire noise 104a and 104b are generated. Here, the function of the phase control circuit 24 of each motor drive unit 2 makes it possible to operate the inverter based on carriers of any desired phase. For example, by making the carriers used in the two motor drive units 2 out of phase with each other, the power line noise 103a and 103b can be made out of phase. Then, the earth wire noise 104a and 104b that flows through the stray capacitance 105 to the earth wire 102 will also be out of phase. When noises with out of phase in this way flow into the common earth wire 102, they have the effect of canceling each other out.

[0039] As described above, the linear motor drive device of Embodiment 1 provides a linear motor drive device that improves the controllability of the inverter circuit, suppresses increases in manufacturing costs and circuit size, and suppresses electromagnetic noise generated from the inverter circuit.

[0040] Embodiment 2. The linear motor drive device of Embodiment 2 is configured to include one or more rectifiers and to supply a DC voltage obtained from one of the rectifiers to multiple motor drive units.

[0041] The linear motor drive unit 2000 of Embodiment 2 will be described, focusing on the differences from Embodiment 1, based on Figure 7, which is an overall configuration diagram of Embodiment 2. In the drawings of Embodiment 2, parts that are the same as or equivalent to those in Embodiment 1 are denoted by the same reference numerals. To distinguish it from Embodiment 1, the linear motor drive unit 2000, noise filters 4a and 4b, and rectifiers 5a and 5b are used. In addition, Figure 7 shows the addition of a stator unit 1-5 and a motor drive unit 2-5.

[0042] In Embodiment 1, one noise filter 4 and one rectifier 5 were provided, and the rectified DC power supply was supplied to each motor drive unit 2-1, 2-2, ..., 2-N through a power cable 8. In Embodiment 2, as shown in FIG. 7, a plurality of noise filters and rectifiers are provided. In FIG. 7, the noise filter 4a and the rectifier 5a supply a DC power supply to the motor drive units 2-1, ..., 2-4, and the noise filter 4b and the rectifier 5b supply a DC power supply to the motor drive units 2-5, ..., 2-8 (not shown). When the noise filters 4a and 4b are described together, they are described as the noise filter 4, and when the rectifiers 5a and 5b are described together, they are described as the rectifier 5.

[0043] In Embodiment 2, by supplying power from the outputs of the rectifiers 5a and 5b to a plurality of motor drive units 2, it is possible to aggregate the propagation paths of the generated noise, and the cancellation of the noise of the opposite phase is effectively performed as in Embodiment 1. As shown in FIG. 7, by using a plurality of noise filters 4 and rectifiers 5, the output of the rectifier can be configured to be shared by some of the motor drive units 2 in the whole. With this configuration, the current flowing through each noise filter 4 can be reduced, so that magnetic saturation of the noise filter 4 can be prevented.

[0044] As described above, according to the linear motor drive device of Embodiment 2, the controllability of the inverter circuit is improved, an increase in manufacturing cost and an increase in circuit scale are suppressed, and electromagnetic noise generated from the inverter circuit can be suppressed. Furthermore, magnetic saturation of the noise filter can be prevented.

[0045] Embodiment 3. The linear motor drive device of Embodiment 3 is such that the number of motor drive units receiving power supply from one rectifier is an even number.

[0046] Regarding the linear motor drive device of Embodiment 3, based on FIG. 1 which is the overall configuration diagram of Embodiment 1 and FIG. 7 which is the overall configuration diagram of Embodiment 2, the differences from Embodiment 1 will be mainly described.

[0047] When supplying power to the motor drive unit 2 through one or more rectifiers 5 as shown in FIG. 1 or FIG. 7, it is desirable that the number of motor drive units 2 receiving power supply from each of the rectifiers 5 be an even number. This is because if the number of motor drive units 2 is odd, there will be a remainder in the pairs with opposite phases, resulting in noise that cannot be canceled out. For example, if the phases of the noise generated from five motor drive units 2 are 0°, 180°, 0°, 180°, 0°, and assuming that the amount of noise generated from each motor drive unit 2 is equal, the noise generated at the 0° phase cannot be canceled out. Therefore, by making the number of motor drive units 2 receiving power supply from each rectifier 5 an even number, no noise without a canceling partner will occur, and noise suppression can be effectively performed.

[0048] As described above, according to the linear motor drive device of Embodiment 3, the controllability of the inverter circuit can be improved, an increase in manufacturing cost and an increase in circuit scale can be suppressed, and electromagnetic noise generated from the inverter circuit can be suppressed. Furthermore, the noise suppression effect can be enhanced.

[0049] Embodiment 4. The linear motor drive device of Embodiment 4 is one in which each of the inverter circuits is a single-phase inverter.

[0050] Regarding the linear motor drive device of Embodiment 4, based on FIG. 8 which is a connection diagram of the stator and the inverter circuit, the differences from Embodiment 1 will be mainly described. In the drawings of Embodiment 4, the same or corresponding parts as those in Embodiment 1 are denoted by the same reference numerals.

[0051] As shown in FIG. 8, as a specific configuration of the inverter circuit 23, a single-phase inverter circuit 23F with a full-bridge configuration is used by using a switching element 230. In this case, one single-phase inverter circuit 23F is connected to one stator 11 through a power cable 101. Therefore, the number n of single-phase inverter circuits 23F of one motor drive unit 2 matches the number k of stators 11 in the stator unit 1.

[0052] IGBTs and MOSFETs are used as switching elements 230 that constitute the single-phase inverter circuit 23F. In this way, even when a single-phase inverter circuit 23F is used as the specific configuration of the inverter circuit 23, the noise suppression effect described in Embodiments 1 to 3 can be obtained.

[0053] As described above, the linear motor drive device of Embodiment 4 improves the controllability of the inverter circuit, suppresses increases in manufacturing costs and circuit size, and reduces electromagnetic noise generated from the inverter circuit. Furthermore, it can suppress electromagnetic noise in a linear motor drive device using a single-phase inverter.

[0054] Embodiment 5. The linear motor drive device of Embodiment 5 is configured to reduce the number of inverter circuits by connecting the winding terminals of adjacent stators.

[0055] The linear motor drive device of Embodiment 5 will be explained, focusing on the differences from Embodiment 1, based on Figure 9, which is a connection diagram of the stator and inverter circuit. In the drawings of Embodiment 5, parts that are the same as or equivalent to those in Embodiment 1 are denoted by the same reference numerals.

[0056] As a specific configuration of the inverter circuit 23, two switching elements 230 can be connected in series to form an inverter circuit 23T, as shown in Figure 9. In Figure 9, one winding terminal 11B of stator 11 and the other winding terminal 11B of an adjacent stator 11 are electrically connected at a connection node 300. Each of these connection nodes 300 is connected via a power cable 101 to the output terminal 234 of the inverter circuit 23T, which consists of two switching elements 230. One winding terminal 11B of stators 11-1 and 11-k located at both ends of the stator unit 1 (the left side of the winding terminal 11B of stator 11-1 and the right side of the winding terminal 11B of stator 11-k in Figure 9) is connected via a power cable 101 to the output terminal 234 of the inverter circuit 23T, rather than via a connection node 300, because there are no adjacent stators.

[0057] The switching elements 230 used in the inverter circuit 23T are IGBTs and MOSFETs, etc. In this circuit configuration, the number n of inverter circuits 23T in one motor drive unit 2 and the number k of stators 11 in one stator unit 1 are different, and the relationship is n = k + 1.

[0058] Thus, when using the inverter circuit 23T as shown in Figure 9 as the specific configuration of the inverter circuit 23, the number of inverter circuits can be reduced by approximately half compared to when using the single-phase inverter circuit 23F in the inverter circuit 23 described in Embodiment 4, thereby simplifying the inverter circuit. Furthermore, even when using the inverter circuit 23T as the specific configuration of the inverter circuit 23, the noise suppression effect described in Embodiments 1 to 3 can be obtained.

[0059] As described above, the linear motor drive device of Embodiment 5 improves the controllability of the inverter circuit, suppresses increases in manufacturing costs and circuit size, and reduces electromagnetic noise generated from the inverter circuit. Furthermore, the inverter circuit can be simplified.

[0060] The control unit 21 is composed of a processor 3000 and a storage device 3001, as shown in Figure 10 as an example of the hardware. The storage device 3001 includes a volatile storage device such as random access memory (not shown) and a non-volatile auxiliary storage device such as flash memory. Alternatively, a hard disk may be provided as an auxiliary storage device instead of flash memory. The processor 3000 executes the program input from the storage device 3001. In this case, the program is input from the auxiliary storage device to the processor 3000 via the volatile storage device. The processor 3000 may also output data such as calculation results to the volatile storage device of the storage device 3001, or it may save the data to the auxiliary storage device via the volatile storage device.

[0061] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed in this specification. For example, these include modifying, adding or omitting at least one component, or extracting at least one component and combining it with a component from another embodiment.

[0062] 1, 1-1, 1-2, 1-3, 1-4, 1-5, 1-N Stator unit, 2, 2-1, 2-2, 2-3, 2-4, 2-5, 2-8, 2-N Motor drive unit, 3 Upper device, 4, 4a, 4b Noise filter, 5, 5a, 5b Rectifier, 6 Guide rail, 7 Movable element, 8, 8a, 8b Power cable, 9, 9a, 9b Communication cable, 10 Support housing, 11, 11-1, 11-2, 11-3, 11-4, 11-k Stator, 11A Stator winding, 11B Winding terminal, 21 Control unit, 22 PWM control circuit, 22-1, 22-2, 22-n Comparator, 23, 23-1, 23-2, 23-n Inverter circuit, 23F Single-phase inverter circuit, 23T Inverter circuit, 24 Phase control circuit, 25 Carrier generation circuit, 100 Ground, 101 Power cable, 102 Ground wire, 103a, 103b Power line noise, 104a, 104b Ground wire noise, 105 Stray capacitance, 230 Switching element, 234 Output terminal, 300 Connection node, 1000, 2000 Linear motor drive unit, 3000 Processor, 3001 Memory device.

Claims

1. A linear motor drive system comprising a plurality of stator units each housing a plurality of stators, a plurality of motor drive units each corresponding to the plurality of stator units and equipped with an inverter circuit for supplying power to the stators, and a higher-level device for supplying synchronization signals to the motor drive units, wherein each motor drive unit comprises a phase control circuit that generates timing pulses based on preset carrier phase information and the synchronization signal from the higher-level device, and a carrier generation circuit that generates carriers from the timing pulses, the inverter circuit is PWM controlled based on the carriers, each of the motor drive units is synchronously controlled, and at least one of the motor drive units uses a different carrier phase than the other motor drive units.

2. The linear motor drive device according to claim 1, wherein at least different carrier phases are used in adjacent motor drive units.

3. The linear motor drive device according to claim 1 or 2, wherein the motor drive unit is provided with a frequency division function for dividing the synchronization signal of the higher-level device.

4. A linear motor drive device according to any one of claims 1 to 3, comprising at least one rectifier for obtaining a DC voltage from an AC power source, and supplying the DC voltage obtained from one of the rectifiers to a plurality of motor drive units.

5. The linear motor drive device according to claim 4, wherein the number of motor drive units that receive power from one of the rectifiers is even.

6. The linear motor drive device according to any one of claims 1 to 5, wherein each of the inverter circuits is a single-phase inverter, and one single-phase inverter is connected to any one of the winding terminals of the stator.

7. A linear motor drive device according to any one of claims 1 to 5, wherein any two adjacent winding terminals of the stator unit, excluding both ends, are electrically connected, and one of the winding terminals of the stator at both ends is electrically connected to the winding terminal of the adjacent stator, the output terminal of the inverter circuit is connected to the connection point of the winding terminals of the stator, and the other of the winding terminals of the stator at both ends is connected to the output terminal of the inverter circuit.

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