Linear motor drive device and linear motor

Abstract

Provided is a linear motor drive device which has a plurality of half-bridges (11-17) and a stator in which a plurality of coils (1-6) connected in series are arranged so as to be lined up, both ends of the serial body of the coils and contact points between the coils being respectively connected to output points of different half-bridges, and an AC voltage being applied to each of the coils (1-6). Said linear motor drive device is configured so as to comprise: a half-bridge output voltage computation unit (81) which, on the basis of voltage application commands for voltages to be applied to the coils (1-6), performs computation to obtain output voltage commands for the respective half-bridges (11-17); and a switching controller (8) which obtains switching signals for controlling switches of the respective half-bridges (11-17) by using the respective half-bridge output voltage commands that have been obtained.

Description

[Technical field]

[0001] The present application relates to a linear motor drive device and a linear motor. [Background technology]

[0002] A linear motor is composed of a stator on which multiple coils are arranged, and a mover composed of a permanent magnet that is arranged at a distance from the stator and moves in the direction in which the stator coils are arranged. In this linear motor, a technology has been commercialized that proposes new added value to linear motors by individually controlling the current flowing through each coil of the stator, particularly by independently controlling multiple movers. In conventional technology, in order to realize individual control of the current of each coil, a method is used in which a full-bridge or half-bridge single-phase inverter is connected to each coil and a voltage is applied to each coil individually (for example, Patent Document 1, Fig. 2a and Fig. 2b).

[0003] Also, in a DC linear motor, a linear motor drive device is known in which multiple lined-up coils are electrically connected in series, the connection points between the coils are connected to the output points of half-bridge circuits, each of which has a switch connected in series, a DC power supply voltage is applied to the input of each half-bridge, and each switch is controlled by a logic circuit that uses a position sensor signal as an input to pass a DC current through each coil to drive the coils (for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Specification No. 2019 / 0386588 [Patent Document 2] Japanese Unexamined Patent Publication No. 1466 / 1986 Summary of the Invention [Problem to be solved by the invention]

[0005] In the method disclosed in Patent Document 1, the degree of freedom of the voltage waveform that can be applied to each coil is high, but when two switches are used for one coil as in a half bridge, the maximum voltage that can be applied to the coil is restricted to half the voltage of the DC power supply. Also, in order to apply positive and negative voltages of the DC power supply to the coil, four switches are required for one coil as in a full bridge, which doubles the number of switches compared to when a half bridge is used.

[0006] On the other hand, the linear motor drive system disclosed in Patent Document 2 is merely a drive system in which the conduction to the positive or negative power supply by the brushes in a DC linear motor is replaced by switching of a half bridge. Therefore, it is not possible to apply an arbitrary voltage to each coil, and the degree of freedom in controlling the movement of the mover is very low.

[0007] The present application has been made to solve the above-mentioned problems, and has an object to provide a linear motor drive device which has a small number of switches, has a high degree of freedom in the voltage waveform applied to each coil, can apply positive and negative DC power supply voltages, and has a high degree of freedom in controlling the movement of the mover. [Means for solving the problem]

[0008] The linear motor driving device disclosed in the present application has a stator in which a number of coils are arranged in a row, and a half bridge consisting of a series arrangement of a number of switches, the number of which is one more than the number of the coils, the multiple coils being electrically connected in series, with both ends of this series arrangement of coils connected in series and each connection point between the coils being connected to an output point of a different half bridge, both ends of each half bridge being connected to a DC source, and an AC voltage being applied to each coil, the linear motor driving device is provided with a half-bridge output voltage calculator that calculates an output voltage command for each of the half bridges based on each application voltage command for a voltage applied to each of the multiple coils, and a switching controller that uses the half-bridge output voltage commands for each of the half bridges determined by the half-bridge output voltage calculator to determine a switching signal that controls the switch of each of the half bridges, and controls the driving of the switches of all of the half bridges. Effect of the Invention

[0009] According to the present application, it is possible to provide a linear motor drive device which has a small number of switches, has a high degree of freedom in the voltage waveform applied to each coil, can apply positive and negative DC power supply voltages, and has a high degree of freedom in controlling the movement of the mover. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic circuit diagram showing a configuration of a linear motor drive device according to a first embodiment. [Diagram 2] FIG. 1 is a schematic diagram showing a configuration of a typical linear motor. [Diagram 3] 1 is a block diagram showing the configuration of a linear motor drive device according to a first embodiment, including a mover. [Figure 4] 2 is a diagram showing the structure of a switching controller of the linear motor driving device according to the first embodiment. FIG. [Diagram 5]4 is a diagram showing an example of a waveform of an induced voltage generated in a coil of the driving device for the linear motor according to the first embodiment. [Figure 6] 4 is a diagram showing an example of a switching operation of the linear motor driving device according to the first embodiment, using waveforms. FIG. [Figure 7] FIG. 11 is a block diagram showing the configuration of a linear motor drive device according to a second embodiment. [Figure 8] 10 is a diagram showing an example of a waveform of an induced voltage generated in a coil of a driving device for a linear motor according to the second embodiment. FIG. [Figure 9] 13 is a diagram showing an internal structure of a half-bridge output voltage calculator 81 of a driving device for a linear motor according to an embodiment 3. FIG. [Figure 10] 13 is a diagram showing an example of a waveform of an induced voltage generated in a coil of a driving device for a linear motor according to embodiment 3. FIG. [Figure 11] 13 is a diagram showing another example of a waveform of an induced voltage generated in a coil of the driving device for the linear motor according to the third embodiment. FIG. [Figure 12] 13 is a diagram showing still another example of a waveform of an induced voltage generated in a coil of the driving device for the linear motor according to the third embodiment. FIG. [Figure 13] FIG. 11 is a block diagram showing the configuration of a linear motor drive device according to a fourth embodiment. [Figure 14] FIG. 11 is a block diagram showing another configuration of the linear motor drive device according to the fourth embodiment. [Figure 15] FIG. 15 is a block diagram showing an internal structure of a coil current calculator in the configuration of FIG. 14 of the linear motor driving device according to embodiment 4. [Figure 16] FIG. 13 is a block diagram showing the configuration of a linear motor driving device according to a fifth embodiment. [Figure 17] FIG. 13 is a diagram showing the structure of a switching controller of a driving device for a linear motor according to a fifth embodiment. [Figure 18] 13 is a diagram showing an example of a waveform of an induced voltage generated in a coil of a driving device for a linear motor according to embodiment 5. FIG. [Figure 19]13 is a diagram showing another example of a waveform of an induced voltage generated in a coil of the driving device for a linear motor according to embodiment 5. FIG. [Figure 20] FIG. 13 is a diagram showing still another example of a waveform of an induced voltage generated in a coil of the driving device for the linear motor according to the fifth embodiment. [Figure 21] FIG. 13 is a diagram showing still another example of a waveform of an induced voltage generated in a coil of the driving device for the linear motor according to the fifth embodiment. [Figure 22] 17 is a diagram showing an internal structure of a current controller 100 in the configuration of FIG. 16 for a linear motor driving device according to embodiment 5. FIG. [Diagram 23] 23 is a diagram showing an internal structure of integral calculators 1030 to 1035 in the configuration of FIG. 22 of the driving device for the linear motor according to the fifth embodiment. FIG. [Figure 24] 13 is a diagram showing an example of voltage and current waveforms applied to a coil of a driving device for a linear motor according to embodiment 5. FIG. [Diagram 25] 13 is a diagram showing another example of voltage and current waveforms applied to the coil of the driving device for the linear motor according to the fifth embodiment. FIG. [Figure 26] 2 is a block diagram showing an example of a specific configuration of a switching controller of a driving device for a linear motor according to the present application; FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Embodiment 1 FIG. 1 is a schematic circuit diagram showing the configuration of a linear motor drive device according to the first embodiment, and FIG. 2 is a schematic diagram showing the configuration of a general linear motor. As shown in FIG. 2, the linear motor is composed of a stator 20 and a mover 9 arranged at a distance from the stator 20 and composed of a permanent magnet. The stator 20 is configured by arranging a plurality of coils side by side, and the mover 9 moves in the direction in which the coils of the stator 20 are arranged. In FIG. 1, coils 1 to 6 are coils wound around the stator 20 of the linear motor. One end of the coil 1 arranged at one end is connected to a connection point of the switches 11a and 11b connected in series, and the other end of the coil 1 is connected to one end of the coil 2 and to a connection point of the switches 12a and 12b connected in series. The other end of the coil 2 is connected to one end of the coil 3 and to a connection point of the switches 13a and 13b connected in series. Similarly, coils 3, 4, 5, and 6 are connected in series, and the connection points between the coils are also connected to the connection points of switches 14a and 14b, switches 15a and 15b, and switches 16a and 16b, which are connected in series. The other end of coil 6, which is located at the other end, is connected to the connection point of switches 17a and 17b, which are connected in series. In addition, both ends of the switches connected in series are connected to the positive (+) and negative (-) sides of a common DC power source 7 to receive power.

[0012] Thus, in the linear motor driving device according to the first embodiment, the coils of the linear motor stator are connected in series, and the outputs of half bridges with multiple switches connected in series are connected to both ends of the series body of coils and to the connection points between the coils. The linear motor driving device shown in FIG. 1 shows an example of a stator with six coils, but the linear motor driving device disclosed in the present application has any number of coils, and is configured such that N+1 half bridge circuits are connected to N coils. However, in order for the effect of having multiple independent stator coils to be reflected in the actual movement of the mover, the number of coils generally needs to be four or more, and therefore the linear motor driving device disclosed in the present application is effective when the number of coils is four or more and the number of half bridge circuits is five or more.

[0013] The basic operation of the linear motor driving device according to the first embodiment will be described. The coil 1, the switches 11a and 11b, and the switches 12a and 12b form a full bridge circuit, so that the voltage Vdc of the DC power supply 7 can be applied to the coil 1 in the positive and negative directions by switching the four switches 11a, 11b, 12a, and 12b, and an intermediate voltage can be applied to the coil on average by switching the switches at high speed. Similarly, since a full bridge circuit is formed by the switches connected to both ends of each coil, the driving circuit of FIG. 1 can apply an AC voltage with a maximum amplitude ranging from -Vdc to +Vdc to each coil, as in the conventional full bridge circuit described in Patent Document 1, for example. Of course, depending on the movement of the movable element to be controlled, a certain coil may be applied with only the positive or negative AC voltage.

[0014] On the other hand, if we compare the number of switches, a conventional configuration in which one full-bridge circuit is connected to each coil requires four times the number of coils, whereas the linear motor drive device according to embodiment 1 can be configured with (number of coils + 1) x 2 switches. For example, in the case of 6 coils as shown in Fig. 1, a conventional full-bridge circuit requires 24 switches, whereas the circuit in Fig. 1 makes it possible to configure a drive circuit with 14 switches, and it is clear that the number of switches can be significantly reduced.

[0015] Next, the operation of the linear motor driving device according to the first embodiment will be described. Fig. 3 is a block diagram showing the configuration of the linear motor driving device according to the first embodiment, including the mover 9 of the linear motor. In Fig. 3, an example is shown in which the mover 9 of the linear motor is equipped with permanent magnet poles (N pole, S pole), and the voltages applied to the coils 1 to 6 change depending on the position, speed, and thrust to be generated of this mover 9. In Fig. 3, the switch 11a and the switch 11b are collectively shown as a half bridge 11, and the other half bridges 12 to 17 are also shown in the same manner.

[0016] The voltage command applied to each coil 1, 2, 3, 4, 5, and 6 to control the linear motor is v 1 * , v 2 * , v 3 * , v 4 * , v 5 * , v 6 * The switching controller 8 controls these applied voltage commands v 1 * ~v 6 * Based on the switching signal g 11 , g 12 , g 13 , g 14 , g 15 , g 16 , g 17and outputs it to each of the half bridges 11 to 17. If the switching signal is 1, each half bridge turns on the upper switch and turns off the lower switch, and if the switching signal is 0, the upper switch is turned off and the lower switch is turned on.

[0017] FIG. 4 is a diagram showing the structure of the switching controller 8 of the linear motor driving device according to the first embodiment. 1 * ~v 6 * is input to the half-bridge output voltage calculator 81, and each half-bridge output voltage command v 11 * , v 12 * , v 13 * , v 14 * , v 15 * , v 16 * , v 17 * The applied voltage command is defined as the right coil terminal being the positive side and the left coil terminal being the negative side. Here, the half-bridge output voltage command v 11 * The reference voltage is set to 0. The applied voltage command is calculated for each coil using the linear motor's characteristic parameters based on the position and speed of the mover for each coil, the desired current value to be passed through the coil, etc., and the calculated applied voltage command is expressed as v 1 * ~v 6 * Let us assume that.

[0018] v 11 * =0 v 12 * =v 11 * +v 1 * v 13* =v 12 * +v 2 * v 14 * =v 13 * +v 3 * v 15 * =v 14 * +v 4 * v 16 * =v 15 * +v 5 * v 17 * =v 16 * +v 6 *

[0019] Each of these half-bridge output voltage commands v 11 * ~v 17 * are the gains 2 / V dc is multiplied to obtain the modulation factor m 11 ~m 17 is calculated, where V dc is the voltage applied to each half bridge output by the DC power supply 7.

[0020] A carrier generator 84 generates a carrier wave c for pulse width modulation, for example a triangular wave, and in the case of FIG. 4, the triangular wave changes between -1 and 1 depending on the relationship with the gain of the modulation factor calculator 82. A comparator 83 calculates the half-bridge modulation factor m 11 ~m 17 The magnitude of the carrier wave c input from the carrier generator 84 is compared, and if the modulation rate is larger, it is set to 1, and if the carrier wave is larger, it is set to 0. 11 ~g 17The output is then sent to each half bridge.

[0021] FIG. 5 shows the waveform of the induced voltage generated in the coils by the permanent magnet magnetic flux of the mover 9 when the mover 9 moves at a constant speed over the coils 1 to 3 as shown in FIG. 3. In FIG. 5, the induced voltage in the coil 1 is v 1 , the induced voltage in coil 2 is v 2 , the induced voltage in coil 3 is v 3 and the horizontal axis represents the passage of time t. In the linear motor shown in Fig. 3, the magnetic pole pitch of mover 9 (the distance between the center of the N pole and the center of the S pole) is equal to the distance between adjacent coils that are wound independently, so if the induced voltage generated when mover 9 passes a certain coil is one cycle of a sine wave, as shown in Fig. 5, the induced voltage in the adjacent coil will have a waveform that is 180° phase shifted from this sine wave.

[0022] At this time, in order to prevent the mover 9 from generating a thrust, for example, the current flowing through each coil should be set to 0, and a voltage equal to the induced voltage should be applied to each coil. In this case, at time t 1 In the above, the applied voltage command for each coil is v 1 * ~v 6 * Although not shown in Figure 5, at time t 1 The voltages applied to coils 4, 5, and 6 are all 0.

[0023] v 1 * =a v 2 * =-a v 3 * =0 v 4 * =0 v 5 * =0 v 6 * =0

[0024] This applied voltage command is input to the half-bridge output voltage calculator 81 of the switching controller 8, and the following half-bridge output voltage commands v 11 * ~v 17 * is calculated.

[0025] v 11 * =0 v 12 * =v 11 * +v 1 * =a v 13 * =v 12 * +v 2 * =0 v 14 * =v 13 * +v 3 * =0 v 15 * =v 14 * +v 4 * =0 v 16 * =v 15 * +v 5 * =0 v 17 * =v 16 * +v 6 * =0

[0026] FIG. 6 shows an example of the switching operation of the drive circuit described above in the form of waveforms. 11 * ~v 17 * The modulation factor calculator 82 calculates each half-bridge modulation factor m 11 ~m 17The comparator 83 calculates the switching signal g based on this modulation rate and the carrier wave c. 11 ~g 17 As shown above, the modulation rate is the half-bridge output voltage command, which is the gain 2 / V dc multiplied by V dc The modulation ratio is obtained by dividing the modulation ratio by 1 / 2. For example, a half bridge with a modulation ratio of 0.5 turns on the positive switch for 50% of the carrier wave period, and a half bridge with a modulation ratio of -0.5 turns on the negative switch for 50% of the carrier wave period. For example, when the modulation ratio is 1, the half bridge keeps the positive switch on for the period when the modulation ratio is 1, and when the modulation ratio is -1, the half bridge keeps the negative switch on for the period when the modulation ratio is -1. When the modulation ratio exceeds 1, the half bridge keeps the positive switch on for the period when the modulation ratio exceeds 1, just as when the modulation ratio is 1. When the modulation ratio exceeds -1, the half bridge keeps the negative switch on for the period when the modulation ratio exceeds -1, just as when the modulation ratio is -1. In this way, the modulation ratio is the ratio of the period when the positive or negative switch of the half bridge is on. Each half bridge is driven by a switching signal based on this modulation ratio, and a voltage v is generated at the half bridge output point shown in Figure 3. 11 ~v 17 is applied to both ends of coils 1 to 6. The voltage at each half-bridge output point is shown in FIG. 6. The voltage applied to each coil is the voltage difference between the half-bridge outputs connected to both ends of the coil. The coil applied voltage v 1 , v 2 As shown above, on average, a voltage equivalent to the applied voltage command for each coil is applied, and since the voltages at the half-bridge output points on both ends of coils 3, 4, 5, and 6 are the same, the coil applied voltage is 0. In the above explanation, we have described a case where the thrust generated in the mover 9 is set to 0, but by manipulating the applied voltage command for each coil, it is possible to cause the mover 9 to generate a desired thrust or perform a desired operation. In the above explanation, -V dc ~+V dcAlthough a method of performing pulse width modulation using a triangular wave to generate an intermediate voltage between these voltages has been described, it goes without saying that other voltage generation methods can also be used with effect.

[0027] By the above operation, the linear motor driving device according to the first embodiment can apply any + or - voltage up to the voltage of the DC power supply to each coil, just like a conventional full-bridge circuit, while significantly reducing the number of required switches compared to a driving device using a conventional full-bridge circuit such as that described in Patent Document 1. This makes it possible to realize a linear motor driving device that has the same degree of freedom of control as the conventional method, while reducing the size and cost of the driving circuit.

[0028] Embodiment 2 Fig. 7 is a block diagram showing the configuration of a linear motor drive device according to embodiment 2, showing an example in which two movers 9a and 9b are driven. When movers 9a and 9b are located at the positions shown in Fig. 7 and each is moving at a constant speed in the direction of the arrow, and mover 9a is moving at half the speed of mover 9b, Fig. 8 shows the waveform of the induced voltage generated in the coil by the permanent magnet magnetic flux of the mover. In Fig. 8, the induced voltage in coil 1 is v 1 , the induced voltage in coil 2 is v 2 , the induced voltage in coil 3 is v 3 , the induced voltage in coil 4 is v 4 , the induced voltage in coil 5 is v 5 , the induced voltage in coil 6 is v 6 In the linear motor shown in Fig. 7, the relationship between the magnetic pole pitch of the mover and the distance between each coil is the same as in Fig. 3, and the induced voltage generated by the mover moving at a constant speed has a waveform in which the phase of a sine wave is shifted by 180° in the adjacent coils, and the amplitude of the sine wave is proportional to the moving speed of the mover. In Fig. 8, the amplitude of the induced voltage generated in the coil by mover 9b is indicated as a.

[0029] At this time, in order to prevent the movers 9a and 9b from generating thrust, for example, the current flowing through each coil should be set to zero, and a voltage equal to the induced voltage should be applied to each coil. In this case, at time t 2 In the above, the applied voltage command for each coil is v 1 * ~v 6 * would be as follows:

[0030] v 1 * =a / 2 v 2 * =-a / 2 v 3 * =0 v 4 * =0 v 5 * =a v 6 * =-a

[0031] This applied voltage command is input to the half-bridge output voltage calculator 81 of the switching controller 8, and the following half-bridge output voltage commands v 11 * ~v 17 * is calculated.

[0032] v 11 * =0 v 12 * =v 11 * +v 1 * =a / 2 v 13 * =v 12 * +v 2 * =0 v 14 * =v 13 * +v 3 * =0 v 15 * =v 14 * +v 4 * =0 v 16 * =v 15 * +v 5 * =a v 17 * =v 16 * +v 6 * =0

[0033] According to the above half-bridge output voltage commands, each half-bridge 11-17 operates according to a signal generated by the switching controller 8 in the same manner as in the first embodiment, and a desired voltage is applied to each coil. In the above description, the thrust generated in the movers 9a and 9b is set to 0, but by manipulating the voltage command applied to each coil, it is possible to cause the movers 9a and 9b to generate a desired thrust or perform a desired operation. In the above example, the description was given of a case in which there are two movers and six coils, but it goes without saying that operation is possible with a combination of more movers and coils. In other words, by controlling including the voltage command applied to each coil when at least two movers are present at a position corresponding to the series body of serially connected coils, it is possible to cause the multiple movers to perform a desired operation.

[0034] As a result of the above-mentioned operations, the linear motor drive device according to embodiment 2 has a high degree of freedom in controlling the movement of the movers while drastically reducing the number of required switches compared to conventional drive devices such as those described in Patent Document 1, and is capable of causing multiple movers to perform desired operations as with conventional circuits. This makes it possible to achieve the same functions as conventional methods while reducing the size and cost of the drive circuit.

[0035] Embodiment 3 FIG. 9 is a diagram showing the internal structure of a half-bridge output voltage calculator 81 in a linear motor driving device according to the third embodiment, and other parts are the same as those in the first and second embodiments. In order to show the effect of the half-bridge output voltage calculator 81 shown in FIG. 9, first, each half-bridge output voltage command v 11 * ~v 17 * As described in the first embodiment, in a linear motor in which the magnetic pole pitch (the distance between the center of the N pole and the center of the S pole) of the mover 9 is equal to the distance between adjacent coils that are wound independently as shown in Fig. 3, when the mover 9 moves on the coils at a constant speed, the permanent magnet magnetic flux of the mover 9 generates an induced voltage in each coil as shown in Fig. 5, which causes a time t 1 Each half-bridge output voltage command v 11 * ~v 17 * The above is reprinted as follows:

[0036] v 11 * =0 v 12 * =v 11 * +v 1 * =a v 13 * =v 12 * +v 2 * =0 v 14 * =v 13 * +v 3 * =0 v 15 * =v 14 * +v 4 * =0 v 16 * =v 15 * +v5 * =0 v 17 * =v 16 * +v 6 * =0

[0037] At this time t 1 is the output voltage command for each half-bridge v 11 * ~v 17 * This is one of the points where the difference between the maximum and minimum values ​​of each half-bridge output voltage command v 11 * ~v 17 * has a maximum value of a and a minimum value of 0, and in this case it can be seen that the half-bridge output voltage command is biased to the positive side. The absolute value of the modulation factor increases when the half-bridge output voltage command becomes biased. In the relationship between the carrier wave and modulation factor shown in Figure 6, if the modulation factor is greater than 1, which is the peak of the carrier wave, or less than -1, the half-bridge output voltage will no longer track the modulation factor, and correct voltage output will not be possible.

[0038] To correct the bias of the half-bridge output voltage command and maximize the half-bridge output voltage, v 11 * Instead of 0 as the reference voltage, give an appropriate value to v. 11 * ~v 17 * The maximum value of is a and the minimum value is 0, so the value -a / 2 that cancels the average of the maximum and minimum values, a / 2, is set as the corrected reference voltage and the output voltage command v of the half bridge 11 is 11 * This will give the corrected half-bridge output voltage command v 11 ** ~v 17 ** The above process results in the coil voltage command v 1* ~v 6 * It can be seen that the maximum value of the half-bridge output voltage command is corrected to a / 2 and the minimum value to -a / 2 while maintaining the above, and the bias of the half-bridge output voltage command is eliminated.

[0039] v 11 ** =-a / 2 v 12 ** =v 11 ** +v 1 * =a / 2 v 13 ** =v 12 ** +v 2 * =-a / 2 v 14 ** =v 13 ** +v 3 * =-a / 2 v 15 ** =v 14 ** +v 4 * =-a / 2 v 16 ** =v 15 ** +v 5 * =-a / 2 v 17 ** =v 16 ** +v 6 * =-a / 2

[0040] The operation of the half-bridge output voltage calculator 81 according to the third embodiment, which is shown in FIG. 9 and which adds this correction function, will be described. 1 * ~v 6 * First, the first half-bridge output voltage command v 1 *is set to 0, and the half-bridge output voltage command before compensation v 12 * ~v 17 * are calculated sequentially by the adder, and these half-bridge output voltage commands v 11 * ~v 17 * Proper correction from half-bridge output voltage command v 11 ** is calculated by the voltage compensator 85, and the compensated half-bridge output voltage command v 11 ** Correction based on half-bridge output voltage command V 12 ** ~v 17 ** are sequentially calculated by the adder and output.

[0041] Here, we will explain the change in the induced voltage waveform in each coil due to the relationship between the magnetic pole pitch of the mover of the linear motor and the distance between each coil. The voltage waveform shown in Fig. 5 is for a linear motor in which the magnetic pole pitch of the mover is equal to the distance between adjacent coils that are wound independently, and in this case the waveform is a sine wave with a phase shift of 180° between adjacent coils. Figure 10 shows an example of the induced voltage waveform in each coil when, unlike Fig. 5, the magnetic pole pitch is 1.5 times the distance between adjacent coils. At time t 3 Each half-bridge output voltage command v before correction 11 * ~v 17 * is as follows.

[0042] v 11 * =0 v 12 * =v 11 * +v 1 * =a v 13 * =v 12 * +v 2 *=a / 2 v 14 * =v 13 * +v 3 * =0 v 15 * =v 14 * +v 4 * =0 v 16 * =v 15 * +v 5 * =0 v 17 * =v 16 * +v 6 * =0

[0043] FIG. 11 shows an example of the induced voltage waveform of each coil when the magnetic pole pitch is twice the distance between adjacent coils. 4 Each half-bridge output voltage command v before correction 11 * ~v 17 * is as follows.

[0044] v 11 * =0 v 12 * =v 11 * +v 1 * =a / √2 v 13 * =v 12 * +v 2 * =2a / √2 v 14 * =v 13 * +v 3 * =a / √2 v 15* =v 14 * +v 4 * =0 v 16 * =v 15 * +v 5 * =0 v 17 * =v 16 * +v 6 * =0

[0045] Furthermore, an example of the induced voltage waveform of each coil when the magnetic pole pitch is three times the distance between adjacent coils is shown in Fig. 12. 5 Each half-bridge output voltage command v before correction 11 * ~v 17 * is as follows.

[0046] v 11 * =0 v 12 * =v 11 * +v 1 * =√3a / 2 v 13 * =v 12 * +v 2 * =√3a v 14 * =v 13 * +v 3 * =0 v 15 * =v 14 * +v 4 * =√3a / 2 v 16 * =v 15 *+v 5 * =0 v 17 * =v 16 * +v 6 * =0

[0047] As shown in Figure 5, when the magnetic pole pitch of the mover and the distance between adjacent coils are equal, each half-bridge output voltage command v 11 * ~v 17 * The difference between the maximum and minimum values ​​of is equal to the induced voltage amplitude a of each coil. Also, as shown in Figure 10, when the magnetic pole pitch of the mover is 1.5 times the distance between the adjacent coils, each half-bridge output voltage command v 11 * ~v 17 * The difference between the maximum and minimum values ​​of is equal to the induced voltage amplitude a of each coil. In this case, if the half-bridge output voltage calculator 81 equipped with the voltage corrector 85 according to the third embodiment is used, the bus voltage V dc The half-bridge output voltage can follow the modulation rate and output the correct voltage until the coil induced voltage amplitude a is equal to the modulation rate. This is equal to the voltage range that the full-bridge circuit can apply to the coil. Even if multiple movers are moving, if the direction of movement of the movers is the same, as shown in the second embodiment, the necessary half-bridge output voltage command v 11 * ~v 17 * The difference between the maximum and minimum values ​​of is equal to the induced voltage amplitude a of the mover moving at the fastest speed, so there is no difficulty in voltage output. If the movers are moving in opposite directions, the signs of the induced voltages will be opposite, so the output voltage range will be restricted, but in actual equipment movements, it is unlikely that multiple movers will move at high speed in opposite directions on the same orbit consisting of a finite number of coils, so this is not a practical restriction.

[0048] In contrast, as shown in Fig. 11, when the magnetic pole pitch of the mover is twice the distance between adjacent coils, each half-bridge output voltage command v11 * ~v 17 * If the difference between the maximum and minimum values ​​of is 2a / √2 and the pole pitch of the mover is three times the distance between adjacent coils, each half-bridge output voltage command v 11 * ~v 17 * The difference between the maximum and minimum values ​​is √3a, which exceeds the induced voltage amplitude a of each coil. In this case, the range of induced voltage amplitude of each coil in which the linear motor driving device of the present application can operate normally is smaller than that of the conventional full-bridge circuit, and operational constraints such as reducing the maximum moving speed of the mover are generated. In particular, when the magnetic pole pitch of the mover is three times the distance between adjacent coils, the effect of expanding the coil applied voltage range according to the present application is almost lost compared to the half-bridge circuit. This operational constraint becomes stronger as the magnetic pole pitch of the mover becomes larger compared to the distance between adjacent coils, so in a linear motor to which the linear motor driving device of the present application is applied, it is appropriate from a design perspective to set the magnetic pole pitch of the mover to preferably 1.5 times or less the distance between adjacent coils, and 2.5 times or less considering the benefits of cost and size.

[0049] In addition, in the case of the linear motor drive device of the present application, the above-mentioned constraints on the operation of the mover due to the half-bridge output voltage can also be avoided by changing the connection method between the drive circuit and the coils, for example by reversing the winding direction of adjacent coils to invert the sign of the induced voltage generated, or by connecting the half bridge and coils alternately to coils that are distant from each other instead of sequentially, to invert the sign of the coil induced voltage generated between adjacent half bridges. With such a drive circuit and coil connection method, the voltage constraints are alleviated, but the current flowing through the half bridge increases, but it can be applied as a design option.

[0050] As a result of the above-mentioned operation, the linear motor driving device according to the third embodiment is able to apply the same or similar voltages to each coil as the conventional device for linear motors with suitable design conditions while drastically reducing the number of switches required compared to conventional driving devices such as those described in Patent Document 1. This makes it possible to achieve the same functionality as the conventional method while reducing the size and cost of the driving device.

[0051] Embodiment 4 FIG. 13 shows the configuration of a linear motor driving device according to the fourth embodiment. In addition to the configuration shown in FIG. 3, this configuration detects the current flowing through each of the coils 1 to 6 and calculates the coil current measurement value i 1 ~i 6 and the current command for each coil (hereinafter referred to as the coil current command) i 1 * ~i 6 * and the measured coil current value i 1 ~i 6 Based on the voltage command v to each coil 1 * ~v 6 * In this embodiment, the switching controller 80 is configured by the current controller 10 and a controller 88 having the same function as the switching controller 8 shown in FIG. 3 or FIG. 7. The coil current command i 1 * ~i 6 * are given by a higher-level controller (not shown) to control the thrust generated by the mover 9 and the position and speed of the mover. The current controller 10 outputs coil current commands i 1 * ~i 6 * and the measured coil current value i 1 ~i 6 So that the applied voltage command v 1 * ~v 6 *For example, a current feedback controller calculates the deviation between a current command and a current measurement value for each coil current and outputs an applied voltage command for each coil via a proportional integral controller.

[0052] In FIG. 14, the current detection by the current sensors 21 to 26 is changed from the coils 1 to 6 to the output current of the half bridges 11 to 16, and the current sensors 21 to 26 output the half bridge current signals i 11 ~i 16 Each half-bridge current signal i 11 ~i 16 is input to the coil current calculator 101, and each coil current measurement value i 1 ~i 6 is calculated and output. Here, the switching controller 80 is composed of a controller 88 having the same function as the switching controller 8 shown in FIG. 3 or FIG. 7, a current controller 10, and a coil current calculator 101. FIG. 15 shows the internal structure of the coil current calculator 101. Due to the connection relationship between each of the coils 1 to 6 and the half bridges 11 to 16, each half bridge current signal i 11 ~i 16 From each coil current measurement value i 1 ~i 6 is calculated using the following formula:

[0053] i 1 =i 11 , i 2 =i 1 +i 12 i 3 =i 2 +i 13 i 4 =i 3 +i 14 i 5 =i 4 +i 15 i 6 =i 5 +i 16

[0054] By calculating the coil current measurement value from the half-bridge current signal as described above, it is no longer necessary to connect the coils within the drive circuit, and the number of terminals connecting the drive circuit and the coils can be reduced.Instead of providing each current sensor at the half-bridge circuit output as shown in Figure 14, if a current detection resistor is inserted at the connection between each half-bridge and the negative terminal of the DC power supply to enable current detection and a method is used in which the current is detected at the position where the coil is connected to the negative terminal of the DC power supply by switching the half-bridge circuit, a signal equivalent to the half-bridge current signal can be obtained as a voltage signal with the negative terminal of the DC power supply as a common potential, making it possible to achieve equivalent performance with even cheaper components.

[0055] As a result of the above-mentioned operation, the linear motor drive device according to the fourth embodiment controls each coil current to match a command value according to a current command, so that the linear motor can be controlled with higher precision. Also, by using a coil current calculator that calculates each coil current from each half-bridge circuit output current, it is possible to reduce the number of connection terminals between the drive circuit and the coils while achieving the same functionality as the conventional method described in Patent Document 1, for example.

[0056] Fifth embodiment Fig. 16 shows the configuration of a linear motor driving device according to the fifth embodiment. In addition to the configuration shown in Fig. 14, this configuration has the same function as the switching controller 8 shown in Fig. 3 or Fig. 7, and the modulation factor m 11 ~m 17 and the controller 881 which outputs the modulation factor m 11 ~m 17 Detect each modulation rate saturation signal fm 11 ~fm 17 and a modulation rate saturation detector 882 that outputs each modulation rate saturation signal fm 11 ~fm 17 Detect each coil voltage saturation signal fc 11 ~fc 16In the fifth embodiment, a controller 881, a modulation factor saturation detector 882, a coil voltage saturation detector 883, the coil current calculator 101 shown in FIG. 14, and each coil current command i 1 * ~i 6 * and the measured coil current value i 1 ~i 6 and the saturation signal fc detected by the coil voltage saturation detector 883 11 ~fc 16 Based on the voltage command v to each coil 1 * ~v 6 * The switching controller 880 is configured by the current controller 100 that calculates

[0057] The modulation factor saturation detector 882 detects each modulation factor m 11 ~m 17 Detect each modulation factor m 11 ~m 17 If the absolute value of is greater than 1, each modulation factor m 11 ~m 17 For each modulation rate saturation signal fm 11 ~fm 17 If fm is smaller than 1, the modulation factor saturation signal fm 11 ~fm 17 The coil voltage saturation detector 883 has a function of outputting 0. 11 ~fm 17 By detecting and converting each modulation rate saturation signal into a coil voltage saturation signal, each coil voltage saturation signal fc 11 ~fc 16 The current controller 100 outputs the coil current command i for each of the coils 1 to 6, similarly to the current controller 10 shown in FIG. 1 * ~i 6 * and the measured coil current value i 1 ~i 6 So that the applied voltage command v 1 * ~v 6* The controller group performs control by operating the current feedback controller, which calculates the deviation between the current command and the current measurement value for each coil and outputs the applied voltage command for each coil via a proportional calculator and an integral calculator. However, the integral calculator calculates the deviation between the current command and the current measurement value for each coil and outputs the applied voltage command for each coil via a proportional calculator and an integral calculator. 11 ~fc 16 Detect each coil voltage saturation signal fc 11 ~fc 16 When is 1, it has the function of stopping or updating the integral calculation of the integral calculator.

[0058] FIG. 17 is a diagram showing the internal structure of the controller 881 shown in FIG. 16. The controller 881 has the same function as the switching controller 8 shown in FIG. 3 or FIG. 7, and further includes a modulation factor calculator 82 that calculates each modulation factor m 11 ~m 17 It has the function of outputting.

[0059] In order to demonstrate the effect of the current controller 100 shown in FIG. 16, the mover 9 passes over the coils 1 to 6 and the current 6 This section explains the case where the induced voltage generated in the coil exceeds the possible output voltage when the mover speed becomes 3 / 2 times faster.

[0060] In FIG. 18, the mover 9 passes over the coils 1 to 6, and at time t 6 The waveform of the induced voltage generated in the coil when the mover speed is 3 / 2 times faster at v 1 , the induced voltage in coil 2 is v 2 , the induced voltage in coil 3 is v 3、 The induced voltage in coil 4 is v 4 , the induced voltage in coil 5 is v 5、 The induced voltage in coil 6 is v 6 where the horizontal axis represents the passage of time t.

[0061] At this time, in order to prevent the mover 9 from generating a thrust, for example, a voltage equal to the induced voltage may be applied to each coil, as in the third embodiment. In this case, this applied voltage command is input to the half-bridge output voltage calculator 81 of the controller 881, and each half-bridge output voltage command v 11 * ~v 17 * The waveform of each half-bridge output voltage command v 11 * ~v 17 * This waveform is input to a voltage corrector 85, which calculates the voltage correction amount shown in FIG.

[0062] Each corrected half-bridge output voltage command v shown in Fig. 21 11 ** ~v 17 ** In the voltage compensator 85, each half-bridge output voltage command v 11 * ~v 17 * 20 is applied. By applying the voltage correction amount, the waveform at time t 6 Before the mover speed becomes 3 / 2 times, each correction half-bridge output voltage command v 11 ** ~v 17 ** The maximum value of is a / 2 and the minimum value is -a / 2. 6 After the mover speed becomes 3 / 2 times faster, each correction half-bridge output voltage command v 11 ** ~v 17 ** The maximum value is 3a / 4 and the minimum value is -3a / 4.

[0063] At this time, in FIG. 6 After that, as the induced voltage increases, each corrective half-bridge output voltage command v 11 ** ~v 17 ** rises, and the modulation factor m of each half bridge calculated by the modulation factor calculator 82 shown in FIG. 11~m 17 Suppose the absolute value of exceeds 1.

[0064] At this time, at time t 6 Hereafter, the modulation factor saturation signal fm output by the controller 881 shown in FIG. 11 ~fm 17 The coil voltage saturation detector 883 detects each modulation factor saturation signal fm 11 ~fm 17 Input each coil voltage saturation signal fc 11 ~fc 16 Each modulation rate saturation signal fm 11 ~fm 17 and each coil voltage saturation signal fc 11 ~fc 16 The input / output relationship is as follows:

[0065] ·fm 11 If =1, fc 11 =Output 1. ·fm 12 If =1, fc 11 =1, fc 12 =Output 1. ·fm 13 If =1, fc 12 =1, fc 13 =Output 1. ·fm 14 If =1, fc 13 =1, fc 14 =Output 1. ·fm 15 If =1, fc 14 =1, fc 15 =Output 1. ·fm 16 If =1, fc 15 =1, fc 16 =Output 1. ·fm 17 If =1, fc 16 =Output 1. In all other cases, the coil voltage saturation signal outputs 0. In the above, the modulation factor m 11 ~m 17In this example, the absolute value of the modulation factor exceeds 1, but there may be cases where the absolute value of the modulation factor of only some half bridges exceeds 1. In this case, the coil voltage saturation signal of the coil connected to the half bridge that exceeds 1 is set to 1.

[0066] FIG. 22 is a diagram showing the internal structure of a current controller 100 for achieving the above-described functions. The current controller 100 controls each coil current command i 1 * ~i 6 * and the measured coil current value i 1 ~i 6 The output of the proportional calculator 1020 which multiplies the deviation of the coil voltage saturation signal fc by a factor of 10.5 is added to the output of the integral calculator 1030 to 1035 which performs integral calculation. 11 ~fc 16 is input to the current controller 100.

[0067] 23 is a diagram showing the internal structure of the integrators 1030 to 1035 provided in the current controller 100, and a group of the integrators is indicated as 100a. Each of the integrators 1030 to 1035 outputs a coil voltage saturation signal fc 11 ~fc 16 Each coil current command i 1 * ~i 6 * and the measured coil current value i 1 ~i 6 The difference is whether the deviation of is input to the integrator (block shown as 1 / s in Figure 22) or 0 is input to the integrator. The coil voltage saturation signal fc 11 ~fc 16 The integrators with a value of 1 are input with 0 (i.e., the integral calculation is stopped), and the coil voltage saturation signal fc 11 ~fc 16 The integrator with a value of 0 is the coil current command i 1 * ~i 6 * and the coil current measurement value i 1 ~i 6 Input the deviation of each coil voltage saturation signal fc11 ~fc 16 The input of the integrator to which the coil voltage saturation signal 1 is input is set to 0 to stop the integral calculation in the voltage saturation section, and each coil voltage saturation signal fc 11 ~fc 16 This can suppress hunting in the measured coil current value, which occurs when the integrated current value stored in the integrator is released when the input voltage switches from 1 to 0. Hunting refers to the phenomenon in which the current jumps out, as shown in Figure 24.

[0068] Figure 24 shows the coil voltage saturation signal fc 11 ~fc 16 When the integral calculation of the current controller is not stopped in the section where the output of 1 * ~v 6 * , the applied voltage command for coil 4 v 4 * and the coil applied voltage v 4 *** , coil current command i 4 * and the coil current measurement value i 4 In the integral calculator 1033 shown in FIG. 4 * and the coil current measurement value i 4 The current integration value calculated from the deviation of the applied voltage command v 4 * Since the commanded voltage cannot be applied because it exceeds the available output voltage, the coil current measurement value i 4 Also, the coil voltage saturation signal fc 14 Since the integral calculation was not stopped in the section where the coil current command i 4 * and the coil current measurement value i 4 The deviation of the coil voltage saturation signal fc 14 At the moment when the current measurement value i 4 Hunting occurs in the coil current measurement value i 4 Coil current command i 4* The convergence to is slower.

[0069] Figure 25 shows the coil voltage saturation signal fc 11 ~fc 16 The voltage command v applied to the coil when the integral calculation of the current controller is stopped in the section where 1 * ~v 6 * , the applied voltage command for coil 4 v 4 * and the coil applied voltage v 4 *** , coil current command i 4 * and the coil current measurement value i 4 In the integral calculator 1033 shown in FIG. 4 * and the coil current measurement value i 4 The current integration value calculated from the deviation of the coil voltage saturation signal fc 14 By stopping the integral calculation in the section where the coil voltage saturation signal fc 14 The moment that changes from 1 to 0, the current integration value output from the integral calculator is suppressed, and the coil current measurement value i 4 Therefore, hunting is suppressed.

[0070] At this time, the current measurement value i 4 In order to suppress the hunting of the coil voltage saturation signal fc 14 Rather than stopping the integrator in the section where it outputs 1, it is preferable to update the integral calculation value to a value different from the value integrated up to that point so that the appropriate integral calculation value will be obtained when the voltage saturation section is exited. By performing this process, it is possible to further suppress hunting of the current measurement value after exiting the voltage saturation section, and the coil current measurement value i 4 The convergence will also be faster.

[0071] As described above, according to the linear motor driving device of embodiment 5, the applied voltage commands for each coil are created by a current controller having an integrator that receives as input the deviation between the measured value of the current flowing through that coil and the respective current command for that coil, and the current controller stops the integral calculation of the integrator for the coil connected to the half bridge having an absolute value of the modulation rate that exceeds 1 among the multiple half bridges (the two coils when two coils are connected to the half bridge such as half bridges 12 to 16, or the single coil when only one coil is connected to a half bridge at both ends such as half bridges 11 and 17), or updates the previous integral value of the integrator to a different value, thereby suppressing hunting of the coil current.

[0072] Specifically, as shown in FIG. 26, the switching controller in each of the above embodiments includes an arithmetic processing device 801 such as a central processing unit (CPU), a storage device 802 for exchanging data with the arithmetic processing device 801, and an input / output interface 803 for inputting and outputting signals between the arithmetic processing device 801 and the outside. The arithmetic processing device 801 may include an application specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a field programmable gate array (FPGA), and various signal processing circuits. In addition, the arithmetic processing device 801 may include a plurality of devices of the same type or different types, and each process may be shared and executed. The storage device 802 includes a random access memory (RAM) configured to be able to read and write data from the arithmetic processing device 801, a read only memory (ROM) configured to be able to read data from the arithmetic processing device 801, and the like. The input / output interface 803 receives, for example, the applied voltage command v for each coil, and outputs the voltage command v to the input / output interface 803. 1 * ~v 6 *Or the current command i 1 * ~i 6 * to the command processing device 801, and the coil current measurement values ​​i 1 ~i 6 to the arithmetic processing device 801, and a drive circuit for outputting a drive signal to each switching element.

[0073] Although various exemplary embodiments and examples are described in this application, various features, aspects, and functions described in one or more embodiments are not limited to the application of a specific embodiment, but can be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are expected within the scope of the technology disclosed in this specification. For example, the modification, addition, or omission of at least one component, and the extraction and combination of at least one component with components of other embodiments are included. [Explanation of symbols]

[0074] 1, 2, 3, 4, 5, 6 coil, 7 DC power supply, 8, 80, 880 switching controller, 9 mover, 10, 100 current controller, 11, 12, 13, 14, 15, 16, 17 half bridge, 21, 22, 23, 24, 25, 26 current sensor, 81 half bridge output voltage calculator, 85 voltage compensator, 101 coil current calculator, 1030 to 1035 integral calculator, i 1 , i 2 , i 3 , i 4 , i 5 , i 6 Measured coil current, i 1 * , i 2 * , i 3 * , i 4 * , i 5 * , i 6* Coil current command, v 1 * , v 2 * , v 3 * , v 4 * , v 5 * , v 6 * Applied voltage command, v 11 * , v 12 * , v 13 * , v 14 * , v 15 * , v 16 * , v 17 * Half-bridge output voltage command, m 11 , m 12 , m 13 , m 14 , m 15 , m 16 , m 17 Half-bridge modulation rate

Claims

1. The present invention has a stator in which a plurality of coils are arranged in a row, and a half bridge composed of a plurality of switches connected in series, the number of the half bridge being one more than the number of the coils, a linear motor driving device in which the plurality of coils are electrically connected in series, both ends of the series body of the coils connected in series and each connection point between the coils are connected to output points of different half bridges, both ends of each half bridge are connected to a DC source, and an AC voltage is applied to each coil, A linear motor drive device comprising: a half-bridge output voltage calculator that calculates an output voltage command for each of the half-bridges based on each applied voltage command for a voltage applied to each of the plurality of coils; and a switching controller that uses the half-bridge output voltage commands for each of the half-bridges calculated by the half-bridge output voltage calculator to calculate switching signals that control the switches of each of the half-bridges, and controls driving of the switches of all of the half-bridges.

2. 2. The linear motor driving device according to claim 1, wherein each of the applied voltage commands is given as a voltage waveform.

3. 2. The linear motor drive device according to claim 1, wherein the half-bridge output voltage calculator uses the applied voltage commands to determine each of the half-bridge output voltage commands, starting from the half-bridge output voltage command of the half-bridge to which one end of the series coil is connected.

4. 4. The linear motor drive device of claim 3, wherein the half-bridge output voltage calculator sets a half-bridge output voltage command of a half bridge to which one end of the series coil is connected as a reference voltage, and uses each of the applied voltage commands to determine each of the half-bridge output voltage commands, starting from the half-bridge output voltage command of the half bridge connected to the other end of the coil connected to the half bridge, up to the half-bridge output voltage command of the half bridge connected to the other end of the series coil.

5. 5. The linear motor driving device according to claim 4, wherein the half-bridge output voltage calculator sets the reference voltage to zero.

6. 5. The linear motor drive device according to claim 4, wherein the half-bridge output voltage calculator determines each of the half-bridge output voltage commands by correcting the reference voltage based on each of the half-bridge output voltage commands determined by setting the reference voltage to 0.

7. 7. The linear motor drive device according to claim 1, wherein each of the applied voltage commands is created based on a measured value of a current flowing through each of the coils and a current command for each of the coils.

8. 8. The linear motor driving device of claim 7, wherein each of the applied voltage commands is created by a current controller having an integrator that inputs the deviation between the measured value of the current flowing through each of the plurality of coils and the current command for that coil, and the current controller stops the integral calculation of the integrator for a coil connected to one of the plurality of half bridges whose absolute value of the modulation rate exceeds 1, or updates the previous integral value of the integrator to a different value.

9. 7. The linear motor drive device according to claim 1, wherein the number of coils of the stator is four or more.

10. 7. A linear motor comprising the linear motor drive device according to claim 1 and a mover movably provided at a distance from the stator, A linear motor in which the magnetic pole pitch of the mover is 2.5 times or less the distance between adjacent coils in the stator.

11. 7. A linear motor comprising the linear motor drive device according to claim 1 and a plurality of movers movably provided at intervals from the stator, The linear motor, wherein the respective applied voltage commands include respective applied voltage commands when at least two movers are present at positions corresponding to the series body of coils.

12. 12. The linear motor according to claim 11, wherein the magnetic pole pitch of the mover is 2.5 times or less the distance between adjacent coils in the stator.

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