JP4175721B2 - Motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device that rotates a motor such as a brushless motor in a predetermined rotation mode.
[0002]
[Prior art]
As an example, a three-phase brushless motor has been conventionally used in industrial fields such as home appliances and industrial use. FIG. 5 is a block diagram showing an electrical configuration of the control device 1 of such a brushless motor (hereinafter referred to as a motor). With reference to FIG. 5, the control device of the prior art will be described. This prior art control device 1 intends to control a plurality of motors 2 at a time, and as an example provided in each motor 2, rotation signals from three rotation speed detection elements 3 are detected in position. Each signal is input to the circuit 9, converted into a signal whose frequency is positively correlated with the rotational speed of the motor 2 by the position detection circuit 9, and input to the frequency / voltage conversion circuit 4. This signal is converted into a voltage signal positively correlated with the frequency by the frequency / voltage conversion circuit 4, and this voltage signal is input to one input terminal of the comparison circuit 5. A speed command signal having a voltage level corresponding to a reference speed for each motor 2 from a speed command unit 6 common to each motor 2 is input to the other input terminal of each comparison circuit 5.
[0003]
Each comparison circuit 5 compares the voltage levels of each voltage signal and each speed command signal with each other, and outputs a signal corresponding to the difference to each PWM (pulse width modulation) control circuit 7. In the PWM control circuit 7, the rotation speed of each motor 2 is increased or decreased based on the signal from the comparison circuit 5, and the rotation speed of each motor 2 corresponds to the speed command signal from the speed command unit 6. A control signal based on a pulse width modulation system that provides a reference speed is generated and output to each inverter circuit 8 provided for each motor 2. Each inverter circuit 8 flows through the upper stage transistors Q1, Q2, and Q3 including power transistors that supply drive signals to the respective coils U, V, and W of the corresponding three-phase motor 2, and the coils U, V, and W. The lower upper transistors Q4, Q5, and Q6 into which the drive signal flows are provided.
[0004]
The control device 1 is configured to include the rotation speed detection element 3, the frequency / voltage conversion circuit 4, the comparison circuit 5, the speed command unit 6, the PWM control circuit 7, and the inverter circuit 8. With such a configuration, the rotation speed of each motor 2 is controlled.
[0005]
[Problems to be solved by the invention]
In such a conventional control device 1, an inverter circuit 8 is required for each motor 2, and in the conventional example, only 6 transistors × n (the number of installed motors) are required, which increases the number of parts and costs. Become up. Further, each motor 2 requires the rotational speed detecting element 3, the frequency / voltage conversion circuit 4, the comparison circuit 5, the speed command unit 6, the PWM control circuit 7, and the inverter circuit 8, and the configuration becomes large and complicated. . Further, when the motors 2 are operated in synchronism with each other, the frequency / voltage conversion circuit 4, the comparison circuit 5, the PWM control circuit 7, and the inverter circuit 8 that are provided for each motor 2 may have different gain settings. It is difficult to synchronize the rotation with high accuracy. Further, each motor 2 requires the rotational speed detecting element 3, the frequency / voltage conversion circuit 4, the comparison circuit 5, the speed command unit 6, the PWM circuit 7 and the inverter circuit 8, and each motor 2 is overshot. , Undershoot and hunting occur.
[0006]
The present invention has been made to solve the above-mentioned problems, and its purpose is to simplify the configuration necessary for simultaneously controlling a plurality of motors and to control each motor with high accuracy. An object of the present invention is to provide a motor control device that can prevent the occurrence of malfunction.
[0007]
[Means for Solving the Problems]
  The motor control device according to claim 1 generates a rotating magnetic field.n three phasesmotor(Where n is an integer greater than or equal to 2)The drive signal to the coilTheInverter including switching meanscircuitA control device comprising:The inverter circuit is formed by connecting, in parallel, three series circuits formed by connecting (n + 1) stages of the switching means in series of (n + 1) stages, and k-stage switching means arranged in parallel with (k + 1). ) Three connection points with the switching means of the stage (where k is an integer from 1 to n) are respectively connected to different phases of one of the three-phase motors, and n A motor control device that controls a three-phase motor.
[0008]
  The motor control device according to claim 2, wherein the rotation speed of the motor matches the predetermined reference rotation speed.circuitofSaidSwitching meansofThe control unit for controlling the switching operation is the invertercircuitofSaidSwitching meansTheControl is common to each motor.
[0009]
  The motor control device according to claim 1 includes a plurality of control devices.nof3 phaseWhen controlling the motor,The inverter circuit is formed by connecting in parallel three series circuits in which (n + 1) switching means are connected in series in (n + 1) stages, and the k-th switching means and (k + 1) stages arranged in parallel. Three connection points with the eye switching means (where k is an integer from 1 to n) are respectively connected to different phases of one of the three three-phase motors.
[0010]
In other words, assuming that another motor is connected to the subsequent stage of one motor, the drive signal supplied from the supply switching means to one motor passes through the coil in the motor and flows into the one motor. Flows into the switching means. On the other hand, the same switching means is used as the inflow switching means corresponding to the one motor and the supply switching means of the other motor adjacent to the one motor in the electrical connection order. Accordingly, the inflow switching means of the one motor becomes the supply switching means of the other motor.
[0011]
In this way, when the motor is in m phase, the number of switching means is 2 mn when the supply switching means and the inflow switching means are used for each motor, whereas in the present invention, m (n + 1) ) Become a piece. Thereby, the number of switching means is
{M (n + 1) / 2mn} = (n + 1) / 2n (1)
As a result, the cost can be significantly reduced and the cost can be reduced.
[0012]
  3. The motor control device according to claim 2, wherein the rotation speed of the motor matches a predetermined reference rotation speed.Inverter circuitofSaidSwitching meansofThe control unit that controls the switching operation,Inverter circuitofSaidSwitching meansTheControl is common to each motor.
[0013]
Accordingly, it is possible to eliminate the necessity of providing each motor with a circuit configuration necessary for controlling the rotational speed of the motor, and to greatly simplify the configuration of the motor control device, thereby reducing costs. In addition, since the configuration of the control device can be simplified, the number of circuit elements that need to be adjusted, such as gain, can be reduced, and a single control device can share the rotational speed control of multiple motors across each motor. Therefore, it is possible to prevent a malfunction such as a loss of synchronization of operation of each motor due to a gain setting deviation in the control device for each motor.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing an electrical configuration of a motor control device 11 according to a first embodiment of the present invention, and FIG. 2 is a diagram for explaining the operation of this embodiment.
[0015]
Hereinafter, the configuration of the control device 11 of this embodiment will be described with reference to FIGS. 1 and 2.
[0016]
The control device 11 of the present embodiment is intended to collectively control a plurality of motors 12a and 12b (indicated by reference numeral 12 when collectively referred to) as two examples in the present embodiment. As an example provided in the motors 12a and 12b, rotation signals Sv from three rotation speed detection elements 13au, 13av, 13aw, 13bu, 13bv, and 13bw are respectively input to the position detection circuit 19, and the position detection circuit 19 The signal is converted into a signal whose frequency is positively correlated with the rotational speed of 12, and is converted into a voltage signal positively correlated with the frequency by the frequency / voltage conversion circuit 14 common to the two motors 12a and 12b. Is also input to one input terminal of the comparison circuit 15 common to the motors 12a and 12b. A speed command signal having a voltage level corresponding to a reference speed common to the motors 12 a and 12 b from the speed command unit 16 common to the motors 12 a and 12 b is input to the other input terminal of the comparison circuit 15.
[0017]
The comparison circuit 15 compares the voltage levels of the voltage signals and the speed command signals with each other, and outputs a signal corresponding to the difference to a PWM (pulse width modulation) control circuit 17 common to the motors 12a and 12b. . The PWM control circuit 17 increases or decreases the rotational speeds of the motors 12 a and 12 b based on the signal from the comparison circuit 15, and the rotational speeds of the motors 12 a and 12 b are converted into speed commands from the speed command unit 16. A control signal that provides a reference speed corresponding to the signal is output to each inverter circuit 18 provided for each of the motors 12a and 12b. The inverter circuit 18 includes first-stage transistors Q1, Q2, and Q3 including power transistors that supply drive signals to the coils Ua, Va, Wa, Ub, Vb, and Wb of the corresponding three-phase motors 12a and 12b. Second stage transistors Q4, Q5, Q6 and third stage transistors Q7, Q8, Q9 are provided.
[0018]
The collectors of the first stage transistors Q1, Q2, and Q3 are connected to a common power supply potential (not shown), and the emitters are connected to the coils Ua, Va, and Wa of the motor 12a that are star-connected as an example. And connected to the collectors of the second stage transistors Q4, Q5, Q6, respectively. The emitters of the second stage transistors Q4, Q5, and Q6 are connected to the coils Ub, Vb, and Wb of the motor 12b that are star-connected as an example, and are connected to the collectors of the third stage transistors Q7, Q8, and Q9. Each is connected. The emitters of the third stage transistors Q7, Q8, Q9 are respectively connected to a common ground potential (not shown).
[0019]
The control device includes the rotation speed detection elements 13au, 13av, 13aw, 13bu, 13bv, 13bw, the frequency / voltage conversion circuit 14, the comparison circuit 15, the speed command unit 16, the PWM control circuit 17, and the inverter circuit 18. 11 is configured, and the control device 11 controls the rotation speeds of the motors 12a and 12b by such a configuration.
[0020]
In the present embodiment, a driving signal is supplied from the first stage transistors Q1, Q2, and Q3 to the motor 12a, and the driving signal that has flowed through the motor 12a flows into the second stage transistors Q4, Q5, and Q6 and the second stage transistors. The transistors Q4, Q5, Q6 are supplied as drive signals to the motor 12b. The drive signal that has flowed through the motor 12b flows into the third stage transistors Q7, Q8, and Q9.
[0021]
The motors 12a and 12b are adjacent to each other in the electrical connection order, and the first stage transistors Q1, Q2, Q3, which are supply switching means for supplying the drive signal to the motor 12a which is one motor, and Of the second-stage transistors Q4, Q5, and Q6 that are inflow switching means into which the current flowing through the motor 12a flows, the second-stage transistors Q4, Q5, and Q6 supply a drive signal to the motor 12b that is another motor. The function of the supply switching means is realized. The inflow switching means into which the current flowing through the motor 12b flows is realized by the third stage transistors Q7, Q8, Q9. That is, the same switching means is used for the inflow switching means for the motor 12a and the supply switching means for the motor 12b.
[0022]
An example of the control of the transistors Q1 to Q9 when such an inverter circuit 18 is used is shown in FIG. Symbols Q1 to Q9 in FIG. 2 indicate the respective transistors Q1 to Q9 in FIG. 1. The hatched portions indicate the on state of the transistors, and the unshaded portions indicate the off states of the transistors.
[0023]
Hereinafter, the operation of the control device 11 will be described with reference to FIG. In the control step of mode 1 in FIG. 2, the transistors Q1, Q5, and Q7 are controlled to be on and the other transistors are controlled to be off. At this time, in the block diagram of FIG. 1, the drive signal flows in the order of the transistor Q1, the coil Ua, the coil Wa, the transistor Q5, the coil Wb, the coil Ub, and the transistor Q7. In the control step of mode 2 in FIG. 2, the transistors Q1, Q6, and Q7 are controlled to be on and the other transistors are controlled to be off. At this time, in the block diagram of FIG. 1, the drive signal flows in the order of the transistor Q1, the coil Ua, the coil Va, the transistor Q6, the coil Vb, the coil Ub, and the transistor Q7.
[0024]
In the control step of mode 3 in FIG. 2, the transistors Q2, Q6, and Q8 are controlled to be on and the other transistors are controlled to be off. At this time, in the block diagram of FIG. 1, the drive signal flows in the order of the transistor Q2, the coil Wa, the coil Va, the transistor Q6, the coil Vb, the coil Wb, and the transistor Q8. In the control step of mode 4 in FIG. 2, the transistors Q2, Q4, and Q8 are controlled to be on and the other transistors are controlled to be off. At this time, in the block diagram of FIG. 1, the drive signal flows in the order of the transistor Q2, the coil Wa, the coil Ua, the transistor Q4, the coil Ub, the coil Wb, and the transistor Q8.
[0025]
In this way, in the control example shown in FIG. 2, the motors 12a and 12b are rotated at the same speed in FIG.
[0026]
Thus, when the motors 12a and 12b are three-phase as in this embodiment, the supply switching means and the inflow switching means are used for each of the two motors 12a and 12b as in the prior art. As shown in FIG.
2 stages x 3 phases x 2 units = 12 (2)
In contrast, in this embodiment,
3 phases x (2 + 1) units = 9 pieces (3)
become. As a result, the number of transistors required to control the motors 12a and 12b is
9/12 pieces = 3/4 (4)
Thus, the cost can be significantly reduced as compared with the case of the prior art, and the cost can be reduced.
[0027]
In this embodiment, the circuit configuration necessary for controlling the rotational speeds of the motors 12a and 12b is the rotational speed detecting elements 13au, 13av, 13aw, 13bu, 13bv, 13bw, and the frequency / voltage conversion circuit 14 as described above. The single control device 11 including the comparison circuit 15, the speed command unit 16, the PWM control circuit 17, and the inverter circuit 18 controls a plurality of motors 12a and 12b in common. Therefore, as in the prior art, the necessity of providing the rotational speed detecting elements 13au, 13av, 13aw, 13bu, 13bv, 13bw and the like for each motor 12a, 12b is eliminated, and the configuration of the control device 11 is greatly simplified. Cost reduction.
[0028]
In addition, since the configuration of the control device 11 can be simplified, circuit elements that require adjustment of gain and the like can be reduced, and the single control device 11 can control the rotational speeds of the plurality of motors 12a and 12b. Since the operations are performed in common over the motors 12a and 12b, it is possible to prevent a situation in which a malfunction such as a loss of synchronization of operation of the motors 12a and 12b occurs due to a gain setting deviation in the control device for each of the motors 12a and 12b. The
[0029]
FIG. 3 is a block diagram showing the electrical configuration of the motor control device 11a according to the second embodiment of the present invention, and FIG. 4 is a diagram for explaining the operation of this embodiment. Hereinafter, the configuration of the control device 11a of the present embodiment will be described with reference to FIGS. This embodiment is similar to the configuration of the first embodiment, and corresponding portions are denoted by the same reference numerals. A feature of the present embodiment is that a four-stage transistor is used as the inverter circuit 18a in order to collectively control the three motors 12a, 12b, and 12c. Specifically, the inverter circuit 18a is a first stage that supplies drive signals to the coils Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, and Wc of the corresponding three motors 12a, 12b, and 12c. Transistors Q1, Q2, Q3, second stage transistors Q4, Q5, Q6, third stage transistors Q7, Q8, Q9, and fourth stage transistors Q10, Q11, Q12 are provided.
[0030]
The collectors of the first stage transistors Q1, Q2, and Q3 are connected to a common power supply potential (not shown), and the emitters are connected to the coils Ua, Va, and Wa of the motor 12a that are delta-connected as an example. And connected to the collectors of the second stage transistors Q4, Q5, Q6, respectively. The emitters of the second stage transistors Q4, Q5, and Q6 are connected to the coils Ub, Vb, and Wb of the motor 12b that are delta-connected as an example, and are connected to the collectors of the third stage transistors Q7, Q8, and Q9. Each is connected. The emitters of the third stage transistors Q7, Q8, and Q9 are connected to the coils Uc, Vc, and Wc of the motor 12c that are delta-connected as an example, and are connected to the collectors of the fourth stage transistors Q10, Q11, and Q12, respectively. Each is connected. The emitters of the fourth stage transistors Q10, Q11, and Q12 are connected to a common ground potential (not shown).
[0031]
Further, in this embodiment, as shown in FIG. 3, with respect to the rotational speed detection elements installed in the motors 12a, 12b, 12c, the rotational speed detection element 13a is arranged between the coils Ua, Wa of the motor 12a, The rotational speed detecting element 13b is disposed between the coils Ub and Vb of the motor 12b, and the rotational speed detecting element 13c is disposed between the coils Vc and Wc of the motor 12c. The rotational speed signals output from the rotational speed detection elements 13a, 13b, and 13c arranged one by one for each of the motors 12a, 12b, and 12c are input to the position detection circuit 19, respectively.
[0032]
In the control device 11a, the configuration other than the above configuration is the same as the configuration of the control device 11 of the first embodiment. As in the first embodiment, the control device 11a includes a rotation speed detecting element 13, a frequency / voltage conversion circuit 14, a comparison circuit 15, a speed command unit 16, a PWM control circuit 17, and an inverter circuit 18a. And this control apparatus 11a controls the rotational speed of each motor 12a, 12b, 12c by such a structure.
[0033]
In such a control device 11a of the second embodiment, a drive signal is supplied from the first stage transistors Q1, Q2, and Q3 to the motor 12a, and the drive signal that has flowed through the motor 12a is changed to the second stage transistors Q4, Q5, This signal flows into Q6, and this signal is supplied from the second stage transistors Q4, Q5, Q6 to the motor 12b as a drive signal. The drive signal that has flowed through the motor 12b flows into the third stage transistors Q7, Q8, and Q9. Further, this signal is supplied as a drive signal from the third stage transistors Q7, Q8, Q9 to the motor 12c, and the drive signal flowing through the motor 12c flows into the fourth stage transistors Q10, Q11, Q12.
[0034]
The motors 12a and 12b and the motors 12b and 12c are adjacent to each other in the electrical connection order. As described in the first embodiment, the motors 12a and 12b share the second stage transistors Q4, Q5, and Q6. In this embodiment, the motor 12b is another motor in the claims with respect to the motor 12a, and is one motor in the claims with respect to the motor 12c. Of the second stage transistors Q4, Q5, and Q6 that are supply switching means for supplying the drive signal, and the second stage transistors Q7, Q8, and Q9 that are inflow switching means for the current flowing through the motor 12b to flow, The stage transistors Q4, Q5, and Q6 realize a function of supply switching means for supplying a drive signal to the motor 12b that is one motor. The inflow switching means into which the current flowing through the motor 12b flows is realized by the third stage transistors Q7, Q8, Q9.
[0035]
Further, with respect to the motor 12c, which is another motor with respect to the motor 12b, the third stage transistors Q7, Q8, Q9 realized the function as supply switching means, and flowed through the third stage transistors Q7, Q8, Q9. The drive signal flows into the fourth stage transistors Q10, Q11, Q12 which are inflow switching means.
[0036]
That is, in this embodiment, the second-stage transistors Q4, Q5, Q6, which are the same switching means as the inflow switching means for the motor 12a and the supply switching means for the motor 12b, are used, and the inflow switching means for the motor 12b and the motor 12c. The third stage transistors Q7, Q8, Q9, which are the same switching means as the supply switching means, are used.
[0037]
An example of the control of each of the transistors Q1 to Q12 when such an inverter circuit 18a is used is shown in FIG. Symbols Q1 to Q12 in FIG. 4 indicate the respective transistors Q1 to Q12 in FIG. 3. The hatched portions indicate the on state of the transistors, and the unshaded portions indicate the off states of the transistors.
[0038]
Hereinafter, the operation of the control device 11a will be described with reference to FIG. In the control step of mode 1 in FIG. 4, the transistors Q1, Q5, Q7, and Q11 are controlled to be in an on state and the other transistors are controlled to be in an off state. At this time, in the block diagram of FIG. 3, the drive signal flows in the order of the transistor Q1, the coil Ua, the coil Wa, the transistor Q5, the coil Wb, the coil Ub, the transistor Q7, the coil Uc, the coil Wc, and the transistor Q11.
[0039]
In the control step of mode 2 in FIG. 4, the transistors Q1, Q6, Q7 and Q12 are controlled to be in an on state and the other transistors are controlled to be in an off state. At this time, in the block diagram of FIG. 3, the drive signal flows in the order of the transistor Q1, the coil Ua, the coil Wa, the transistor Q6, the coil Vb, the coil Ub, the transistor Q7, the coil Uc, the coil Vc, and the transistor Q12.
[0040]
In the control step of mode 3 in FIG. 4, the transistors Q2, Q6, Q8, and Q12 are turned on and the other transistors are turned off. At this time, in the block diagram of FIG. 3, the drive signal flows in the order of the transistor Q2, the coil Wa, the coil Va, the transistor Q6, the coil Vb, the coil Wb, the transistor Q8, the coil Wc, the coil Vc, and the transistor Q12. In the control step of mode 4 in FIG. 4, the transistors Q2, Q4, Q8, and Q10 are controlled to be on and the other transistors are controlled to be off. At this time, in the block diagram of FIG. 3, the drive signal flows in the order of the transistor Q2, the coil Wa, the coil Ua, the transistor Q4, the coil Ub, the coil Wb, the transistor Q8, the coil Wc, the coil Uc, and the transistor Q10.
[0041]
In this manner, in the control example shown in FIG. 4, the motors 12a, 12b, and 12c are rotated at the same speed in FIG.
[0042]
Thus, as in the present embodiment, when the motors 12a, 12b, 12c are three-phase, the supply switching means and the inflow for each of the three motors 12a, 12b, 12c, as can be easily understood from the prior art. When using switching means, as can be seen from FIG.
2 stages x 3 phases x 3 units = 18 (5)
In contrast, in this embodiment,
3 phases x (3 + 1) units = 12 pieces (6)
become. As a result, the number of transistors required to control the motors 12a, 12b, 12c is
12/18 = 2/3 (7)
Thus, the cost can be significantly reduced as compared with the case of the prior art, and the cost can be reduced.
[0043]
In this embodiment, the circuit configuration necessary for controlling the rotational speeds of the motors 12a, 12b, and 12c is as described above. The rotational speed detecting element 13, the frequency / voltage conversion circuit 14, the comparison circuit 15, and the speed command unit. 16, a single control device 11a including a PWM control circuit 17 and an inverter circuit 18a controls a plurality of motors 12a, 12b, 12c in common. Therefore, as in the prior art, the necessity of providing the configuration such as the rotational speed detecting element 13 for each motor 12a, 12b, 12c is eliminated, and the configuration of the control device 11a can be greatly simplified and the cost can be reduced. it can.
[0044]
In addition, since the configuration of the control device 11a can be simplified, circuit elements that require adjustment of gain and the like can be reduced, and the single control device 11a can control the rotational speed of the plurality of motors 12a, 12b, and 12c. Is performed in common over the motors 12a, 12b, and therefore malfunctions such as loss of synchronization of operation of the motors 12a, 12b, 12c due to a gain setting deviation in the control device for each of the motors 12a, 12b, 12c. The situation that occurs is prevented.
[0045]
Further, regarding the reduction in the number of transistors in the inverter circuit 18a, generally speaking, when the motor 12 is in m phase, when power transistors are used as supply switching means and inflow switching means for each motor 12 as in the prior art. However, in the present embodiment, the number of power transistors is m (n + 1). Thereby, the number of power transistors is
{M (n + 1) / 2mn}
= (N + 1) / 2n
= 1/2 + 1 / 2n (8)
Thus, the cost can be significantly reduced and the cost can be reduced. In addition, this effect can be reduced to half that of the prior art as the number of motors to be controlled increases, and the operational effect increases when a large-scale motor group is controlled.
[0046]
In each of the above embodiments, a three-phase motor has been described. However, the present invention does not limit the type of motor or the number of phases thereof, and the above-described eighth equation is established for a motor having an arbitrary number of phases.
[0047]
The present invention is not limited to the above-described embodiments, and has a wide variety of modifications without departing from the spirit of the present invention.
[0048]
【The invention's effect】
  As described above, the motor control device according to claim 1 includes a plurality of motor control devices.nof3 phaseWhen controlling the motor,The inverter circuit is formed by connecting in parallel three series circuits in which (n + 1) switching means are connected in series in (n + 1) stages, and the k-th switching means and (k + 1) stages arranged in parallel. Three connection points with the eye switching means (where k is an integer from 1 to n) are respectively connected to different phases of one of the three three-phase motors.
[0049]
In other words, assuming that another motor is connected to the subsequent stage of one motor, the drive signal supplied from the supply switching means to one motor passes through the coil in the motor and flows into the one motor. Flows into the switching means. On the other hand, the same switching means is used as the inflow switching means corresponding to the one motor and the supply switching means of the other motor adjacent to the one motor in the electrical connection order. Accordingly, the inflow switching means of the one motor becomes the supply switching means of the other motor.
[0050]
In this way, when the motor is in m phase, the number of switching means is 2 mn when the supply switching means and the inflow switching means are used for each motor, whereas in the present invention, m (n + 1) ) Become a piece. As a result, the number of switching means becomes {m (n + 1) / 2mn} = (n + 1) / 2n, which can be significantly reduced and the cost can be reduced.
[0051]
  3. The motor control device according to claim 2, wherein the rotation speed of the motor matches a predetermined reference rotation speed.Inverter circuitofSaidSwitching meansofThe control unit that controls the switching operation,Inverter circuitofSaidSwitching meansTheControl is common to each motor.
[0052]
Accordingly, it is possible to eliminate the necessity of providing each motor with a circuit configuration necessary for controlling the rotational speed of the motor, and to greatly simplify the configuration of the motor control device, thereby reducing costs. In addition, since the configuration of the control device can be simplified, the number of circuit elements that need to be adjusted, such as gain, can be reduced, and a single control device can share the rotational speed control of multiple motors across each motor. Therefore, it is possible to prevent a malfunction such as a loss of synchronization of operation of each motor due to a gain setting deviation in the control device for each motor.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an electrical configuration of a control device 11 according to a first embodiment of the present invention.
FIG. 2 is a diagram for explaining the operation of this embodiment.
FIG. 3 is a block diagram illustrating an electrical configuration of a control device 11a according to a second embodiment.
FIG. 4 is a diagram for explaining the operation of this embodiment.
FIG. 5 is a block diagram showing an electrical configuration of a control device 1 according to the prior art.
[Explanation of symbols]
11, 11a Control device
12, 12a, 12b, 12c Motor
13a, 13b, 13c Rotational speed detection element
14 Frequency / voltage conversion circuit
15 Comparison circuit
16 Speed command unit
17 PWM control circuit
18, 18a Inverter circuit
Ua, Va, Wa, Ub, Vb, Wb, Uc, Vc, Wc Coil
Q1, Q2, Q3 First stage transistor
Q4, Q5, Q6 Second stage transistor
Q7, Q8, Q9 Third stage transistor
Q10, Q11, Q12 Fourth stage transistor

Claims (2)

N number of 3-phase motor for generating a rotating magnetic field (where, n is an integer of 2 or more) and a control device including an inverter circuit including a switching means for supplying a drive signal to the coil of
The inverter circuit is formed by connecting, in parallel, three series circuits formed by connecting (n + 1) stages of the switching means in series of (n + 1) stages, and k-stage switching means arranged in parallel with (k + 1). ) Three connection points with the switching means of the stage (where k is an integer from 1 to n) are respectively connected to different phases of one of the three-phase motors, and n A motor control device that controls a three-phase motor. Rotational speed of the motor, the control unit for controlling the switching operation of said switching means of said inverter circuit to match the reference rotational speed is predetermined, over the switching means of the inverter circuit to each motor The motor control device according to claim 1, which is commonly controlled.

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