Control device for wound-rotor induction motor and method thereof, and wound-rotor induction motor system

Abstract

To provide wound induction motor control device and method, and a wound induction motor system that can automatically change a secondary resistance value.SOLUTION: A wound induction motor control device according to the present invention includes a secondary resistance unit RU that is connected to a secondary winding of a wound induction motor IM and has a variable resistance value, a pattern generation unit 12 that generates a plurality of different time-series resistance value patterns in the secondary resistance unit RU, a prediction unit 13 that predicts, for each of the plurality of time-series resistance value patterns, the value of a predetermined physical quantity related to the control purpose of the motor IM as a predicted value when the resistance value of the secondary resistance unit RU is changed in the time-series resistance value pattern, a pattern selection unit 14 that selects, from the plurality of time-series resistance value patterns, a time-series resistance value pattern corresponding to the predicted value with the highest evaluation among the predicted values of the motor IM, and a secondary resistance control unit 15 that controls the secondary resistance unit RU on the basis of this selected time-series resistance value pattern.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wound-type induction motor control device and a control method for a wound-type induction motor that controls a wound-type induction motor having a primary winding and a secondary winding, and to a wound-type induction motor system that includes the wound-type induction motor control device. [Background technology]

[0002] Induction motors are broadly classified into wound-rotor induction motors and squirrel-cage induction motors. Wound-rotor induction motors can control torque and rotation speed by controlling the secondary resistance, and are therefore used in equipment that requires a relatively large capacity, such as pumps, trains, and cranes. For example, Patent Document 1 describes this secondary resistance control.

[0003] Patent document 1 discloses a system including a wound-type induction motor, a speed detector, a diode rectifier, a secondary resistor, and a secondary switching control circuit which connects the secondary winding of the wound-type induction motor to the diode rectifier via a conductor when the rotational speed of the wound-type induction motor detected by the speed detector is 50% to 70% or more of the rated rotational speed, and connects the secondary winding of the wound-type induction motor to the secondary resistor via another conductor when the rotational speed of the wound-type induction motor detected by the speed detector is less than this value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-229725 A Summary of the Invention [Problem to be solved by the invention]

[0005] 1 to 3 of the secondary resistor in the above-mentioned Patent Document 1, the resistance value of which can be changed is shown to be variable, but the method of changing the resistance value is not disclosed. In general, the resistance value of the secondary resistor is changed manually, for example, to obtain a desired rotation speed.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a control device for a wound-rotor induction motor and a control method for a wound-rotor induction motor that can automatically change the secondary resistance value, and a wound-rotor induction motor system equipped with the wound-rotor induction motor control device. [Means for solving the problem]

[0007] As a result of various investigations, the inventors have found that the above object can be achieved by the present invention described below. That is, a control device for a wound-type induction motor according to one aspect of the present invention is a device for controlling a wound-type induction motor having a primary winding and a secondary winding, comprising: a secondary resistance section connected to the secondary winding and having a variable resistance value, a pattern generation section for generating a plurality of time-series resistance value patterns for the secondary resistance section such that the resistance values ​​are different from one another, a prediction section for predicting, for each of the plurality of time-series resistance value patterns generated by the pattern generation section, a value of a predetermined physical quantity related to a control objective of the wound-type induction motor when the resistance value of the secondary resistance section is changed in the time-series resistance value pattern, a pattern selection section for selecting, from the plurality of time-series resistance value patterns generated by the pattern generation section, a time-series resistance value pattern corresponding to a predicted value having the highest evaluation among the predicted values ​​of the wound-type induction motor predicted by the prediction section, and a secondary resistance control section for controlling the secondary resistance section based on the time-series resistance value pattern selected by the pattern selection section.

[0008] Such a controller for a wound-rotor induction motor can determine the resistance value of the secondary resistance section by predictive control, and therefore can automatically change the secondary resistance value.

[0009] In another aspect, in the above-mentioned control device for a wound-rotor induction motor, the secondary resistance section includes at least one resistance element unit including a resistance element and a change-over switch for switching whether or not the resistance element is connected to the secondary winding. Preferably, in the above-mentioned control device for a wound-rotor induction motor, the secondary resistance section includes a plurality of resistance element units connected in cascade.

[0010] Such a control device for a wound-rotor induction motor can increase the number of resistance value patterns by the simple method of increasing the number of resistance element units in cascade connection. By increasing the number of resistance element units, the predetermined physical quantity related to the control purpose of the wound-rotor induction motor can be set finely (set with high resolution), and the wound-rotor induction motor can be controlled finely (with high resolution).

[0011] In another aspect, in the above-mentioned control device for a wound-rotor induction motor, the predetermined physical quantity related to the control objective of the wound-rotor induction motor is a rotation speed.

[0012] This makes it possible to provide a control device for a wound-rotor induction motor capable of controlling the rotation speed.

[0013] In another aspect, in the above-mentioned control device for a wound-rotor induction motor, the predetermined physical quantity related to the control objective of the wound-rotor induction motor is torque.

[0014] This makes it possible to provide a control device for a wound-rotor induction motor capable of controlling torque.

[0015] In another aspect, in the above-described control device for a wound-rotor induction motor, the pattern selection unit selects the most highly evaluated predicted value by using an evaluation value based on the deviation between a control target value and the predicted value.

[0016] Such a control device for a wound-rotor induction motor evaluates a predicted value using an evaluation value based on the deviation between a control target value and a predicted value, so that a predicted value with high trackability to the control target value can be selected.

[0017] In another aspect, in the above-mentioned control device for a wound-rotor induction motor, when the pattern generation unit generates the multiple time-series resistance value patterns, the pattern generation unit selects the later resistance value of two resistance values ​​that are arranged one behind the other in the time series from among the previous resistance value, a resistance value that is one greater than the previous resistance value, and a resistance value that is one less than the previous resistance value when the multiple resistance values ​​that can be variably generated in the secondary resistance unit are arranged in order of magnitude.

[0018] Such a control device for a wound-rotor induction motor controls the secondary resistance section so that the resistance values ​​are shifted by one from each other from the two resistance values ​​that are arranged one after the other in time series, thereby controlling the wound-rotor induction motor to operate smoothly.

[0019] A control method for a wound-type induction motor according to another embodiment of the present invention is a method for controlling a wound-type induction motor having a primary winding and a secondary winding connected to a secondary resistance section having a variable resistance value, the method comprising: a pattern generation step of generating a plurality of time-series resistance value patterns for the secondary resistance section, the time-series resistance value patterns being different from one another; a prediction step of predicting, for each of the plurality of time-series resistance value patterns generated in the pattern generation step, the value of a predetermined physical quantity related to a control purpose of the wound-type induction motor when the resistance value of the secondary resistance section is changed in the time-series resistance value pattern; a pattern selection step of selecting, from the plurality of time-series resistance value patterns generated in the pattern generation step, a time-series resistance value pattern corresponding to the most highly evaluated predicted value among the predicted values ​​of the wound-type induction motor predicted in the prediction step; and a secondary resistance control step of controlling the secondary resistance section based on the time-series resistance value pattern selected in the pattern selection step.

[0020] Such a control method for a wound-rotor induction motor can determine the resistance value of the secondary resistance section by predictive control, and therefore can automatically change the secondary resistance value.

[0021] A wound-type induction motor system according to another aspect of the present invention comprises a wound-type induction motor having a primary winding and a secondary winding, and a wound-type induction motor control unit that controls the wound-type induction motor, the wound-type induction motor control unit being any one of the above-mentioned wound-type induction motor control devices.

[0022] According to this, it is possible to provide a wound-rotor induction motor system including any one of the above-mentioned controllers for a wound-rotor induction motor. Since the above-mentioned wound-rotor induction motor system includes any one of the above-mentioned controllers for a wound-rotor induction motor, the resistance value of the secondary resistance section can be determined by predictive control, and therefore the secondary resistance value can be automatically changed. Effect of the Invention

[0023] The control device for a wound-rotor induction motor and the control method for a wound-rotor induction motor according to the present invention can automatically change the secondary resistance value. According to the present invention, it is possible to provide a wound-rotor induction motor system including the control device for a wound-rotor induction motor. [Brief description of the drawings]

[0024] [Figure 1] 1 is a diagram showing a configuration of a wound-rotor induction motor system according to an embodiment; [Diagram 2] 4 is a diagram for explaining an example of a time-series resistance value pattern that can be realized in a secondary resistance unit of the wound-rotor induction motor system. FIG. [Diagram 3] 4 is a flowchart showing an operation of the wound-type induction motor system. [Figure 4] 13 is a diagram for explaining an example of a time-series resistance value pattern when a constraint is imposed. FIG. [Diagram 5] FIG. 13 is a diagram showing a simulation result in the case of no load. [Figure 6] FIG. 13 is a diagram showing a simulation result when a load torque is applied. [Figure 7] FIG. 2 is a diagram showing a schematic configuration of the wound-type induction motor system when applied to a trolley truck. [Figure 8] FIG. 8 is a diagram showing a simulation result when the wound-type induction motor system shown in FIG. 7 is applied to a trolley cart. [Figure 9] FIG. 13 is a diagram showing a simulation result of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Hereinafter, one or more embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the disclosed embodiments. In addition, configurations with the same reference numerals in each drawing indicate that they are the same configurations, and their description will be omitted as appropriate. In this specification, when referring to a general term, a reference numeral without a subscript is used, and when referring to an individual configuration, a reference numeral with a subscript is used.

[0026] A wound-type induction motor system according to an embodiment includes a wound-type induction motor having a primary winding and a secondary winding, and a wound-type induction motor control unit that controls the wound-type induction motor. The wound-type induction motor control unit includes a secondary resistance unit connected to the secondary winding and having a variable resistance value, a pattern generation unit that generates a plurality of different time-series resistance value patterns for the secondary resistance unit, a prediction unit that predicts, for each of the plurality of time-series resistance value patterns generated by the pattern generation unit, a value of a predetermined physical quantity related to a control purpose of the wound-type induction motor when the resistance value of the secondary resistance unit is changed in the time-series resistance value pattern, as a predicted value, a pattern selection unit that selects, from the plurality of time-series resistance value patterns generated by the pattern generation unit, a time-series resistance value pattern corresponding to a predicted value having the highest evaluation among the predicted values ​​of the wound-type induction motor predicted by the prediction unit, and a secondary resistance control unit that controls the secondary resistance unit based on the time-series resistance value pattern selected by the pattern selection unit. A wound-rotor induction motor system including such a control unit for a wound-rotor induction motor will be described in more detail below.

[0027] Fig. 1 is a diagram showing the configuration of a wound-rotor induction motor system in an embodiment. Fig. 1A shows the whole system, and Fig. 1B is a block diagram showing the configuration of an MPC control unit. Fig. 2 is a diagram for explaining an example of a time-series resistance value pattern that can be realized by a secondary resistance unit of the wound-rotor induction motor system.

[0028] 1A, the wound-type induction motor system SM in the embodiment includes a wound-type induction motor IM having a primary winding and a secondary winding, a predictive control control unit (MPC control unit) CL, and a secondary resistance unit RU. In the present embodiment, as will be understood later, the secondary resistance unit RU and the MPC control unit CL correspond to a wound-type induction motor control unit that controls the wound-type induction motor, that is, an example of a linear induction motor control device.

[0029] A wound-rotor induction motor IM is supplied with three-phase AC power from a power source (not shown), and a secondary resistance unit RU is connected to the secondary winding.

[0030] The secondary resistance unit RU is a resistor having a variable resistance value. The secondary resistance unit RU is connected to the MPC control unit CL, and changes its resistance value according to the control of the MPC control unit CL. The secondary resistance unit RU may be a variable resistor of a slider type or a rotary type, etc., in which the slider position, rotation position, etc. can be electrically controlled. For example, in this embodiment, the secondary resistance unit RU includes at least one resistance element unit UT including a resistance element R and a changeover switch S for switching whether or not the resistance element R is connected to the secondary winding, and changes the resistance value in a stepped manner (discretely changes the resistance value). In the example shown in FIG. 1A, the secondary resistance unit RU includes four resistance element units UT, namely, first to fourth resistance element units UT. 1 ~UT 4 The resistance value R of the secondary winding in the wound-type induction motor IM is rm Including the above, the resistance value of the secondary side (secondary circuit, secondary winding side) can be changed in five steps, as shown in the following table 1.

[0031] More specifically, the fourth resistor element unit UT 4 is the resistance element R of the first phase 4and the second phase resistor R 4 and the third phase resistor R 4 and switch S which turns on and off the connection between the first and second phases. 4 and switch S which turns on and off the connection between the second and third phases. 4 and switch S which turns on and off the connection between the 3rd phase and the 1st phase. 4 and connected to the secondary winding. 3 is the resistance element R of the first phase 3 and the second phase resistor R 3 and the third phase resistor R 3 and switch S which turns on and off the connection between the first and second phases. 3 and switch S which turns on and off the connection between the second and third phases. 3 and switch S which turns on and off the connection between the 3rd phase and the 1st phase. 3 and a fourth resistor element unit UT 4 Similarly, the second resistor element unit UT 2 is the resistance element R of the first phase 2 and the second phase resistor R 2 and the third phase resistor R 2 and switch S which turns on and off the connection between the first and second phases. 2 and switch S which turns on and off the connection between the second and third phases. 2 and switch S which turns on and off the connection between the 3rd phase and the 1st phase. 2 and a third resistor element unit UT 3 The first resistor element unit UT 1 is the resistance element R of the first phase 1 and the second phase resistor R 1 and the third phase resistor R 1 and switch S which turns on and off the connection between the first and second phases. 1 and switch S which turns on and off the connection between the second and third phases. 1 and switch S which turns on and off the connection between the 3rd phase and the 1st phase. 1 The first, second and third phases are connected to each other. In other words, the first phase line is connected to the fourth resistor unit UT 4 The first phase resistance element R 4, the third resistor element unit UT 3 The first phase resistance element R 3 , second resistor element unit UT 2 The first phase resistance element R 2 and the first resistor element unit UT 1 The first phase resistance element R 1 are connected in series in this order, and the second phase line is connected to the fourth resistor element unit UT 4 The second phase resistance element R 4 , the third resistor element unit UT 3 The second phase resistance element R 3 , second resistor element unit UT 2 The second phase resistance element R 2 and the first resistor element unit UT 1 The second phase resistance element R 1 are connected in series in this order, and the third phase line is connected to the fourth resistor element unit UT 4 The third phase resistor R 4 , the third resistor element unit UT 3 The third phase resistor R 3 , second resistor element unit UT 2 The third phase resistor R 2 and the first resistor element unit UT 1 The third phase resistor R 1 are connected in series in this order, and the resistance element R 1 , R 1 , R 1 are connected to each other. The secondary winding and the fourth resistor element unit UT 4 The resistance element R of each phase 4 , R 4 , R 4 Between them, the fourth resistor element unit UT 4 Each switch S 4 , S 4 , S 4 is arranged, and the fourth resistor element unit UT 4 The resistance element R of each phase 4 , R 4 , R 4 and the third resistor element unit UT 3The resistance element R of each phase 3 , R 3 , R 3 The third resistor element unit UT 3 Each switch S 3 , S 3 , S 3 is arranged, and the third resistor element unit UT 3 The resistance element R of each phase 3 , R 3 , R 3 and the second resistor unit UT 2 The resistance element R of each phase 2 , R 2 , R 2 Between them, the second resistor element unit UT 2 Each switch S 2 , S 2 , S 2 is arranged, and the second resistor element unit UT 2 The resistance element R of each phase 2 , R 2 , R 2 and the first resistor element unit UT 1 The resistance element R of each phase 1 , R 1 , R 1 Between the first resistor element unit UT 1 Each switch S 1 , S 1 , S 1 Each of these switches S 4 , S 4 , S 4 , S 3 , S 3 , S 3 , S 2 , S 2 , S 2 , S 1 , S 1 , S 1 are connected to the MPC control unit CL, and their on / off is controlled by the MPC control unit CL. 4 , S 4 , S 4 , S 3 , S 3 , S 3 , S 2 , S 2 , S2 , S 1 , S 1 , S 1 Each of the resistors 111 and 112 includes a power switching element such as an insulated gate bipolar transistor (IGBT). For convenience of explanation, the reference symbol R of a resistor element also indicates its resistance value.

[0032] In the secondary resistor unit RU having such a configuration, when changing to the first resistance value, the number of notches n is set to 1, and all the switches S 4 , S 4 , S 4 , S 3 , S 3 , S 3 , S 2 , S 2 , S 2 , S 1 , S 1 , S 1 is controlled to be OFF, and this first resistance R r 1 As shown in Table 1, rm +R 4 +R 3 +R 2 +R 1 (R r 1 =R rm +R 4 +R 3 +R 2 +R 1 When changing to the second resistance value, the number of notches n is set to 2, and as shown in Table 2, the first resistance element unit TU 1 Each switch S 1 , S 1 , S 1 Only the switch S is controlled to be on (ON), and the remaining switches S 3 , S 3 , S 3 , S 2 , S 2 , S 2 , S 1 , S 1 , S 1 is controlled to be off, and this second resistance R r 2As shown in Table 1, R rm +R 4 +R 3 +R 2 (R r 2 =R rm +R 4 +R 3 +R 2 ) In the case of changing to the third resistance value, the number of notches is n=3, and as shown in Table 2, the first and second resistance element units TU 1 , T.U. 2 Each switch S 1 , S 1 , S 1 , S 2 , S 2 , S 2 is controlled to be on, and the remaining switches S 4 , S 4 , S 4 , S 3 , S 3 , S 3 is controlled to be off, and this third resistor R r 3 As shown in Table 1, R rm +R 4 +R 3 (R r 3 =R rm +R 4 +R 3 In the case of changing to the fourth resistance value, the number of notches n is set to 4, and the first to third resistance element units TU 1 , T.U. 2 , T.U. 3 Each switch S 1 , S 1 , S 1 , S 2 , S 2 , S 2 , S 2 , S 2 , S 2 is controlled to be on, and the remaining switches S 4 , S 4 , S 4 Only the fourth resistor R r 4 As shown in Table 1, R rm +R4 (R r 4 =R rm +R 4 ) In the case of changing to the fifth resistance value, the number of notches is n=5, and as shown in Table 2, all the switches S 4 , S 4 , S 4 , S 3 , S 3 , S 3 , S 2 , S 2 , S 2 , S 1 , S 1 , S 1 is turned on, and this fifth resistor R r 5 As shown in Table 1, rm (R r 5 =R rm , i.e., the resistance value of the secondary resistor unit RU is 0).

[0033] In addition, when increasing the number of resistance values ​​of the secondary resistor portion RU in the example shown in FIG. 1A, the number of resistance element units UT corresponding to the number of resistance values ​​to be increased is 1 In other words, in this embodiment, the resistance value R of the secondary winding in the wound-type induction motor IM is set as one of the resistance values ​​on the secondary side. rm Since the number of resistance values ​​on the secondary side is α (including the resistance value 0 of the secondary resistance unit RU), the secondary resistance unit RU can be constructed by sequentially cascading first resistance element units TU whose number is α minus 1 (α-1).

[0034] [Table 1]

[0035] [Table 2]

[0036] The MPC control unit CL is a device for controlling the wound-rotor induction motor IM by predictive control by controlling the resistance value of the secondary resistance unit RU. The MPC control unit CL is configured, for example, by a microcomputer equipped with a CPU (Central Processing Unit), a memory and its peripheral circuits. The MPC control unit CL is functionally configured with a control unit 11, a pattern generation unit 12, a prediction unit 13, a pattern selection unit 14 and a secondary resistance control unit 15 by executing a predetermined program.

[0037] The control unit 11 controls each part of the wound-rotor induction motor system SM in accordance with the function of each part, and is responsible for controlling the entire wound-rotor induction motor system SM.

[0038] The pattern generating unit 12 generates a plurality of time-series resistance value patterns in the secondary resistor unit RU, each of which is different from the others. That is, the pattern generating unit 12 executes a pattern generating process for generating a plurality of time-series resistance value patterns in the secondary resistor unit RU, each of which is different from the others. In this embodiment, the secondary resistor unit RU has five resistance values ​​R r i(i=1, 2, 3, 4, 5). The time-series voltage pattern is determined by a prediction horizon, which is the number of control periods to be predicted, and a control horizon, which is the number of control periods in which the resistance value, which is the control input, is variable. For this reason, the MPC control unit CL is preset with appropriate values ​​of the prediction horizon and the control horizon according to the specifications of the wound-rotor induction motor system S, and the pattern generation unit 12 generates a plurality of time-series voltage patterns that differ from each other according to the resistance value (five in the above example) that can be varied by the secondary resistance unit RU, the prediction horizon value, and the control horizon value. In FIG. 2, as an example, all time-series resistance value patterns that can be realized by the secondary resistance unit RU when the prediction horizon is 2 and the control horizon is 1 are illustrated in a tree diagram. In FIG. 2, since the prediction horizon is 2 for the resistance value in the k-th control of the current (Current), the resistance value in the next (k+1)-th control and the resistance value in the next (k+2)-th control are predicted. Since the control horizon is 1, all time-series voltage patterns that can be realized by the secondary resistance unit RU are predicted from the resistance value in the current k-th control to the resistance value in the next (k+1)-th control, which are the first to fifth resistance values ​​R r 1 ~R r 5 Then, in the next (k+2)th control, each resistance value R r 1 ~R r 5 From the above, the corresponding resistance value R r 1 ~R r 5 As another example, when the prediction horizon is 2 and the control horizon is 2, the resistance value in the next (k+1)th control and the resistance value in the further next (k+2)th control are predicted for the resistance value in the current kth control because the prediction horizon is 2. Since the control horizon is 2, all the time-series resistance value patterns that can be realized by the secondary resistance unit RU are the first to fifth resistance values ​​R in the (k+1)th control and the (k+2)th control, respectively. r 1 ~Rr 5 It branches into 25 (=5 × 5) sets of time-series resistance value patterns.

[0039] The prediction unit 13 predicts, for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12, the value of a predetermined physical quantity related to the control objective of the wound-type induction motor IM when the resistance value of the secondary resistance unit RU is changed in the time-series resistance value pattern. That is, the prediction unit 13 performs a prediction process to predict, for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12, the value of a predetermined physical quantity related to the control objective of the wound-type induction motor IM when the resistance value of the secondary resistance unit RU is changed in the time-series resistance value pattern. More specifically, in this embodiment, the predetermined physical quantity related to the control objective of the wound-type induction motor IM is the rotation speed, and therefore, for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12, the prediction unit 13 calculates the output torque T e The rotation speed ω is calculated by the following equation 2. m n represents the number of notches, and therefore the output torque T e n (k+1) is the output torque T at the notch step number n in the (k+1)th control, and the rotation speed ω m n (k+1) is the rotation speed ω at the notch step number n in the (k+1)th control.

[0040]

number

[0041]

number

[0042] T in Equation 2 l is the load torque, and is, for example, an estimated value estimated by the following equation 3.

[0043]

number

[0044] In the above example, in the current k-th control, the first to fifth resistance values ​​R that can be realized by the secondary resistor unit RU are r 1 ~R r 5 The prediction unit 13 predicts five sets of [T ei (k+1), T e i (k+2)] and [ω m i (k+1), ω m i (k+2)] is calculated as each predicted value (i=1, 2, 3, 4, 5).

[0045] The pattern selection unit 14 selects, from among the multiple time-series resistance value patterns generated by the pattern generation unit 12, a time-series resistance value pattern corresponding to the most highly evaluated predicted value among the predicted values ​​of the wound-rotor induction motor IM predicted by the prediction unit 13. That is, the pattern selection unit 14 performs a pattern selection process of selecting, from among the multiple time-series resistance value patterns generated by the pattern generation unit 12, a time-series resistance value pattern corresponding to the most highly evaluated predicted value among the predicted values ​​of the wound-rotor induction motor IM predicted by the prediction unit 13. The pattern selection unit 14 selects the most highly evaluated predicted value by using an evaluation value based on the deviation between a control target value and the predicted value. More specifically, for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12, since the predetermined physical quantity related to the control objective of the wound-rotor induction motor IM is the rotation speed in the above example, the pattern selection unit 14 selects the most highly evaluated predicted value [ω m i (k+1), ω m i (k+2)], for example, by the evaluation formula g n By using the time-series resistance value patterns, the time-series resistance value patterns are quantitatively evaluated, and the most highly evaluated predicted value of the rotation speed [ω m i (k+1), ω m i (k+2)]. In this formula 4, the smaller the value, the higher the evaluation.

[0046]

number

[0047] The secondary resistance control unit 15 controls the secondary resistance unit RU based on the time-series resistance value pattern selected by the pattern selection unit 14. That is, the secondary resistance control unit 15 performs a secondary resistance control process to control the secondary resistance unit RU based on the time-series resistance value pattern selected by the pattern selection unit 14. More specifically, in this embodiment, when the kth control is currently being performed, the secondary resistance control unit 15 calculates the resistance value R r i So, each switch S 4 , S 4 , S 4 , S 3 , S 3 , S 3 , S 2 , S 2 , S 2 , S 1 , S 1 , S 1 The control signal for switching the on / off state is output to the

[0048] Then, the control unit 11 causes the pattern generation unit 12, the prediction unit 13, the pattern selection unit 14 and the secondary resistance control unit 15 to repeatedly perform the pattern generation process, the prediction process, the pattern selection process and the secondary resistance control process at a predetermined control period.

[0049] Next, the operation of this embodiment will be described with reference to a flow chart shown in Fig. 3, which illustrates the operation of the wound-type induction motor system.

[0050] When the power is turned on in such a wound-rotor induction motor system SM, the necessary initialization of each unit is performed and the unit starts to operate. Then, for example, by executing a program, the CPU is functionally configured with a control unit 11, a pattern generating unit 12, a predicting unit 13, a pattern selecting unit 14, and a secondary resistance control unit 15.

[0051] Then, each of steps S11 to S15 shown in FIG. 3 is repeatedly executed by the control unit 11 at predetermined control intervals until the driving of the wound-rotor induction motor IM is stopped.

[0052] In FIG. 3, first, in this (k-th) case, the MPC control unit CL detects the rotation speed ω m (k) is obtained (S11).

[0053] Next, the MPC control unit CL generates a plurality of different time-series resistance value patterns for the secondary resistance unit RU by the pattern generating unit 12 (S12, pattern generating process). In this embodiment, a plurality of time-series resistance value patterns are generated according to a preset prediction horizon value and a control horizon value.

[0054] Next, the MPC control unit CL predicts, by the prediction unit 13, the value of a predetermined physical quantity related to the control objective of the wound-type induction motor IM when the resistance value of the secondary resistance unit RU is changed in each of the multiple time-series resistance value patterns generated by the pattern generation unit 12 in the process S12, as a predicted value (S13, prediction process). In this embodiment, the predetermined physical quantity is the rotation speed, and for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12 in the process S12, the output torque T e is obtained, and the rotation speed ω m is required.

[0055] Next, the MPC control unit CL selects, by the pattern selection unit 14, from among the multiple time-series resistance value patterns generated by the pattern generation unit 12 in process S12, a time-series resistance value pattern corresponding to the most highly evaluated predicted value of the wound-rotor induction motor IM predicted by the prediction unit 13 in process S13 (S14, pattern selection process). In this embodiment, for each of the multiple time-series resistance value patterns generated by the pattern generation unit 12 in process S12, its evaluation value is calculated by Equation 4, and the time-series resistance value pattern giving the smallest evaluation value is selected.

[0056] Then, the MPC control unit CL controls the secondary resistance unit RU by the secondary resistance control unit 15 based on the time-series resistance value pattern selected by the pattern selection unit 14 in process S14, and ends this process at the current control timing (S15, secondary resistance control process). In this embodiment, the resistance value R r i The secondary resistor unit RU is controlled so that

[0057] In this way, the wound-rotor induction motor IM rotates at the target speed ω m * The control is performed and driven by predictive control so that

[0058] As described above, the control device for a wound-rotor induction motor in the embodiment (secondary resistance unit RU and MPC control unit CL) and the control method for a wound-rotor induction motor implemented therein, and the wound-rotor induction motor system SM can determine the resistance value of the secondary resistance unit RU by predictive control, and therefore can automatically change the secondary resistance value.

[0059] The above-mentioned control device for a wound-rotor induction motor, control method for a wound-rotor induction motor, and wound-rotor induction motor system SM can increase the resistance value patterns by the simple method of increasing the number of resistance element units UT in cascade connection. By increasing the number of resistance element units UT, the predetermined physical quantity related to the control purpose of the wound-rotor induction motor IM (the rotation speed in the above example) can be set finely (set with high resolution), so that the wound-rotor induction motor IM can be controlled finely (with high resolution).

[0060] The above-mentioned wound-rotor induction motor control device, wound-rotor induction motor control method, and wound-rotor induction motor system SM evaluate a predicted value using an evaluation value based on the deviation between a control target value and a predicted value, and therefore can select a predicted value that has high tracking ability to the control target value.

[0061] According to this embodiment, a control device for a wound-rotor induction motor capable of controlling the rotational speed, a control method for a wound-rotor induction motor, and a wound-rotor induction motor system SM can be provided, and a wound-rotor induction motor system SM equipped with the wound-rotor induction motor control device can be provided.

[0062] In the above embodiment, the pattern selection unit 14 can select any one of the multiple time-series resistance value patterns as long as it has the highest evaluation value. However, the options may be restricted. More specifically, the options are restricted by, for example, restricting the options when generating the multiple time-series resistance value patterns. For example, when generating the multiple time-series resistance value patterns, the pattern generation unit 12 selects the latter resistance value of two resistance values ​​that are arranged in chronological order from the previous resistance value, a resistance value that is one value larger than the previous resistance value, and a resistance value that is one value smaller than the previous resistance value when the multiple resistance values ​​that can be variably generated in the secondary resistance unit RU are arranged in order of magnitude. Such a control device for a wound-type induction motor, a control method for a wound-type induction motor, and a wound-type induction motor system SM control the secondary resistance unit RU so that the resistance values ​​are shifted by one value from the two adjacent resistance values, and therefore the wound-type induction motor IM can be controlled to drive smoothly.

[0063] Fig. 4 is a diagram for explaining an example of a time-series resistance value pattern when a constraint is set. For example, the five sets of time-series resistance value patterns shown in Fig. 2 become three sets of time-series resistance value patterns shown in Fig. 4, and the pattern selection unit 14 selects the resistance value pattern that gives the highest evaluation value from these three sets of time-series resistance value patterns.

[0064] Simulation results for this modified embodiment are shown in Figs. 5 and 6, respectively. Fig. 5 is a diagram showing simulation results in the case of no load. Fig. 6 is a diagram showing simulation results in the case of applying a load torque. Figs. 5A and 6A respectively show the time change in rotation speed, and Figs. 5B and 6B show the time change in the number of notch stages at that time. The horizontal axis of each of Figs. 5A and 6A is the elapsed time from the start of starting (start of speed control), and each of these vertical axes is the rotation speed. The horizontal axis of each of Figs. 5B and 6B is the elapsed time from the start of starting, and each of these vertical axes is the number of notch stages.

[0065] From FIG. 5A, it can be seen that when speed control with acceleration is performed without load, the target speed can be followed without delay or large deviation. From FIG. 5B, it can be seen that the speed control can be performed by changing the notch step number by one at this time. On the other hand, FIG. 6 shows the simulation result when a load torque is applied while driving a wound-type induction motor at a constant speed, and from FIG. 6A, it can be seen that the target speed can be followed as in the case of FIG. 5A. Even in this case, it can be seen from FIG. 6B that the speed control can be performed by changing the notch step number by one at this time. Note that in FIGS. 5 and 6, the actual measurement results are shown by solid lines and the simulation results are shown by dashed lines, but these are almost overlapped and cannot be distinguished from each other.

[0066] In these simulations, the control period is 30 [Hz], and therefore the switching period of the notch stage number is also a maximum of 30 [Hz]. In general, when an inverter is used to control an electric motor, the switching period of the inverter is on the order of several kHz. For this reason, when an inverter is used in a secondary circuit, there is a high possibility that a large surge voltage will be generated, which may result in effects such as accelerating the deterioration of peripheral devices such as slip rings. In the wound-type induction motor system of this embodiment, good control can be achieved at 30 [Hz], which is less than 1 / 100 of that, as described above, and since the switching period is small, the above-mentioned effects expected when using an inverter can be significantly reduced.

[0067] Also, a simulation result when the wound-rotor induction motor system SM in the embodiment is applied to a trolley truck and a simulation result of a comparative example will be described.

[0068] FIG. 7 is a diagram showing a schematic configuration when the wound-type induction motor system is applied to a trolley cart. FIG. 8 is a diagram showing a simulation result when the wound-type induction motor system shown in FIG. 7 is applied to a trolley cart. FIG. 9 is a diagram showing a simulation result of a comparative example. FIGS. 8A and 9A respectively show the time change of the position of the trolley cart, FIGS. 8B and 9B respectively show the time change of the rotation speed at that time, and FIGS. 8C and 9C show the time change of the notch step number at that time. The horizontal axis of each of FIGS. 8A and 9A is the elapsed time from the start of starting (start of speed control), and each of these vertical axes is the position of the trolley cart. The horizontal axis of each of FIGS. 8B and 9B is the elapsed time from the start of starting, and each of these vertical axes is the rotation speed. The horizontal axis of each of FIGS. 8C and 9C is the elapsed time from the start of starting, and each of these vertical axes is the notch step number. 8 and 9, the actual measurement results are shown by solid lines, and the simulation results are shown by dashed lines.

[0069] The wound-rotor induction motor system SM in the embodiment is used for position control of the trolley cart VC. As shown in FIG. 7, the wound-rotor induction motor IM is used as a power source for the trolley cart VC, and the output shaft of the wound-rotor induction motor IM is connected to a driving wheel DT of the trolley cart VC via a reduction gear GA. As a result, the output torque of the wound-rotor induction motor IM is transmitted to the driving wheel DT via the reduction gear GA, causing the driving wheel DT to rotate and the trolley cart VC to move. The current position x of the trolley cart VC and the position control target value x * The difference between these is calculated by the differencer SB, and the difference is P-controlled (proportional controlled) by the P-controller PCL to obtain the control target value ω m * and input to the MPC control unit CL. The MPC control unit CL controls the resistance value of the secondary resistance unit RU by predictive control as described above at a control period of 20 [Hz], prediction horizon 5, and control horizon 1, thereby controlling the rotation speed of the wound-rotor induction motor IM.

[0070] As shown in FIG. 8, such a wound-rotor induction motor system SM has a rotation speed control target value ω m * The control target value x * Although there is a slight deviation, the position x of the trolley cart VC can be determined with high accuracy.

[0071] On the other hand, in the comparative example, instead of the above-mentioned MPC control unit CL, a speed feedback control unit that performs general speed feedback control is used. In this comparative example, as shown in Fig. 9, the number of notch steps is determined according to the magnitude of the position deviation, so the amount of change in the input notch step number is large and relatively large pulsation occurs in the rotation speed. In particular, in the simulation results around 25 [s], if a larger notch step number is selected, the position control target value x *Even in situations where the maximum switching frequency exceeds the limit, control is performed to increase the number of notches, resulting in position deviation. By increasing the switching period and control period, the position deviation can be reduced, but there is a possibility that a large surge voltage will occur.

[0072] When controlling the rotation speed by switching the secondary resistance, it is difficult to adjust the rotation speed precisely, and it is necessary to ensure control precision by increasing the switching period and control period. However, by using the wound-rotor induction motor system SM in this embodiment, it is possible to achieve more precise control than conventional methods while keeping the switching period to a few tens of Hz.

[0073] Furthermore, in the above-described embodiment, the predetermined physical quantity related to the control objective of the wound-rotor induction motor is the rotational speed, but the predetermined physical quantity related to the control objective of the wound-rotor induction motor may be torque. This provides a control device for a wound-rotor induction motor, a control method for a wound-rotor induction motor, and a wound-rotor induction motor system SM that are capable of torque control. In this case, for example, the following equation 5 is used to calculate the evaluation value, instead of equation 4 for finding the evaluation value. Alternatively, for example, a rotational speed limit ω m_lim When the above formula is provided, the following formula 6 is used.

[0074]

number

[0075]

number

[0076] In order to express the present invention, the present invention has been described adequately and sufficiently through the embodiments with reference to the drawings in the above description, but it should be recognized that those skilled in the art can easily change and / or improve the above-mentioned embodiments. Therefore, unless the changes or improvements made by those skilled in the art are at a level that departs from the scope of the claims described in the claims, the changes or improvements are interpreted as being included in the scope of the claims. [Explanation of symbols]

[0077] SM Wound Rotor Induction Motor System IM Wound-rotor induction motor CL Predictive control unit (MPC control unit) RU secondary resistance section UT Resistance Element Unit S Switch R Resistance element 11 Control section 12 Pattern Generation Section 13 Prediction Department 14 Pattern selection section 15 Secondary resistance control section

Claims

1. A control device for a wound-rotor induction motor that controls a wound-rotor induction motor having a primary winding and a secondary winding, a secondary resistance section connected to the secondary winding and having a variable resistance value; a pattern generating unit that generates a plurality of different time-series resistance value patterns in the secondary resistor unit; a prediction unit that predicts, for each of a plurality of time-series resistance value patterns generated by the pattern generation unit, a value of a predetermined physical quantity related to a control purpose of the wound-type induction motor when the resistance value of the secondary resistance unit is changed in the time-series resistance value pattern; and a pattern selection unit which selects, from among the plurality of time-series resistance value patterns generated by the pattern generation unit, a time-series resistance value pattern corresponding to a most highly evaluated predicted value among the predicted values ​​of the wound-rotor induction motor predicted by the prediction unit; a secondary resistance control unit that controls the secondary resistance unit based on the time-series resistance value pattern selected by the pattern selection unit. Control device for wound-rotor induction motor.

2. the secondary resistance section includes at least one resistance element unit including a resistance element and a change-over switch for switching whether or not the resistance element is connected to the secondary winding; 2. The control device for a wound-rotor induction motor according to claim 1.

3. The predetermined physical quantity related to the control objective of the wound-rotor induction motor is a rotation speed.

3. The control device for a wound-rotor induction motor according to claim 1 or 2.

4. The predetermined physical quantity related to the control objective of the wound-rotor induction motor is torque.

3. The control device for a wound-rotor induction motor according to claim 1 or 2.

5. the pattern selection unit selects the most highly evaluated predicted value by using an evaluation value based on a deviation between a control target value and the predicted value; 5. The control device for a wound-rotor induction motor according to claim 1.

6. When generating the plurality of time-series resistance value patterns, the pattern generating unit selects a subsequent resistance value among two resistance values ​​arranged in a chronological order from a previous resistance value, a resistance value that is one step larger than the previous resistance value, and a resistance value that is one step smaller than the previous resistance value when a plurality of resistance values ​​that can be variably generated in the secondary resistance unit are arranged in order of magnitude.

6. The control device for a wound-rotor induction motor according to claim 1.

7. 1. A control method for a wound-type induction motor, comprising: a pattern generating step of generating a plurality of time-series resistance value patterns in the secondary resistance portion, the resistance value patterns being different from one another; a prediction step of predicting, for each of a plurality of time-series resistance value patterns generated in the pattern generation step, a value of a predetermined physical quantity related to a control purpose of the wound-type induction motor when the resistance value of the secondary resistance unit is changed in the time-series resistance value pattern; a pattern selection step of selecting, from the plurality of time-series resistance value patterns generated in the pattern generation step, a time-series resistance value pattern corresponding to a most highly evaluated predicted value among the predicted values ​​of the wound-rotor induction motor predicted in the prediction step; and a secondary resistance control step of controlling the secondary resistance unit based on the time-series resistance value pattern selected in the pattern selection step. A control method for a wound rotor induction motor.

8. a wound-type induction motor having a primary winding and a secondary winding; a control unit for a wound-rotor induction motor that controls the wound-rotor induction motor, The control unit for the wound-rotor induction motor is a control device for a wound-rotor induction motor according to any one of claims 1 to 6. Wound rotor induction motor system.

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