Method for improving speed control system of three-phase ac commutator motor

Abstract

To provide a method for improving the speed control system of a three-phase AC commutator motor, which can control the drive of the three-phase AC commutator motor while suppressing renovation costs.SOLUTION: A method for improving a speed control system 70 in a three-phase AC commutator motor 20 (see Figure 5) is a method for improving the speed control system that controls the positions of brushes α and β (see Figure 2) that adjust the rotational speed on the basis of the detection results of a speedometer generator 21 that detects the rotational speed of the motor 20, and includes a first step S2 of replacing the motor that drives a speed adjustment mechanism with a three-phase motor 72, a third step S3 of adjusting the resistance value of a variable resistor unit 79 such that a predetermined output voltage is output when a voltage output from the speedometer generator 21 is input while the motor 20 is operating in high-speed mode, and a fourth step S4 of calibrating a control unit 76 that controls the drive of the three-phase motor 72 based on the output voltage of the variable resistor unit 79 based on the rotational speed of the motor 20.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for modifying a speed control system in a three-phase AC commutator motor. [Background technology]

[0002] In recent years, drive systems using three-phase AC motors have been used as the drive source for cableways such as ski lifts. In these drive systems, the speed of the three-phase AC motor is controlled by changing the connection position of the secondary winding relative to the commutator. The connection position of the secondary winding is variably controlled by a single-phase motor. Furthermore, the drive control of this single-phase motor is performed using a servo amplifier composed of semiconductor elements such as a triac and an amplifier, which is configured to reference the output voltage of a speed detection unit provided in the motor and the output voltage of the single-phase motor.

[0003] For example, Patent Document 1 discloses a commutator generator that includes a three-phase AC commutator (three-phase AC commutator motor) 3, an operating motor 5 that moves the brush position of the commutator 3, and a control amplifier 6 that drives the operating motor 5, and that operates the control amplifier 6 to obtain induction generator characteristics. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Publication No. 3-36238 Summary of the Invention [Problem to be solved by the invention]

[0005] In the three-phase AC commutator motor described in Patent Document 1, the semiconductor elements that make up the servo amplifier that controls the drive of the single-phase motor need to be replaced during maintenance and inspection, but there is a problem that servo amplifiers become difficult to obtain due to the discontinuation of production of some semiconductor elements, which causes problems in the operation of cableway facilities. Also, while it is possible to replace the drive source from the three-phase AC motor with another prime mover, there is a problem that huge repair costs will be incurred.

[0006] The present invention provides a method for modifying a speed control system for a three-phase AC commutator motor, which is capable of controlling the drive of the three-phase AC commutator motor while suppressing the modification cost. [Means for solving the problem]

[0007] The method for modifying a speed control system for a three-phase AC commutator motor according to the present invention is a method for modifying a speed control system for a three-phase AC commutator motor configured to perform position control of a speed adjustment mechanism that adjusts the rotational speed based on the detection results of a speed detection unit that detects the rotational speed of the three-phase AC commutator motor, and comprises the following steps: a first step of replacing the motor that drives the speed adjustment mechanism with a three-phase motor; a second step of setting the resistance value of the resistor unit so that a predetermined output voltage is output when a voltage output from the speed detection unit is input while the motor is rotating at a predetermined rotational speed; and a third step of calibrating a control unit that controls the drive of the three-phase motor based on the output voltage of the resistor unit, based on the rotational speed of the motor.

[0008] In the method for modifying a speed control system in a three-phase AC commutator motor according to the present invention, the calibration may be performed via an external terminal connected to the control unit.

[0009] In the method for modifying a speed control system of a three-phase AC commutator motor according to the present invention, the preset rotation speed may be the maximum rotation speed of the motor. [Effects of the Invention]

[0010] According to the method for modifying a speed control system for a three-phase AC commutator motor of the present invention, after replacing the motor that drives the speed adjustment mechanism with a three-phase motor, the variable resistor unit can be set so that a predetermined output is obtained when the output voltage from the speed detection unit is input, and calibration can be performed based on the rotational speed of the motor. This makes it possible to modify the speed control system without replacing the three-phase AC commutator motor with another drive source. As a result, the speed control system for a three-phase AC commutator motor can be modified while keeping modification costs down. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a three-phase AC commutator motor. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the arrangement of the coils around the commutator shown in FIG. [Figure 3] FIG. 3 is a block diagram of a speed control system in the drive mechanism shown in FIG. [Figure 4] FIG. 4 is a graph showing the relationship between the rotation output of the motor and the detected voltage using a solid line. [Figure 5] FIG. 5 is a block diagram of a drive system for a three-phase AC commutator motor in the case where a single-phase motor is replaced with a three-phase motor. [Figure 6] FIG. 6 is a flowchart showing the procedure for modifying a speed control system in a three-phase AC commutator motor. DETAILED DESCRIPTION OF THE INVENTION

[0012] A method for modifying a speed control system 10 for a three-phase AC commutator motor according to one embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of a three-phase AC commutator motor 20. FIG. 2 is a cross-sectional view schematically showing the arrangement of coils around the commutator 30 shown in FIG. 1. As shown in FIGS. 1 and 2, the speed control system 10 includes the three-phase AC commutator motor 20, a single-phase motor (single-phase AC motor) 50, and a servo amplifier 56 that controls the drive of the single-phase motor 50.

[0013] 1 and 2, electric motor 20 is a Schlage-type three-phase AC commutator motor (hereinafter referred to as "electric motor 20" as appropriate). A primary winding (three phases) 24 and an adjusting winding 26 are housed in the same slot in the iron core of rotor 22 in electric motor 20, and secondary windings 32A, 32B, and 32C (hereinafter referred to as "secondary winding 32" as appropriate when there is no particular need to distinguish between them) are provided in stator 31.

[0014] The primary winding 24 is connected to slip rings RG1, RG2, and RG3 (hereinafter referred to as "slip rings RG" when no distinction is required) attached to the shaft SH, and receives power from the main power supply PW via the slip rings RG and brushes that slide against the rings RG. Each coil end of the adjustment winding 26 is connected to a commutator segment (not shown). Both ends of each phase of the secondary windings 32A, 32B, and 32C are electrically connected via deflection conductors to one-end brushes α1, α2, and α3 (hereinafter referred to as "brush α" when no distinction is required) and the other-end brushes β1, β2, and β3 (hereinafter referred to as "brush β" when no distinction is required) arranged on the commutator 30, so that an adjustment voltage can be applied to the secondary winding 32 at the slip frequency via the commutator 30 and the brushes α and β.

[0015] Furthermore, a front brush rocker ring 42 and a rear brush rocker ring 44 are provided in front of and behind the commutator 30 of the electric motor 20. Brushes α on one end of each secondary winding 32 shown in FIG. 2 are attached to the brush rocker rings 42, 44 at 120° intervals from each other, and brushes β on the other end are also attached to the brush rocker rings 42, 44 via brush holders (not shown). The brush rocker rings 42, 44 are configured to simultaneously move in opposite directions via a gear mechanism 46, thereby simultaneously adjusting the opening angle of the secondary winding 32 for each phase. Changing the opening angle of the secondary winding 32 changes the insertion voltage value of the secondary winding 32, thereby changing the speed of the electric motor 20. In this embodiment, the front brush rocker ring 42, rear brush rocker ring 44, secondary winding 32, and brushes α, β correspond to a speed adjustment mechanism.

[0016] The single-phase motor 50 serves to rotate and drive the above-mentioned gear mechanism 46. The single-phase motor 50 is provided with a speedometer generator 52 that detects the rotational speed, and the above-mentioned electric motor 20 also has a speedometer generator (speed detection unit) 21 that detects the rotational speed attached to the output shaft AX.

[0017] Fig. 3 is a block diagram of the speed control system 10 for the electric motor 20 shown in Fig. 1. As shown in Fig. 3, the servo amplifier 56 includes semiconductor elements such as an amplifier 57 and a triac 58, and controls the driving of the single-phase motor 50 so that the rotation speed of the electric motor 20 becomes a target rotation speed based on the detection voltage TG transmitted from the speedometer generator 21 described above, the detection voltage PG transmitted from the speedometer generator 52, and the target speed setting voltage set by the speed setter 54 (see Fig. 3). In this embodiment, the detection voltage PG is, for example, a DC voltage of 10 to 12 V, and the detection voltage TG is, for example, a DC voltage of about 50 to 80 V.

[0018] Here, the output characteristics of the rotation output of the electric motor 20 and the detected voltage TG will be explained using Fig. 4. Fig. 4 is a graph showing the relationship between the rotation output of the electric motor 20 and the detected voltage TG using a solid line. In Fig. 4, the vertical axis represents the detected voltage TG, and the horizontal axis represents the rotation speed of the electric motor 20. The detected voltage TGmax shown in Fig. 4 is the detected voltage when the rotation output of the electric motor 20 is at the rated rotation speed, that is, the maximum rotation speed (hereinafter referred to as "high-speed mode" as appropriate), the detected voltage TGmd is the detected voltage when the rotation output of the electric motor 20 is at 90% of the rated rotation speed (hereinafter referred to as "medium-speed mode" as appropriate), and the detected voltage TGlw is the detected voltage when the rotation output of the electric motor 20 is at 80% of the rated rotation speed (hereinafter referred to as "low-speed mode" as appropriate).

[0019] 4, as the rotational output of the electric motor 20 increases, the detected voltage TG also increases, but the increase is not linear (proportional) but rather the detected voltage PG increases nonlinearly. For this reason, the detected voltages TGmd and TGlw cannot be calculated proportionally from the relationship between the rotational speed of the electric motor 20, 1000 RPM, and the detected voltage TGmax.

[0020] Therefore, the target speed voltage for each operation mode (high speed mode, medium speed mode, low speed mode) can be set individually based on the actual measurement values ​​(detected voltages TGmax, TGmd, TGlw) via the speed setter 54. This makes it possible to perform speed control with high precision in each operation mode.

[0021] When one of the high-speed, medium-speed, and low-speed modes is selected based on an operation performed via an operation control panel (not shown), the servo amplifier 56 is set to drive the single-phase motor 50 to achieve a target speed voltage corresponding to the selected operation mode, thereby controlling the connection position of the secondary winding 32, i.e., the positions of the brushes α and β.

[0022] Next, a speed control system for the electric motor 20 in the above-described speed control system 10 in which the single-phase motor 50 is replaced with a three-phase motor (three-phase AC motor) 72 will be described with reference to Fig. 5. Fig. 5 is a block diagram showing the configuration of the speed control system 70 in which the single-phase motor 50 is replaced with the three-phase motor 72.

[0023] As shown in FIG. 5, the speed control system 70 has the same configuration as the speed control system 10 except that it includes a three-phase motor 72 and a servo amplifier 74 instead of the single-phase motor 50 and the servo amplifier 56 .

[0024] 5, the servo amplifier 74 includes an inverter circuit 75 that controls the driving of the three-phase motor 72, a control unit 76 that controls the inverter circuit 75, an isolator 78, and a variable resistor unit 79. The control unit 76 is configured to be able to set a target speed voltage corresponding to each of the high-speed mode, medium-speed mode, and low-speed mode, and has a function of controlling the connection position of the secondary winding 32 (position of the brushes α and β) via the three-phase motor 72 so as to achieve the target speed voltage corresponding to one of the above operation modes based on operation operations performed via an operation panel (not shown).

[0025] The variable resistor unit 79 also serves to adjust the output voltage of the variable resistor unit 79 to a preset target speed voltage when the detected voltage TGmax during high-speed mode is input, thereby adjusting (in other words, calibrating) the actual measured value of the output voltage during high-speed mode, which is input to the control unit 76 via the isolator 78, to the target speed voltage value.

[0026] The isolator 78 is a signal isolator that serves to convert the DC voltage output from the variable resistor unit 79 into a range of DC voltage values ​​(for example, up to about 10 V) that can be input to the control unit 76 located downstream.

[0027] The control unit 76 controls the drive of the three-phase motor 72 by outputting a control signal to the inverter circuit 75 based on the output voltage from the isolator 78 and an operation mode (high-speed mode, medium-speed mode, or low-speed mode) selected by an operation control panel (not shown). In addition, the control unit 76 is configured to be able to adjust the target speed voltage value corresponding to each of the above operation modes by connecting an external information terminal PC such as a tablet, personal computer, or dedicated setting device.

[0028] The resistance value of the variable resistor unit 79 and the target speed voltage value corresponding to each operation mode of the control unit 76 are set to initial settings, respectively, which allows test operation of the motor 20 even before the calibration work is performed.

[0029] 6 is a flowchart showing the procedure of a modification method for modifying the position control of brushes α and β in secondary winding 32 from single-phase motor 50 to three-phase motor 72. As shown in FIG. 6, in a first step S1, single-phase motor 50 and servo amplifier 56 shown in FIG. 3 are removed from control system 10 of electric motor 20. Then, in a second step S2, as shown in FIG. 5, three-phase motor 72 and servo amplifier 74 used for drive control of three-phase motor 72 are installed.

[0030] In the third step S3, the three-phase motor 72 is controlled via an information terminal PC connected to the control unit 76 to rotate the electric motor 20, and the rotational speed of the electric motor 20 is adjusted to, for example, a rated rotational speed. In this case, the rotational speed of the electric motor 20 may be calculated from the rotational speed of a rotating body, such as a pulley, driven via the output shaft AX. Then, the resistance value of the variable resistor unit 79 is adjusted so that the voltage value output from the variable resistor unit 79 becomes a preset target speed voltage when a detected voltage TGmax output when the rotational speed of the electric motor 20 is the rated rotational speed (in other words, high-speed mode) is input. This allows high-speed mode calibration, i.e., the first-stage calibration process, to be performed.

[0031] In a fourth step S4, the three-phase motor 72 is driven via the information terminal PC so that the rotational speed of the electric motor 20 is set to a rotational speed during execution of the medium-speed mode (900 RPM, for example, in this embodiment). The voltage output from the variable resistor unit 79 corresponding to the detected voltage TGmd at this time is stored in the control unit 76 as a target speed voltage value for the medium-speed mode. Similarly, the voltage output from the variable resistor unit 79 corresponding to the detected voltage TGld when the rotational speed of the electric motor 20 is set to a rotational speed during execution of the low-speed mode (800 RPM, for example, in this embodiment) is stored in the control unit 76 as a target speed voltage value for the low-speed mode via the information terminal PC. This allows calibration of the medium-speed mode and the low-speed mode, i.e., a second-stage calibration process. In this way, by performing calibration using the actual measured values ​​of the rotational speed of the electric motor 20 during execution of each operation mode, the influence of the nonlinear output characteristics of the detected voltage TG can be avoided.

[0032] According to the method for modifying the speed control system of the three-phase AC commutator motor 20 of this embodiment, after replacing the motor that controls the positions of the brushes α and β of the secondary winding 32 with a three-phase motor 72, the variable resistor unit 79 can be set so as to obtain a predetermined output when the detection voltage TG output from the speedometer generator 21 is input, and the target speed voltage can be calibrated based on the rotation output of the motor 20. This makes it possible to modify the speed control system 70 of the three-phase AC commutator motor without replacing the three-phase AC commutator motor 20 with another drive source. As a result, the speed control system 70 can be modified while keeping the modification costs down.

[0033] In the above embodiment, the rated rotation speed of the electric motor 20 is 1000 RPM, but the present invention is not limited to this. For example, the rated rotation speed may be less than 1000 RPM or may be 1000 RPM or greater, and as an example, the rated rotation speed may be 1650 RPM.

[0034] In the above embodiment, the control unit 76 has been described as having a high-speed mode, a medium-speed mode, and a low-speed mode, but the present invention is not limited to this. For example, the control unit 76 may also have a second low-speed mode in which the three-phase motor 72 is driven at an even slower speed than the low-speed mode, or a reverse mode in which the three-phase motor 72 is rotated in the reverse direction. In this case, the second-stage calibration process may be performed in the fourth step S4 for the second low-speed mode and the reverse mode, just as for the medium-speed mode and the low-speed mode. In this case, the same effects as those of the above embodiment can be obtained.

[0035] The present invention can be implemented in various forms, including improvements, modifications, and variations based on the knowledge of those skilled in the art, without departing from the spirit of the invention. Furthermore, the invention can be implemented in a form in which any of the features of the invention are replaced with other technology, as long as the same action or effect is achieved. [Explanation of symbols]

[0036] 10,70 Speed ​​Control System 20 Three-phase AC commutator motor 21 Speedometer generator (speed detection unit) 22 rotor 24 Primary Winding 30 commutator 31 Stator 32A, 32B, 32C, 32 Secondary winding (speed adjustment mechanism) 42 Front brush rocker ring (speed adjustment mechanism) 44 Rear brush rocker ring (speed adjustment mechanism) 50 Single-phase motor 52 Speedometer generator 56,74 Servo amplifier 75 Inverter circuit 78 Isolator 79 Variable Resistor Unit PC information terminal RG1, RG2, RG3, RG slip ring S1~S5 Process (Steps) PG,TG detection voltage α1, α2, α3, α Brashi (speed adjustment mechanism) β1,β2,β3,β ブラシ (speed adjustment mechanism)

Claims

1. A method for improving a speed control system for a three-phase AC commutator motor configured to perform position control of a speed adjustment mechanism that adjusts a rotation speed of the three-phase AC commutator motor based on a detection result of a speed detection unit that detects the rotation speed of the three-phase AC commutator motor, comprising: a first step of replacing a motor that drives the speed adjustment mechanism with a three-phase motor; a second step of setting a resistance value of the resistor unit so that a predetermined output voltage is output when a voltage output from the speed detection unit is input while the electric motor is rotating at a preset rotation speed; and a third step of calibrating a control unit that controls the drive of the three-phase motor based on the output voltage of the resistor unit, based on the rotational speed of the motor. A method for improving the speed control system of a three-phase AC commutator motor.

2. the calibration is performed via the external terminal connected to the control unit. The method for modifying a speed control system in a three-phase AC commutator motor according to claim 1.

3. The preset rotation speed is the maximum rotation speed of the electric motor. The method for modifying a speed control system in a three-phase AC commutator motor according to claim 1.

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