JP2024017460A - Motor testing device and method for measuring characteristics of tested motor by using motor testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor testing device for accurately measuring transition response characteristics, T-N characteristics, and start torque of a tested motor.

SOLUTION: A motor testing device includes: a first coupling connected to a rotating shaft of a tested motor; a torque meter having a first rotating shaft connected to the first coupling, and a second rotating shaft; a second coupling connected to the second rotating shaft of the torque meter; an electric brake having a rotating shaft connected to the second coupling and having a coreless motor structure; an AC/DC conversion portion that is electrically connected to a coil of the electric brake and converts an AC induction voltage generated in the coil to a DC voltage; and a DC load portion that is electrically connected to the AC/DC conversion portion and consumes power by the DC voltage. The DC load portion is configured such that a variable current control portion adjusting a DC current value variably and a resistor are disposed in series between two input terminals to which the DC voltage is applied.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a motor testing device and a method of measuring characteristics of a motor under test using the same.

Patent Document 1 describes a motor testing device that measures the characteristics of a motor under test. This motor testing device connects the motor under test and the load motor via a gear, and uses a simulator section that outputs a speed command to the load motor.The controller controls the load motor according to the speed command input from the simulator section. drive

Japanese Patent Application Publication No. 2004-012340

However, the above-mentioned conventional technology has a problem in that it is difficult to accurately measure the transient response characteristics of the motor under test in response to rapid transient changes. Furthermore, in the past, there was a problem in that it was difficult to accurately measure the TN characteristics and starting torque of the motor under test.

The present disclosure has been made to solve at least part of the above-mentioned problems, and can be realized as the following forms.

According to one aspect of the present disclosure, a motor testing device used for testing the characteristics of a motor under test is provided. This motor testing device includes a first coupling coupled to a rotating shaft of the motor to be tested, a first rotating shaft coupled to the first coupling, and a second rotating shaft, and a torque meter that measures torque between a rotating shaft and the second rotating shaft; a second coupling connected to the second rotating shaft of the torque meter; and a rotating shaft connected to the second coupling. an electric brake having a coreless motor structure, and an AC/DC conversion section that is electrically connected to a coil of the electric brake and converts an AC induced voltage generated in the coil into a DC voltage; A DC load unit that is electrically connected to the AC/DC conversion unit and consumes power from the DC voltage. The DC load section has a configuration in which a variable current control section that variably adjusts a DC current value and a resistor are arranged in series between two input terminals to which the DC voltage is applied.
According to this motor testing device, an electric brake having a coreless motor structure is used, and the AC induced voltage of the electric brake generated by the rotation of the motor under test is converted into DC voltage, and the electric power is consumed in the DC load section. It is possible to test the transient response characteristics of the motor under test against sudden transient changes.

FIG. 1 is a block diagram showing the configuration of a motor test system in a first embodiment. Graph showing IT characteristics of electric brake. The figure which shows an example of the internal structure of an AC/DC conversion part. FIG. 3 is an explanatory diagram showing the operation of the polarity separation circuit. The figure which shows an example of the internal structure of a DC load part. An explanatory diagram showing an example of a load pattern in a transient response test. Graph showing loss characteristics of motor test equipment. Graph showing loss characteristics of motor test equipment. FIG. 4 is an explanatory diagram showing the process of determining loss TN characteristics of the motor testing device. 2 is a flowchart showing the procedure for testing the TN characteristics of the motor under test. A graph showing the efficiency of a motor under test in a motor test device. A graph showing an example of TN characteristics of a motor under test. FIG. 2 is a block diagram showing the configuration of a motor test system that measures the starting torque of a motor under test in a second embodiment. FIG. 7 is an explanatory diagram showing the principle of measuring the starting torque of the motor under test in the second embodiment. 7 is a flowchart for measuring the starting torque of the motor under test in the second embodiment. 7 is a graph showing the starting torque of the motor under test obtained in the second embodiment. FIG. 7 is a block diagram showing the configuration of a motor test system that measures the starting torque of a motor under test in a third embodiment. 12 is a flowchart for measuring the starting torque of the motor under test in the third embodiment. 7 is a graph showing the starting torque of the motor under test obtained in the third embodiment. FIG. 7 is a block diagram showing the configuration of a motor test system that measures the starting torque of a motor under test in a fourth embodiment. 10 is a flowchart for measuring starting torque of a motor under test in a fourth embodiment. FIG. 7 is an explanatory diagram showing a state in which a rectangular pulse voltage is applied to a specific phase coil in the fourth embodiment.

A. First embodiment:
FIG. 1 is a block diagram showing the configuration of a motor testing system in a first embodiment. This motor test system includes a motor under test 100, a motor test device 200, and a test control device 300.

As the motor under test 100, any type of motor having any number of phases can be used. In this embodiment, the motor under test 100 has a magnetic sensor 104 that measures the rotational position of the rotor. However, when driving the motor under test 100 without a sensor, the magnetic sensor 104 can be omitted. The motor under test 100 is electrically connected to a drive circuit 120. A DC input voltage Ei is supplied to the drive circuit 120 from a constant voltage power supply 130. The voltage value of the input voltage Ei can be adjusted by the test control device 300. The drive circuit 120 is a motor driver configured as, for example, an H-bridge circuit, and the transistors in the drive circuit 120 are turned on/off in response to a control signal Sd supplied from the test control device 300. The control signal Sd is, for example, a signal for performing PWM control of the motor under test 100. In PWM control, the rotational position of the motor under test 100 is detected according to the output of the magnetic sensor 104, and the control signal Sd for each phase is generated according to this rotational position. An input ammeter 150 that measures the input current Ii and an input voltmeter 160 that measures the input voltage Ei are provided in the wiring between the constant voltage power supply 130 and the drive circuit 120. A phase ammeter 151 that measures the phase current Is of each phase and a phase voltmeter 161 that measures the phase voltage Es of each phase are provided in the wiring between the drive circuit 120 and the non-test motor 100. Ammeters 150, 151 and voltmeters 160, 161 are used to determine the input power to motor 100 under test. Preferably, the constant voltage power supply 130 is configured to supply voltage by remote sensing to detect the terminal voltage of the drive circuit 120 to reduce voltage drops and voltage fluctuations between lines.

The motor testing device 200 includes a first coupling 211, a torque meter 220, a second coupling 212, an electric brake 230, an AC/DC conversion section 240, a DC load section 250, and a power meter 260. . A mechanical connection structure including the first coupling 211, the torque meter 220, the second coupling 212, and the electric brake 230 is referred to as a test connection structure 270.

The rotating shaft 110 of the motor under test 100 and the first rotating shaft 221 of the torque meter 220 are connected by a first coupling 211 . The torque meter 220 has a first rotating shaft 221 and a second rotating shaft 222, and measures the torque T between the first rotating shaft 221 and the second rotating shaft 222. Preferably, the torque meter 220 is further configured to be able to measure the rotational speed N of the rotating shafts 221 and 222. Instead of measuring the rotation speed N with the torque meter 220, the rotation speed N may be measured using the magnetic sensor 104 provided in the motor under test 100. The second rotating shaft 222 of the torque meter 220 and the rotating shaft 232 of the electric brake 230 are connected by a second coupling 212. The electric brake 230 has a coreless motor structure with little iron loss (cogging loss, hysteresis loss, etc.). The electric brake 230 is configured, for example, as a two-phase or three-phase brushless motor. In this embodiment, the electric brake 230 includes a magnetic sensor 234 that measures the rotational position of the rotor. In this embodiment, the magnetic sensor 234 is a sensor that is fixed to the stator and measures the magnetic flux density of a permanent magnet provided in the rotor. The magnetic sensor 234 is configured by, for example, a Hall IC. However, the magnetic sensor 234 can be omitted.

The AC/DC converter 240 is electrically connected to the multi-phase coils of the electric brake 230, and performs full-wave rectification on the AC induced voltage Vi generated in the coil to convert it into a DC voltage Vd. The DC load section 250 is electrically connected to the AC/DC conversion section 240 and consumes power from the DC voltage Vd. The DC load unit 250 includes a variable current control unit 252 that variably adjusts the DC current value, and a resistor 256. Specific examples of the AC/DC conversion section 240 and the DC load section 250 will be described later.

The power meter 260 calculates the rotational energy P[W] from the torque T[N·m] and the rotational speed N[rpm] according to the following equation.
P = T×2πN/60…(1)
Torque T, rotational speed N, and rotational energy P are supplied from power meter 260 to test control device 300. The power meter 260 calculates the input voltage value Ei measured by the input voltmeter 160, the input current value Ii measured by the input ammeter 150, the torque T and rotation speed N measured by the torque meter 220, and the phase voltage. Using a plurality of input signals including the phase voltage value Es measured by the total 161 and the phase current value Is measured by the phase ammeter, the effective value, effective value, and power factor of the output of the motor under test 100 are determined. Calculate.

The test control device 300 controls each part of the motor test device 200, and also controls the drive circuit 120 and constant voltage power supply 130 of the motor under test 100. The test control device 300 can be realized by, for example, a personal computer. Various tests regarding the motor under test 100 are realized by the processor executing a motor test application program stored in the memory 310.

In this embodiment, the electric brake 230 has a coreless motor structure. Coreless motor structure has the following advantages over cored motor structure.
(a) Coil inductance is small because no iron core is used.
(b) There is no cogging loss or hysteresis loss.
(c) There is no magnetic saturation of the coil current due to the iron core characteristics.

Since the coil inductance of the electric brake 230 is extremely small, it is possible to accurately measure the transient response characteristics of the motor under test 100 against sudden transient changes. It is preferable that the self-inductance of each phase coil of the electric brake 230 is, for example, 4 μH or less. Furthermore, since the electric brake 230 has no cogging loss or hysteresis loss, it can apply a stable load to the motor 100 under test.

FIG. 2 is a graph showing the IT characteristics of the electric brake 230. The black points are actually measured points. As can be understood from this figure, since the electric brake 230 has no magnetic saturation of the coil, it is possible to obtain torque proportional to the coil current when the coil current becomes large. In other words, a load proportional to the coil current of the electric brake 230 can be applied to the motor 100 under test. Furthermore, since the electric brake 230 of this embodiment has an extremely small loss, the IT characteristic is almost a straight line passing through the origin.

Since the electric brake 230 has a coreless motor structure, iron loss is negligible, and mechanical loss caused by bearings and the like is also extremely small. For example, the mechanical loss of the electric brake 230 is preferably 10 watts or less at a rotation speed of 10,000 rpm. By using the electric brake 230 with such a small loss, it is possible to accurately test the transient response characteristics of the motor under test against sudden transient changes. The electric brake 230 with small loss can be realized, for example, by a coreless electromechanical device having a two-phase structure or a three-phase structure described in WO2018-139245A1.

FIG. 3 is a diagram showing an example of the internal configuration of the AC/DC converter 240. The AC/DC converter 240 includes a full-wave rectifier circuit 241A for the A-phase coil 231A of the electric brake 230, a full-wave rectifier circuit 241B for the B-phase coil 231B, a smoothing capacitor 242, and a polarity separation circuit for the A-phase. 243A, and a B-phase polarity separation circuit 243B. In this embodiment, the full-wave rectifier circuits 241A and 241B are configured as MOSFET bridge circuits with little voltage drop. The polarity separation circuits 243A, 243B generate polarity signals Pa, Pb indicating the A-phase and B-phase sections according to the sensor outputs MPa, MPb of the A-phase magnetic sensor 234A and the B-phase magnetic sensor 234B of the electric brake 230. .

FIG. 4 is an explanatory diagram showing the operation of polarity separation circuits 243A and 243B. The sensor output MPa of the A-phase magnetic sensor 234A exhibits a sinusoidal waveform depending on the rotational position of the permanent magnet of the rotor of the electric brake 230. The same applies to the sensor output MPb of the B-phase magnetic sensor 234B. The polarity separation circuit 243A separates a first polarity signal Pa+ that rises from L level to H level at the zero cross position of sensor output MPa, and a second polarity signal Pa- that falls from H level to L level at the zero cross position of sensor output MPa. generate. Similarly, the polarity separation circuit 243B outputs a first polarity signal Pb+ that rises from L level to H level at the zero cross position of sensor output MPb, and a second polarity signal Pb- that falls from H level to L level at the zero cross position of sensor output MPb. and generate. These polarity signals Pa+, Pa-, Pb+, and Pb- are used as gate signals for the MOSFETs of the full-wave rectifier circuits 241A and 241B. As a result, the induced AC voltage generated in the A-phase coil 231A and the induced AC voltage generated in the B-phase coil 231B are converted into DC voltage Vdc by the full-wave rectifier circuits 241A and 241B. The DC voltage Vdc is smoothed by a smoothing capacitor 242 and output from output terminals 246p and 246n. In this way, by using the AC/DC converter 240 having the full-wave rectifier circuits 241A and 241B configured with MOSFETs, the power loss caused by the AC/DC converter 240 can be suppressed to a small level. However, the AC/DC converter 240 may be configured using a full-wave rectifier circuit configured with diodes.

FIG. 5 is a diagram showing an example of the internal configuration of the DC load section 250. The DC load section 250 has a configuration in which a variable current control section 252 and a resistor 256 are arranged in series between two input terminals 251p and 251n. The variable current control section 252 is configured as a constant current circuit that can variably adjust the value of the DC current flowing through the resistor 256. In this embodiment, the variable current control section 252 includes a transistor 253, an operational amplifier 254, and a current command section 255. Current command unit 255 inputs current command value Vt to operational amplifier 254 in response to a command from test control device 300. The output of operational amplifier 254 is supplied to the gate electrode of transistor 253. The output voltage Vm of the transistor 253 is fed back to the operational amplifier 254, and the operational amplifier 254 adjusts the level of the gate signal of the transistor 253 according to the difference between the output voltage Vm of the transistor 253 and the current command value Vt. As a result, a direct current having a current value Ir corresponding to the current command value Vt flows from the transistor 253 to the resistor 256.

In this way, by using the DC load section 250 having a configuration in which the variable current control section 252 and the resistor 256 are connected in series, the induced electromotive force generated in the electric brake 230 is consumed by the resistor 256 at a constant current value. can. As a result, it is possible to provide stable load torque to the motor under test 100.

FIG. 6 is an explanatory diagram showing examples of load patterns P1 to P4 in a transient response test. In the motor test system of this embodiment, it is possible to perform a transient response test of the motor under test 100 according to such various load patterns. In particular, in this embodiment, since the electric brake 230 having a coreless motor structure is used as the load device, it is possible to test transient response characteristics that involve rapid transient changes. For example, load patterns P1, P2, and P4 all include substantially vertical load changes. It is impossible to realize load patterns P1, P2, and P4 that involve such rapid transient changes when a cored motor is used as a load device.

When performing a transient response test, a predetermined load pattern is stored in the memory 310 of the test control device 300, and feedback control is executed using the load pattern. Specifically, the load torque of the load pattern is set as the target value, the torque measured by the torque meter 220 is set as the controlled variable, and the current command value of the DC load section 250 is set as the manipulated variable. That is, the current command value of the DC load section 250 is adjusted so that the difference between the load torque target value of the load pattern and the torque measured by the torque meter 220 becomes zero.

The motor testing device 200 can be used for various measurements and tests, such as measuring TN characteristics and starting torque characteristics, in addition to transient response tests. The inventor of the present disclosure found that the influence of loss in the motor testing device 200 cannot be ignored in measuring the TN characteristics of the motor 100 under test. As explained below, more accurate TN characteristics are obtained by correcting the torque measured in the TN characteristic measurement of the motor under test 100 with a loss torque corresponding to the loss of the motor testing device 200. Is possible.

FIG. 7 is a graph showing the loss-revolutions characteristic of the motor testing device 200. The first loss Pd is the loss of the motor testing apparatus 200 when the motor under test 100 is not connected to the first coupling 211. The second loss Pb is a loss of the electric brake 230 alone. As can be understood from this figure, the loss Pb of the electric brake 230 is extremely small. Since the electric brake 230 has almost negligible iron loss, the loss Pb can be considered to be a mechanical loss. Preferably, the loss Pb of the electric brake 230 is 10 watts or less at a rotation speed of 10,000 rpm. By using the electric brake 230 with such a small loss, it is possible to accurately test the transient response characteristics of the motor under test against sudden transient changes.

FIG. 8 is a graph showing the loss TN characteristics of the motor testing device 200. The first loss torque Td is a torque corresponding to the loss of the motor testing device 200 in a state where the motor under test 100 is not connected to the first coupling 211, and is calculated from the loss Pd shown in FIG. 7 according to the above equation (1). This is the calculated value. The second loss torque Tb is a loss of the electric brake 230 alone, and is calculated from the loss Pb shown in FIG. 7 according to the above equation (1). The lower part of FIG. 8 shows the vertical axis of the loss torque Tb of the electric brake 230 alone in an enlarged manner. The reason why the loss torque Tb increases rapidly when the rotational speed becomes about 5000 rpm or more is estimated to be due to mechanical loss in the bearing of the electric brake 230.

The loss TN characteristic of the motor test device 200 in a state where the motor under test 100 is not connected is stored in the memory 310 of the test control device 300 and used to correct the TN characteristic of the motor under test 100. .

FIG. 9 is an explanatory diagram showing the process of determining the loss TN characteristic of the motor testing device 200. In step S1, the motor under test 100 is not connected to the motor testing device 200, and the motor under test 100 is rotated without a load, and the torque Ts0, the output Ps0, and the rotation speed N are measured. This measurement is performed with the input voltage Ei to the drive circuit 120 of the motor under test 100 set to a plurality of values. Furthermore, the current flowing through the DC load section 250 is set to 0 so that no braking action occurs in the electric brake 230. Alternatively, the connection between the electric brake 230 and the AC/DC converter 240 may be disconnected.

The torque Ts0 [N·m] of the motor under test 100 is calculated according to the following equation using the output Ps0 [W] and the rotation speed N [rpm] of the motor under test 100.
Ts0=Ps0×60/2πN…(2)

In step S2, with the motor under test 100 connected to the motor testing device 200, the motor under test 100 is rotated under no load as in step S1, and the torque meter 220 measures the torque Ts1, the output Ps1, and the rotational speed N. Measure. Similar to step S1, this measurement is also performed with the input voltage Ei to the drive circuit 120 of the motor under test 100 set to a plurality of values.

In step S3, using the results of step S1 and step S2, the loss Pd of the motor testing device 200 and the loss torque Td corresponding to the loss Pd are determined by the following equation.
Pd=Ps1-Ps0...(3a)
Td=Ts1-Ts0...(3b)

Steps S1 and S2 are each executed with the input voltage Ei set to a plurality of values, so the loss torque Td is calculated according to the plurality of rotational speeds N, respectively.

Through steps S1 to S3 described above, the loss TN characteristics of the motor testing apparatus 200 in a state where the motor under test 100 is not connected can be created. This loss TN characteristic can be stored in memory 310. As explained below, the test control device 300 uses this loss TN characteristic to correct the TN characteristic of the motor under test 100.

FIG. 10 is a flowchart showing the procedure for testing the TN characteristics of the motor under test 100. In step S10, the TN characteristics of the motor under test 100 are measured with the motor under test 100 connected to the motor testing device 200. This measurement is performed for a specific input voltage Ei. In step S20, the loss TN characteristic of the motor testing device 200 is read from the memory 310 of the test control device 300. In step S30, the TN characteristic of the motor under test 100 is corrected using the loss TN characteristic of the motor testing apparatus 200. That is, by performing a correction in which the loss torque Td of the loss TN characteristic shown in FIG. 8 is added to the torque of the TN characteristic of the motor under test 100, the corrected TN characteristic of the motor under test 100 is Desired. By performing the process shown in FIG. 10, it is possible to obtain a corrected TN characteristic of the motor under test 100 alone, which does not include a loss torque component corresponding to the loss of the motor testing apparatus 200.

FIG. 11 is a graph showing the efficiency of the motor under test 100 before and after loss correction in the motor testing apparatus 200. The horizontal axis of this graph is torque, and the vertical axis is efficiency (=output/input). The output of the motor under test 100 is calculated according to the above equation (1) according to the torque T measured by the torque meter 220 and the rotation speed N. The input of the motor under test 100 is calculated by multiplying the phase current value Is measured by the phase ammeter 151, the phase voltage value Es measured by the phase voltmeter 161, and the power factor. The graph before correction shows the efficiency corresponding to the TN characteristic obtained in step S10 in FIG. 10, and the graph after correction shows the efficiency corresponding to the corrected TN characteristic after correction in step S30. There is. The efficiency after correction can be considered to indicate the true efficiency of the motor 100 under test.

As can be understood from the graph of FIG. 11, in a rotating state where the torque T is small and close to no-load, the influence of the loss of the motor testing device 200 is quite large. As a result, with the normal TN characteristics obtained in step S10 in FIG. 10, the torque and efficiency of the motor under test 100 tend to be lower than their true values. On the other hand, if the torque and output of the motor under test 100 are corrected using the loss torque Td corresponding to the loss of the motor testing device 200, the true torque and efficiency of the motor under test 100 can be calculated correctly.

FIG. 12 is a graph showing an example of the TN characteristics of the motor under test 100. This TN characteristic is a characteristic for a constant input voltage Ei, and is a characteristic after correction according to FIG. 10. The test area indicated by the broken line indicates the range in which measurements can be performed in a normal TN characteristic test. The starting torque Ts when the rotational speed N is zero is determined by extrapolating the TN characteristic in the test region.

As described above, in the first embodiment, the electric brake 230 having a coreless motor structure is used, and the AC induced voltage of the electric brake 230 generated by the rotation of the motor 100 under test is converted into DC voltage, and the DC voltage is applied to the DC load section 250. Since the power is consumed, the transient response characteristics of the motor under test 100 to rapid transient changes can be tested.

The motor testing device 200 can also be used as a device for conducting various tests such as those described below.
(1) Using a motor with a normal PWM frequency of about 20 KHz as the motor under test 100, finer electrical angle control is performed and high-resolution electrical angle control is performed with the PWM frequency raised to 100 KHz to 200 KHz or more. A device that measures properties.
(2) The motor used in the drone is the motor under test 100, and in order to adapt to transient changes in the natural environment such as updrafts and turbulence, characteristics such as transient response of forward/reverse rotation control of the propeller and self-sustaining balance controllability. A device that evaluates
(3) The test motor 100 is a motor used for rudder and flap operations used for takeoff, landing, and direction changes in the aviation industry. A device that evaluates characteristics such as responsiveness and self-sustaining balance controllability.
(4) The motor under test 100 is a motor used in a fluid compression device, and the characteristics of heat exchangers, artificial respirators, high-concentration oxygen generators, water discharge fire prevention pumps, etc. that involve compression with high torque in a short period of time. A device that evaluates

B. Second embodiment:
The starting torque Ts obtained by the conventional measurement method is greatly influenced by the drive characteristics of the drive circuit 120 (on-resistance of the transistor, voltage attenuation of the substrate wiring, drive waveform, phase angle, etc.). In the second embodiment, a method of measuring the starting torque Ts without being affected by the drive characteristics of the drive circuit 120 will be described.

FIG. 13 is a block diagram showing the configuration of a motor test system that measures the starting torque of the motor under test 100 in the second embodiment. The differences in system configuration between the second embodiment and the first embodiment are that a constant current power supply 140 is used instead of the constant voltage power supply 130, that the drive circuit 120 of the motor under test 100 is omitted, and , and the provision of a drive circuit 235 that drives the electric brake 230 as a motor, and the other configurations are the same as the first embodiment. Although the constant voltage power supply 130 and the constant current power supply 140 will be explained separately for the sake of explanation, a constant voltage constant current power supply having both functions may be used. This point also applies to other embodiments described later.

FIG. 14 is an explanatory diagram showing the principle of measuring the starting torque of the motor under test 100 in the second embodiment. The upper part of FIG. 14 shows the PWM waveform of the A-phase coil in a normal driving state of the motor under test 100 and the torque change generated in the A-phase coil. Here, it is assumed that the motor under test 100 is a two-phase motor, but the measurement principle is almost the same for motors with three or more phases. The PWM waveform is an effective voltage waveform applied to the A-phase coil, and has a substantially sinusoidal shape. A sinusoidal torque is generated from the A-phase coil in accordance with this PWM waveform. This torque change can be considered to be a change in torque depending on the rotation angle of the motor 100 under test. Further, the maximum value of this torque change is equal to the starting torque Ts of the motor 100 under test.

Considering the principle of torque generation under normal driving conditions, the starting torque of the motor 100 under test can be determined by measuring the change in torque generated from the A-phase coil according to the rotation angle and finding the maximum value. It can be seen that it is possible to measure Ts. Therefore, in the second embodiment, as shown in the lower part of FIG. 14, the electric brake 230 is driven by the drive circuit 235 while DC power of a constant input current value is input to the A-phase coil. The rotating shaft 100 is rotated and the change in torque is measured using the torque meter 220, and the maximum value thereof is measured as the starting torque Ts. Preferably, the torque is measured over a rotational angle range Δθ corresponding to at least 2π in electrical angle. Although it is possible to obtain the starting torque Ts with only the single A phase, it is possible to obtain the starting torque Ts with the B-phase coil as well, taking into account phase variations.

FIG. 15 is a flowchart for measuring the starting torque of the motor under test 100 in the second embodiment. In the second to fourth embodiments, it is assumed that the motor under test 100 is a coreless motor having M-phase coils, where M is an integer of 2 or more. In typical examples, M is 2 or 3. However, the motor under test 100 may be a motor with a core.

In step S110, a DC current of a constant current value is input to one specific phase coil of the M-phase coils of the motor under test 100, and the input voltage to the specific phase coil is measured. When the motor under test 100 is a two-phase motor, one of the A-phase coil and the B-phase coil is selected as the specific phase coil and DC current is input to the other, and no DC current is input to the other. Further, when the motor under test 100 is a three-phase motor, one phase coil among the U-phase coil, V-phase coil, and W-phase coil is selected as the specific phase coil, and DC current is input, and the other phase coil is selected as the specific phase coil. No DC power is input to the two-phase coil. However, when the U-phase coil is used as a specific phase coil, the DC current input to the U-phase coil flows to both the V-phase coil and the W-phase coil via the U-phase coil. The current value Ii of the DC current input to the specific phase coil is measured by an input ammeter 150, and the input voltage value Ei is measured by an input voltmeter 160.

In step S120, while a direct current having the same constant current value as in step S110 is supplied to the specific phase coil of the motor under test 100, rotation is applied to the motor under test 100 by the electric brake 230, and the torque change due to rotation is maximized. Torque is measured with a torque meter 220. At this time, it is preferable that the rotational range of the motor under test 100 is 2π or more in electrical angle of the motor under test 100. As shown in FIG. 14, the torque of the motor depends on the electrical angle and exhibits a sinusoidal waveform that peaks in a rotation angle range of 2π in terms of electrical angle. Therefore, by rotating the motor under test 100 over a rotation angle range of 2π or more in electrical angle, it is possible to determine the maximum torque generated by the motor under test 100.

Control of applying rotation to the motor under test 100 by the electric brake 230 is performed by a drive circuit 235. Note that in step S120, the torque may be measured while rotating the rotating shaft 110 of the motor under test 100 slowly, or the torque may be measured while the rotating shaft 110 of the motor under test 100 is stopped at a plurality of rotation angles. May be measured.

In step S130, it is determined whether or not to execute the processes in steps S110 and S120 using another current value. In the second embodiment, steps S110 and S120 are executed with a plurality of current values. When executing the processing in steps S110 and S120 with another current value, the process advances to step S140, changes the current value of the DC current, and returns to step S110. In this way, by executing steps S110 and S120 using a plurality of current values, it is possible to obtain a plurality of maximum torques corresponding to a plurality of input voltages with respect to one specific phase coil.

In step S150, it is determined whether or not to execute the processes of steps S110 to S140 described above using coils of other phases. If the processing in steps S110 to S140 is not completed for all M-phase coils of the motor under test 100, the process returns from step S150 to step S110, the specific phase coil is changed, and steps S110 to S140 are executed again. . When the processing of steps S110 to S140 is completed for all the M-phase coils, the process advances to step S160.

In step S160, for each of the plurality of input voltages, from the M maximum torques obtained for the M-phase coil of the motor under test 100, a starting torque characteristic curve showing a change in starting torque according to the plurality of input voltages. Create. At this time, the starting torque of the motor under test 100 is determined from the M maximum torques obtained for the M-phase coils for each input voltage. For example, the average value, maximum value, or minimum value of M maximum torques can be determined as the starting torque. If the average value of the maximum torques is selected as the starting torque, the expected value of the starting torque expected of the motor under test 100 can be set as the starting torque. Furthermore, by selecting the maximum value of the maximum torques as the starting torque, the starting torque can be the torque that can be generated when the rotating shaft 110 of the motor under test 100 is at the most advantageous rotational position for torque generation. By selecting the minimum value of the maximum torque as the starting torque, the starting torque can be the torque that can be generated when the rotating shaft 110 of the motor under test 100 is at the most unfavorable rotational position with respect to torque generation.

Note that it is not necessary to execute the processes of steps S110 to S140 for all M-phase coils, and the processes of steps S110 to S140 may be executed for at least one phase coil. For example, when executing steps S110 to S140 for only one phase coil, the maximum torque obtained for that coil is directly determined as the starting torque.

FIG. 16 is a graph showing the starting torque characteristics of the motor under test 100 obtained in the second embodiment. The horizontal axis in FIG. 16 is the input voltage, and the vertical axis is the starting torque. A plurality of black circles indicate measurement points, and a dotted line indicates a starting torque characteristic curve G2 created from the plurality of measurement points.

The starting torque characteristic curve G2 can be expressed by an approximation function that approximates a plurality of measurement points. In the example of FIG. 16, the starting torque characteristic curve G2 is a straight line. When the motor 100 under test is a coreless motor, the starting torque characteristic curve G2 can be represented by a straight line. Note that the input voltage Ei measured in the process of FIG. 15 is usually an extremely small value compared to the rated voltage of the motor 100 under test. In the example of FIG. 16, when the rated voltage of the motor under test 100 is 10 [V], the value of the input voltage Ei at the measurement point is 1/10 or less. The reason for this is that if the DC voltage value is set to a large value so that the input voltage Ei is close to the rated voltage, the coil of the motor under test 100 may overheat and damage the motor under test 100. This is because there is such a problem, and also because the key point in this test is to perform measurements so as not to be affected by the heat generated by the motor under test 100 itself. In this sense, in the process of FIG. 15, it is more preferable that the input voltage Ei is set to be 1/10 or less of the rated voltage of the motor under test 100.

In step S170, the starting torque for a specific voltage higher than the plurality of input voltages used in the measurements in steps S110 to S140 is calculated by extrapolating the starting torque characteristic curve G2. In the example of FIG. 16, the specific voltage is 10V, and the starting torque Ts for that specific voltage is calculated by extrapolation of the starting torque characteristic curve G2. In this embodiment, the starting torque characteristic curve G2 is a straight line, so by extrapolating it, it is possible to accurately determine the starting torque Ts for a specific voltage. However, even if the starting torque characteristic curve G2 is not a straight line, it is possible to calculate the starting torque for an input voltage higher than the measurement point by extrapolating the starting torque characteristic curve G2, although the accuracy is slightly lowered.

The starting torque characteristic curve G2 in FIG. 16 is a characteristic measured without connecting the drive circuit 120 to the motor under test 100, and shows the starting torque characteristic of the motor under test 100 alone. In this way, in the second embodiment, the starting torque characteristics of the motor under test 100 alone can be accurately measured without being affected by the characteristics of the drive circuit 120.

C. Third embodiment:
FIG. 17 is a block diagram showing the configuration of a motor test system that measures the starting torque of the motor under test 100 in the third embodiment. The only difference between the system configurations of the third embodiment and the second embodiment is that a drive circuit 120 is added between the constant current power supply 140 and the motor under test 100, and the other configurations are different from the second embodiment. It's the same.

FIG. 18 is a flowchart for measuring the starting torque of the motor under test 100 in the third embodiment. In this processing procedure, step S110 of the processing procedure of the second embodiment shown in FIG. 15 is replaced with steps S210 and S220, and the other steps are the same as in the second embodiment.

In step S210, one of the M-phase coils of the motor under test 100 is selected as the specific phase coil, and the PWM duty of the drive circuit 120 regarding the specific phase coil is set to 100%. In step S220, while maintaining the state of step S210, a DC current of a constant current value Is (=Ii) is input to the specific phase coil, and the input voltage Ei to the drive circuit 120 is measured. This input voltage Ei corresponds to the total value of the voltages generated in the drive circuit 120 and the specific phase coil. The processes after step S120 are the same as those in the second embodiment described in FIG. 15, so the description will be omitted.

FIG. 19 is a graph showing the starting torque characteristics of the motor under test 100 obtained in the third embodiment. A plurality of black circles indicate measurement points, and a dotted line indicates a starting torque characteristic curve G3 created from the plurality of measurement points. Although this starting torque characteristic curve G3 is also a straight line like the starting torque characteristic curve G2 of the second embodiment shown in FIG. 16, it may be an approximate curve other than a straight line. In the third embodiment as well, in the process of FIG. 18, the input voltage Ei is preferably set to be 1/10 or less of the rated voltage of the motor under test 100.

The starting torque characteristic curve G3 in FIG. 19 is a characteristic measured with the drive circuit 120 connected to the motor under test 100, and is the starting torque characteristic for the drive system composed of the motor under test 100 and the drive circuit 120. It shows. In this way, in the third embodiment, the starting torque characteristics of the motor under test 100 can be accurately measured in a state including the influence of the characteristics of the drive circuit 120. Furthermore, a starting torque characteristic curve G2 for the motor under test 100 alone is determined according to the method of the second embodiment, and a starting torque characteristic curve G3 for the drive system including the motor under test 100 and the drive circuit 120 is determined according to the method of the third embodiment. By determining the difference, it is possible to determine whether the performance of the drive circuit 120 is superior or inferior based on the difference.

D. Fourth embodiment:
FIG. 20 is a block diagram showing the configuration of a motor test system that measures the starting torque of the motor under test 100 in the fourth embodiment. The difference in system configuration between the fourth embodiment and the third embodiment is that a constant voltage power supply 130 is used in addition to the constant current power supply 140, and a switch circuit 170 is added to switch between the two and connect them to the drive circuit 120. The other configuration is the same as that of the third embodiment.

FIG. 21 is a flowchart of measuring the starting torque of the motor under test 100 in the fourth embodiment. In step S310, the motor under test 100 is rotated by the electric brake 230 while a constant current value of DC current is input to the specific phase coil. In step S310, the constant current power supply 140 is connected to the drive circuit 120 via the switch circuit 170, and the DC current from the constant current power supply 140 is input to the specific phase coil via the drive circuit 120. Note that the DC current from the constant current power supply 140 may be input to the motor under test 100 without going through the drive circuit 120. The operation in step S310 is substantially the same as the operation in step S120 of the second embodiment described in FIG. 15. In step S310, the torque meter 220 measures changes in torque due to rotation, and the maximum value of torque due to rotation is determined.

In step S320, the rotating shaft is fixed at the rotational position where the torque reaches the maximum value, and the input of direct current is stopped. The rotation shaft is fixed by actuating an electromagnetic brake 236 connected to the rotation shaft of the electric brake 230 by a drive circuit 237. Note that under normal conditions, the electromagnetic brake 236 is kept in a non-braking state, and the rotating shaft of the electric brake 230 is kept in an unfixed state. A braking device other than the electromagnetic brake 236 may be used to fix the rotating shaft of the motor under test 100 at the rotational position where the torque is at its maximum value.

In step S330, the torque meter 220 is set to peak hold mode, and the power supply to the motor under test 100 is switched from the constant current power supply 140 to the constant voltage power supply 130. The peak hall mode is a mode in which the peak value of the measured torque is held.

In step S340, a rectangular pulse voltage is applied to the specific phase coil of the motor under test 100 to measure the peak torque.

FIG. 22 is an explanatory diagram showing a state in which the rectangular pulse voltage Vp is applied to the specific phase coil in step S340. The drive circuit 120 includes an H-bridge circuit composed of four transistors 121 to 124 that drive the A-phase coil 101. Control signals Sd1 to Sd4 are input to the gate electrodes of the four transistors 121 to 124, respectively. When using the A-phase coil 101 as a specific phase coil, the control signals Sd1 and Sd4 of the two transistors 121 and 124 are set to the on level, and the control signals Sd2 and Sd3 of the other two transistors 122 and 123 are set to the off level. , it is possible to apply the rectangular pulse voltage Vp to the A-phase coil 101. The voltage level Es of the rectangular pulse voltage Vp is approximately the same as the input voltage Ei supplied from the constant voltage power supply 130. In this way, in the process of step S350, the peak torque generated by the motor under test 100 can be measured in a state where the specific input voltage Ei is supplied to the specific phase coil of the motor under test 100. This peak torque corresponds to the starting torque.

The on period To of the rectangular pulse voltage Vp can be arbitrarily set by the test control device 300. However, if the length of the on-period To is too short, the starting torque may not be measured properly, so it is preferable to set the on-period To to 100 μs or more. On the other hand, if the length of the on-period To is too long, the specific phase coil may generate excessive heat, so it is preferable to set the on-period To to 20 ms or less, and more preferably to 10 ms or less. .

When measuring the peak torque in step S340, for example, the initial value of the on-period To of the rectangular pulse voltage Vp is set to a sufficiently small value, and while the on-period To is gradually increased, the length of the on-period To is At each time, the peak value of torque is measured by the torque meter 220. Then, the torque at the time when the peak value does not substantially increase even if the on-period To is increased can be determined as the "peak torque." For example, the maximum value of a moving average of peak values over a certain number of times may be determined as the "peak torque."

In step S350, it is determined whether or not to execute the processes of steps S310 to S340 described above using coils of other phases. If the processing in steps S310 to S340 is not completed for all M-phase coils of the motor under test 100, the process returns from step S350 to step S310, the specific phase coil is changed, and steps S310 to S340 are executed again. . When the processing of steps S310 to S340 is completed for all M-phase coils, the process advances to step S360.

In step S360, the starting torque of the motor under test 100 is determined from the M peak torques obtained for the M phase coils of the motor under test 100. For example, the average value, maximum value, or minimum value of M peak torques can be determined as the starting torque.

Note that it is not necessary to execute the processes of steps S310 to S340 for all M-phase coils, and the processes of steps S310 to S140 may be executed for at least one phase coil. For example, when the processes of steps S310 to S340 are executed for only one phase coil, the peak torque obtained for that coil is directly determined as the starting torque.

In the fourth embodiment, it is possible to measure the starting torque in a state where a constant input voltage Ei is applied to the specific phase coil. This input voltage Ei can be set to a higher voltage value than the input voltage generated according to the DC current in the second and third embodiments, and can be set to a value equal to the rated voltage of the motor 100 under test. Configurable. Further, since the rectangular pulse voltage Vp is used when measuring the starting torque, it is possible to measure the starting torque of the motor under test 100 without causing excessive heat generation in the specific phase coil.

The present disclosure is not limited to the embodiments, embodiments, and modifications described above, and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, embodiments, and modifications corresponding to the technical features in each form described in the summary column of the disclosure may be used to solve some or all of the above-mentioned problems, or In order to achieve some or all of the above-mentioned effects, it is possible to perform appropriate replacements or combinations. Further, unless the technical feature is described as essential in this specification, it can be deleted as appropriate.

(1) According to one embodiment of the present disclosure, a motor testing device used for characteristic testing of a motor under test is provided. This motor testing device includes a first coupling coupled to a rotating shaft of the motor under test, a first rotating shaft coupled to the first coupling, and a second rotating shaft, and a torque meter that measures torque between a rotating shaft and the second rotating shaft; a second coupling coupled to the second rotating shaft of the torque meter; and a rotating shaft coupled to the second coupling. an electric brake having a coreless motor structure; and an AC/DC conversion unit that is electrically connected to a coil of the electric brake and converts an AC induced voltage generated in the coil into a DC voltage; A DC load unit that is electrically connected to the AC/DC conversion unit and consumes power from the DC voltage. The DC load section has a configuration in which a variable current control section that variably adjusts a DC current value and a resistor are arranged in series between two input terminals to which the DC voltage is applied.
According to this motor testing device, an electric brake having a coreless motor structure is used, and the AC induced voltage of the electric brake generated by the rotation of the motor under test is converted into DC voltage, and the electric power is consumed in the DC load section. It is possible to test the transient response characteristics of the motor under test against sudden transient changes.

(2) A method of measuring the characteristics of the motor under test using the motor testing device, the method comprising: connecting the motor under test to the motor testing device and measuring the TN characteristics of the motor under test. The loss torque of the loss TN characteristic created in advance showing the relationship between the process, the loss torque corresponding to the loss of the motor test device in a state where the motor under test is not connected, and the rotation speed, A method comprising the step of determining a corrected TN characteristic for the motor under test by performing a correction that is added to the torque of the TN characteristic of the motor under test.
According to this method, it is possible to obtain the corrected TN characteristic of the motor under test alone, which does not include a loss torque component corresponding to the loss of the motor test device.

(3) A method of measuring the starting torque of the motor under test using the motor test device, wherein (a) where M is an integer of 2 or more, the motor under test having an M-phase coil is (b) measuring the input voltage of the specific phase coil by inputting a DC current of a constant current value to one specific phase coil of the M phase coils while connected to a test device; (c) determining the maximum torque of the torque change accompanying the rotation by applying rotation to the motor under test with the electric brake while the DC current of the current value is input to the specific phase coil; (d) determining a plurality of the maximum torques corresponding to the plurality of input voltages with respect to the specific phase coil by changing the current value and performing the steps (a) to (b) a plurality of times; (e) creating a starting torque characteristic curve showing a change in starting torque according to the plurality of input voltages using the plurality of maximum torques corresponding to the plurality of input voltages; and calculating a starting torque for a specific voltage higher than the plurality of input voltages by extrapolation.
According to this method, the starting torque of the motor under test alone can be accurately measured without being influenced by the drive circuit.

(4) A method of measuring the starting torque of the motor under test using the motor test device, wherein (a) where M is an integer of 2 or more, the motor under test having an M-phase coil is Connected to a test device, with the PWM duty of the drive circuit of the motor under test regarding one specific phase coil of the M-phase coils set to 100%, a constant voltage is applied to the specific phase coil via the drive circuit. (b) measuring the input voltage of the drive circuit by inputting the DC current of the constant current value to the specific phase coil by the electric brake; (c) changing the constant current value and performing the steps (a) to (b) multiple times; (d) calculating the plurality of maximum torques corresponding to the plurality of input voltages with respect to the specific phase coil; (e) calculating a starting torque for a specific voltage higher than the plurality of input voltages by extrapolating the starting torque characteristic curve; and, including.
According to this method, the starting torque regarding the drive system including the motor under test and the drive circuit can be accurately measured.

(5) In the above method, in the step (d), one phase coil among the M phase coils is sequentially selected as the specific phase coil and the steps (a) to (c) are executed; The method may include a step of selecting an average value, a maximum value, or a minimum value of the M maximum torques for the M-phase coil as the starting torque for each of the plurality of input voltages.
According to this method, the starting torque can be determined more accurately.

(6) A method for measuring the starting torque of the motor under test using the motor test device, wherein (a) where M is an integer of 2 or more, the motor under test having an M-phase coil is While connected to a test device and inputting a constant current value of DC current to one specific phase coil of the M-phase coils through the drive circuit of the motor under test, the electric brake is applied to the motor under test. (b) stopping the rotation of the electric brake at the rotation angle at which the maximum torque value of the torque changes is reached to maintain the rotation angle; and (c) measuring the peak torque by applying a rectangular pulse voltage of a specific voltage value to the specific phase coil of the motor under test via the drive circuit while maintaining the rotation angle of the electric brake. and (d) determining a starting torque of the motor under test using the peak torque.
According to this method, the starting torque of the motor under test for a specific voltage value can be accurately measured.

(7) In the above method, in the step (d), one phase coil of the M phase coils is sequentially selected as the specific phase coil and the steps (a) to (c) are executed; The method may include a step of selecting an average value, a maximum value, or a minimum value of the M peak torques for the M-phase coil as the starting torque.
According to this method, the starting torque can be determined more accurately.

DESCRIPTION OF SYMBOLS 100... Motor under test, 101... A phase coil, 104... Magnetic sensor, 110... Rotating shaft, 120... Drive circuit, 121-124... Transistor, 130... Constant voltage power supply, 140... Constant current power supply, 150... Input ammeter , 151... Phase ammeter, 160... Input voltmeter, 161... Phase voltmeter, 170... Switch circuit, 200... Motor test device, 211... First coupling, 212... Second coupling, 220... Torque meter, 221 ...First rotating shaft, 222... Second rotating shaft, 230... Electric brake, 231A... A phase coil, 231B... B phase coil, 232... Rotating shaft, 234... Magnetic sensor, 234A... A phase magnetic sensor, 234B... B Phase magnetic sensor, 235...Drive circuit, 236...Electromagnetic brake, 237...Drive circuit, 240...AC/DC converter, 241A...Full wave rectifier circuit, 241B...Full wave rectifier circuit, 242...Smoothing capacitor, 243A...Polarity separation Circuit, 243B... Polarity separation circuit, 246p, 246n... Output terminal, 250... DC load section, 251p, 251n... Input terminal, 252... Variable current control section, 253... Transistor, 254... Operational amplifier, 255... Current command section, 256 ...Resistor, 260...Power meter, 270...Test connection structure, 300...Test control device, 310...Memory

Claims (7)

A motor testing device used for characteristic testing of a motor under test,
a first coupling connected to the rotating shaft of the motor under test;
a torque meter having a first rotating shaft and a second rotating shaft connected to the first coupling, and measuring torque between the first rotating shaft and the second rotating shaft;
a second coupling connected to the second rotating shaft of the torque meter;
an electric brake having a rotating shaft connected to the second coupling, the electric brake having a coreless motor structure;
an AC/DC converter that is electrically connected to the coil of the electric brake and converts an AC induced voltage generated in the coil into a DC voltage;
a DC load unit electrically connected to the AC/DC conversion unit and consuming power from the DC voltage;
Equipped with
The DC load unit has a configuration in which a variable current control unit that variably adjusts a DC current value and a resistor are arranged in series between two input terminals to which the DC voltage is applied.
Motor testing equipment. A method for measuring characteristics of the motor under test using the motor testing device according to claim 1, comprising:
connecting the motor under test to the motor testing device and measuring the TN characteristics of the motor under test;
The loss torque of the loss TN characteristic created in advance, which shows the relationship between the loss torque corresponding to the loss of the motor testing device in a state where the motor under test is not connected, and the rotation speed, is calculated by the test object. determining a corrected TN characteristic for the motor under test by performing a correction that is added to the torque of the TN characteristic of the motor;
method including. A method for measuring the starting torque of the motor under test using the motor testing device according to claim 1, comprising:
(a) When M is an integer of 2 or more, when the motor under test having an M-phase coil is connected to the motor testing device, a constant current value is applied to one specific phase coil among the M-phase coils. inputting a direct current and measuring the input voltage of the specific phase coil;
(b) applying rotation to the motor under test with the electric brake while inputting the DC current of the constant current value to the specific phase coil, and determining the maximum torque of the torque change accompanying the rotation;
(c) determining a plurality of maximum torques corresponding to a plurality of input voltages with respect to the specific phase coil by changing the constant current value and performing the steps (a) to (b) a plurality of times; and,
(d) using the plurality of maximum torques corresponding to the plurality of input voltages to create a starting torque characteristic curve showing a change in starting torque according to the plurality of input voltages;
(e) calculating a starting torque for a specific voltage higher than the plurality of input voltages by extrapolating the starting torque characteristic curve;
including methods. A method for measuring the starting torque of the motor under test using the motor testing device according to claim 1, comprising:
(a) When M is an integer of 2 or more, the motor under test having an M-phase coil is connected to the motor testing device, and the motor under test is driven with respect to one specific phase coil among the M-phase coils. inputting a DC current of a constant current value to the specific phase coil via the drive circuit with the PWM duty of the circuit set to 100%, and measuring the input voltage of the drive circuit;
(b) applying rotation to the motor under test with the electric brake while inputting the DC current of the constant current value to the specific phase coil, and determining the maximum torque of the torque change accompanying the rotation;
(c) determining a plurality of maximum torques corresponding to a plurality of input voltages with respect to the specific phase coil by changing the constant current value and performing the steps (a) to (b) a plurality of times; and,
(d) using the plurality of maximum torques corresponding to the plurality of input voltages to create a starting torque characteristic curve showing a change in starting torque according to the plurality of input voltages;
(e) calculating a starting torque for a specific voltage higher than the plurality of input voltages by extrapolating the starting torque characteristic curve;
including methods. The method according to claim 3 or 4,
The step (d) includes:
One phase coil among the M phase coils is sequentially selected as the specific phase coil and the steps (a) to (c) are performed, and for each of the plurality of input voltages, the M phase coils for the M phase coil are selecting an average value, a maximum value, or a minimum value of the maximum torques as the starting torque;
including methods. A method for measuring the starting torque of the motor under test using the motor testing device according to claim 1, comprising:
(a) When M is an integer of 2 or more, the motor under test having an M-phase coil is connected to the motor testing device, and one of the M-phase coils is connected to the motor testing device through the drive circuit of the motor under test. a step of applying rotation to the motor under test with the electric brake while inputting a DC current of a constant current value to a specific phase coil, and measuring a torque change accompanying the rotation;
(b) stopping the rotation of the electric brake at the rotation angle at which the maximum torque value among the torque changes is achieved, and maintaining the rotation angle;
(c) measuring peak torque by applying a rectangular pulse voltage of a specific voltage value to the specific phase coil of the motor under test via the drive circuit while maintaining the rotation angle of the electric brake; ,
(d) determining a starting torque of the motor under test using the peak torque;
method including. 7. The method according to claim 6,
The step (d) includes:
One phase coil among the M phase coils is sequentially selected as the specific phase coil and the steps (a) to (c) are executed, and the average value and the maximum value of the M peak torques for the M phase coil are determined. selecting a value or a minimum value as the starting torque;
including methods.

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