JP2018207702A - Power measurement device - Google Patents

Abstract

To reduce variation of a power measured without performing an average processing.SOLUTION: An input power Pin to an inverter device 53, a u-phase voltage Vu that outputs to a motor 54 on the basis of the input power Pin, an output power Pout of the inverter device 53 that generates the v-phase voltage Vv and a w-phase voltage Vw, and a motor output Pm on the basis of the number of rotations N measured from a torque T measured from a torque signal St output from a torque measure 55 mounted to the motor 54 and an A-phase pulse Sa output from a rotation detector 56 are measured at a mechanical angle one period (one period of a Z-phase pulse Sz output from a rotation detector 6) unit of the motor 54.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power measuring device that measures the power of an inverter device that drives a motor.

  As this type of power measuring apparatus, a power measuring apparatus disclosed in Non-Patent Document 1 below is known. First, a configuration of a motor drive system including an inverter device and a motor that are measurement targets of the power measurement device will be described with reference to FIG. The motor drive system 51 includes a power source 52, an inverter device 53, a motor (synchronous motor) 54, a torque meter 55, and a rotation detector (rotometer or rotary encoder in this example) 56, and an output shaft of the motor 54 It is comprised so that the load 61 connected to can be driven. In this case, for example, when the motor 54 is a three-phase motor, the inverter device 53 uses the three-phase AC voltage (u-phase voltage Vu) having a phase difference of 120 degrees based on the input power Pin input from the power source 52. , V-phase voltage Vv and w-phase voltage Vw) are generated and output to motor 54, thereby driving motor 54.

  As shown in FIG. 2, the power measurement device 71 disclosed in Non-Patent Document 1 includes, for example, a power measurement function for four channels CH1 to CH4 and a motor analysis function, and is input to the inverter device 53. The power Pin is measured, the output power Pout output from the inverter device 53 to the motor 54, and the motor output (motor power) Pm of the motor 54 is measured, and the measured input power Pin, output power Pout and motor are measured. Each efficiency of the inverter device 53 and the motor 54 is measured based on the output Pm.

  Specifically, as shown in FIG. 2, the power measuring device 71 measures the input power Pin based on the input voltage Vin and the input current Iin to the inverter device 53 detected by one channel CH1. Further, the power measuring device 71 includes the uv phase voltage Vuv and u phase current Iu to the motor 54 detected by one channel CH2, and the vw phase voltage Vvw and v phase to the motor 54 detected by one channel CH3. Output power Pout is measured based on current Iv, wu-phase voltage Vwu to motor 54 detected by one channel CH4, and w-phase current Iw. The power measuring device 71 also measures the torque T [N · m] measured based on the torque signal St output from the torque meter 55 and the A-phase pulse Sa as the rotation pulse signal output from the rotation detector 56. Alternatively, the motor output Pm is measured based on the rotational speed N [rpm] measured based on the B-phase pulse Sb.

  In addition, the power measuring device 71 is, for example, one input waveform in order to accurately measure the input power Pin, the output power Pout and the motor output Pm, and the efficiency of the inverter device 53 and the motor 54 calculated from these. A zero cross point of (reference waveform) is detected, and a section (measurement section) to be measured is determined based on the detected zero cross point. For example, the power measuring device 71 detects the zero-cross point using any one of the u-phase current Iu, the v-phase current Iv, and the w-phase current Iw as a reference waveform, and detects the next new point from the detection timing of the new zero-cross point. An interval until the detection timing of the zero cross point (that is, one electrical angle period of the motor 54) is determined as one common measurement interval, and the input power Pin, the output power Pout, the motor output Pm, etc. are determined for each measurement interval. taking measurement.

High-accuracy power measurement of SiC inverter (UG_PW6001_SiCInv_J2-6ZM-1.pdf), Hioki Electric Co., Ltd. website, [Search May 11, 2017], Internet <https://www.hioki.co.jp/hdfile .jsp? id = 31531>

  However, the power measuring device 71 described above has the following problems to be improved. Specifically, the magnetic force generated in each magnetic pole of the stator constituting the motor 54 is completely aligned, the magnetic force of each magnetic pole of the rotor is completely aligned, or in the rotation direction (circumferential direction) of the rotor. It is difficult to form the positions of the magnetic poles of the rotor along the rotor and the positions of the magnetic poles of the stator along the rotation direction at equal angular intervals. For this reason, since the motor 54 always has rotation irregularity in one electrical angle cycle, the motor output Pm measured for each electrical angle cycle varies, and as a result, the output power Pout of the inverter device 53 and thus the inverter device. There is a problem that the input power Pin 53 also varies every electrical angle cycle. About this, in the power measuring device 71, variation is reduced by individually performing addition average processing and exponential moving average processing on the input power Pin, the output power Pout, and the motor output Pm that are measured every electrical angle cycle. Although it is possible to increase the response time (the time until the measurement result is displayed) by the time required for the average process, it is not preferable to perform such an average process.

  The present invention has been made to solve such a problem, and a main object of the present invention is to provide a power measuring apparatus that can reduce variations in measured power without performing an averaging process.

  In order to achieve the above object, the power measuring device according to claim 1 is characterized in that at least one of the input power of the inverter device that generates an AC voltage output to the motor based on the input power and the output power output to the motor. A power measuring device for measuring, wherein one of the motors is measured in units of one mechanical angle cycle.

  The power measuring device according to claim 2 is the power measuring device according to claim 1, wherein the input power and the output power are measured, and the efficiency and loss of the inverter device are determined based on the input power and the output power. At least one is measured.

  The power measuring device according to claim 3 is an output power output to the motor of an inverter device that generates an alternating voltage to be output to the motor based on input power, and a torque signal output from a torque meter attached to the motor. And a power measuring device that measures at least one of the motor outputs of the motor based on the rotation pulse signal output from the rotation detector, and measures the one in units of one cycle of the mechanical angle of the motor.

  According to a fourth aspect of the present invention, there is provided the power measuring apparatus according to the third aspect, wherein at least one of the efficiency and loss of the motor is measured based on the measured output power and motor output.

  In the power measuring device according to claim 1, at least one of input power and output power of an inverter device constituting a motor drive system including a motor having one mechanical angle of a plurality of cycles of electrical angles, Measured in units of one mechanical angle cycle. Therefore, according to this power measuring apparatus, it is possible to cancel the variation occurring in each of the input power and the output power for each electrical angle cycle included in one mechanical angle cycle, thereby measuring each mechanical angle cycle. Variation in at least one of input power and output power can be greatly reduced. Further, according to the power measuring apparatus, one of the input power and the output power is measured every one electrical angle cycle, and the average processing is performed on this one measured in a plurality of electrical angle one cycles to obtain the final result. Unlike the apparatus configured to obtain a typical value, the execution of such an average process is unnecessary, so that the response time can be shortened by an amount that can eliminate the time required for executing the average process.

  According to the power measuring device of claim 2, based on the input power and the output power in which the variation is greatly reduced, at least one of the efficiency and the loss of the inverter device is measured in a state in which the variation is greatly reduced. Can do.

  The power measuring device according to claim 3, wherein the output power to the motor of the inverter device constituting the motor drive system including the motor including one motor having one mechanical angle period corresponding to a plurality of electrical angles, and the torque attached to the motor. At least one of the motor output of the motor based on the torque signal output from the meter and the rotation pulse signal output from the rotation detector is measured in units of one mechanical angle. Therefore, according to this power measuring apparatus, it is possible to cancel the variation occurring in each of the output power and the motor output for each electrical angle period included in one mechanical angle period, thereby measuring each mechanical angle period. Variations in at least one of output power and motor output can be greatly reduced. Further, according to this power measuring apparatus, one of the output power and the motor output is measured for each electrical angle cycle, and the average processing is performed on this one measured in a plurality of electrical angle cycles to obtain the final result. Unlike the apparatus configured to obtain a typical value, the execution of such an average process is unnecessary, so that the response time can be shortened by an amount that can eliminate the time required for executing the average process.

  According to the power measuring apparatus of the fourth aspect, based on the output power and the motor output in which the variation is greatly reduced, at least one of the motor efficiency and the loss can be measured in a state in which the variation is greatly reduced. it can.

It is explanatory drawing for demonstrating the connection relationship of the motor drive system MDS containing the inverter apparatus 53, and the electric power measurement apparatus 1. FIG. It is explanatory drawing for demonstrating the connection relation of the motor drive system 51 containing the inverter apparatus 53, and the electric power measurement apparatus 71. FIG.

  Hereinafter, embodiments of a power measuring device will be described with reference to the accompanying drawings.

  First, the configuration of a motor drive system MDS including an inverter device 53 and a motor (for example, a synchronous motor) 54 to be measured will be described with reference to FIG.

  As shown in FIG. 1, as an example, the motor drive system MDS includes a power source 52, an inverter device 53, a motor 54, a torque meter 55, and a rotation detector (a rotary meter that outputs an analog rotation signal or a rotary pulse signal that outputs a rotation pulse signal). The encoder 61 is provided, and a load 61 connected to the output shaft of the motor 54 can be driven. In this case, the power source 52 is configured by a DC power supply device as an example, and outputs a DC voltage Vin (DC constant voltage) to the inverter device 53.

  Inverter device 53 generates an AC voltage to be output to motor 54 based on input power Pin (DC voltage (input voltage) Vin and DC current (input current) Iin input from power supply 52). In this example, as will be described later, the motor 54 is composed of a three-phase six-pole 18-slot synchronous motor, so that the inverter device 53 has a three-phase voltage (u-phase voltage Vu whose phases are shifted by 120 ° each other). , V-phase voltage Vv and w-phase voltage Vw) are generated as AC voltages for driving motor 54.

  As an example, the motor 54 includes a three-phase six-pole 18-slot motor as a synchronous motor. Specifically, the motor 54 has a six-pole rotor (see FIG. 5) having three N-pole and S-pole permanent magnets formed on the outer peripheral surface at an angular interval of 60 ° along the circumferential direction. And a stator (not shown) formed by forming 18 teeth on the inner peripheral surface at an angular interval of 20 ° along the circumferential direction. One end side of this functions as an output shaft (not shown).

  In the motor 54 having the above-described configuration, a cycle in which the rotor makes one rotation (one mechanical angle) is configured by three electrical angles. In this example, it is assumed that the motor 54 to be measured is composed of a plurality of cycles of electrical angles in one mechanical angle cycle.

  The torque meter 55 is attached to the output shaft of the motor 54 and outputs a torque signal St indicating the detected torque T while detecting the torque T [N · m] of the output shaft in real time. The rotation detector 6 is attached to the output shaft of the motor 54 and outputs a rotation pulse signal indicating the rotation speed N [rpm] of the output shaft. In this example, as an example, the rotation detector 6 is composed of a rotary encoder, and each of the A-phase pulse Sa and the B-phase pulse Sb and the Z-phase pulse Sz having a phase difference of 90 ° between them is a rotation pulse signal. Output as. Each pulse Sa, Sb, Sz is a pulse train output in accordance with the rotational displacement of the output shaft of the motor 54, that is, the rotor of the motor 54. Among these, the A-phase pulse Sa and the B-phase pulse Sb are rotated. Each rotation of the rotor is output as a pulse train composed of a plurality of predetermined pulses (for example, several hundreds), and the Z-phase pulse Sz is composed of one pulse for each rotation of the rotor. Output as a pulse train.

  Next, the configuration of the power measuring apparatus 1 will be described with reference to FIG.

  The power measuring apparatus 1 includes, for example, a plurality of A / D conversion units, a processing unit, a display unit, and a storage unit (all not shown), and includes a power measurement function for at least four channels and a motor analysis. With functionality. As shown in FIG. 1 as an example, the power measuring apparatus 1 of this example includes a pair of voltage detection terminals and current detection terminals (both not shown) corresponding to four channels CH1 to CH4, and each channel. A voltage detection signal input via a voltage detection probe (not shown) connected to a pair of voltage detection terminals of CH1 to CH4 and a current detection probe (not shown) connected to a current detection terminal Based on the current detection signal, the instantaneous values of the power P1, P2, P3, and P4 (four types of power) for four channels can be measured in real time at the same timing.

  In this power measuring apparatus 1, as shown in FIG. 1, a voltage detection signal and a direct current Iin (DC voltage Vin (input voltage of the inverter 53) output from the power source 52 to the inverter 53 are included in the channel CH1. The current detection signal for the input current of the inverter device 53 is input. The channel CH2 includes a voltage detection signal for the uv-phase voltage Vuv between the u-phase voltage Vu and the v-phase voltage Vv output from the inverter device 53 to the motor 54, and a current detection signal for the u-phase current Iu. In the channel CH3, a voltage detection signal for the vw phase voltage Vvw between the v phase voltage Vv and the w phase voltage Vw output from the inverter device 53 to the motor 54 and a current detection for the v phase current Iv. The channel CH4 receives a voltage detection signal for the wu-phase voltage Vwu between the w-phase voltage Vw and the u-phase voltage Vu output from the inverter device 53 to the motor 54, and the w-phase current Iw. A current detection signal is input. Thereby, the power measuring device 1 measures the input power Pin to the inverter device 53 as power P1 (hereinafter also referred to as input power Pin). Further, the power measuring device 1 measures the power for each phase output from the inverter device 53 to the motor 54 as each power P2, P3, P4 and adds each power P2, P3, P4 to The output power Pout output from the device 53 to the motor 54 is measured.

  Further, as shown in FIG. 1 as an example, the power measuring device 1 includes a torque detection terminal Pt1 for inputting a torque signal St, and based on the input torque signal St, the instantaneous value of the torque T of the motor 54 is obtained in real time. It is configured to be measurable. Also, in the power measuring apparatus 1, as shown in the figure as an example, at least one of the A-phase pulse Sa and the B-phase pulse Sb (in this example, the A-phase pulse Sa is used as an example. A pulse detection terminal Pt2 for inputting a pulse Sb) is provided, and the rotation speed N of the output shaft of the motor 54 (rotation of the rotor) is based on the input phase pulse (A-phase pulse Sa in this example). Number) instantaneous values can be measured in real time.

  Further, as shown in FIG. 1 as an example, the power measuring device 1 includes a pulse detection terminal Pt3 for inputting a Z-phase pulse Sz, and one cycle of the input Z-phase pulse Sz is defined as one measurement section. Based on the voltage detection signal and the current detection signal input to each of the channels CH1 to CH4 in the measurement section, each power P1, P2, P3, P4 in the measurement section is measured. Therefore, in this example, the power measuring device 1 measures the input power Pin to the inverter device 53 and the output power Pout from the inverter device 53 to the motor 54 in units of this one measurement section. Further, the power measuring apparatus 1 measures the torque T in units of the one measurement section based on the torque signal St input to the torque detection terminal Pt1 in the same one measurement section. Based on the A-phase pulse Sa input to the pulse detection terminal Pt2, the rotational speed N is measured in units of this one measurement section, and based on the torque T and the rotational speed N thus measured, The motor output (motor power) Pm of the motor 54 is measured in the unit of the measurement section.

  Further, the power measuring device 1 measures the loss in the inverter device 53 and the efficiency of the inverter device 53 based on the input power Pin and the output power Pout in the same one measurement period measured in this way, and outputs them. Based on the electric power Pout and the motor output Pm, the loss in the motor 54 and the efficiency of the motor 54 are measured, and these measured values (the input power Pin, the output power Pout, the motor output Pm, the loss and efficiency of the inverter device 53) are measured. And the loss and efficiency of the motor 54) are stored in the storage unit and displayed on the display unit.

  Subsequently, the operation of the power measuring apparatus 1 will be described. When the power measurement device 1 detects an input of a new Z-phase pulse Sz via the pulse detection terminal Pt3, the power measurement device 1 starts measurement processing of the input power Pin, the output power Pout, and the motor output Pm in a new measurement section. The measurement process is continued until the input of the next new Z-phase pulse Sz is detected (until the end of the new measurement section), and then is terminated.

  In this case, in this one measurement section, as described above, the motor 54 always has a rotation unevenness in one electrical angle cycle, and thus the motor output Pm varies for each electrical angle cycle. The output power Pout for the inverter device 53 and thus the input power Pin also vary, but the power measuring device 1 has one mechanical angle section including a plurality of electrical angles (three electrical angles in this example). As measurement intervals, input power Pin, output power Pout, and motor output Pm are measured. For this reason, variations in the input power Pin, the output power Pout, and the motor output Pm for each cycle of the electrical angle included in this measurement section are offset. As a result, variations in the input power Pin, the output power Pout, and the motor output Pm measured for each measurement section are significantly reduced. As a result, the measurement section is based on the input power Pin, the output power Pout, and the motor output Pm. The variation in the loss in the inverter device 53 and the efficiency of the inverter device 53 measured every time, and the loss in the motor 54 and the efficiency of the motor 54 are also greatly reduced. The input power Pin, the output power Pout, and the motor output Pm measured in this one measurement period are the sum of the input powers in one cycle of a plurality of electrical angles included in this one measurement period, and the output power And the total motor output. Therefore, by dividing the input power Pin, the output power Pout, and the motor output Pm measured in this one measurement period by the number of one electrical angle period (three in this example), one electrical angle period is obtained. The input power, the output power, and the motor output may be calculated.

  As described above, the power measuring apparatus 1 measures the input power Pin, the output power Pout, the motor output Pm, and the like for the motor drive system MDS including the motor 54 in which one cycle of the mechanical angle is composed of a plurality of cycles of the electrical angle. A section having the same length as one cycle of the mechanical angle is executed as one measurement section. Therefore, according to the power measuring apparatus 1, variations in the input power Pin, the output power Pout, and the motor output Pm for each electrical angle cycle included in the one measurement section (mechanical angle 1 cycle) can be offset. Variations in the input power Pin, output power Pout, and motor output Pm measured for each measurement section can be greatly reduced. As a result, according to the power measuring device 1, the loss in the inverter device 53 measured for each measurement section based on the input power Pin, the output power Pout, and the motor output Pm, the efficiency of the inverter device 53, and Variations in the loss in the motor 54 and the efficiency of the motor 54 can be greatly reduced. Moreover, in this electric power measurement apparatus 1, one electric measurement period is set as one period of electrical angle, and input electric power Pin, output electric power Pout, and motor output Pm are measured for every electric angle period, and are measured in one electric angle period. Unlike an apparatus configured to perform average processing on each of the input power Pin, output power Pout, and motor output Pm to measure the final input power Pin, output power Pout, and motor output Pm, Since the execution of the process is unnecessary, the response time can be shortened by an amount that can eliminate the time required for executing the average process.

  In the power measuring apparatus 1 described above, one cycle of the mechanical angle of the motor 54 is measured based on the Z-phase pulse Sz output from the rotary encoder as the rotation detector 6 arranged in the motor drive system MDS. Although the structure which detects as an area is employ | adopted, it is not limited to this structure. For example, when the specifications of the rotary encoder are known, the number of A-phase pulses Sa and B-phase pulses Sb output during one mechanical angle cycle of the motor 54 is also a known number of pulses. It is also possible to employ a configuration in which one of the B-phase pulses Sb is counted and it is detected that one cycle of the mechanical angle has arrived each time the counted number of pulses reaches the known number of pulses. Although not shown, a magnetic sensor is arranged in the motor drive system MDS to detect an induced voltage generated in the winding formed on the stator of the motor 54, and one cycle of the detected induced voltage is converted into an electrical angle. By measuring as one period, and multiplying this measured one electrical angle period according to the specifications of the motor 54 (specification that one mechanical angle period is composed of a plurality of known electrical angle periods), A configuration for detecting that one cycle of the mechanical angle has arrived can also be adopted.

  In the above example, the motor drive system MDS includes the power source 52 that outputs the DC voltage Vin to the inverter device 53. However, the DC voltage Vin is not included in the motor drive system MDS, but the motor drive system MDS. It can also be set as the structure input from the outside. When the measurement target of the power measuring device 1 is only the inverter device 53, only the measurement of the input power Pin and the output power Pout and the loss in the inverter device 53 and the efficiency of the inverter device 53, or the input power Pin and the output. A configuration may be adopted in which only the measurement of the power Pout or only one of the input power Pin and the output power Pout is performed with a section having the same length as one mechanical angle period as one measurement section. In this case, since the motor output Pm is not measured, the torque meter 55 becomes unnecessary. When the measurement target of the power measuring apparatus 1 is only the motor 54, only the measurement of the output power Pout and the motor output Pm and the loss in the motor 54 and the efficiency of the motor 54, or the output power Pout and the motor output Pm are measured. A configuration may be adopted in which only the measurement or only one of the output power Pout and the motor output Pm is executed with a section having the same length as one cycle of the mechanical angle as one measurement section. In any of these configurations, it is possible to cancel the variation that occurs in each cycle of the electrical angle, and as a result, it is possible to greatly reduce the variation in the input power Pin and output power Pout that are measured in each measurement section.

1 Power measuring device
6 Rotation detector 53 Inverter device 54 Motor 55 Torque meter 56 Rotation detector Pin input power Pm Motor output Pout Output power Vu, Vv, Vw u phase voltage, v phase voltage, w phase voltage

Claims (4)

A power measuring device that measures at least one of the input power of the inverter device that generates an AC voltage output to the motor based on the input power and the output power output to the motor,
An electric power measuring apparatus that measures the one in units of one mechanical angle of the motor.   The power measurement device according to claim 1, wherein the input power and the output power are measured, and at least one of efficiency and loss of the inverter device is measured based on the input power and the output power. Output power output to the motor of the inverter device that generates an AC voltage to be output to the motor based on the input power, a torque signal output from a torque meter attached to the motor, and a rotation pulse output from the rotation detector A power measuring device that measures at least one of the motor outputs of the motor based on a signal,
An electric power measuring apparatus that measures the one in units of one mechanical angle of the motor.   The power measuring apparatus according to claim 3, wherein at least one of efficiency and loss of the motor is measured based on the measured output power and motor output.

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