JP2014167433A - Device for detecting number of revolutions and testing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress incorrect calculation of the number of revolutions of a motor.SOLUTION: A first signal conversion part 44 is provided near an encoder 42, a second signal conversion part 46 is provided near a number-of-revolutions calculation part 48, and the first signal conversion part 44 and the second signal conversion part 46 are connected to each other by a plurality of signal conductors. Then, in the first signal conversion part 44, a pulse signal from the encoder 42 is converted into a plurality of signals having a frequency less than a carrier frequency of a converter 26 and an inverter 28 and they are outputted. In the second signal conversion part 46, the plurality of signals from the first signal conversion part 44 are used and decoded into the pulse signal from the encoder 42, and the pulse signal is outputted to the number-of-revolutions calculation part 48. Thereby, the number of revolutions of the motor can be accurately calculated even if a harmonic noise due to switching of the converter 26 and the inverter 28 is superimposed on the signal of a communication wire between the first signal conversion part 44 and the second signal conversion part 46.

Description

  The present invention relates to a rotation speed detection device and a test device.

  Conventionally, a drive motor connected via a flexible coupling to the output side or input side of the power transmission system device, a load sensor unit disposed between the power transmission system device mounting surface and the device support unit mounting surface, The load sensor unit is mounted oppositely to the power transmission system device mounting surface and the device support unit mounting surface, and the center of the transmission shaft of the power transmission system device is sandwiched between the mounting plates. And a plurality of load sensors arranged at equidistant positions from each other, a power transmission system equipment testing apparatus has been proposed (see, for example, Patent Document 1). In this test equipment, the performance of the power transmission system is judged by calculating the torque reaction force, thrust direction component force, and radial direction component force of the power transmission device mounting surface by the arithmetic processing unit using the signal from the load sensor. And doing analysis.

JP 2000-105171 A

  In such a test apparatus, an encoder is attached to the rotating shaft of the drive motor, and the rotation speed of the drive motor may be calculated by an arithmetic processing unit using an output signal (pulse signal) from the encoder. In this case, when the frequency of the output signal from the encoder is high, noise due to switching of the inverter driving the drive motor is superimposed on the signal line connecting the encoder and the arithmetic processing unit, and the rotational speed of the drive motor is erroneously calculated. May occur.

  The main object of the rotational speed detection device and the test device of the present invention is to suppress erroneous calculation of the rotational speed of the motor.

  The rotational speed detection device and the test device of the present invention employ the following means in order to achieve the main object described above.

The rotational speed detection device of the present invention is
A rotation speed detection device that is mounted on a test apparatus including a motor attached to a rotating shaft to be tested and an inverter for driving the motor, and detects the rotation speed of the motor,
An encoder attached to the rotating shaft of the motor;
First signal conversion means for converting an output signal from the encoder into a plurality of signals and outputting the signals;
Second signal conversion means for decoding and outputting a plurality of output signals from the first signal conversion means to output signals from the encoder;
A rotational speed calculating means for calculating the rotational speed of the motor using an output signal from the second signal converting means;
It is a summary to provide.

  In this rotational speed detection device of the present invention, an output signal (pulse signal) from an encoder attached to the rotating shaft of the motor is converted into a plurality of signals by the first signal conversion means and output, and the first signal conversion means The plurality of output signals are decoded into output signals from the encoder by the second signal conversion means and output, and the rotational speed of the motor is calculated using the output signals from the second signal conversion means. Therefore, if the first signal converting means converts the signals into a plurality of signals having a frequency lower than the carrier frequency of the inverter and outputs the signals to the second signal converting means, the communication between the first signal converting means and the second signal converting means. Even if harmonic noise due to switching of the inverter is superimposed on the signal of the line, the rotational speed of the motor can be accurately calculated.

  In such a rotational speed detection device of the present invention, the first signal conversion means is means for converting the output signal from the encoder into a plurality of signals having a frequency lower than the carrier frequency of the inverter and outputting the signal. You can also

  Further, in the rotation speed detection device of the present invention, the first signal converting means has a post-conversion frequency obtained by dividing the frequency of the output signal from the encoder by a coefficient corresponding to the frequency of the output signal from the encoder. A signal and a coefficient corresponding signal corresponding to the coefficient value, and the second signal converting means outputs the signal from the encoder using the signal of the converted frequency and the coefficient corresponding signal. It can also be a means for decoding and outputting a signal. In this way, the signal can be easily converted by the first signal converting means and the second signal converting means.

  In the rotational speed detection device of the present invention of this aspect, the first signal converting means and the second signal converting means are configured to calculate one of the signals for the converted frequency and the maximum frequency of the output signal from the encoder. The value divided by the power of value 2 may be connected by the number of the sum of the minimum number of powers that is less than the carrier frequency of the inverter. By so doing, it is possible to connect the first signal conversion means and the second signal conversion means with the minimum necessary signal lines.

The test apparatus of the present invention
A test apparatus comprising: a motor attached to a rotation shaft to be tested; an inverter for driving the motor; and a rotation speed detection device that detects the rotation speed of the motor,
The rotational speed detection device is
An encoder attached to the rotating shaft of the motor;
First signal conversion means for converting an output signal from the encoder into a plurality of signals and outputting the signals;
Second signal conversion means for decoding and outputting a plurality of output signals from the first signal conversion means to output signals from the encoder;
A rotational speed calculating means for calculating the rotational speed of the motor using an output signal from the second signal converting means;
It is a summary to provide.

  In the test apparatus of the present invention, an output signal (pulse signal) from an encoder attached to the rotating shaft of the motor is converted into a plurality of signals by the first signal converting means and output, and a plurality of signals from the first signal converting means are output. The output signal is decoded into an output signal from the encoder by the second signal conversion means and output, and the rotational speed of the motor is calculated using the output signal from the second signal conversion means. Therefore, if the first signal converting means converts the signals into a plurality of signals having a frequency lower than the carrier frequency of the inverter and outputs the signals to the second signal converting means, the communication between the first signal converting means and the second signal converting means. Even if harmonic noise due to switching of the inverter is superimposed on the signal of the line, the rotational speed of the motor can be accurately calculated.

It is a block diagram which shows the outline of a structure of the test apparatus 20 provided with the rotation speed detection apparatus as one Example of this invention. 4 is a flowchart illustrating an example of a first signal conversion routine executed by a first signal conversion unit 44. 4 is a flowchart illustrating an example of a second signal conversion routine executed by a second signal conversion unit 46.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a test apparatus 20 including a rotation speed detection apparatus as an embodiment of the present invention. The test apparatus 20 according to the embodiment is an apparatus used for testing the transmission 10 as a test target. As illustrated, a rotor and a three-phase coil attached to the input shaft 12 of the transmission 10 are provided. A motor 22 having a wound stator, and a converter 26 that converts AC power from an AC power source (for example, three-phase, 210 V, 60 Hz, etc.) 24 into DC power of a predetermined voltage (for example, 350 V) and outputs the same An inverter 28 that drives the motor 22 by converting DC power from the converter 26 into AC power and supplies the motor 22; an electronic control unit (hereinafter referred to as ECU) 30 that controls the converter 26 and the inverter 28; Torque loss from a rotational speed detection device 40 that detects the rotational speed Nm of the motor 22 and a sensor (not shown) attached to the transmission 10. A digital / analog / CAN converter 60 that converts a signal, a hydraulic signal, an oil temperature signal, and the like into a signal for CAN (Controller Area Network) communication and outputs the signal, and an ECU 30 and a rotational speed detection device 40 via a CAN-BUS 68, A personal computer (hereinafter referred to as a PC) 70 that communicates with the digital / analog / CAN converter 60 by CAN communication, and a touch panel 80 that can communicate with the PC 70 are provided.

  Although not shown, the ECU 30 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. The ECU 30 receives a resolver signal from a resolver 32 attached to the rotating shaft of the motor 22, a torque command Tm * from the PC 70, a target rotational speed Nm *, and the like. From the ECU 30 to the converter 26 and the inverter 28. The control signal is output. The ECU 30 calculates the rotational position θm of the rotor of the motor 22 based on the resolver signal from the resolver 32, controls the converter 26 so that a predetermined voltage of DC power is supplied to the inverter 28, and uses the torque command Tm *. The inverter 28 is controlled based on the rotational position θm so that the motor 22 is driven.

  The rotation speed detection device 40 includes an encoder 42 attached to the rotation shaft of the motor 22, a first signal conversion unit 44 that converts a signal from the encoder 42 into a plurality of signals and outputs the signals, and a first signal conversion unit 44. The second signal conversion unit 46 that decodes and outputs the plurality of signals to the signal from the encoder 42, and calculates the rotational speed Nm of the motor 22 based on the signal from the second signal conversion unit 46, and the PC 70 by CAN communication. A rotation speed calculation unit 48 that outputs to The first signal conversion unit 44 is disposed in the vicinity of the encoder 42, the second signal conversion unit 46 is disposed in the vicinity of the rotation speed calculation unit 48, and the first signal conversion unit 44 and the second signal conversion unit 46 are For example, they are connected by a plurality of signal lines of about several m to several tens m.

  The encoder 42 is a known rotary including a disk having slits formed on the outer peripheral side at predetermined intervals, and a light emitting element and a light receiving element disposed at corresponding positions in the rotation axis direction of the motor 22 with the disk interposed therebetween. It is configured as an encoder. The encoder 42 outputs a pulse signal as the rotating shaft (disk) of the motor 22 rotates.

  Although not shown, each of the first signal conversion unit 44, the second signal conversion unit 46, and the rotation speed calculation unit 48 is configured as a microprocessor centered on a CPU, and stores a processing program in addition to the CPU. A ROM, a RAM for temporarily storing data, and an input / output port are provided. The rotation speed calculation unit 48 calculates the rotation speed Nm of the motor 22 by counting the number of pulses per unit time (for example, 0.01 seconds).

  In the embodiment, the number of slits (number of pulses per rotation) of the disk of the encoder 42 is 1000 and the maximum number of rotations Nmax of the motor 22 is 6000 rpm (= 100 rps), that is, pulses from the encoder 42. The maximum frequency Fmax of the signal is 100 kHz. Further, the converter 26 and the inverter 28 are driven at a carrier frequency (switching frequency) of 12.5 kHz. Furthermore, the first signal conversion unit 44 and the second signal conversion unit 46 are connected by four signal lines (transmission paths).

  In the test apparatus 20 of the embodiment configured as described above, as a test of the transmission 10, a test condition (for example, a torque command Tm * of the motor 32, a target rotational speed Nm *, etc.) is input by the user to the touch panel 80. When the start is instructed, the test conditions are transmitted from the touch panel 80 to the motor 22 via the PC 70, and the converter 26 and the inverter 28 are controlled according to the test conditions. Then, the rotational speed Nm of the motor 22 at that time is detected by the rotational speed detector 40 and input to the PC 70, or the loss torque, hydraulic pressure, oil temperature, etc. are detected by a sensor (not shown) of the transmission 10 and the like. The data is input to the PC 70 via the analog / CAN converter 60, and the PC 70 performs analysis based on such information.

  Next, the operation of the rotation speed detection device 40 included in the test apparatus 20 of the embodiment configured as described above, particularly, the operation of the first signal conversion unit 44 and the second signal conversion unit 46 will be described. FIG. 2 is a flowchart showing an example of a first signal conversion routine executed by the first signal conversion unit 44, and FIG. 3 shows an example of a second signal conversion routine executed by the second signal conversion unit 46. It is a flowchart. These routines are executed repeatedly. Hereinafter, it demonstrates in order.

  When the first signal conversion routine is executed, the first signal conversion unit 44 inputs the frequency of the output signal from the encoder 42 as the encoder output frequency Fin (step S100). Here, the encoder output frequency Fin is input by counting the number of pulses per unit time (for example, 0.01 seconds).

  When the encoder output frequency Fin is input in this way, the input encoder output frequency Fin is compared with 1/8 (12.5 kHz) of the maximum frequency Fmax (step S110), and the encoder output frequency Fin is 1/8 of the maximum frequency Fmax. If less than the value, the encoder output frequency Fin is set as the post-conversion frequency Ftmp, the mode signal Mode1 is set to the value 0, the mode signal Mode2 is set to the value 0, and the mode signal Mode3 is set to the value 0 (step S120). A pulse signal of frequency Ftmp and mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is terminated.

  When the encoder output frequency Fin is equal to or greater than 1/8 of the maximum frequency Fmax in step S110, the encoder output frequency Fin is compared with 2/8 (25 kHz) of the maximum frequency Fmax (step S130), and the encoder output frequency Fin is the maximum. When the frequency is less than two-eighth of the frequency Fmax, half of the encoder output frequency Fin is set as the converted frequency Ftmp, the mode signal Mode1 has a value 1, the mode signal Mode2 has a value 0, and the mode signal Mode3 has a value 0. Is set (step S140), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is terminated. In this case, the post-conversion frequency Ftmp is a frequency within the range of 6.25 kHz or more and less than 12.5 kHz.

  When the encoder output frequency Fin is 2/8 or more of the maximum frequency Fmax in step S130, the encoder output frequency Fin is compared with 3/8 (37.5 kHz) of the maximum frequency Fmax (step S150), and the encoder output frequency Fin Is less than 3/8 of the maximum frequency Fmax, 1/3 of the encoder output frequency Fin is set as the converted frequency Ftmp, and the value 0 is set to the mode signal Mode1, the value 1 is set to the mode signal Mode2, and the mode signal Mode3 is set to The value 0 is set (step S160), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is finished. In this case, the post-conversion frequency Ftmp is a frequency within a range of about 8.3 kHz to less than 12.5 kHz.

  When the encoder output frequency Fin is not less than 3/8 of the maximum frequency Fmax in step S150, the encoder output frequency Fin is compared with 4/8 (50 kHz) of the maximum frequency Fmax (step S170), and the encoder output frequency Fin is maximum. When the frequency is less than 4/8 of the frequency Fmax, one fourth of the encoder output frequency Fin is set as the converted frequency Ftmp, and the mode signal Mode1 has a value 1, the mode signal Mode2 has a value 1, and the mode signal Mode3 has a value 0. Is set (step S180), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2 and Mode3 are output (step S260), and this routine is terminated. In this case, the post-conversion frequency Ftmp is a frequency within a range of about 9.4 kHz or more and less than 12.5 kHz.

  When the encoder output frequency Fin is not less than 4/8 of the maximum frequency Fmax in step S170, the encoder output frequency Fin is compared with 5/8 (62.5 kHz) of the maximum frequency Fmax (step S190). Is less than 5/8 of the maximum frequency Fmax, 1/5 of the encoder output frequency Fin is set as the post-conversion frequency Ftmp, the mode signal Mode1 has the value 0, the mode signal Mode2 has the value 0, and the mode signal Mode3 has the The value 1 is set (step S200), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is finished. In this case, the post-conversion frequency Ftmp is a frequency within the range of 10 kHz or more and less than 12.5 kHz.

  When the encoder output frequency Fin is 5/8 or more of the maximum frequency Fmax in step S190, the encoder output frequency Fin is compared with 6/8 (75 kHz) of the maximum frequency Fmax (step S210), and the encoder output frequency Fin is maximum. When the frequency is less than 6/8 of the frequency Fmax, 1/6 of the encoder output frequency Fin is set as the converted frequency Ftmp, the mode signal Mode1 has a value 1, the mode signal Mode2 has a value 0, and the mode signal Mode3 has a value 1 Is set (step S220), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is terminated. In this case, the post-conversion frequency Ftmp is a frequency within a range of about 10.4 kHz or more and less than 12.5 kHz.

  When the encoder output frequency Fin is not less than 6/8 of the maximum frequency Fmax in step S210, the encoder output frequency Fin is compared with 7/8 (87.5 kHz) of the maximum frequency Fmax (step S230). Is less than 7/8 of the maximum frequency Fmax, 1/7 of the encoder output frequency Fin is set as the post-conversion frequency Ftmp, the mode signal Mode1 has a value 0, the mode signal Mode2 has a value 1, and the mode signal Mode3 has a The value 1 is set (step S240), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2, Mode3 are output (step S260), and this routine is finished. In this case, the post-conversion frequency Ftmp is a frequency within a range of about 10.7 kHz to less than 12.5 kHz.

  If the encoder output frequency Fin is 7/8 or more of the maximum frequency Fmax in step S230, 1/8 of the encoder output frequency Fin is set as the converted frequency Ftmp, and the mode signal Mode1 is set to the value 1, and the mode signal Mode2 is set. The value 1 is set to the value 1 and the mode signal Mode3 (step S250), the pulse signal of the set post-conversion frequency Ftmp and the mode signals Mode1, Mode2 and Mode3 are output (step S260), and this routine is finished. In this case, the post-conversion frequency Ftmp is a frequency within the range of about 10.9 kHz to less than 12.5 kHz.

  As described above, in the first signal conversion unit 44, the pulse signal of the converted frequency Ftmp less than 12.5 kHz according to the encoder output frequency Fin and the encoder output frequency Fin (the encoder output frequency Fin and the converted frequency). Mode signals Mode 1, Mode 2, Mode 3 (showing the relationship with Ftmp) are output to the second signal converter 46. Since the mode signals Mode1, Mode2 and Mode3 are on or off signals, they are naturally signals having a frequency of less than 12.5 kHz.

  When the encoder 42 and the rotation speed calculation unit 48 are connected by a single signal line (transmission path), harmonic noise (noise having a frequency that is an integral multiple of the carrier frequency) due to switching of the switching elements of the converter 26 and the inverter 28 occurs. If the signal line from the encoder 42 to the rotation speed calculation unit 48 is affected, the rotation speed calculation unit 48 may erroneously calculate the rotation speed. In contrast, in the embodiment, the four signals output from the first signal conversion unit 44 to the second signal conversion unit 46 all have a frequency less than 12.5 kHz, that is, the carrier of the converter 26 and the inverter 28. Since the frequency becomes less than the frequency, harmonic noise due to switching of the switching elements of the converter 26 and the inverter 28 is changed from the first signal conversion unit 44 arranged in the vicinity of the encoder 42 to the second signal arranged in the vicinity of the rotational speed calculation unit 48. It can suppress affecting the signal line to the conversion part 46, and can suppress miscalculating the rotation speed of the motor 22. FIG.

  Note that the number of signal lines connecting the first signal conversion unit 44 and the second signal conversion unit 46 is one for the pulse signal having the converted frequency Ftmp and the maximum frequency Fmax of the pulse signal from the encoder 42. If the sum of the value divided by the power of 2 (two types of on / off for each mode signal) (the number of mode signals) is less than the carrier frequency of the converter 26 or the inverter 28, The number of signal lines can be minimized. In the embodiment, since the maximum frequency Fmax of the pulse signal from the encoder 42 is 100 kHz and the converter 26 and the inverter 28 are driven at a carrier frequency of 12.5 kHz, a value obtained by dividing 100 kHz by a power of 2 is obtained. The minimum value of the power to be less than 12.5 kHz is a value of 3. Therefore, the first signal conversion unit 44 and the second signal conversion unit 46 may be connected by four signal lines (transmission paths).

  Next, the second signal conversion routine of FIG. 3 will be described. When the second signal conversion routine is executed, the second signal conversion unit 46 first calculates the frequency (converted frequency) Ftmp of the pulse signal from the first signal conversion unit 44 and the mode signals Mode1, Mode2, Mode3. Input (step S300).

  When data is input in this way, the values of the input mode signals Mode1, Mode2 and Mode3 are examined (steps S310 to S370). When the mode signal Mode3 is 0, the mode signal Mode2 is 0, and the mode signal Mode1 is 0 (steps S310, S320, S330), the converted frequency Ftmp is set to the output frequency Fout (step S380). The pulse signal having the set output frequency Fout is output to the rotation speed calculation unit 48 (step S460), and this routine is terminated. By such processing, the output signal from the encoder 42 can be decoded and output to the rotation speed calculation unit 48.

  When the mode signal Mode3 is 0 and the mode signal Mode2 is 0 and the mode signal Mode1 is 1 (steps S310, S320, S330), a value obtained by multiplying the converted frequency Ftmp by the value 2 is set as the output frequency Fout. (Step S390), a pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is terminated.

  When the mode signal Mode3 is 0, the mode signal Mode2 is 1 and the mode signal Mode1 is 0 (steps S310, S320, S340), a value obtained by multiplying the converted frequency Ftmp by the value 3 is set as the output frequency Fout. (Step S400), the pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is finished.

  When the mode signal Mode3 is 0, the mode signal Mode2 is 1 and the mode signal Mode1 is 1 (steps S310, S320, S340), a value obtained by multiplying the converted frequency Ftmp by the value 4 is set as the output frequency Fout. (Step S410), the pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is finished.

  When the mode signal Mode3 is the value 1, the mode signal Mode2 is the value 0, and the mode signal Mode1 is the value 0 (steps S310, S350, S360), a value obtained by multiplying the converted frequency Ftmp by the value 5 is set as the output frequency Fout. (Step S420), a pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is finished.

  When the mode signal Mode3 is the value 1, the mode signal Mode2 is the value 0, and the mode signal Mode1 is the value 1 (steps S310, S350, S360), a value obtained by multiplying the converted frequency Ftmp by the value 6 is set as the output frequency Fout. (Step S430), a pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is terminated.

  When the mode signal Mode3 is the value 1, the mode signal Mode2 is the value 1, and the mode signal Mode1 is the value 0 (steps S310, S350, S370), a value obtained by multiplying the converted frequency Ftmp by the value 7 is set as the output frequency Fout. (Step S440), a pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is terminated.

  When the mode signal Mode3 is the value 1, the mode signal Mode2 is the value 1, and the mode signal Mode1 is the value 1 (steps S310, S350, S370), a value obtained by multiplying the converted frequency Ftmp by the value 8 is set as the output frequency Fout. (Step S450), a pulse signal of the set output frequency Fout is output to the rotation speed calculation unit 48 (Step S460), and this routine is terminated.

  The second signal converter 46 converts the frequency of the pulse signal from the converted frequency Ftmp to the output frequency Fout using the pulse signal of the converted frequency Ftmp and the mode signals Mode1, Mode2, Mode3 (the encoder output frequency Fin The signal is decoded into a pulse signal), and the pulse signal having the output frequency Fout is output to the rotation speed calculation unit 48.

  According to the rotation speed detection device 40 provided in the test apparatus 20 of the embodiment described above, the first signal conversion unit 44 is provided in the vicinity of the encoder 42 and the second signal conversion unit 46 is provided in the vicinity of the rotation speed calculation unit 48. The first signal converter 44 and the second signal converter 46 are connected by a plurality of signal lines. The first signal conversion unit 44 converts the pulse signal from the encoder 42 into a plurality of signals lower than the carrier frequency of the converter 26 and the inverter 28 and outputs the signals, and the second signal conversion unit 46 outputs the first signal conversion unit. The plurality of signals from 44 are decoded into pulse signals from the encoder 42 and output to the rotation speed calculation unit 48. As a result, even if harmonic noise due to switching of the converter 26 or the inverter 28 is superimposed on the signal of the communication line between the first signal conversion unit 44 and the second signal conversion unit 46, the rotational speed of the motor is accurately determined. It can be calculated.

  In the rotation speed detection device 40 included in the test device 20 of the embodiment of the embodiment, the first signal conversion unit 44 and the second signal conversion unit 46 are connected to one for the pulse signal of the converted frequency Ftmp and the encoder 42. The value obtained by dividing the maximum frequency Fmax of the pulse signal by a power of 2 is connected by the number of the sum of the minimum number of powers that is less than the carrier frequency of the converter 26 and the inverter 28, It is good also as what connects by the more number. For example, in the embodiment, when the maximum frequency Fmax of the pulse signal from the encoder 42 is 100 kHz and the converter 26 and the inverter 28 are driven at a carrier frequency of 12.5 kHz, the first signal converter 44 and the second signal converter 46 is connected by four signal lines (transmission paths), but in this case, it may be connected by five or six signal lines.

  In the test apparatus 20 of the embodiment, the AC power from the AC power source 24 is converted into DC power by the converter 26 and the DC power is converted to AC power by the inverter 28 and supplied to the motor 22. It is also possible to convert the DC power from the AC power into AC power by the inverter 28 and supply it to the motor 22.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor 22 corresponds to a “motor”, the inverter 28 corresponds to an “inverter”, the test device 20 corresponds to a “test device”, and the rotation speed detection device 40 corresponds to a “rotation speed detection device”. The encoder 42 corresponds to “encoder”, the first signal converter 44 corresponds to “first signal signal converter”, the second signal converter 46 corresponds to “second signal signal converter”, The rotation speed calculation unit 48 corresponds to “rotation speed calculation means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of rotational speed detection devices and test devices.

  DESCRIPTION OF SYMBOLS 10 Transmission, 12 Input shaft, 20 Test apparatus, 22 Motor, 24 AC power supply, 26 Converter, 28 Inverter, 30 Electronic control unit (ECU), 32 Resolver, 40 Speed detector, 42 Encoder, 44 1st signal conversion Unit, 46 second signal conversion unit, 48 revolution number calculation unit, 60 digital-analog / CAN converter, 68 CAN-BUS, 70 PC, 80 touch panel.

Claims (5)

A rotation speed detection device that is mounted on a test apparatus including a motor attached to a rotating shaft to be tested and an inverter for driving the motor, and detects the rotation speed of the motor,
An encoder attached to the rotating shaft of the motor;
First signal conversion means for converting an output signal from the encoder into a plurality of signals and outputting the signals;
Second signal conversion means for decoding and outputting a plurality of output signals from the first signal conversion means to output signals from the encoder;
A rotational speed calculating means for calculating the rotational speed of the motor using an output signal from the second signal converting means;
A rotational speed detection device comprising: The rotation speed detection device according to claim 1,
The first signal converting means is means for converting the output signal from the encoder into a plurality of signals having a frequency lower than the carrier frequency of the inverter and outputting the converted signal.
Rotational speed detection device. The rotation speed detection device according to claim 1 or 2,
The first signal converting means includes a signal having a converted frequency obtained by dividing the frequency of the output signal from the encoder by a coefficient corresponding to the frequency of the output signal from the encoder, and a coefficient corresponding to the value of the coefficient And a corresponding signal.
The second signal converting means is means for decoding and outputting an output signal from the encoder using the signal of the converted frequency and the coefficient corresponding signal.
Rotational speed detection device. The rotation speed detection device according to claim 3,
The first signal converting means and the second signal converting means include one for the signal having the converted frequency and a value obtained by dividing the maximum frequency of the output signal from the encoder by a power of 2 Connected by the number of the sum of the minimum number of powers that is less than the carrier frequency of
Rotational speed detection device. A test apparatus comprising: a motor attached to a rotation shaft to be tested; an inverter for driving the motor; and a rotation speed detection device that detects the rotation speed of the motor,
The rotational speed detection device is
An encoder attached to the rotating shaft of the motor;
First signal conversion means for converting an output signal from the encoder into a plurality of signals and outputting the signals;
Second signal conversion means for decoding and outputting a plurality of output signals from the first signal conversion means to output signals from the encoder;
A rotational speed calculating means for calculating the rotational speed of the motor using an output signal from the second signal converting means;
A test apparatus comprising:

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