JP2011061923A - Device for detecting motor revolution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor revolution detection device that restrains the number of revolutions far from the real number of revolutions of a motor from being detected. <P>SOLUTION: In the motor revolution detection device, a memory 42 stores the cycle of pulse signals measured with a measurement unit 43 in order as cyclic data. An operation unit 41 calculates the moving average of a specified number of pieces from the newer one out of stored cyclic data each time the memory 42 stores the cyclic data, and calculates the number of revolutions of the first fan motor 101 and the second fan motor 102 from the moving average. Thereby, even when noise is received as a pulse signal and that an abnormal value is stored as cyclic data, the abnormal value is smoothed by the moving average of the cyclic data for a specified number pieces, so it is restrained that the number of revolutions far from the real number of revolutions is computed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a motor rotation speed detection device, and more particularly to a motor rotation speed detection device used in a motor drive device equipped with an inverter.

  Conventionally, as a means for detecting the rotational speed of a brushless DC motor, a method for calculating the rotational speed based on a position detection signal from a Hall element is disclosed in Patent Document 1 (fourth embodiment of Japanese Patent Application Laid-Open No. 2008-109835). Has been.

  In the motor rotation speed detection means of Patent Document 1, a waveform having a constant cycle is synthesized based on a position detection signal repeatedly output from each Hall element, and the rotation speed is calculated from the cycle. However, when noise is mixed between the waveforms, the noise is discriminated as a regular waveform, and there is a possibility that a rotational speed far from the actual rotational speed is calculated.

  An object of the present invention is to provide a motor rotation speed detection device that suppresses detection of a rotation speed far from the actual rotation speed of a motor.

  A motor rotation number detection device according to a first aspect of the present invention is a motor rotation number detection device that receives the number of pulse signals proportional to the rotation number of the motor and detects the rotation number of the motor, and includes a measurement unit, a storage unit, And an arithmetic unit. The measurement unit measures the period of the pulse signal. The storage unit sequentially stores the cycle as cycle data. Each time the storage unit stores the cycle data, the calculation unit calculates a predetermined number of moving average values from the newer one of the stored cycle data, and calculates the number of rotations of the motor from the moving average value.

  In this motor rotation number detection device, even when noise is received as a pulse signal and an abnormal value is stored as periodic data, the abnormal value is smoothed by a moving average of a predetermined number of periodic data. A period that is extremely far from is not calculated. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotation speed detection device according to a second aspect of the present invention is a motor rotation speed detection device that detects the rotation speed of a motor by receiving a number of pulse signals proportional to the rotation speed of the motor, and includes a measurement unit, a storage unit, And an arithmetic unit. The measurement unit measures the period of the pulse signal. The storage unit sequentially stores the cycle as cycle data. Each time the storage unit stores a predetermined number of period data, the calculation unit calculates an average value of the remaining period data excluding at least the minimum value from the predetermined number of period data, and the motor value is calculated from the average value. Calculate the rotation speed.

  In this motor rotation speed detection device, for example, even when noise enters between two pulse signals and is received as a normal signal, and an abnormal period shorter than the actual period is stored as data, it is the minimum value. It is definitely excluded from the target data for calculating the average value. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotational speed detection device according to a third aspect of the invention is the motor rotational speed detection device according to the second aspect of the invention, wherein the arithmetic unit removes the minimum value and the next smallest value from the predetermined number of period data. The average value of the cycle data is calculated, and the motor speed is calculated from the average value.

  In this motor rotation number detection device, for example, even when noise enters between two pulse signals and is received as a normal signal and two abnormal cycles shorter than the actual cycle are stored as data, The minimum value and the next smallest value after the minimum value are surely excluded from the target data for calculating the average value. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotation number detection device according to a fourth aspect of the invention is the motor rotation number detection device according to the second aspect of the invention, wherein the arithmetic unit removes the minimum value and the maximum value from the cycle data for a predetermined number. Is calculated, and the number of rotations of the motor is calculated from the average value.

  In this motor rotation speed detection device, for example, when noise enters so as to fill in between two adjacent pulse signals and a pulse signal longer than normal is received, a cycle longer than the actual cycle is stored as cycle data. The However, the period data is surely excluded from the target data for calculating the average value as the maximum value. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotation number detection device according to a fifth aspect of the present invention is a motor rotation number detection device that receives the number of pulse signals proportional to the rotation number of the motor and detects the rotation number of the motor, and includes a measurement unit, a storage unit, And an arithmetic unit. The measurement unit measures the period of the pulse signal. The storage unit sequentially stores the cycle as cycle data. Each time the storage unit stores the cycle data, the calculation unit calculates the average value of the remaining cycle data excluding at least the minimum value from a predetermined number of cycle data counted from the newer one of the stored cycle data. Then, the number of rotations of the motor is calculated from the average value.

  In this motor rotation number detection device, even when noise is received as a pulse signal and an abnormal value is stored as periodic data, the moving average value is calculated after the minimum value is excluded from the predetermined number of periodic data. Therefore, a period that is extremely different from the actual period is not calculated. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotation number detection device according to a sixth aspect of the present invention is a motor rotation number detection device that receives the number of pulse signals proportional to the rotation number of the motor and detects the rotation number of the motor, and includes a measurement unit, a storage unit, And an arithmetic unit. The measurement unit measures the period of the pulse signal. The storage unit sequentially stores the cycle as cycle data. Each time the storage unit stores the cycle data, the calculation unit counts from the newer one of the stored cycle data, and removes the minimum value and the next smallest value from the predetermined number of cycle data. Is calculated, and the number of rotations of the motor is calculated from the average value.

  In this motor rotation number detection device, even when noise is received as a pulse signal and an abnormal value is stored as periodic data, the movement is performed after the minimum value and the next smallest value are excluded from the predetermined number of periodic data. Since the average value is calculated, a period extremely different from the actual period is not calculated. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  A motor rotation number detection device according to a seventh aspect of the present invention is a motor rotation number detection device that receives the number of pulse signals proportional to the rotation number of the motor and detects the rotation number of the motor, comprising a measurement unit, a storage unit, And an arithmetic unit. The measurement unit measures the period of the pulse signal. The storage unit sequentially stores the cycle as cycle data. Each time the storage unit stores the cycle data, the calculation unit calculates the average of the remaining cycle data excluding the minimum value and the maximum value from the predetermined number of cycle data counted from the newer one of the stored cycle data. The value is calculated, and the rotational speed of the motor is calculated from the average value.

  In this motor rotation speed detection device, even when noise is received as a pulse signal and an abnormal value is stored as periodic data, the moving average value is obtained after the minimum value and the maximum value are excluded from the predetermined number of periodic data. Therefore, a period that is extremely different from the actual period is not calculated. As a result, the calculation of the rotational speed far from the actual rotational speed of the motor is suppressed.

  In the motor rotation speed detection device according to any one of the first to seventh inventions, the calculation of the rotation speed far from the actual rotation speed of the motor due to noise is suppressed.

The circuit diagram of the motor drive device provided with the motor rotation speed detection apparatus which concerns on one Embodiment of this invention. The schematic structure figure of the motor adopted as the 1st fan motor and the 2nd fan motor. The chart figure of the pulse signal sent to MCU from the 1st fan motor and the 2nd fan motor. The chart figure when noise has entered between two adjacent pulse signals among the pulse signals sent to MCU from the 1st fan motor and the 2nd fan motor. The chart figure when noise has entered so that between two adjacent pulse signals among the pulse signals sent to MCU from the 1st fan motor and the 2nd fan motor may be filled.

<Motor drive device>
FIG. 1 is a circuit diagram of a motor drive device provided with a motor rotation speed detection device according to an embodiment of the present invention. In FIG. 1, a first fan motor 101 and a second fan motor 102 are brushless DC motors that rotate a blower (not shown) of a refrigeration apparatus. The first fan motor 101 is integrated with the drive circuit 61, and the second fan motor 102 is also integrated with the drive circuit 62.

  The motor 103 is a brushless DC motor that rotates a compressor of the refrigeration apparatus. The motor driving device 1 can detect the rotational speed of the rotor of the motor 103 based on the voltage waveform generated in the shunt resistor 17.

  The motor drive device 1 includes a power supply circuit 10, an inverter 20, and an MCU (micro controller unit) 40. The power supply circuit 10 includes a bridge circuit 11 made of a diode and an electrolytic capacitor 12, generates a DC voltage from the commercial power supply 100, and supplies it to the inverter 20, the first fan motor 101, and the second fan motor 102. The inverter 20 is a bridge circuit composed of six transistors. The MCU 40 inputs a drive signal to each transistor of the inverter 20 and controls the rotation speed of the motor 103.

  Further, the MCU 40 changes the rotation speed by a PWM (pulse width modulation) method so that the first fan motor 101 and the second fan motor 102 have a predetermined rotation speed. The PWM system is a system in which the rotation speed is changed by changing the ratio (hereinafter referred to as duty ratio) of the on time and off time of the voltage input to the drive circuits 61 and 62, and the duty ratio is controlled. A signal is input from the MCU 40 to the drive circuits 61 and 62.

  FIG. 2 is a schematic structural diagram of motors employed in the first fan motor and the second fan motor. In FIG. 2, the motor is a three-phase brushless DC motor, and has a stator 92 and a rotor 93. The stator 92 includes drive coils 92u, 92v, and 92w. The rotor 93 includes an N-pole magnet 93 a and an S-pole magnet 93 b that face the stator 92.

  Three Hall elements 94 are arranged at 120 ° intervals on the stator 92 side. Since these three Hall elements 94 convert a change in magnetic flux caused by the rotation of the rotor 93 into a voltage and output a position detection signal, the position of the rotor 93 is detected from the position detection signal. The position detection signal of the Hall element 94 is used not only for detecting the position of the rotor 93 but also for detecting the number of rotations of the rotor 93.

  In the first fan motor 101 and the second fan motor 102, each time the rotor 93 makes one rotation, position detection signals output from the three Hall elements are converted into pulse signals and sent to the MCU 40. In the present embodiment, the MCU 40 receives four pulse signals every time the rotor 93 rotates once.

  FIG. 3 is a chart of pulse signals sent from the first fan motor and the second fan motor to the MCU. In FIG. 3, conventionally, the falling edge of the pulse signal is counted five times, and the time from the first falling edge to the fifth falling edge, that is, the required time per one rotation is measured. The rotational speeds of the motor 101 and the second fan motor 102 were detected. Time measurement is performed by a sampling method using a 1 msec counter.

  However, if the falling edge of noise is erroneously read as the falling edge of a normal pulse signal, an incorrect rotation speed is calculated. Therefore, in the present embodiment, the MCU 40 measures the period for each pulse signal as shown in FIG. 3, calculates a moving average value for a predetermined number from the newer one of the period data, and based on the moving average value. The rotational speeds of the first fan motor 101 and the second fan motor 102 are calculated.

  The MCU 40 includes a calculation unit 41, a storage unit 42, and a measurement unit 43. The measurement unit 43 measures the cycle of the pulse signal, and the storage unit 42 sequentially stores the cycle as cycle data t. Each time the storage unit 42 stores the periodic data t, the calculating unit 41 calculates a predetermined number of moving average values S from the newer one of the stored periodic data t.

  Since four cycles correspond to the time required for one rotation, the relational expression between the moving average value S and the rotation speed N is N = 1 / 4S rotation per second. When calculating the moving average value, considering that the four periods correspond to the time required for one rotation, even if the average value is calculated with only four pieces of data, the abnormal component is not smoothed. Six to eight are preferable.

  Specifically, in FIG. 3, the measurement unit 43 measures the time from the falling edge of the pulse signal to the falling edge of the next pulse signal as each period data (t1 etc.) using a 1 msec counter. Alternatively, the time from the rising edge of the pulse signal to the rising edge of the next pulse signal may be measured. The calculation unit 41 obtains the number of rotations based on the average value of the new eight cycle data t1 to t8 stored in the storage unit 42, and then calculates the average value of the new eight cycle data t2 to t9. Based on this, a newer rotational speed is obtained, and then a newer rotational speed is obtained based on the average value of the new eight period data t3 to t10. The rotational speed N is sequentially updated in such a procedure.

  For example, FIG. 4 is a chart when noise is present between two adjacent pulse signals among the pulse signals sent from the first fan motor and the second fan motor to the MCU. In FIG. 4, the period t2 and the period t3 are abnormal values, but are smoothed to a value close to the actual period by the moving average.

  FIG. 5 is a chart when there is noise so as to fill in the space between two adjacent pulse signals among the pulse signals sent from the first fan motor and the second fan motor to the MCU. In FIG. 5, the period t1 is an abnormal value, but is smoothed to a value close to the actual period by the moving average.

  As described above, the MCU 40 configures the motor rotation number detection device by the measurement unit 43, the storage unit 42, and the calculation unit 41, and based on the pulse signals transmitted from the first fan motor 101 and the second fan motor 102, Their rotational speed can be detected.

<Features>
In the motor rotation number detection device, the storage unit 42 sequentially stores the cycle of the pulse signal measured by the measurement unit 43 as cycle data. Each time the storage unit 42 stores the cycle data, the calculation unit 41 calculates a moving average value for a predetermined number from the newer one of the stored cycle data, and the first fan motor 101 and the first fan motor 101 and the The number of rotations of the two fan motor 102 is calculated. As a result, even when noise is received as a pulse signal and abnormal values are stored as periodic data, the abnormal values are smoothed by a moving average of a predetermined number of periodic data. It is not calculated.

<First Modification>
The average value of the periodic data need not be limited to the moving average value. In the first modification, every time the storage unit 42 stores a predetermined number of pieces of periodic data, an average value of the remaining periodic data obtained by removing at least the minimum value from the predetermined number of pieces of periodic data is calculated. Based on the average value, the rotational speeds of the first fan motor 101 and the second fan motor 102 are calculated.

  For example, in FIG. 4, when the average value is calculated every time four pieces of periodic data are stored, among the periods t1 to t4, the periods t2 and t3 are shorter than the normal periods t1 and t4. The minimum t2 is definitely excluded from the target data for calculating the average value. It is clear from FIG. 4 that the average value of t1, t3, and t4 is closer to the actual cycle than the average value of t1 to t4.

<Second Modification>
The calculation unit 41 calculates the average value of the remaining period data obtained by removing the minimum value and the next smallest value from the predetermined number of period data, and based on the average value, the first fan motor 101 and the second fan data are calculated. The rotation speed of the fan motor 102 can also be calculated.

  For example, in FIG. 4, when an average value is calculated every time four pieces of period data are stored, the period t2 is the minimum value and the period t3 is the next smallest value among the periods t1 to t4. It is definitely excluded from the calculation target data. It is clear from FIG. 4 that the average value of t1 and t4 is closer to the actual cycle than the average value of t1 to t4.

<Third Modification>
The calculation unit 41 calculates the average value of the remaining period data obtained by removing the minimum value and the maximum value from the predetermined number of period data, and based on the average value, the first fan motor 101 and the second fan motor. The number of rotations of 102 can also be calculated.

  For example, in FIG. 5, when the average value is calculated every time four pieces of period data are stored, the period t2 (which is one of t2, t3, and t4) among the periods t1 to t4. The minimum value is excluded from the average value calculation target data, and the period t1 is excluded as the maximum value from the average value calculation target data. As a minimum value, the period t2 that is not affected by noise is excluded, but the periods t3 and t4 that are also not affected by noise remain. It is clear from FIG. 5 that the average value of t3 and t4 is closer to the actual cycle than the average value of t1 to t4.

<Fourth Modification>
Moreover, the calculating part 41 can also calculate a moving average value except an abnormal value. That is, the embodiment described above and any one of the first to third modifications can be combined. For example, when the embodiment and the first modification are combined, the calculation unit 41 counts a predetermined number of counts from the newer one of the stored cycle data each time the storage unit 42 stores the cycle data. The average value of the remaining period data excluding the minimum value is calculated from the period data, and the rotation speeds of the first fan motor 101 and the second fan motor 102 are calculated based on the average value.

  Specifically, in FIG. 4, the rotation speed is obtained based on an average value of seven periodic data obtained by excluding the minimum value t2 from the new eight periodic data t1 to t8. The seven period data includes the next smaller value t3 after the minimum value t2, but since the abnormal component is smoothed by the moving average, it is not significantly different from the actual period. Thereafter, a newer rotation speed is obtained based on the average value of the seven period data obtained by excluding the minimum value t2 from the next eight period data t2 to t9. The seven period data also include the next smaller value t3 after the minimum value t2, but since the abnormal component is smoothed by the moving average, it is not significantly different from the actual period. Thereafter, a new rotational speed is obtained based on the average value of the seven period data obtained by excluding the minimum value t3 from the next eight period data t3 to t10. It is clear from FIG. 4 that since the 7 period data does not include an abnormal value, the average value thereof is almost the same as the actual period.

<Fifth Modification>
Similarly, when combining the above embodiment and the second modified example, every time the storage unit 42 stores periodic data, the calculation unit 41 counts a predetermined number of counts from the newest stored periodic data. The average value of the remaining period data excluding the minimum value and the next smallest value is calculated from the period data, and the rotation speeds of the first fan motor 101 and the second fan motor 102 are calculated based on the average value. .

  Specifically, in FIG. 4, the rotational speed is obtained based on the average value of six period data obtained by excluding the minimum value t2 and the next smallest value t3 from the new eight period data t1 to t8. It is clear from FIG. 4 that the average value is almost the same as the actual period because the six period data does not include abnormal values. Thereafter, the rotational speed is obtained based on the average value of the six period data obtained by excluding the minimum value t2 and the next smaller value t3 from the next eight new period data t2 to t9. Since the six period data does not include an abnormal value, it is clear that the average value thereof is almost the same as the actual period. After that, the average value of the six period data excluding the minimum value t3 and the next smallest value (any one when t4 to t10 are the same) from the next eight period data t3 to t10. Based on the above, a new rotational speed is obtained. Since the six period data does not include an abnormal value, it is clear that the average value thereof is almost the same as the actual period.

<Sixth Modification>
Similarly, when combining the above embodiment and the third modified example, every time the storage unit 42 stores the period data, the calculation unit 41 counts a predetermined number of counts from the newest stored period data. From the period data, the average value of the remaining period data excluding the minimum value and the maximum value is calculated, and the rotation speeds of the first fan motor 101 and the second fan motor 102 are calculated based on the average value.

  Specifically, in FIG. 5, six period data obtained by excluding the minimum value (any one when t2 to t8 are the same) and the maximum value t1 from the new eight period data t1 to t8. The number of rotations is obtained based on the average value. It is clear from FIG. 5 that the average value is almost the same as the actual period because the six period data does not include abnormal values. Thereafter, the number of rotations is obtained based on the average value of the six period data obtained by excluding the minimum value and the maximum value from the next eight period data t2 to t9. Since the six period data does not include an abnormal value, it is clear that the average value thereof is almost the same as the actual period. Thereafter, a new rotation number is obtained based on the average value of the six period data obtained by excluding the minimum value and the maximum value from the next eight period data t3 to t10. Since the six period data does not include an abnormal value, it is clear that the average value thereof is almost the same as the actual period.

  As described above, according to the present invention, the present invention is useful as a motor rotation speed detection device for a motor drive device equipped with an inverter.

41 arithmetic unit 42 storage unit 43 measuring unit 101 first fan motor 102 second fan motor

Fourth Embodiment of Japanese Patent Laid-Open No. 2008-109835

Claims (7)

A motor rotation number detection device for detecting the rotation number of the motor (101, 102) by receiving a number of pulse signals proportional to the rotation number of the motor (101, 102),
A measurement unit (43) for measuring the period of the pulse signal;
A storage unit (42) for sequentially storing the cycle as cycle data;
Each time the storage unit (42) stores the period data, a moving average value for a predetermined number is calculated from a newer one of the stored period data, and the motor (101, 102) is calculated from the moving average value. A calculation unit (41) for calculating the rotation speed of
A motor rotational speed detection device comprising: A motor rotation number detection device for detecting the rotation number of the motor (101, 102) by receiving a number of pulse signals proportional to the rotation number of the motor (101, 102),
A measurement unit (43) for measuring the period of the pulse signal;
A storage unit (42) for sequentially storing the cycle as cycle data;
Each time the storage unit (42) stores a predetermined number of the period data, the average value of the remaining period data obtained by removing at least a minimum value from the predetermined number of the period data is calculated, and the average value is calculated. A calculation unit (41) for calculating the number of rotations of the motor (101, 102) from
A motor rotational speed detection device comprising: The calculation unit (41) calculates an average value of the remaining period data obtained by removing a minimum value and a next smallest value from the predetermined number of the period data, and the motor (101, 102) is calculated from the average value. )
The motor rotation speed detection apparatus according to claim 2. The calculation unit (41) calculates an average value of the remaining period data obtained by removing a minimum value and a maximum value from the predetermined number of the period data, and from the average value, the motor (101, 102). Calculate the rotation speed,
The motor rotation speed detection apparatus according to claim 2. A motor rotation number detection device for detecting the rotation number of the motor (101, 102) by receiving a number of pulse signals proportional to the rotation number of the motor (101, 102),
A measurement unit (43) for measuring the period of the pulse signal;
A storage unit (42) for sequentially storing the cycle as cycle data;
Each time the storage unit (42) stores the period data, the remaining period data excluding at least the minimum value from a predetermined number of the period data counted from the newer one of the stored period data. A calculation unit (41) for calculating an average value and calculating the number of rotations of the motor (101, 102) from the average value;
A motor rotational speed detection device comprising: A motor rotation number detection device for detecting the rotation number of the motor (101, 102) by receiving a number of pulse signals proportional to the rotation number of the motor (101, 102),
A measurement unit (43) for measuring the period of the pulse signal;
A storage unit (42) for sequentially storing the cycle as cycle data;
Each time the storage unit (42) stores the period data, the remainder obtained by removing the minimum value and the next smallest value from the predetermined number of the period data counted from the newest one of the stored period data A calculation unit (41) for calculating an average value of the period data of the motor and calculating a rotation speed of the motor (101, 102) from the average value
A motor rotational speed detection device comprising: A motor rotation number detection device for detecting the rotation number of the motor (101, 102) by receiving a number of pulse signals proportional to the rotation number of the motor (101, 102),
A measurement unit (43) for measuring the period of the pulse signal;
A storage unit (42) for sequentially storing the cycle as cycle data;
Each time the storage unit (42) stores the periodic data, the remaining number obtained by removing the minimum value and the maximum value from the predetermined number of the periodic data counted from the newer one of the stored periodic data. A calculation unit (41) for calculating an average value of the period data and calculating a rotation speed of the motor (101, 102) from the average value;
A motor rotational speed detection device comprising:

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