JP2018017697A - Motor rotation velocity detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor rotation velocity detection device that allows the smaller number of hole sensors than a phase number of a motor to accurately detect a rotation velocity.SOLUTION: A rotation velocity detection device for the number of magnetic pole pairs P and a M-phase motor, comprises: a first to N-th hole sensors that are arranged at an interval of an integral multiple of an electric angle 180/M°; a section discrimination unit that creates a first to N-th signals in which only an i-th signal is a signal expressing a first state, and all other signals are a signal expressing a second state different from the first state from an output signal of the first to N-th hole sensors in each of sections Bij (j is an integer equal to or more than 1, and equal to or less than 2P), of which each has a phase interval of (180/MP)*Li°, to be obtained by further dividing each of sections having a phase section by one rotation of the M-phase motor divided into 2P pieces into N pieces; a counter that counts a clock pulse of a frequency fc/Li; and a rotation velocity calculation unit that calculates a rotation velocity of the motor on the basis of a count value of the counter.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a motor rotation speed detection device.

  As a method for detecting the rotational speed of a brushless motor, a method using a hall sensor or an encoder is generally used. In particular, among rotation speed detection methods using a Hall sensor, a method using three Hall sensors is generally widely known.

  FIG. 13 is a diagram illustrating the operating principle of a conventional three-phase brushless motor. With reference to FIG. 13, the operation of the conventional motor rotation speed detection device will be described.

The rotor of the brushless motor includes a magnetic pole pair composed of an N pole and an S pole. Around the rotor, _three hall sensors, ie, a hall sensor HS ₁ , a hall sensor HS ₂ , and a hall sensor HS ₃ as position sensors, are arranged at equal intervals of an electrical angle of 120 °.

The brushless motor is configured such that the rotor rotates. Each Hall sensor detects when the magnetic pole is switched from the S pole to the N pole or from the N pole to the S pole as the rotor rotates around the rotation axis, and the state of the output signal as shown in FIG. Change (high level, low level). FIG. 14 shows the situation of the output signals Hu, Hv, Hw with respect to the rotational phase angle of the rotors of the hall sensors HS ₁ , HS ₂ , HS ₃ . FIG. 3 shows the output signal value (high level is 1 and low level is 0). The rotor rotation phase angle can be divided into six state sections B1 to B6 at equal intervals of 60 degrees by a combination of the output signal values of Hu, Hv, and Hw.

Therefore, the rotational speed of the rotor can be detected using the output signals of the hall sensors. That is, by counting the number of clock pulses in each of the sections B1 to B6 with a counter, the rotational speed of the motor (the average rotational speed in each of the sections B1 to B6) can be detected. Now, assuming that the frequency of the clock pulse is fc [Hz], in each of the sections B1 to B6 having a phase interval of 60 °, the counter counts the number n of clock pulses with respect to 1/6 rotation. Is
Ω = 60 fc / 6n = 10 fc / n [rpm] (1)
Can be calculated.

JP-A-6-144274

  Here, for example, in order to reduce the cost of the motor rotation speed detection device or to reduce the size for mounting on a small-scale device, the number of hall sensors smaller than the number of phases of the motor, for example, the output signal Hu of the hall sensor , Hv, and Hw are considered to detect the rotational speed with two signals Hu and Hv. The values of the Hall sensor output signals Hu and Hv with respect to the rotor rotation phase angle are shown in FIG. In this case, the rotor rotational phase angle can be divided into four state sections B1 'to B4'.

  In this case, the phase interval between the sections B1 'and B3' is 120 °, but the phase interval between the sections B2 'and B4' is 60 °, which is different from the phase interval between the sections B1 'and B3'. Therefore, since the time for counting the clock pulses is different between the sections B2 'and B4' and the sections B1 'and B3', it is impossible to accurately detect the rotational speed by applying the conventional method as it is.

  Accordingly, an object of the present invention is to provide a motor rotation speed detection device that can accurately detect the rotation speed by using a smaller number of Hall sensors than the number of phases of the motor.

  One aspect of the present invention is an apparatus for detecting the number of magnetic pole pairs P and the rotational speed of an M-phase motor, which is arranged at first to Nth (N is 1) arranged at intervals of an integral multiple of electrical angle 180 / M °. A Hall sensor of a large integer smaller than M) and each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P parts are further divided into N parts, each of which is (180 / MP ) · Li ° (where i is an integer from 1 to N and Li is an integer from 1 to (M−N + 1)) in a section Bij (j is an integer from 1 to 2P) In each of the first to N-th signals, only the i-th signal is a signal representing the first state, and all other signals are signals representing the second state different from the first state. Section generated and output from output signals of the first to Nth hall sensors A determination unit and a clock pulse output unit that outputs a clock pulse having a frequency fc / Li in a section Bij when the i-th signal among the first to N-th signals is a signal representing the first state. And a counter for counting the clock pulses output from the output unit for each of the sections Bij, and a rotation speed calculation unit for calculating the rotation speed of the motor based on the count value of the counter A device is provided.

  The clock pulse output unit generates first to Kth clock generators for generating first to Kth clock pulses for different first to Kth frequencies of the frequency fc / Li. And the first to Nth arithmetic units, and a logical sum arithmetic unit, and the i th arithmetic unit is configured to detect the frequency fc when the i th signal is a signal representing the first state. The output from the clock generator that generates the clock pulse of / Li is output, and the OR operation unit calculates the OR of the output signals from the first to Nth operation units, and in the section Bi, A clock pulse having a frequency fc / Li can be output.

  The first state is a first logic, the second state is a second logic different from the first logic, and the first to Nth operation units are AND operation units. The i-th arithmetic unit calculates a logical product of the output from the clock generator that generates the clock pulse of the frequency fc / Li and the logic represented by the i-th signal. it can.

  The clock pulse output unit is configured to generate a clock generator that generates a clock pulse having a frequency fc, and to output an output from the clock generator when the i-th signal is a signal representing the first state. It is possible to provide a clock frequency converter that multiplies Li and generates a clock pulse of frequency fc / Li in the section Bij.

  Another aspect of the present invention is an apparatus for detecting the number of magnetic pole pairs P and the rotational speed of an M-phase motor, wherein the first to Nth (N is 1) arranged at intervals of an integral multiple of an electrical angle of 180 / M °. A Hall sensor of a large integer smaller than M) and each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P parts are further divided into N parts, each of which is (180 / MP ) · Li ° (where i is an integer from 1 to N and Li is an integer from 1 to (M−N + 1)) in a section Bij (j is an integer from 1 to 2P) In each of the first to N-th signals, only the i-th signal is a signal representing the first state, and all other signals are signals representing the second state different from the first state. A section size generated from the output signals of the first to Nth hall sensors and output. A separate unit, a clock pulse output unit that outputs a clock pulse of frequency fc, a counter that counts the clock pulses output from the output unit for each of the sections Bij, and the first to Nth signals When the i-th signal is a signal representing the first state, a rotation speed calculation unit that calculates the rotation speed of the motor based on a value obtained by multiplying the count value of the counter by 1 / Li for the section Bij A motor rotation speed detection device is provided.

  P = 1, M = 3, N = 2, and the section determination unit calculates exclusive OR of the output signals of the first and second Hall sensors and negation of the exclusive OR, Calculation results may be output as the first signal and the second signal, respectively.

  According to the present invention having the above configuration, there is provided a motor rotation speed detection device capable of accurately detecting the rotation speed by the number of hall sensors that is smaller than the number of phases of the motor.

It is a figure which shows the principle of the motor rotational speed detection apparatus which concerns on the 1st Embodiment of this invention. 1 is a diagram illustrating an overall configuration of a motor rotation speed detection device according to a first embodiment of the present invention. It is a figure which shows an example of the circuit structure of the area discrimination | determination part and clock signal output part of the motor rotational speed detection apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the example of the relationship between a slot and a division | segmentation area. It is a figure which shows the whole structure of the motor rotational speed detection apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows an example of the circuit structure of the area discrimination | determination part and clock pulse output part which concern on the 2nd Embodiment of this invention. Is a diagram showing an output of a Hall sensor HS _1, HS _2, values and section determination unit of the output signal of the HS ₃ with respect to the rotor rotational phase angle. It is a figure which shows an example of the circuit structure of the area discrimination | determination part and clock pulse output part which concern on the 2nd Embodiment of this invention. Is a diagram showing an output of a Hall sensor HS _1, HS _2, values and section determination unit of the output signal of the HS ₃ with respect to the rotor rotational phase angle. It is a figure which shows an example of the circuit structure of the area discrimination | determination part and clock pulse output part which concern on the 2nd Embodiment of this invention. Is a diagram showing an output of a Hall sensor _{HS 1, HS 2, HS 3} , the value of the output signal of the HS ₄ and section determination unit to the rotor rotational phase angle. It is a figure which shows an example of the circuit structure of the area discrimination | determination part and clock pulse output part which concern on the 2nd Embodiment of this invention. It is a figure which shows the principle of operation of the conventional 3 phase brushless motor. Shows the Hall sensor HS _1, HS _2, the output signal Hu with respect to the rotational phase angle of the HS ₃ of rotor, Hv, the status of Hw. Hall sensor HS _1, HS _2, the output signal Hu with respect to the rotational phase angle of the HS ₃ of rotor, Hv, is a diagram illustrating the value of Hw. It is a figure which shows the value of the output signals Hu and Hv of a Hall sensor with respect to a rotor rotational phase angle.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating the principle of a motor rotation speed detection device according to a first embodiment of the present invention.

  As described above, when three hall sensors are used, the clock pulse is counted by the counter for each of the sections B1 to B6, and the rotation speed of the motor can be calculated based on the counted value. It was.

  In the conventional method, a problem when two hall sensors are used is caused by counting clock pulses having the same frequency in sections having different phase intervals. Therefore, the present inventors have found that the problem can be solved by switching the frequency of the clock pulse to be counted in the sections B1 ′ and B3 ′ and the sections B2 ′ and B4 ′.

  Therefore, it is necessary to discriminate between the sections B1 'and B3' whose phase interval is 120 ° and the sections B2 'and B4' whose phase interval is 60 °. For example, the respective sections can be determined by the XOR operation of the output signals Hu and Hv of the hall sensor and the NOT operation thereof. FIG. 1 shows the calculation result.

  Therefore, in the sections B1 ′ and B3 ′ in which the phase interval is 120 °, the clock pulses of fc / 2 [Hz] are counted, and in the sections B2 ′ and B4 ′ in which the phase interval is ½ of 60 °, If the clock pulses of fc [Hz] are counted, the rotational speed can be detected by the same counter.

That is, in the sections B1 ′ and B3 ′ in which the phase interval is 120 °, the number N of clock pulses of fc / 2 [Hz] is counted for 1/3 rotation, so the rotational speed Ω is
Ω = 60fc / 2 / 3N = 10fc / N [rpm] (2)
It becomes.
On the other hand, in the sections B2 ′ and B4 ′ where the phase interval is 60 °, the number N of clock pulses of fc [Hz] is counted for 1/6 rotation.
Ω = 60fc / 6N = 10fc / N [rpm] (3)
It becomes.
Therefore, the rotational speed can be detected by the same counter even with two Hall sensors having a smaller number of phases of the motor.

  FIG. 2 is a diagram showing an overall configuration of the motor rotation speed detection device according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an example of circuit configurations of the section determination unit and the clock pulse output unit of the motor rotation speed detection device according to the first embodiment of the present invention.

The motor rotation speed detection device 1 includes a clock pulse output unit 13 for each of the first hall sensor HS ₁ , the second hall sensor HS ₂ , the section determination unit 11, the clock pulse output unit 13, and the sections B 1 ′ to B 4 ′. The counter 15 that counts the clock pulses output from the counter 15 and the rotational speed calculator 17 that calculates the rotational speed of the motor based on the count value of the counter 15 are provided.

The first hall sensor HS ₁ and the second hall sensor HS ₂ are arranged clockwise with an electrical angle of 120 °.

The section determining unit 11 includes an XOR element 111 and a NOT element 113. The clock pulse output unit 13 includes a first clock pulse generator 131 ₁ that generates a clock pulse having a frequency fc / 2, a second clock pulse generator 131 ₂ that generates a clock pulse having a frequency fc, An AND element 133 ₁ , a second AND element 133 ₂ , and an OR element 135 are provided.

Output lines of the first hall sensor HS ₁ and the second hall sensor HS ₂ are connected to an input line of the XOR element 111. The output line of the XOR element 111 and the output line of the first clock pulse generator 131 ₁ are connected to the input line of the _first AND element 133 ₁ . Also, the output line of the XOR element 111 is connected to a second AND element 133 and _second input lines through the NOT element 113, a second clock pulse generator 131 _second output line and a second AND element It is connected to 133 ₂ input lines. The output line of the _first AND element 133 _{1 and} the output line of the second AND element 133 ₂ are connected to the input line of the OR element 135, and the output from the OR element 135 is output as the output of the clock pulse output unit 13. The

  The counter 15 counts the clock pulses output from the clock pulse output unit 13, and when any of the sections B1 ′ to B4 ′ changes to another section based on the output from the XOR element 111, the counter 15 counts the clock pulses. The count value is reset. Thereby, the clock pulses output from the clock pulse output unit 13 can be counted for each of the sections B1 ′ to B4 ′.

  The rotation speed calculation unit 17 calculates the rotation speed of the motor based on the count value of the counter 15.

  Based on the above apparatus configuration, the operation of the motor rotation speed detection apparatus according to the first embodiment of the present invention will be described.

Referring to FIG. 1, the output from XOR element 111 is 1 in sections B1 ′ and B3 ′. Therefore, the section determination unit 11 generates and outputs a first signal whose value is 1 in the first state and a second signal whose value is 0 in the second state. The first AND element 133 ₁ receives a first signal having a value of 1 from the section discriminating unit 11 and a clock pulse having a frequency fc / 2 from the _first clock pulse generator 131 ₁ . On the other hand, the second AND element 133 ₂ receives the second signal having a value of 0 from the section determination unit 11. Therefore, from the OR element 135, that is, from the clock pulse output unit 13, the clock pulse having the frequency fc / 2 that is the output from the _first clock pulse generator 1311 is output as it is. At this time, since the phase interval between the sections B1 ′ and B3 ′ is 120 °, the counter 15 counts the number n of clock pulses of fc / 2 [Hz] with respect to 1/3 rotation. Based on this, the calculation unit 17 calculates the rotational speed Ω from the above equation (2).

In contrast, in the sections B2 ′ and B4 ′, the output from the XOR element 111 is zero. Therefore, the section determination unit 11 generates and outputs a first signal whose value is 0 in the second state and a second signal whose value is 1 in the first state. The first AND element 133 ₁ receives the second signal having a value of 0 from the section determination unit 11. On the other hand, the second AND element 133 ₂ receives the second signal having a value of 1 from the section discriminating unit 11 and the clock pulse having the frequency fc from the _first clock pulse generator 131 ₁ . Therefore, from the OR element 135, that is, from the clock pulse output unit 13, the clock pulse having the frequency fc that is the output from the _second clock pulse generator 1312 is output as it is. At this time, since the phase interval between the sections B2 ′ and B4 ′ is 60 °, the counter 15 counts n of the number of clock pulses of fc [Hz] with respect to 1/6 rotation. Based on this, 17 calculates the rotational speed Ω from the above equation (3).

In this case, as can be seen from FIG. 1, the output signal of the _first AND element 133 _{1 and} the output signal of the second AND element 133 ₂ are contradictory (when one is 1, the other is 0), The output signal of the _first AND element 133 _{1 and} the output signal of the second AND element 133 ₂ are not input to the counter 15 at the same time.

  In the above embodiment, “0” is used as the first state and “1” is used as the second state. However, the circuit configuration of the section determination unit and the clock pulse output unit is changed, and “1” is set as the first state. ”,“ 0 ”may be used as the second state, or any suitable different distinguishable state may be used.

  When two types of clock pulse generators of fc [Hz] and fc / 2 [Hz] cannot be prepared, the clock pulse output unit 13 uses the clock pulse generator of one fc [Hz] from the XOR element 111. Each section is discriminated based on the output of, and in the sections B1 ′ and B3 ′, the clock pulse from the clock pulse output unit 13 is divided by half and output, and in the sections B2 ′ and B4 ′. The clock pulse may be output as it is.

  Alternatively, using one fc [Hz] clock pulse generator, the counter 15 discriminates each section based on the output from the XOR element 111, and in the sections B1 ′ and B3 ′. The count value of the clock pulse from the clock pulse output unit 13 is halved and output to the rotation speed calculation unit 17, and the count value of the clock pulse from the clock pulse output unit 13 in the sections B2 ′ and B4 ′. May be output to the rotational speed calculation unit 17 as it is.

  With such a configuration, the rotational speed of the motor can be detected by a smaller number of Hall sensors than the number of phases of the motor.

(Second Embodiment)
The motor rotation speed detection device according to the first embodiment detects the rotation speed of a three-phase motor having one magnetic pole pair with two hall sensors. In the present embodiment, this is generalized, and the rotation speed of the M-phase motor having the number P of magnetic pole pairs is set to an interval that is an integral multiple of 360 / N ° (N is an integer greater than 1 and less than M) in the clockwise direction. It is detected by N hall sensors arranged in (1).

  First, consider the case where the number of magnetic pole pairs is one. When N hall sensors are used, the phase can be divided into two for each hall sensor, so that the phase can be divided into 2N sections. On the other hand, the minimum value of the phase interval of the divided section is 180 / M °. Therefore, if the section of the minimum value 180 / M ° of the phase interval is called “slot”, the number of slots per one rotation of the rotor is 360 / (180 / M) = 2M.

  Thus, when the number N of hall sensors to be used is determined, the number of rotor phase divisions is uniquely determined. However, the phase interval of the divided sections (hereinafter, the minimum value 180 / M ° is assumed to be the basic unit 1) is N. It depends on which Hall sensor output signal is used.

At this time, the number of cases in which the phase interval M is divided into N, that is, _M C _N cases, occurs. The maximum phase interval of the section becomes MN + 1 of the phase interval of the remaining one section when the phase interval of the N−1 sections is 1. FIG. 4 shows an example of the relationship between slots and divided sections.

  It is obtained by dividing the phase section for one rotation of the M-phase motor into N parts, each of which is (180 / M) · Li (i is an integer from 1 to N, Li is 1 or more (M−N + 1) In each of the sections Bi having a phase interval of any integer below, only the i-th signal is a signal representing the first state (for example, high level = 1), and all other signals are A logic operation circuit that generates first to Nth signals, which are signals representing a second state (for example, low level = 0) different from the first state, from output signals of the first to Nth Hall sensors. Can be configured. That is, since the output signal combinations of the section Bi and the first to Nth hall sensors correspond one-to-one, the output signals of the first to Nth hall sensors are logical values, and only the i-th signal is the first. A logic function that outputs a signal representing a second state (for example, low level = 0) that is different from the first state in which the other signal is a signal representing the state (for example, high level = 1). Conceivable. Although there are many logical expressions that express the same logical function, it is possible to configure the logical operation circuit so that a logical expression generated from the output signals of the first to Nth Hall sensors is created.

  Therefore, a clock pulse generator having a frequency fc / Li [Hz] corresponding to the phase interval Li of each section is prepared, and the i-th signal among the first to N-th signals represents the first state. In this case, the rotation speed can be detected with the same counter by outputting a clock pulse with the frequency fc / Li in the section Bi and counting the clock pulse with the counter.

That is, since the number n of clock pulses of fc / Li [Hz] is counted for Li / 2M rotation, the rotation speed Ω is
Ω = 60 × (Li / 2M) × (fc / (nLi)) = 30 fc / Mn [rpm] (4)
Thus, regardless of the phase interval Li of the section, the rotation speed can be detected by the same counter even with N Hall sensors that are smaller than the number of phases of the motor.

ここで、ｍはＰ以下の整数である。 The above discussion was performed with the number of magnetic pole pairs being 1, but it is easy to expand the number of magnetic pole pairs to be generalized to P. When the number of magnetic pole pairs is P, the number of phase divisions is P times. The output signal of the hall sensor in the divided state that has become P times only repeats the same cycle. Each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P parts is further divided into N parts, each of which is (180 / MP) · Li (i is 1 or more and N or less) A section Bij (j is an integer of 1 to 2P) having a phase interval of 1 and Li (any integer of 1 to (M−N + 1)) has the following properties.
(1) Logics in the interval Bij where j is an odd number and j are even numbers match. That is,
Bi1 = Bi3 = ... = Bi, (2m-1)
Bi2 = Bi4 = ... = Bi, 2m.
(2) The logic in the interval Bij in which j is different from each other by 1 has an inverted relationship. That is,

Here, m is an integer equal to or less than P.

  In each of the sections Bij, only the i-th signal is a signal representing the first state, and all the other signals are signals representing the second state different from the first state. A logic operation circuit that generates N signals from output signals of the first to Nth Hall sensors can be configured. That is, since the output signal combinations of the section Bij and the first to Nth hall sensors correspond one-to-one, the output signals of the first to Nth hall sensors are logical values, and only the i-th signal is the first. A logic function that outputs a signal representing a second state (for example, low level = 0) that is different from the first state in which the other signal is a signal representing the state (for example, high level = 1). Conceivable. Although there are many logical expressions that express the same logical function, it is possible to configure the logical operation circuit so that a logical expression generated from the output signals of the first to Nth Hall sensors is created.

  Therefore, a clock pulse generator having a frequency fc / Li [Hz] corresponding to the phase interval Li of each section is prepared, and the i-th signal among the first to N-th signals represents the first state. In this case, the rotation speed can be detected with the same counter by outputting a clock pulse with the frequency fc / Li in the section Bij and counting the clock pulse with the counter.

That is, since the number n of clock pulses of fc / Li [Hz] is counted for Li / 2MP rotation, the rotational speed Ω is
Ω = 60 × (Li / (2MP)) × (fc / (nLi)) = 60 fc / 2MPn [rpm] (5)
Thus, regardless of the phase interval Li of the section, the rotation speed can be detected by the same counter even with N Hall sensors that are smaller than the number of phases of the motor.

  FIG. 5 is a diagram illustrating an overall configuration of a motor rotation speed detection device 1 according to the second embodiment of the present invention, and FIG. 6 is a section determination unit of the motor rotation speed detection device according to the second embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a circuit configuration of a clock pulse output unit. 5 and 6, parts corresponding to those in FIGS. 2 and 3 are denoted by the same reference numerals, and redundant description of the first embodiment is omitted.

The motor rotation speed detection device 1 includes clock pulses output from the clock pulse output unit 13 for each of the first to Nth hall sensors HS _{1 to} HS _N , the section determination unit 11, the clock pulse output unit 13, and the section Bij. And a rotation speed calculation unit 17 that calculates the rotation speed of the motor based on the count value of the counter 15.

The first to Nth hall sensors HS _{1 to} HS _N are arranged at intervals of an integral multiple of an electrical angle of 180 / M ° in a clockwise direction.

The section discriminating unit 11 is obtained by further dividing each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P pieces, each of which is (180 / MP) · Li ° (i Is an integer greater than or equal to 1 and less than or equal to N, and Li is an integer greater than or equal to 1 and greater than or equal to (M−N + 1). In each of the sections Bij (j is an integer greater than or equal to 1 and less than or equal to 2P), The first to Nth signals are signals that represent the first state and all other signals represent the second state different from the first state. It generates from the output signals of the hall sensors HS _{1 to} HS _N and outputs them.

The clock pulse output unit 13 generates first to Kth clock pulse generators for generating first to Kth frequency clock pulses for the first to Kth frequencies which are different frequencies of the frequency fc / Li. 131 ₁ provided to 131 and _K, first to N aND element 133 ₁ to 133 _N is an operation unit of the first to N, the OR element 135 is a logical sum operation unit. The i-th AND element 133 _i generates the i-th signal output from the section determination unit 11 and the clock pulse having the frequency fc / Li among the _first to K-th clock pulse generators 131 _{1 to} 131 _K. The clock pulse from the clock pulse generator 131 _j to be input is input. An output from the _{first to} Nth AND elements 133 _{1 to} 133 _N is input to the OR element 135, and an output from the OR element 135 is output as an output of the clock pulse output unit 13.

  The counter 15 counts the clock pulses output from the clock pulse output unit 13, but based on the output from the section determination unit 11, when any section of the section Bij changes to another section, the count value is Reset. Thereby, the clock pulses output from the clock pulse output unit 13 can be counted for each of the sections Bij.

  The rotation speed calculation unit 17 calculates the rotation speed Ω of the motor from the above equation (4) based on the count value of the counter 15.

  When it is not possible to prepare K types of clock pulse generators of fc / Li [Hz] (i = 1, 2,..., K), a single fc [Hz] clock pulse generator is used to determine a section. Each section may be determined based on the output from 11, and the clock pulse from the clock pulse output unit 13 may be divided into 1 / Li according to the phase interval of the section and output.

  Alternatively, each section is discriminated based on the output from the section discriminating unit 11 using one fc [Hz] clock pulse generator, and the counter count is calculated according to the phase interval of the section. The numerical value may be multiplied by 1 / Li and output to the rotation speed calculation unit 17.

  Several specific examples will be described below.

<Number of magnetic pole pairs 1, number of phases 5, number of hall sensors 3>
When the number of magnetic pole pairs P = 1, the number of phases M = 5, and the number of Hall sensors N = 3, the number of rotor phase divisions is 2N = 6, and six states can be detected. Hall sensor HS for rotor rotation phase angle when using the output signal of the Hall sensor HS, which is arranged at intervals of an electrical angle of 180/5 = 36 ° clockwise _{1, HS 2, HS 3 1} , HS 2, HS 3 The value of the output signal is shown in FIG.

  From FIG. 9, the phase intervals L1 and L2 when the basic unit is 36 ° in the sections B11, B21, B12, and B22 are 2, and the phase interval L3 when the basic unit is 36 ° in the sections B31 and B32 are 1. Therefore, as the clock pulse generator, a first clock pulse generator that generates a clock pulse of frequency fc / 2 [Hz] and a second clock pulse generator that generates a clock pulse of frequency fc [Hz] are prepared. do it. FIG. 8 shows an example of the circuit configuration in this case, and FIG. 9 shows the output of the section discrimination unit 11 in this case.

Next, an electrical angle 72 in the clockwise direction with respect to the first and second Hall sensors HS ₁ , HS ₂ and the second Hall sensor HS ₂ arranged at intervals of clockwise electrical angle 180/5 = 36 °. Output signals of the first, second, and fourth Hall sensors HS ₁ , HS ₂ , HS ₄ with respect to the rotor rotation phase angle when the output signals of the fourth Hall sensor HS ₄ arranged at intervals of ° are used. The values of are shown in FIG.

  From FIG. 10, the phase intervals L1 and L2 when the basic unit is 36 ° in the sections B11, B21, B12, and B22 are 1, and the phase interval L3 is 3 when the basic unit is 36 ° in the sections B31 and B32. Therefore, as the clock pulse generator, a first clock pulse generator that generates a clock pulse of frequency fc [Hz] and a second clock pulse generator that generates a clock pulse of frequency fc / 3 [Hz] are prepared. do it. FIG. 10 shows an example of the circuit configuration in this case, and FIG. 9 shows the output of the section determination unit 11 in this case.

<1 magnetic pole pair, 5 phases, 4 hall sensors>
When the number of magnetic pole pairs P = 1, the number of phases M = 5, and the number of Hall sensors N = 4, the number of rotor phase divisions is 2N = 8, and eight states can be detected. Hall with respect to the rotor rotational phase angle when using the output signals of the first to fourth Hall sensors HS ₁ , HS ₂ , HS ₃ , HS ₄ arranged at intervals of clockwise electrical angle 180/5 = 36 ° FIG. 11 shows values of output signals of the sensors HS ₁ , HS ₂ , HS ₃ , HS ₄ .

  From FIG. 11, the phase intervals L1, L2, and L4 are 1 when the basic unit is 36 ° in the sections B11, B21, B41, B12, B22, and B42, and the basic unit is 36 ° in the sections B31 and B32. Since the phase interval L3 is 2, the clock pulse generator includes a first clock pulse generator that generates a clock pulse having a frequency fc [Hz] and a second clock pulse that generates a clock pulse having a frequency fc / 2 [Hz]. A clock pulse generator may be prepared. FIG. 12 shows an example of the circuit configuration in this case, and FIG. 11 shows the output of the section discrimination unit 11 in this case.

  With such a configuration, the rotational speed of the motor can be detected by a smaller number of Hall sensors than the number of phases of the motor.

  In the above-described embodiment, the brushless motor has been described as an example. However, the present invention is not limited to the brushless motor, and can be applied to all motors (for example, a synchronous motor) having a configuration similar to the brushless motor. Yes.

  Although the present invention has been described above with reference to several embodiments for purposes of illustration, the present invention is not limited thereto and various forms and details may be used without departing from the scope of the present invention. It will be apparent to those skilled in the art that variations and modifications can be made.

HS ₁ , HS ₂ , HS ₃ , HS ₄ , HS _N 1st to 4th and Nth Hall sensors 1 Motor rotation speed detection device 11 Section determination unit 111 XOR element 113 NOT element 13 Clock pulse output unit 131 ₁ , 131 ₂ , 131 _j , 131 _K 1st, 2nd, jth, Kth clock pulse generators 133 ₁ , 133 ₂ , 133 ₃ , 133 _i , 133 _N 1st, 2nd, 3rd, i th, N AND element 135 OR element 15 Counter 17 Rotational speed calculation unit

Claims (6)

A magnetic pole pair number P, a rotational speed detection device for an M-phase motor,
First to Nth (N is an integer larger than 1 and smaller than M) Hall sensors arranged at intervals of an integral multiple of an electrical angle of 180 / M °;
Each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P parts is further divided into N parts, each of which is (180 / MP) · Li ° (i is 1 or more and N or less) , Li is any integer of 1 or more (M−N + 1) or less) in each of the sections Bij (j is an integer of 1 to 2P), only the i-th signal is the first. The first to Nth signals, which are signals representing the second state, in which all other signals represent the second state different from the first state, are the outputs of the first to Nth Hall sensors. An interval discriminator that generates and outputs the signal, and
When the i-th signal among the first to N-th signals is a signal representing the first state, a clock pulse output unit that outputs a clock pulse of the frequency fc / Li in the section Bij;
A counter that counts clock pulses output from the output unit for each of the sections Bij;
A rotation speed calculation unit that calculates the rotation speed of the motor based on the count value of the counter;
A motor rotation speed detection device comprising: The clock pulse output unit generates first to Kth clock generators for generating first to Kth clock pulses for different first to Kth frequencies of the frequency fc / Li. When,
First to Nth arithmetic units;
An OR operation part;
With
The i-th arithmetic unit outputs an output from the clock generator that generates a clock pulse of the frequency fc / Li when the i-th signal is a signal representing the first state,
2. The motor rotation speed according to claim 1, wherein the logical sum calculation unit calculates a logical sum of output signals from the first to Nth calculation units, and outputs a clock pulse having a frequency fc / Li in a section Bi. Detection device. The first state is a first logic;
The second state is a second logic different from the first logic;
The first to Nth operation units are AND operation units,
3. The motor rotation according to claim 2, wherein the i-th operation unit calculates a logical product of an output from the clock generator that generates a clock pulse of the frequency fc / Li and a logic represented by the i-th signal. Speed detection device. The clock pulse output unit generates a clock pulse having a frequency fc;
When the i-th signal is a signal representing the first state, the output from the clock generator is multiplied by 1 / Li, and a clock frequency for generating a clock pulse of frequency fc / Li in the interval Bij A converter,
The motor rotational speed detection apparatus of Claim 1 provided with. A magnetic pole pair number P, a rotational speed detection device for an M-phase motor,
First to Nth (N is an integer larger than 1 and smaller than M) Hall sensors arranged at intervals of an integral multiple of an electrical angle of 180 / M °;
Each of the sections obtained by dividing the phase section for one rotation of the M-phase motor into 2P parts is further divided into N parts, each of which is (180 / MP) · Li ° (i is 1 or more and N or less) In the sections Bij (j is an integer of 1 to 2P) having a phase interval of 1), Li is only the first signal. The first to Nth signals, which are signals representing a state and in which all other signals represent a second state different from the first state, are output signals of the first to Nth Hall sensors. A section discriminating section that generates and outputs from
A clock pulse output unit for outputting a clock pulse of frequency fc;
A counter that counts clock pulses output from the output unit for each of the sections Bij;
When the i-th signal among the first to N-th signals is a signal representing the first state, for the section Bij, based on a value obtained by multiplying the count value of the counter by 1 / Li, A rotation speed calculation unit for calculating the rotation speed;
A motor rotation speed detection device comprising: P = 1, M = 3, N = 2,
The section discriminating unit calculates exclusive OR of the output signals of the first and second Hall sensors and negation of the exclusive OR, and outputs the calculation results as the first signal and the second signal, respectively. The motor rotational speed detection apparatus of any one of Claims 3-5 output as.

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