JP2011153863A - Rotational position detection device, and motor driving system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive, highly-reliable and easily-miniaturizable rotational position detection device. <P>SOLUTION: A resolver 1 includes a rotor having salient poles to the number of 2n-1 (n is a positive integer), a stator having first, second, third and fourth magnetic poles arrayed successively at equal angle intervals, and each single coil (L1-L4) wound on each magnetic pole of the stator. Excitation means 9, 18 supplies a first excitation signal having a prescribed frequency to a connection point between first and second coils L1, L2, and supplies a second excitation signal acquired by inverting the first excitation signal to a connection point between third and fourth coils L3, L4. A signal processing means 7 calculates a rotational position of the rotor based on a first output signal from a connection point between the first and third coils L1, L3 and a second output signal from a connection point between the second and fourth coils L2, L4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rotational position detection device using a resolver and a motor drive system using the rotational position detection device.

  The present applicant has previously proposed a rotational position detection device using a resolver having a pole number of 8N (N is a positive integer). In the resolver of the rotational position detection device according to the prior application, a stator having one detection coil wound around each pole and the number of salient poles are set to (6 ± 1) N or (2 ± 1) N. And a rotor.

  Each detection coil is divided into a first group to a fourth group. Each of the 2N detection coils belonging to each group has an inductance fundamental wave having a phase difference of 45 °, and each inductance belonging to each other group is combined with the inductance obtained by synthesizing these inductance fundamental waves. The phase difference of the inductance obtained by synthesizing the fundamental inductance wave of the detection coil is selected to be 90 °.

JP 2009-98050 A

In the resolver, since the stator is provided with at least eight slots, the total number of coils of the stator is at least eight. Thus, the above resolver with a large number of coils in the stator is inferior in productivity because it takes time for the winding work and the wiring work, and when the inner diameter of the stator is reduced for miniaturization, the winding work is not performed. The inconvenience that it becomes difficult also occurs.
Therefore, the conventional rotational position detection device using the resolver having the above configuration is disadvantageous in terms of cost reduction and size reduction.

  In view of such circumstances, it is an object of the present invention to provide a rotational position detection device that is low-cost, highly reliable, and easy to downsize, and a motor drive system using the rotational position detection device. Yes.

  In order to solve the above-described problems, the present invention provides a single first, second, third, and fourth coil for each of the first, second, third, and fourth magnetic poles that are sequentially arranged at equiangular intervals. A wound stator, 2n-1 (n is a positive integer) salient poles, and a rotor having a shape capable of changing the inductance of the first to fourth coils in a sinusoidal shape A resolver formed by bridge-connecting the first to fourth coils so that the first and fourth coils and the second and third coils are diagonally located, and 1. A first excitation signal having a predetermined frequency is supplied to a connection point between the first and second coils, and a second excitation signal obtained by inverting the first excitation signal is supplied to a connection point between the third and fourth coils. Exciting means, a first output signal from a connection point of the first and third coils, and the second, 4 based on the second output signal from the connection point of the coil has a signal processing means for calculating the rotational position of the rotor. The first to fourth coils are arranged such that the directions of the magnetic fields generated by the first and second coils are both inward or outward of the stator, and the second and fourth coils. The coils are wound such that the directions of the magnetic fields generated by the coils are both inward or outward of the stator.

The signal processing means may be configured to execute a process of expanding a change cycle of the rotational position of the rotor to M / 2 times (M is a positive even number of 4 or more).
In the resolver, the number of salient poles of the rotor is set to 1 or 5, for example.

  For example, the excitation means is configured to form the first excitation signal and the second excitation signal based on a reference pulse signal having a predetermined frequency. In this case, the signal processing means performs processing for generating the reference pulse signal, processing for A / D converting the first signal and the second signal, and a result of the A / D conversion based on the A / D conversion result. A macro processor that executes processing for calculating the rotational position can be provided.

  The present invention also provides a motor drive system for controlling a motor using the rotational position detected by the rotational position detection device according to any one of the above claims.

  According to the present invention, since a resolver having half the number of slots and coils is used, productivity can be improved, cost can be improved, reliability can be improved by reducing connection points, and downsizing can be achieved. An easy rotational position detection device and a motor drive system using the same can be provided.

It is a conceptual diagram which shows the structure of the resolver used for the rotational position detection apparatus which concerns on this invention. The circuit diagram which shows the connection form of the coil of a resolver. It is a circuit diagram showing an embodiment of a rotational position detection device according to the present invention. It is a wave form diagram of the signal output from one output terminal of a resolver. It is a wave form diagram of the signal output from the other output terminal of a resolver. FIG. 5 is a waveform diagram showing a change mode of a signal obtained by A / D converting the signal of FIG. 4. It is a wave form diagram which shows the change aspect of the signal obtained by A / D-converting the signal of FIG. It is a graph which shows an example of the calculation result of the rotation position based on the signal of FIG. 6, FIG. It is a block diagram which shows the structural example of the motor drive system which concerns on this invention. It is a conceptual diagram which shows the other structure of the resolver used for the rotational position detection apparatus which concerns on this invention. It is a circuit diagram which shows embodiment of the rotational position detection apparatus based on this invention which uses the resolver of FIG. It is a wave form diagram of the signal output from one output terminal of the resolver of FIG. It is a wave form diagram of the signal output from the other output terminal of the resolver of FIG. It is a wave form diagram which shows the signal which filtered the signal of FIG. 12 with the band pass filter. It is a wave form diagram which shows the signal which filtered the signal of FIG. 13 with the band pass filter. It is a wave form diagram which shows the change aspect of the signal obtained by A / D-converting the signal of FIG. It is a wave form diagram which shows the change aspect of the signal obtained by A / D-converting the signal of FIG. It is the graph which illustrated the calculation result of the rotation position based on the signal of Drawing 16 and Drawing 17. It is a graph which shows the rotation position change of the double period obtained by extending the calculation result of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing a configuration example of a resolver used in a rotational position detection device according to the present invention. The resolver 1 includes a rotor 3 and a stator 5 both made of a magnetic material.
The rotor 3 has one salient pole. The stator 5 has first, second, third, and fourth magnetic poles that are sequentially arranged at equiangular intervals, and a single coil L1, L3 is wound around the opposing first and third magnetic poles, respectively. The single coils L2 and L4 are wound around the opposing second and fourth magnetic poles, respectively.

As shown in FIG. 2, the coils L1 and L3 are connected in series to each other to form a first coil set, and similarly, the coils L2 and L4 are connected to each other in series to form a second coil set.
The first coil set and the second coil set are connected in parallel between the input terminals T _IN1 and T _IN2 . The common connection point of the coils L1 and L3 is connected to the output terminal _TOUT1, and the common connection point of the coils L2 and L4 is connected to the output terminal _TOUT2 .
That is, the coils L1 to L4 constitute an H bridge circuit in which the coils L1 and L2 are the upper arms and the coils L3 and L4 are the lower arms. In other words, the coils L1 and L4 and the coils L2 and L3 are They are connected so as to constitute an H-bridge circuit located diagonally.

The coils L1 and L3 and the coils L2 and L4 form a magnetic field in the direction indicated by an arrow in FIG. 1 when the input terminal _TIN1 is at a positive potential with respect to the input terminal _TIN2 , that is, the coils L1 and L3. Forms a magnetic field in the radial direction, and the coils L2 and L4 are connected so as to form a magnetic field in the radial direction. When the input terminal T _IN1 has a negative potential with respect to the input terminal T _IN2 , the coils L1 and L3 and the coils L2 and L4 form magnetic fields in the opposite directions to the above.
The coils L1 to L4 may be connected so that they all form a magnetic field in the radial direction or so that they all form a magnetic field in the radial direction.

The shape of the rotor 3 is set so that the inductance of each of the coils L <b> 1 to L <b> 4 changes in a sine wave shape as the rotor 3 rotates.
Therefore, if the coils L1 to L4 are connected as described above, the phase of the fundamental wave of the inductances of the coils L1 and L3 and the fundamental wave of the inductances of the coils L2 and L4 are different by 90 degrees, and a well-balanced magnetic circuit Is configured.

FIG. 3 shows an embodiment of the rotational position detection device according to the present invention using the resolver 1. As shown in FIG. 3, a signal processor 7 using a microprocessor such as a CPU or DSP as a processing means is connected to the resolver 1. The signal processing device 7 includes a signal generation unit 9, an A / D conversion unit 11, and an angle calculation unit 13.
The signal generator 9, the A / D converter 11, and the angle calculator 13 are shown as components having individual functions for convenience of explanation. However, actually, the functions of the signal generator 9, the A / D converter 11, and the angle calculator 13 are brought about by the program processing by the microprocessor.

Signal generating unit 9 generates a reference pulse signal _{e m} is a high-frequency pulse signal of a predetermined frequency (e.g., 20 KHz). The reference pulse signal e _m, which has obtained by dividing processing based clock used by the microprocessor (e.g. 200 MHz), one input terminal T of the resolver 1 through a buffer 15 of the excitation circuit 18 _{The signal} is input to _IN1 and is also input to the other input terminal _TIN2 of the resolver 1 through the inverter 17.
As a result, the coils L1 to L4 of the resolver 1 are alternately excited. For example, when the rotor 3 of the resolver 1 is coupled to the rotation shaft of the motor, the output terminal T of the resolver 1 is accompanied with the rotation of the motor. Pulse-like signals V _1a and V _2a as shown in FIGS. 4 and 5 are output from _{OUT 1} and T _{OUT 2} , respectively. As shown in the figure, the amplitudes of the output signals V _1a and V _2a of the resolver 1 change in a sine wave shape according to a sine wave change in the inductances of the coils L1 to L4 due to a change in the position of the rotor 3 of the resolver 1.

On the other hand, the signal generation unit 9 generates an A / D conversion timing signal and gives this signal to the A / D conversion unit 11. Therefore, the A / D converter 11 A / D converts the output signals V _1a and V _2a of the resolver 1 according to the conversion timing signal.
The conversion timing signal, although in synchronism with the reference pulse signal e _m, are delayed from the edge of the reference pulse signal e _m predetermined time △ t. Here, the delay time Δt will be described.

Although not shown, noise is often superimposed in the vicinity of the edges of the output signals V _1a and V _2a of the resolver 1. This noise is to occur transiently when alternating excitation pulse signal based on the reference pulse signal e _m is applied to the coil L1~L4 is an inductive load. Therefore, the use of the reference pulse signal e _m as it is A / D conversion timing signal, there is a fear that the influence of the noise appears in the A / D conversion result.

The delay time Δt is a predetermined time required for the noise near the edges of the output signals V _1a and V _2a of the resolver 1 to disappear or be reduced to a predetermined value or less, in other words, the output signal V of the resolver 1. _The time required for the values of the pulse waves included in _1a and _V2a to be stabilized is set. Of course, the base point of the delay time △ t is an edge of the reference pulse signal e _m. The delay time Δt (for example, several μsec) is determined in advance by simulation or experiment, and is generated by a timer (not shown) provided in the signal processing device 7.
According to the present embodiment in which the A / D conversion unit 11 starts the conversion operation by the conversion timing signal as described above, it is possible to obtain a highly reliable A / D conversion result.

Output signals V _1a and V _2a of the resolver 1 input to the A / D converter 11 are converted into signals V _1d and V _2d shown in FIGS. The angle calculation unit 13 receives the signals V _1d and V _2d and calculates the rotational position (angle) θ of the rotor 3 based on the following equation (1).
^{_{θ = tan - (V 1d /}} V 2d) (1)
FIG. 8 shows the calculation result of θ (electrical angle). As described above, in the rotational position detection device according to the present embodiment, an electrical signal of one cycle (an electrical angle of 0 ° to 360 °) is electrically generated during one rotation of the rotor 3 (mechanical change from 0 ° to 360 °). Signal) is obtained.

  As described above, in the rotational position detection device according to the present embodiment, the processes in the signal generator 9, the A / D converter 11, and the angle calculator 13 are all executed by the microprocessor such as the CPU and DSP. Hardware components other than the microprocessor are not necessary, and therefore cost reduction and size reduction can be achieved. Note that some or all of the above-described processes may be executed using hardware elements.

The resolver 1 can also be applied as position detecting means for the motor drive system shown in FIG. In this case, the resolver 1 is coupled to the motor 19 so as to rotate together with the motor 19 (for example, a permanent magnet type motor).
The resolver 1 is excited by the excitation pulse signal from the excitation circuit 18 shown in FIG. 3 and outputs the signals V _1a and V _2a . The control circuit 20 incorporates a processing unit comprising a microprocessor in the same way as the signal processing device 7 shown in FIG. 3, and A / D converts the signals V _1a and V _2a by the processing unit, and a signal indicating the conversion result Based on (see FIGS. 6 and 7) and the above equation (1), the rotational position (rotational position of the motor 19) θ of the rotor 3 of the resolver 1 is calculated. The control circuit 20 generates a control signal (for example, a PWM signal) for causing the motor 19 to perform an operation in accordance with the command based on the signal indicating the rotational position θ and a command input from the outside. It is created and output to the drive circuit 21. Therefore, the drive circuit 21 supplies power corresponding to the control signal to the motor 19 using, for example, an inverter circuit, and as a result, the motor 19 operates according to the command signal.

According to this motor drive system, the processing means comprising a microprocessor incorporated in the control circuit 20 executes signal processing similar to that of the signal processing device 7 shown in FIG. 3, so that it is possible to reduce the size and cost. It is.
In this motor drive system, a position signal of one cycle is obtained while the rotor 3 of the resolver 1 makes one rotation. Therefore, a two-pole motor having a pole pair number of 1 is used as the motor 19.
The control circuit 20 may be configured to execute some or all of the processes executed by the microprocessor using hardware elements.

FIG. 10 shows another configuration example of the resolver, and FIG. 11 shows another embodiment of the rotational position detection device according to the present invention using this resolver 10.
The resolver 10 is different from the resolver 1 shown in FIG. 1 in that it includes a rotor 3 ′ having 5 poles. In the resolver 10, the coils L <b> 1 to L <b> 4 are excited by an alternating excitation pulse signal applied via the excitation circuit 18, similarly to the resolver 1. Accordingly, by rotating the rotor 3 ′, the amplitude is sine according to the signals shown in FIGS. 12 and 13 from the output terminals T _OUT1 and T _OUT2 , that is, in accordance with the sinusoidal change in inductance accompanying the rotation of the rotor 3 ′. Pulse-shaped signals V _11a and V _22a that change in a wave shape are output.

The signals V _11a and V _22a are input to the band pass filter 23 shown in FIG. 11 in order to reduce noise included in the signals. As a result, the signals corresponding to the signals V _11a and V _22a are output from the band pass filter 23. V _11a ′ and V _22a ′ are output. 14 and 15 show the signals V _11a ′ and V _22a ′, respectively.
The A / D conversion unit 11 of the signal processing device 7 performs A / D conversion on the signals V _11a ′ and V _22a ′ in accordance with the A / D conversion timing signal output from the signal generation unit 9. Here, the A / D conversion timing signal will be described.
The output signal V _{11a ',} V _22a' of the band-pass filter 23, which has a pulsation waveform of the short cycle of the sine wave and the envelope, its pulsation is synchronized with the reference pulse signal e _m. Therefore, the A / D conversion timing signal is synchronized to the reference pulse signal e _m, and, when the reference pulse signal e _m of predetermined from edge time Delta] t 'only delayed, specifically, the signal V _11a It is set so that each pulsation waveform at “, V _22a ” is generated at the time when it shows a peak value.
The delay time Δt ′ is determined in advance by simulation or experiment, and is generated by a timer (not shown) provided in the signal processing device 7.
According to the present embodiment in which the A / D conversion unit 11 starts the conversion operation by the conversion timing signal as described above, the values on the envelopes of the signals V _11a ′ and V _22a ′ are A / D converted. Highly accurate digital position information can be obtained.

The angle calculation unit 13 of the signal processing device 7 inputs the signals V _11d ′ and V _22d ′ obtained by A / D conversion, and calculates the position (angle) θ of the rotor 3 ′ based on the following equation (2). To do.
_{^{θ = tan - (V 11d '}} / V 22d') (2)
FIG. 18 illustrates the calculation result of the rotational position θ (electrical angle) of the rotor 3. The mechanical angle θ _m of the rotor 3 is
θ _m = (1/5) tan ⁻ (V _11d ′ / V _22d ′) (3)
Therefore, electrical angle 360 ° = mechanical angle 72 °.

According to the embodiment using the band pass filter 23, noise that enters the line connecting the resolver 1 and the signal processing device 7 in addition to the fluctuation noise of the output signals V _11a and V _22a of the resolver 1 is reduced or reduced. Since it is eliminated, it is particularly effective when the coupling line is long.
Of course, the rotational position detection device of this embodiment can also be applied to the motor drive system shown in FIG. 9. In this case, the bandpass filter 23 is inserted between the resolver 10 and the control circuit 20. Since the rotational position detection device using the resolver 10 can obtain a position signal of 5 cycles while the rotor 3 ′ makes one rotation, the motor drive system to which this rotational position detection device is applied has 5 pole pairs as the motor 19. A 10 pole motor is used.

  Incidentally, according to the rotational position detecting device of FIG. 3 using the resolver 1 of FIG. 1 having the rotor 3 having the number of salient poles 1 (n = 1), as shown in FIG. Since a position signal of one cycle (a signal indicating an electrical angle of 0 ° to 360 °) is obtained electrically during a mechanical change (° to 360 °), when applied to the motor drive system shown in FIG. 19 is a two-pole (pole pair number 1) motor.

The present invention is not limited to the above-described embodiment, and includes various modifications.
For example, in the embodiment shown in FIG. 3 and FIG. 11, the resolver 1 having the rotor 3 having the salient pole number 1 and the resolver 10 having the rotor 3 ′ having the salient pole number 5 are used, respectively. The resolver is not limited to a simple configuration. That is, the present invention can be implemented as long as the number of salient poles of the rotor is 2n-1 (n is a positive integer). This means that when this resolver is applied to the motor drive system of FIG. 9, a permanent magnet motor having 2 (2n-1) magnetic poles can be controlled. In addition, this invention is not limited to control of a permanent magnet motor, For example, it can be used also for control of an induction motor.

Further, the one-cycle position change (electrical angle change) shown in FIG. 8 obtained by using the resolver 1 is expanded to a position change of M / 2 (M is a positive even number of 4 or more) cycle by arithmetic processing. It is possible. If such an expansion is performed, the M pole motor can be controlled even when the resolver 1 is applied to the motor drive system of FIG. For example, if M is set to 4 and the result shown in FIG. 8 is expanded to 4/2 = 2 cycles as shown in FIG. 19, it can be applied to control of a 4-pole permanent magnet motor. Become. The above expansion processing can be executed by, for example, the angle calculation unit 13 shown in FIG. 3, that is, the microprocessor. In that case, the angle calculator 13 multiplies the calculation result shown in FIG. 8 by M / 2, and executes a process of reducing the electrical angle 360 ° every time the value reaches the electrical angle 360 °. In the case of FIG. 19, the boundary of each period of change in position (electrical angle change) (the point at which the electrical angle changes from 360 ° to 0 °) is formed by the process of reducing the electrical angle 360 °.
Note that the same expansion process can be performed for a one-cycle position change (electrical angle change) shown in FIG.

Furthermore, in the embodiment shown in FIG. 11, the output signals V _11a and V _22a of the resolver 10 are input to the band pass filter 23, but the band pass filter 23 may be omitted. In this case, the conversion timing signal in the embodiment shown in FIG. 3 is used as the conversion timing signal of the A / D conversion unit 11.
On the other hand, in the rotational position detection apparatus shown in FIG. 3, a band pass filter can be interposed between the resolver 1 and the A / D conversion unit 11 as necessary. The conversion timing signal in the embodiment shown in FIG. 11 is used as the conversion timing signal. When the rotational position detection device is applied to the motor drive system of FIG. 9, the bandpass filter is provided between the resolver 1 and the control circuit 20.

DESCRIPTION OF SYMBOLS 1, 10 Resolver 3, 3 'Rotor 5 Stator L1-L4 Coil 7 Signal processing device 9 Signal generation part 11 A / D conversion part 13 Angle calculation part 15 Buffer 17 Inverter 18 Excitation circuit 19 Motor 20 Control circuit 21 Drive circuit 23 Band Path filter

Claims (8)

A stator in which a single first, second, third, and fourth coil is wound around first, second, third, and fourth magnetic poles that are sequentially arranged at equal angular intervals, and 2n-1 (n is a positive integer) having a number of salient poles and a rotor having a shape capable of changing the inductance of the first to fourth coils in a sine wave shape, the first to fourth coils A resolver that is bridge-connected so that the first and fourth coils and the second and third coils are diagonally located,
A first excitation signal having a predetermined frequency is supplied to a connection point between the first and second coils, and a second excitation signal obtained by inverting the first excitation signal at a connection point between the third and fourth coils. Excitation means for supplying
A signal for calculating the rotational position of the rotor based on the first output signal from the connection point of the first and third coils and the second output signal from the connection point of the second and fourth coils. A processing means,
The first to fourth coils are arranged such that the directions of the magnetic fields generated by the first and second coils are both inward or outward of the stator, and the second and fourth coils. The rotational position detecting device is wound so that the directions of the generated magnetic fields are both directed inward or outward of the stator.   2. The rotational position detection according to claim 1, wherein the signal processing unit executes a process of expanding a change period of the rotational position of the rotor to M / 2 times (M is a positive even number of 4 or more). apparatus.   The rotational position detection device according to claim 1, wherein the resolver has one salient pole of the rotor.   The rotational position detection device according to claim 1, wherein the resolver has five salient poles of the rotor.   2. The rotational position detection device according to claim 1, wherein the excitation unit is configured to form the first excitation signal and the second excitation signal based on a reference pulse signal having a predetermined frequency. .   The signal processing means includes: a process for generating the reference pulse signal; a process for A / D converting the first output signal and the second output signal; and a result of the A / D conversion process. The rotation position detection apparatus according to claim 5, further comprising a macro processor that executes a process of calculating a rotation position of the rotation position.   A motor drive system that controls a motor using the rotational position detected by the rotational position detection device according to any one of the above claims.   The motor drive system according to claim 7, wherein the motor is a permanent magnet motor.

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