JPH09215369A - Motor control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue the control of a synchronous motor by a speed generator even if a Z-phase signal generated in accordance with the rotor position signal of a rectifier sensor shows an abnormality. SOLUTION: The current application to a synchronous motor 1 is controlled by a rotation detector 2 which consists of a rectifier sensor which outputs a rotor position signal corresponding to the rotation position of the rotor of the synchronous motor 1 and a speed generator which outputs an A-phase signal, a B-phase signal and a Z-phase signal which have a frequency corresponding to the revolution of the rotor of the synchronous motor 1. Normally, the Z-phase signal is generated in accordance with the rotor position signal and the current application to the synchronous motor 1 is controlled by the Z-phase signal generated in accordance with the rotor position signal and the A-phase signal and B-phase signal outputted by the speed generator. If the Z-phase signal generated in accordance with the rotor position signal shows an abnormality, the current application to the synchronous motor 1 is controlled in accordance with the A-phase signal and B-phase signal outputted by the speed generator and the Z-phase signal outputted by the speed generator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control method for driving a synchronous motor such as a main motor for an electric vehicle or an industrial control motor. This relates to measures for improving reliability when controlling the energizing current of the.

[0002]

2. Description of the Related Art As a first method for controlling energization of a synchronous motor, a known commutation sensor (CS; Commutat) for magnetically detecting the rotational position of a magnetic pole of a rotor in the synchronous motor.
ion sensor) is attached, a rectangular wave signal is generated based on the rotor position signal of the commutation sensor, and current is supplied to the armature winding of each phase of the synchronous motor according to the rectangular wave signal. As described above, in the method of controlling the drive of the synchronous motor with the rectangular wave, it is possible to perform the field weakening that advances the phase of the current waveform supplied to the armature winding of each phase of the synchronous motor with respect to the rotation phase of the rotor. Therefore, the variable range of the rotation speed of the synchronous motor cannot be widened. As the commutation sensor, a structure that detects changes in the magnetic flux due to the rotation of the main magnet of the synchronous motor with a hall element or a structure that detects the rotational position of the rotor of the synchronous motor by electromagnetic means described later is adopted. To be done.

A second device for controlling energization of a synchronous motor
In this method, an encoder for optically detecting the rotational position of the rotor is attached to the synchronous motor, and a sine wave is output from the waveform storage means based on the A-phase signal, B-phase signal and Z-phase signal output from the encoder. The sine wave corresponding to the rotational position of the rotor is generated in the synchronous motor by sequentially reading the waveform data of and analog-digital converting it.
There is a method of supplying a current to each phase armature winding of the synchronous motor according to this sine wave. In this way, in the method of controlling the drive of the synchronous motor with the sine wave, it becomes possible to perform the field weakening that advances the phase of the current supplied to the armature winding of each phase of the synchronous motor with respect to the rotation phase of the rotor. It is possible to widen the variable range of the rotation speed of the synchronous motor, and for example, in an electric vehicle, it is possible to operate in a wide speed range from low speed running to high speed running without using a transmission. There is an advantage that the rotation of the synchronous motor can be made smooth.

Therefore, in the synchronous motor, a control mode in which the sine wave drive control is mainly performed by the encoder, and the rectangular wave drive control is supplementarily performed by the rectification sensor at the time of low speed rotation such as start-up has been increasing. However, for sinusoidal wave drive control of a synchronous motor used in, for example, an electric vehicle, a speed generator (FG; Fr) that can be manufactured at a lower cost than that of the optical encoder described above and that has good heat resistance and vibration resistance.
It is preferable to use the frequency generator). This speed generator has a structure in which a multi-pole generator, for example, a step motor is used as a generator, and two sets of comb-teeth-shaped magnetic materials are used for teeth of a gear-shaped magnet rotor. It has a structure in which the teeth of the stator are opposed to each other with a phase difference of 90 degrees, and a winding for detection is provided on the stator, and the phase of the frequency corresponding to the rotation speed of the rotor of the synchronous motor is 90 degrees. Different A-phase signals and B-phase signals are output.

Due to the characteristics of this speed generator, the output signal level is zero or extremely low in a stationary or low speed rotation state. Therefore, the sinusoidal wave drive control of the synchronous motor by the speed generator can be performed only when the rotational speed of the synchronous motor becomes high to some extent and the level of the output signal of the speed generator becomes sufficiently high. Performs rectangular wave drive control by the rotor position signal of the commutation sensor.

Further, this speed generator can usually output only the A-phase signal and the B-phase signal, and cannot generate the Z-phase signal for resetting the up-down counter for generating the waveform memory address. , Logically processing the rotor position signal of the rectification sensor to generate a Z-phase signal, and generating the Z-phase signal based on the rotor position signal of the rectification sensor,
The synchronous motor is drive-controlled based on the Z-phase signal generated based on the rotor position signal of the commutation sensor and the A-phase signal and the B-phase signal output from the speed generator.

[0007]

As described above, when the commutation sensor and the speed generator are used together to control the synchronous motor, the rotor position signal of the commutation sensor is logically processed to generate the Z-phase signal. When the Z-phase signal generated based on the rotor position signal of the rectification sensor becomes abnormal due to a failure of the generated logic circuit or a disconnection of its output wiring, for example, the Z-phase signal may not be output at all. In such a case, even if there is no abnormality in the rectification sensor or the speed generator itself, the Z-phase signal is not generated, so that the drive control of the synchronous motor cannot be performed correctly,
We could not meet the reliability requirements for electric vehicles.

An object of the present invention is to provide an abnormal Z-phase signal generated based on the rotor position signal of the rectification sensor,
An object of the present invention is to provide a highly reliable motor control method capable of continuing control of a synchronous motor by a speed generator. Another object of the present invention is to prevent the synchronous motor from stopping rotating even if the Z-phase signal generated based on the rotor position signal of the commutation sensor becomes abnormal. An object of the present invention is to provide a motor control method capable of avoiding danger.

[0009]

According to a first aspect of the present invention, there is provided a motor control method, wherein a commutation sensor for outputting a rotor position signal corresponding to a rotational position of a rotor of a synchronous motor and a frequency corresponding to a rotational speed of a rotor of the synchronous motor. A method of controlling energization of a synchronous motor using a speed generator that outputs an A-phase signal, a B-phase signal and a Z-phase signal, and generates a Z-phase signal based on a rotor position signal of a commutation sensor, The energization of the synchronous motor is controlled based on the Z-phase signal generated based on the rotor position signal of the commutation sensor and the A-phase signal and the B-phase signal output from the speed generator, and based on the rotor position signal of the commutation sensor. When the generated Z-phase signal becomes abnormal,
The energization of the synchronous motor is controlled based on the A-phase signal and the B-phase signal output from the speed generator and the Z-phase signal output from the speed generator.

According to this method, the synchronous motor is usually controlled by using the Z-phase signal generated based on the rotor position signal of the commutation sensor and the A-phase signal and the B-phase signal output from the speed generator, and the commutation sensor is controlled. When the Z-phase signal generated on the basis of the rotor position signal becomes abnormal, synchronization is performed based on the A-phase signal and B-phase signal output from the speed generator and the Z-phase signal output from the speed generator. Since the energization of the motor is controlled, it is possible to continue the control of the synchronous motor by the speed generator to improve reliability, and to prevent the synchronous motor from stopping rotating. The danger of stopping can be avoided.

According to a second aspect of the motor control method of the present invention, in the motor control method of the first aspect, the control region of the synchronous motor includes a normal control region and a field weakening control region, and the rotor position signal of the commutation sensor is in the normal control region. Z generated based on the rotor position signal of the commutation sensor while energizing the synchronous motor based on the Z-phase signal generated based on the Z-phase signal and the A-phase signal and the B-phase signal output from the speed generator. When the phase signal becomes abnormal, the energization control of the synchronous motor is switched based on the rotor position signal of the commutation sensor, and the Z phase signal by the rotor position signal of the commutation sensor and the A phase signal and B output from the speed generator in the field weakening control region. When the Z-phase signal due to the rotor position signal of the commutation sensor becomes abnormal during energization control of the synchronous motor based on the phase signal, the speed generator outputs The rotor position of the commutation sensor is controlled after the energization control is performed using the applied A-phase signal and B-phase signal and the Z-phase signal output from the speed generator so as to shift from the field weakening control region to the normal control region while decelerating. Switch to the energization control of the synchronous motor based on the signal.

According to this method, in the normal control region, the control by the speed generator is switched to the control by the rectification sensor, and in the field weakening control region, the control state by the speed generator is continuously shifted to the normal control region while decelerating. , After entering the normal control area, the control by the speed generator is switched to the control by the commutation sensor, so that the field weakening control state by the speed generator is gradually changed to the normal control state by the commutation sensor without a sudden change in the rotation speed of the synchronous motor. Therefore, it is possible to prevent a sudden change in behavior due to the occurrence of an abnormality during high-speed rotation of the synchronous motor.

According to a third aspect of the motor control method of the present invention, in the motor control method of the first or second aspect, the abnormality of the Z-phase signal generated based on the rotor position signal of the commutation sensor is detected as a speed generator. From the time of appearance of one pulse of the Z-phase signal output from the device to the time of appearance of the next pulse by detecting the presence or absence of the appearance of the pulse of the Z-phase signal generated based on the rotor position signal of the rectification sensor. .

According to this method, since the Z-phase signal output from the speed generator and the Z-phase signal generated based on the rotor position signal of the rectification sensor are generated by different systems, the rotor position of the rectification sensor is generated. Z generated based on the signal
The abnormality of the phase signal can be accurately detected, and the abnormality of the Z-phase signal generated based on the rotor position signal of the rectification sensor based on the Z-phase signal output from the speed generator is detected. Therefore, simple logical processing can be performed. The abnormality of the Z-phase signal can be detected only by performing the operation.

The motor control method according to a fourth aspect is the motor control method according to the second aspect, wherein the energization control of the synchronous motor based on the rotor position signal of the commutation sensor is the rectangular wave drive control, and the output from the speed generator. The energization control of the synchronous motor based on the A-phase signal and the B-phase signal is the sine wave drive control. According to this method, the same operation as the motor control method according to the second aspect is achieved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit block diagram of a motor control device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 is a synchronous motor which is a drive source of an electric vehicle, for example. Reference numeral 2 denotes a rotation detector provided in the synchronous motor 1, which is a combination of a speed generator (FG) and a commutation sensor (CS) integrated with each other.

As the speed generator described above, for example, those shown in FIGS. 6 and 7 are adopted. Here, FIG.
And FIG. 7 shows an example of the structure of the speed generator which can output an A phase signal, a B phase signal, and a Z phase signal. In particular, FIG.
A front view of a portion for generating the A-phase signal and the B-phase signal is shown in (a), a sectional view is shown in the same figure (b), and a rear view of the rotor is shown in the same figure (c). Further, FIG. 7A shows a front view of the Z-phase signal generating portion, FIG. 7B shows a sectional view of the same, and FIG. 7C shows a rear view of the rotor. The structural portion of FIG. 6 and the structural portion of FIG. 7 are arranged side by side in the direction of the rotary shaft of the synchronous motor.

As shown in FIG. 6, this speed generator has a magnet rotor 31 having a large number of gear-shaped irregularities on its outer peripheral edge,
A ring-shaped yoke 32 fixedly arranged so as to surround the magnet rotor 31, and a magnet rotor 3 protruding inwardly from the yoke 32 so as to face the magnet rotor 31 and to be provided at a tip portion thereof.
Four magnetic poles 33 having comb-shaped irregularities with the same pitch as 1
~ 36 and four windings 37-40 wound around four magnetic poles
Consists of The magnet rotor 31 described above rotates in conjunction with the rotary shaft of the synchronous motor.

The structure of the magnet rotor 31 and the four magnetic poles 33 to 36 will now be described. That is, as shown in FIG. 6, the magnet rotor 31 may be an iron disc 31a having a large number of gear-like irregularities on the outer periphery and an iron disc 31b having no irregularities (the same structure as the disc 31a. ) And a ring-shaped permanent magnet 31c sandwiched between them as shown in FIG.
A magnetic flux that enters from the outer peripheral edge of b is generated.

Of the four magnetic poles 33 to 36, the two magnetic poles 33 and 35 are arranged in the same phase relationship with the irregularities of the magnet rotor 31, and the remaining two magnetic poles 34 and 36. Are also arranged in the same phase relationship with the concavities and convexities of the magnet rotor 31, and the magnetic pole 33 and the magnetic pole 34 and the magnetic pole 35 and the magnetic pole 36.
Are arranged in a phase relationship that is offset by 90 degrees with respect to the irregularities of the magnet rotor 31. In this case, when the convex portion of the magnet rotor 31 and the convex portions of the magnetic poles 33 to 36 face each other, the magnetic flux is most likely to pass through, and the convex portion of the magnet rotor 31 and the magnetic poles 33 to 36.
When facing the concave portion of 36, the magnetic flux is most difficult to pass through. Then, the change of the magnetic flux is detected by the windings 37 to 40 and detected by the speed generator detection circuit 14,
An A phase signal and a B phase signal can be generated.

More specifically, the windings 37 and 39 wound around the magnetic poles 33 and 35 take out the A-phase signal.
An AC voltage, which is connected in series and has a frequency proportional to the rotation speed of the rotor of the synchronous motor and whose amplitude increases with the increase of the rotation speed, appears in the speed generator detection circuit 14. By doing so, an A-phase signal is obtained. The winding 3 wound around the magnetic poles 34, 36
Reference numerals 8 and 40 are for extracting the B-phase signal and are connected in series. At both ends, an AC voltage whose frequency is proportional to the rotation speed of the rotor of the synchronous motor and whose amplitude increases with the rotation speed appears. This voltage is 90 degrees out of phase with the voltage appearing on the windings 37 and 39. By detecting this with the speed generator detection circuit 14, B
A phase signal is obtained.

Since the speed generator described above is premised on the use at the time of high speed rotation in which the rotation speed has increased to some extent, a sufficiently high signal level can be obtained even with a structure having many pulses, that is, high resolution. , The S / N ratio is good, and when the synchronous motor is controlled, the detection of pulses is not missed and the synchronous motor can be accurately controlled. Moreover, in terms of cost, it is sufficiently lower than the encoder, and because it is electromagnetic and does not use a semiconductor element, it has good heat resistance.

Further, as shown in FIG. 7, this speed generator is fixed to a magnet rotor 41 having two convex portions 41a and 41b on its outer peripheral edge and a state surrounding the magnet rotor 41. A ring-shaped yoke 42, and two magnetic poles 43, 44 provided on the inner peripheral surface of the yoke 42 so as to project inwardly so as to face the magnet rotor 41 and have convex portions 43a, 44a at their tips. , Windings 45 and 46 wound around the magnetic poles 43 and 44 and connected in series. The magnet rotor 41 rotates in conjunction with the rotary shaft of the synchronous motor, and has two protrusions 4 on the outer peripheral edge.
Reference numerals 1a and 41b denote asymmetrical positions with respect to the rotation axis of the rotor, for example, a straight line connecting the projection 41a and the rotation axis and the projection 41b.
The straight line connecting the rotation axis and the rotation axis has an angle of 90 degrees, but is not limited to 90 degrees.

Here, regarding the structure of the magnet rotor 41,
explain in detail. That is, the magnet rotor 41 includes the iron disc 4 having the two protrusions 41a and 41b on the outer peripheral edge.
1a and an iron disk 41b having no unevenness (the same unevenness as the disk 41a may be provided) sandwiches a polar ring-shaped permanent magnet 41c as shown in the drawing.
A magnetic flux is generated so as to come out from the outer peripheral edge of a and enter from the outer peripheral edge of the disc 41b.

Further, the convex portion 43 at the tip of the magnetic poles 43, 44
a and 44a are formed in the same width as the convex portions 41a and 41b of the magnet rotor 41, and the convex portion 41a faces the convex portion 43a and the convex portion 41b faces the convex portion 44a. The formation position is determined so that
a, 41b and convex portions 43a, 44a face each other, the magnetic flux of the magnet rotor 41 is the highest.
3 and 44, the magnetic flux easily passes once each time the rotor of the synchronous motor makes one revolution. This change in magnetic flux is detected by the windings 45 and 46, and this is detected by the speed generator. A Z-phase signal can be generated by performing detection by the detection circuit 14.

The two convex portions 41 of the magnet rotor 41 are
a and 41b are convex portions 41 at the tips of the magnetic poles 43 and 44, respectively.
It is positioned with respect to the rotary shaft of the rotor of the synchronous motor so that the rotational position of the magnet rotor 41 when exactly facing a and 41b coincides with the rising position of the U-phase rotor position signal of the commutation sensor. . Next, the rotation detector 2
The commutation sensor in 1 is composed of, for example, a well-known magnetic means, and outputs a rotor position signal corresponding to the rotational position of the magnetic pole of the rotor of the synchronous motor 1. The structure will be described below.

FIG. 8 is a schematic diagram showing an example of the structure of a rectification sensor used in the control device for the synchronous motor of FIG. This commutation sensor has a rotor 20 made of a magnetic material that rotates in conjunction with the rotary shaft of a synchronous motor, a ring-shaped yoke 21 fixedly arranged so as to surround the rotor 20, and provided inwardly on the yoke 21. The three exciting magnetic poles 22A, 22B and 22C facing the rotor 20, and the three detecting magnetic poles 23A protruding inward from the yoke 21 and facing the rotor 20.
23B, 23C and magnetic poles 22A, 22B, 22C for excitation
Excitation windings 24A, 24B, 24C wound around the coil and the detection winding 2 wound around the detection magnetic poles 22A, 22B, 22C.
It consists of 5A, 25B and 25C.

Three exciting magnetic poles 22A, 22B, 22C
Are arranged in a predetermined phase relationship with respect to the armature of the synchronous motor, and are arranged with a phase difference of 120 degrees from each other. Similarly, three detection magnetic poles 23A, 23B, 23C
Are arranged in a predetermined phase relationship with respect to the armature of the synchronous motor, and are arranged with a phase difference of 120 degrees from each other. The three excitation magnetic poles 22A, 22B and 22C and the three detection magnetic poles 23A, 23B and 23C are arranged with a phase difference of 60 degrees and a phase difference of 60 degrees. That is, six magnetic poles are arranged 60 degrees apart, and every other three magnetic poles are excitation magnetic poles 22A, 22B and 22C, and the remaining three magnetic poles are detection magnetic poles 23A, 23B and 23C.

The excitation windings 24A, 24B, 24
C is connected in parallel, and these excitation windings 24A, 24
When a high-frequency current is applied to B and 24C from the high-frequency power source 26 to excite the exciting magnetic poles 22A, 22B and 22C with high frequency,
The high frequency voltages W1, W2, W3 determined by the positional relationship between the rotor 20 and the detection magnetic poles 23A, 23B, 23C are induced from the detection windings 25A, 25B, 25C, and the rotor 2
When 0 rotates, as shown in FIGS. 9A, 9B, and 9C, the envelopes of the induced high-frequency voltages W1, W2, and W3 change in a sine wave shape, and the detection windings 25A and 25B, 25C
The phases of the envelopes of the high-frequency voltages W1, W2, and W3 induced from are shifted by exactly 120. The rectifier sensor detection circuit 13 detects the waveforms of FIGS. 9A, 9B, and 9C and shapes the waveform with a predetermined threshold value to obtain a rotor position signal of the rectifier sensor.

When the speed generator stops rotating, the output voltage also disappears. However, with the structure as shown in FIG. 8, the output level depends on only the position of the rotor of the synchronous motor, regardless of the rotational speed of the synchronous motor. The output varies depending on the position of the rotor even when the rotor is stationary, and the sensor can be used as a commutation sensor.

As described above, the rectifying sensor having the structure shown in FIG.
Although the resolution is low, the output can be taken out even in a stationary state, the structure is electromagnetic, the cost is low, the heat resistance is sufficient, and it can be used even at high temperature. The output signal of the speed generator in the rotation detector 2 is, as described above,
By being detected by the speed generator detection circuit 14, it is converted into an A-phase signal, a B-phase signal, and a Z-phase signal having a frequency according to the rotation speed of the rotor of the synchronous motor 1, and input to the circuit in the subsequent stage. However, in the following, the operation of the speed generator will be described assuming that the speed generator includes the speed generator detection circuit 14. Further, the output signal of the rectification sensor in the rotation detector 2 is detected by the rectification sensor detection circuit 13 as described above, so that the synchronous motor 1
Is converted into a rotor position signal according to the rotational position of the magnetic pole of the rotor and input to the circuit in the subsequent stage. In the following, the operation of the rectification sensor is assumed to include the rectification sensor detection circuit 13. Will be explained.

Reference numeral 11 denotes a Z-phase signal generating circuit that logically processes the rotor position signal output from the rectification sensor of the rotation detector 2 to generate a Z-phase signal. The Z-phase signal is
The pulse rises once every time the rotor of the synchronous motor 1 makes one revolution. 3 is a Z-phase signal based on the Z-phase signal generated by the Z-phase signal generation circuit 11 and the A-phase signal and the B-phase signal output from the speed generator of the rotation detector 2 and having a 90-degree phase difference from each other. Is a reset pulse, for example A
A digital address signal (for reading sine wave data) corresponding to the rotor position of the synchronous motor 1 is generated by up / down counting means (up / down is switched depending on the phase relationship between the A phase and the B phase) using the phase signal as count input. Address generating means for generating a digital address signal (for reading a rectangular wave digital signal) by logically processing the rotor position signal of the rectification sensor.

When the Z-phase signal generated by the Z-phase signal generating circuit 11 is abnormal, the address generating means 3 outputs a signal having a 90-degree phase difference A from the speed generator of the rotation detector 2. A digital address signal corresponding to the rotor position of the synchronous motor 1 is generated based on the phase signal and the B phase signal and the Z phase signal output from the speed generator of the rotation detector 2.

Reference numeral 4 denotes synchronization obtained from the torque or speed command input (accelerator input, brake input) and the A phase signal or B phase signal output from the speed generator of the rotation detector 2 or the rotor position signal output from the rectification sensor. Motor 1
The torque / speed control means is composed of a CPU or the like that outputs a torque control command signal in accordance with the difference from the rotation speed. 5
Is a rectangular shape for driving the synchronous motor 1, for example, for storing one cycle of waveform data of, for example, three-phase rectangular wave and sine wave for driving the synchronous motor 1 and using the digital address signal output from the address generating means 3 as an address input. The waveform storage means is a ROM or the like for reading out waveform data of a wave or a sine wave corresponding to the rotor position of the synchronous motor 1.
If the waveform data is stored for two phases, the remaining one phase can be calculated.

Reference numeral 6 multiplies the waveform data for driving the synchronous motor 1 output from the waveform storage means 5 by the torque control command signal output from the torque / speed control means 4 and converts the multiplication result into digital / analog conversion. (Hereafter, D
/ A conversion) for performing integrated D / A conversion means. It should be noted that integration is used to mean multiplication. 7 is total D / A
It is a current control circuit that outputs an error signal between an output signal of the conversion means 6 and a detection signal of a load current flowing through the synchronous motor 1 by a current transformer (not shown) or the like.

Reference numeral 8 is a pulse width modulation (hereinafter referred to as PWM) for generating a pulse width modulation signal according to the output signal of the current control circuit 7.
It is a control circuit. A PWM inverter 9 drives the synchronous motor 1 according to the output signal of the PWM control circuit 8. An abnormality detection circuit 10 outputs Z output from the Z-phase signal generation circuit 11 based on the Z-phase signal generated at the timing of the A-phase signal of the speed generator in the rotation detector 2.
It is determined whether the phase signal, that is, the Z-phase signal generated based on the rotor position signal of the commutation sensor is abnormal. Specifically, after the pulse of the Z-phase signal from the speed generator is input, it is monitored whether the pulse of the Z-phase signal of the rectification sensor is input before the pulse of the next Z-phase signal is input. If there is no input, it is determined to be abnormal.

Reference numeral 12 is a speed converting means for converting an output signal of the rotation detector 2 (A-phase signal, B-phase signal of the speed generator or rotor position signal of the rectification sensor) into a speed signal. It is sent to the speed control means 4. In the case of this figure, the output signal of the rotation detector 2 is obtained from the abnormality detection circuit 10. Here, the output signal of the rotation detector 2 will be described.

The rotor position signal output from the commutation sensor of the rotation detector 2 is a signal that detects the position of the magnetic pole of the rotor of the synchronous motor 1, and detects the position of the magnetic pole of the rotor.
This is for determining which coil is energized, and a signal corresponding to the position of the magnetic pole of the rotor is output regardless of the rotation speed of the rotor. In addition, as a signal for detecting the rotational position of the rotor, the speed generator of the rotation detector 2 generally has a phase difference of 90 degrees from the reference pulse (Z-phase signal; 360 degrees = 1 pulse per rotation). Two-phase pulse train, that is, A
It outputs a phase signal and a B-phase signal. With this phase shift, the rotation direction can be detected, and the rotation angle of the rotor can be detected by counting the pulse train of the A-phase signal or the B-phase signal. Due to the characteristics of the speed generator, if the rotation speed of the rotor does not rise to a certain degree, A
The phase signal, B phase signal and Z phase signal cannot be output.

The rotation angle and the rotation speed are detected as follows. For example, it is assumed that only the rising edges of the A-phase signal and the B-phase signal are counted and 1000 pulses are generated in one rotation. At this time, the phase of the rotor corresponds to 180 degrees at the 500th pulse counted from the Z-phase signal. Further, the speed of the synchronous motor 1 is detected by counting the number of pulses of the A-phase signal or the B-phase signal within a fixed time interval. For example, if 2000 pulses are counted in one second, it means that two rotations are performed in one second, and it is understood that the rotation is 120 rpm. Similarly, the speed of the synchronous motor 1 is also detected by counting the rotor position signal of the commutation sensor.

If the Z-phase signal, the A-phase signal and the B-phase signal are present, it seems that the rotor position signal of the commutation sensor is basically unnecessary. This is because the rotation angle of the rotor can be obtained from the Z-phase signal, the A-phase signal and the B-phase signal. However, the Z-phase signal, the A-phase signal, and the B-phase signal can be effectively used only after the reference Z-phase signal is input. If the number of rotations of the synchronous motor 1 does not reach the number of rotations required for the speed generator, the Z-phase signal, the A-phase signal, and the B-phase signal are not generated from the speed generator. Until the phase signal is input, commutation to the winding of the synchronous motor 1 is controlled according to the rotor position signal of the commutation sensor. After the required number of revolutions is reached and the Z-phase signal is input, the commutation to the winding of the synchronous motor 1 is controlled based on the Z-phase signal.

The operation of the motor control device having the above configuration will be described below together with the motor control method. Based on the output signal of the rotation detector 2 provided in the synchronous motor 1, the address generating means 3 generates a digital address signal corresponding to the rotor position of the synchronous motor 1. In this case, when the number of revolutions is low immediately after the synchronous motor 1 is started or immediately before it is stopped, or before the Z-phase signal is input, the rotation detector 2
Generate a digital address signal for reading the waveform data of the rectangular wave based on the rotor position signal of the commutation sensor, the number of revolutions of the synchronous motor 1 increases to the number of revolutions required for the speed generator, and the Z-phase signal is input. After that, a digital address signal for reading the sine wave waveform data is generated based on the Z-phase signal, the A-phase signal, and the B-phase signal. As the Z-phase signal, the Z-phase signal generated by the Z-phase signal generation circuit 11 from the rotor position signal of the rectification sensor is used. When the Z-phase signal becomes abnormal, the Z-phase signal is output from the speed generator instead. The Z-phase signal is used. Switching from rectangular drive control to sine wave drive control is performed by A
This is performed when the level of the phase signal or the B-phase signal is detected, the level is judged by the voltage judging means, and the value exceeds a predetermined value.

Further, a speed command input from the torque / speed control means 4 and an A phase signal and B output from the rotation detector 2
Synchronous motor 1 obtained from phase signal or rotor position signal
The speed control command signal is output corresponding to the difference from the rotation speed of the. The rotation speed of the synchronous motor 1 is
When the rotation speed is low immediately after the start-up or immediately before the stop, or before the Z-phase signal is input, the rotation speed of the synchronous motor 1 is calculated based on the rotor position signal of the commutation sensor of the rotation detector 2. Speed up to the speed required for the speed generator, and Z
After the phase signal is input, it is calculated based on the Z-phase signal, the A-phase signal, and the B-phase signal.

Further, the digital address signal output from the address generation means 3 is supplied to the waveform storage means 5.
As a result, waveform data of, for example, a U-phase or V-phase sine wave or a rectangular wave for driving the motor corresponding to the actual rotor position is read from the waveform storage means 5. Further, the integrated D / A conversion means 6 outputs a speed control command output from the torque / speed control means 4 to the U-phase and V-phase waveform data for driving the synchronous motor 1 output from the waveform storage means 5. Signals are added and D / A for the addition result
The conversion is performed, the U-phase and V-phase output signals are generated from the integrated D / A conversion means 6, and the output signals of the integrated D / A conversion means 6 are sent to the current control circuit 7.

Based on the U-phase and V-phase output signals in the current control circuit 7 and the detection signal of the load current actually flowing in the synchronous motor 1, the U-phase, V-phase and W-phase current instruction signals (actual U Phase, V phase, W phase current instruction values) are output, and the PWM control circuit 8 generates a pulse width modulation signal according to the output signal of the current control circuit 7, that is, voltage conversion. And
The PWM inverter 9 drives the synchronous motor 1 according to the output signal of the PWM control circuit 8.

In this motor control device, for example, the A-phase signal of the speed generator (even the B-phase signal) is generated based on the Z-phase signal (generated based on the rotor position signal of the rectification sensor) generated by the Z-phase signal generation circuit 11. The number of pulses of the sync. The corresponding digital address is input to the waveform storage means 5 composed of ROM. Therefore, a sine wave or a rectangular wave is output from the waveform storage means 5, and C
A sine wave or a rectangular wave obtained by integrating the speed instruction value of the torque / speed control means 4 made of PU is output in an analog state. The state is shown in FIGS. 2 and 3. In FIG. 2, Z
Phase signal, inverted Z-phase signal, A-phase signal, inverted A-phase signal, B-phase signal, inverted B-phase signal, CS ₁ signal, inverted CS ₁ signal, C
The S ₂ signal, the inverted CS ₂ signal, the CS ₃ signal, the inverted CS ₃ signal, and the output signals (sine waves) of the U, V, and W phases of the waveform storage means (ROM) 5 are shown. In addition, CS _i
The signals indicate three-phase (i = 1 to 3) rotor position signals of V, V, and W. Further, in FIG. 3, the CS ₁ , CS _2, and CS ₃ signals and U, V, and V of the waveform storage means (ROM) 5 are shown.
The output signals (rectangular waves) of each phase of W are shown.

Here, the abnormality detection circuit 10 determines, based on the Z-phase signal output from the speed generator of the rotation detector 2,
Whether the Z-phase signal generated by the Z-phase signal generation circuit 10 is normal or abnormal is monitored, and if abnormal, a signal is transmitted to the CPU (not shown) in the torque / speed conversion means 4. In this case, if the synchronous motor 1 is operating within the normal control area I in FIG. 4, the CPU sends a signal to the address generating means 3 to switch from sine wave drive control to rectangular wave drive control. The address generation means 3 gives the waveform storage means 5 a digital address for outputting rectangular wave waveform data based on the rotor position signal sent from the rotation detector 2. This operation is premised on that the rotor position signal sent from the rotation detector 2 is normally output.

In the field-weakening control region II of FIG. 4, the CPU outputs Z output from the speed generator of the rotation detector 2 instead of the Z-phase signal generated by the Z-phase signal generation circuit 10. The sine wave drive control is continued using the A-phase signal and the B-phase signal in the same manner as the phase signal, and the current instruction is set to 0 or the regeneration instruction is given to shift the speed into the normal control region I while decelerating. , If it enters the normal control area I, C
The PU sends a signal for switching from the sine wave drive control to the rectangular wave drive control to the address generation means 3. The address generation means 3 gives the waveform storage means 5 a digital address for outputting rectangular wave waveform data based on the rotor position signal sent from the rotation detector 2. As a result, Z
After the Z-phase signal generated by the phase signal generation circuit 10 becomes abnormal, the rectangular wave drive control operation is performed only in the normal control region I in which the field weakening control is not performed.

The rotor position signal of the commutation sensor is sent from the abnormality detection circuit 10 to the speed conversion means 12 for driving the rectangular wave. The speed conversion means 12 detects the rotation speed of the synchronous motor 1 based on the rotor position signal of the commutation sensor,
A speed detection signal is sent to the torque / speed control means 4. As a result, also in the case of the rectangular wave drive control, the torque / speed control means 4 gives a signal to the current control circuit 7 in the same manner as in the case of the sine wave drive control, so that the accelerator input, the brake input and the speed converting means 12 are controlled. Speed control will be performed based on the output signal.

Here, when both the Z-phase signal from the rectifying sensor and the Z-phase signal from the speed generator are present and the sine wave control is possible without using the Z-phase signal from the rectifying sensor, the rectifying sensor The reason why the Z-phase signal by the rectifier sensor is mainly used and the Z-phase signal by the speed generator is used when the Z-phase signal by the rectification sensor is abnormal will be described below.

That is, since the speed generator has a structural characteristic that the power generation is insufficient at a low speed and the output signal of the speed generator cannot be used, when the Z-phase signal of the speed generator is used, When the number of rotations of the synchronous motor is extremely reduced, the Z-phase signal may not be obtained suddenly and unstable control may occur. This unstable control means that stable control becomes impossible when a sudden shift to the power generation shortage area occurs (such as a change between Z-phase signal input and the next Z-phase signal input). ing.

On the other hand, if the Z-phase signal from the commutation sensor is used, the Z-phase signal can be continuously obtained even when the number of revolutions of the synchronous motor is extremely decreased, and the Z-phase signal of the speed generator can be obtained. This is because the unstable control as in the case of using a signal does not occur and the reliability can be improved. Also, instead of continuing the sine wave control of the synchronous motor at the time of abnormality,
Although the synchronous motor is finally shifting to rectangular wave control,
The reason is that, as in the above case, when the Z-phase signal of the speed generator is used, when the rotation speed of the synchronous motor is extremely decreased, the Z-phase signal is suddenly not obtained and the unstable control is performed. This is to avoid the occurrence of.

FIG. 5 shows a flow chart of the CPU for performing the above-mentioned processing, and according to this flow chart, the CP
The operation of U will be described. The CPU repeatedly determines whether the Z-phase signal generated by the rotor position signal of the commutation sensor is normal or abnormal (step S1). If the Z-phase signal generated by the rotor position signal of the commutation sensor is abnormal, the speed is determined. The switching to the sine wave drive control operation by the Z-phase signal output from the generator is instructed (step S2). Then, it is determined whether or not the control region of the synchronous motor is the field-weakening control region (step S3), and if it is the field-weakening control region, a deceleration instruction is issued until it exits the field-weakening control region and enters the normal control region (step S4). ), When exiting from the field weakening control area and entering the normal control area, an instruction to switch from sine wave drive control to rectangular wave drive control is issued (step S5).

According to the motor control device of this embodiment, the abnormality detection circuit 10 detects an abnormality in the Z-phase signal generated by the Z-phase signal generation circuit 11, and when the abnormality occurs,
Instead of the Z-phase signal generated by the Z-phase signal generation circuit 11, the Z-phase signal output from the speed generator of the rotation detector 2 and the A-phase signal and the B-phase signal also output from the speed generator.
Since the sine wave control is continued by using the phase signal, the synchronous motor can be continuously controlled by the speed generator, the rotation of the synchronous motor 1 can be continued, and the reliability is improved. The rotation of the electric vehicle can be prevented, and even if a failure occurs in a dangerous place, the electric vehicle can be evacuated to a safe place or moved to a repair shop without stopping at that place. It is possible to avoid the danger of stopping the car.

In the normal control area, the control by the speed generator is switched to the control by the commutation sensor, and in the field weakening control area, the control state by the speed generator is continuously shifted to the normal control area while decelerating, and the normal control is performed. After entering the area, the control by the speed generator is switched to the control by the rectification sensor, so it is possible to gradually shift from the field weakening control state by the speed generator to the normal control state by the rectification sensor. It is possible to gradually shift to the normal control state by the commutation sensor without a sudden change in the rotation speed of the synchronous motor, and it is possible to prevent a sudden behavior change due to the occurrence of an abnormality during high-speed rotation of the synchronous motor. Therefore, for example, the person who is driving the electric vehicle does not feel uneasy. Further, the abnormality of the Z-phase signal generated by the rotor position signal of the rectification sensor is the Z-phase signal output from the speed generator generated by a system different from the Z-phase signal generated based on the rotor position signal of the rectification sensor. Therefore, the abnormality of the Z-phase signal generated based on the rotor position signal of the rectification sensor can be accurately detected, and the rectification sensor can be detected based on the Z-phase signal output from the speed generator. Since the abnormality of the Z-phase signal generated based on the rotor position signal is detected, the abnormality of the Z-phase signal can be detected only by performing a simple logical process.

In the above embodiment, when the Z-phase signal from the commutation sensor becomes abnormal, the synchronous motor is finally switched to the rectangular wave drive control. The operation of may be continued.

[0056]

According to the motor control method of the present invention, Z generated normally based on the rotor position signal of the commutation sensor is used.
When the Z-phase signal generated based on the rotor position signal of the commutation sensor becomes abnormal by controlling the synchronous motor using the phase signal and the A-phase signal and the B-phase signal output from the speed generator, the speed power generation is performed. Since the energization of the synchronous motor is controlled based on the A-phase signal and the B-phase signal output from the machine and the Z-phase signal output from the speed generator, the control of the synchronous motor by the speed generator can be continued. Yes, it ’s more reliable,
Further, the rotation stop of the synchronous motor can be prevented, and the danger due to the stop of the synchronous motor in an electric vehicle or the like can be avoided.

Further, in the normal control area of the synchronous motor, the control by the speed generator is switched to the control by the rectification sensor, and in the field weakening control area, the control state by the speed generator is continuously shifted to the normal control area while decelerating. , After entering the normal control area, the control by the speed generator is switched to the control by the rectification sensor, so it is possible to gradually shift from the field weakening control state by the speed generator to the normal control state by the rectification sensor, and the weakening by the speed generator. It is possible to gradually shift from the field control state to the normal control state by the commutation sensor without a sudden change in the rotation speed of the synchronous motor, and it is possible to prevent a sudden behavior change due to an abnormality occurring during high-speed rotation of the synchronous motor. Therefore, for example, the person who is driving the electric vehicle does not feel uneasy.

Since the Z-phase signal output from the speed generator and the Z-phase signal generated based on the rotor position signal of the commutation sensor are generated in different systems, the Z-phase signal is generated based on the rotor position signal of the commutation sensor. The abnormality of the generated Z-phase signal can be accurately detected, and the abnormality of the generated Z-phase signal is detected based on the rotor position signal of the commutation sensor based on the Z-phase signal output from the speed generator. The abnormality of the Z-phase signal can be detected only by performing the processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a motor control device in an embodiment of a motor control method of the present invention.

FIG. 2 is a time chart of each part of the motor control device.

FIG. 3 is a time chart of each part of the motor control device.

FIG. 4 is a characteristic diagram showing a relationship between torque and rotation speed of a synchronous motor.

FIG. 5 is a flowchart showing the operation of the CPU.

6A is a front view of a portion of the speed generator for generating the A-phase signal and the B-phase signal, FIG. 6B is a sectional view of the same, and FIG. 6C is a rear view of the rotor.

FIG. 7 is a front view of a Z-phase signal generating portion of the speed generator,
(B) is a sectional view of the same and (c) is a rear view of the rotor.

FIG. 8 is a schematic diagram showing a structure of a rectification sensor.

FIG. 9 is a waveform diagram showing the operation of the rectification sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synchronous motor 2 Rotation detector (commutation sensor, speed generator) 3 Address generation means 4 Torque / speed control means 5 Waveform storage means 6 Integrated D / A conversion means 7 Current control circuit 8 PWM control circuit 9 PWM inverter 10 Abnormality detection Circuit 11 Z-phase signal detection circuit 12 Speed conversion means 13 Rectifier sensor detection circuit 14 Speed generator detection circuit

Claims (4)

[Claims] 1. A commutation sensor for outputting a rotor position signal according to a rotational position of a rotor of a synchronous motor, and an A-phase signal, a B-phase signal and a Z-phase signal having a frequency according to a rotational speed of the rotor of the synchronous motor. A motor control method for controlling energization to the synchronous motor by using a speed generator for generating a Z-phase signal based on a rotor position signal of the commutation sensor, and using the rotor position signal of the commutation sensor as a rotor position signal. The Z-phase signal generated based on the Z-phase signal and the A-phase signal and the B-phase signal output from the speed generator are controlled, and Z generated based on the rotor position signal of the commutation sensor. When the phase signal becomes abnormal, the energization of the synchronous motor is controlled based on the A-phase signal and the B-phase signal output from the speed generator and the Z-phase signal output from the speed generator. The motor control method according to claim Rukoto. 2. The control region of the synchronous motor comprises a normal control region and a field-weakening control region, and the Z-phase signal generated based on the rotor position signal of the commutation sensor in the normal control region and the A output from the speed generator. When the Z-phase signal generated based on the rotor position signal of the commutation sensor becomes abnormal during energization control of the synchronous motor based on the phase signal and the B-phase signal, the rotor position signal of the commutation sensor is changed to Based on the Z-phase signal based on the rotor position signal of the commutation sensor and the A-phase and B-phase signals output from the speed generator in the field-weakening control region. When the Z-phase signal due to the rotor position signal of the rectification sensor becomes abnormal during energization control, the A-phase signal and the B-phase signal output from the speed generator Signal and the Z-phase signal output from the speed generator, the energization is controlled so as to shift from the field weakening control region to the normal control region while decelerating, and then the synchronization based on the rotor position signal of the commutation sensor is performed. The motor control method according to claim 1, wherein the control is switched to energization control of the motor. 3. The detection of abnormality of the Z-phase signal generated based on the rotor position signal of the commutation sensor is performed from the appearance time of one pulse of the Z-phase signal output from the speed generator to the appearance time of the next pulse. 3. The motor control method according to claim 1, wherein the motor control method is performed by detecting whether or not a pulse of the Z-phase signal generated based on the rotor position signal of the commutation sensor is detected during the period up to. 4. The energization control of the synchronous motor based on the output signal of the commutation sensor is rectangular wave drive control, and the Z phase signal generated based on the rotor position signal of the commutation sensor and the Z phase output from the speed generator. 3. The motor control method according to claim 2, wherein the energization control of the synchronous motor based on any one of the signals and the A-phase signal and the B-phase signal output from the speed generator is sine wave drive control.