JP2003333885A - Moving element position detector - Google Patents

Abstract

(57) [Problem] To provide a moving element position detecting device capable of improving responsiveness while reducing a position detecting error. The position detecting device includes a control pulse signal (S).
Setting means E for setting a time excluding the falling or rising timing of the pulse included in IG1 as the sampling timing; and a modulated pulse signal SIG2 synchronized with the sampling timing set by the setting means E.
And a determination means J for determining the level of. According to the present apparatus, the sampling pulse is set using the control pulse signal SIG1 as the modulation source, except for the timing at which a spike occurs in the modulation pulse signal SIG2, and the modulation pulse signal SI is synchronized with the sampling timing.
Since the level of G2 is determined, accurate moving element position detection can be performed at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving element position detecting device.

[0002]

2. Description of the Related Art A conventional moving element position detecting device is disclosed in Japanese Unexamined Patent Publication No. Hei 11
-98884. In the device described in the publication, a DC power source is switched by a transistor of an inverter circuit to generate a modulated pulse signal, which is applied to a brushless motor, and PWM (pulse wave modulation) control of the brushless motor is performed.

The waveform of the terminal voltage of the stator armature winding is sampled and converted into digital data. While the microcomputer takes in the digital data,
The captured digital data is low-pass filtered by a numerical calculation process, the low-pass filtered value is compared with a predetermined value to detect the position of the brushless motor slider, and the inverter circuit is based on this position detection. The transistor is driven to calculate the energization switching timing of the brushless motor.

That is, since the modulated pulse signal indirectly indicates the position of the mover, the conventional device filters the modulated pulse signal and then samples it, and compares the sampled value with a predetermined value to determine the position of the mover. It is detecting. And the reason for doing this filtering is
It is said that the modulated pulse signal itself contains spikes at the time of rising and falling, so that an error occurs in position detection when the modulated pulse signal itself is used.

[0005]

However, the conventional moving element position detecting device requires a circuit for filtering, which deteriorates the response of the position detection. The present invention has been made in view of such a problem, and an object of the present invention is to provide a mover position detection device capable of improving responsiveness while reducing position detection error.

[0006]

In order to solve the above problems, the mover position detecting apparatus according to the present invention supplies a modulated pulse signal obtained by modulating a control pulse signal so that the envelope has a sine wave. The position of the mover of a motor having a stator having an armature winding and a mover relatively movable with respect to the stator by a magnetic field formed by the armature winding. In a mover position detection device that detects from a pulse signal, a setting unit that sets the time excluding the falling or rising timing of the pulse included in the control pulse signal as sampling timing, and the sampling timing set by the setting unit. And a determining unit that determines the level of the modulated pulse signal in synchronism.

According to this apparatus, the control pulse signal of the modulation source is used, the sampling timing is set excluding the timing at which the spike occurs in the modulation pulse signal, and the level of the modulation pulse signal is determined in synchronization with this sampling timing. Therefore, accurate moving element position detection can be performed at high speed.

The determined level indicates a specific position of the moving element, and the detected moving element position can be used as a reference synchronizing signal when the control pulse signal is generated by feedback control.

Further, the setting means detects the phase shifting means for shifting the phase of the control pulse signal and the rising or falling timing of the control pulse signal having the phase shifted by the phase shifting means as the sampling timing. However, it is preferable to have a detecting means for instructing the judging means.

That is, when the phase shifting means shifts the phase, the detecting means detects a timing (rise or fall timing after the phase shift) other than the rise or fall timing in the modulated pulse signal before the phase shift processing. be able to. Since the detection means instructs the determined sampling timing to the determination means, as a result, the sampling timing is set at the time when no spike occurs.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A moving element position detecting device according to an embodiment will be described below. The same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a block diagram of a motor control device having a mover position detection device. 2A is a timing chart of the motor terminal voltage (modulation pulse signal), FIG.
2B is a timing chart of a PWM control waveform (control pulse signal before delay), and FIG. 2C is a timing chart of a PWM control phase shift waveform (control pulse signal after delay).

The control pulse signal generation circuit 1 controls the control pulse signal SIG1 based on the input specific moving element position P.
To generate. The control pulse signal SIG1 is input to the modulator 2 such as an inverter circuit and is sinusoidally modulated. In the inverter circuit of this example, a plurality of control pulse signals are input while maintaining a prescribed phase relationship, and the intermediate potential of the DC power supply voltage is pulse-modulated so that the envelope becomes a sine wave. PWM (pulse wave modulation) is performed.

The modulated pulse signal S output from the modulator 2
The IG2 is supplied to the armature winding 3. The number of armature windings 3 is three, and each modulated pulse signal SIG2 is supplied. These modulated pulse signals SIG2 are U phase, V
As a phase and a W phase, a three-phase alternating current having a phase difference of 120 ° is formed. Note that it is not necessary to input all three phases to the determination means J in the subsequent stage, but three phases may be input for improving accuracy.

The armature winding 3 is provided on the stator S, and the magnetic field generated by the armature winding 3 moves (rotates) the mover (rotor) R. The mover R may be provided with a field winding or a permanent magnet. Further, the rotational position P of the moving element R is detected brushlessly, and the control pulse signal SIG is detected based on the position P.
1 is generated. Therefore, this stator S and mover R
And constitute a three-phase brushless motor.

In other words, the mover position detecting apparatus of this embodiment includes the armature winding 3 to which the modulation pulse signal SIG2 obtained by modulating the control pulse signal SIG1 so that the envelope has a sine wave is supplied. The stator S that has and the armature winding 3
The moving element position detecting device detects the position P of the moving element R of the motor having the moving element R relatively movable with respect to the stator S by the magnetic field formed by the modulated pulse signal SIG2.

Here, the position detecting device has setting means E for setting the time excluding the falling or rising timing of the pulse included in the control pulse signal SIG1 as the sampling timing, and the sampling timing set by the setting means E. Modulated pulse signal S in synchronization with
The determination means J for determining the level of IG2 is provided.

According to the present apparatus, the modulation source control pulse signal SIG1 is used, the sampling timing is set excluding the timing at which a spike occurs in the modulation pulse signal SIG2, and the modulation pulse signal SIG2 is synchronized with this sampling timing. Since the level is determined, accurate mover position detection can be performed at high speed.

The determined level indicates the specific position P of the moving element R. The detected mover position P is used as a reference synchronization signal when the control pulse signal SIG1 is generated by feedback control. That is, the control pulse signal SI
Since G1 determines the phase of the three-phase alternating current supplied to the armature winding 3, by determining the phase of the three-phase alternating current so as to synchronize with the detected mover position P, that is,
By determining the phase of the control pulse signal SIG1, it is possible to prevent step-out in the motor.

Next, the setting means E and the judging means J will be described in detail.

The setting means E has a control pulse signal SIG1.
(See FIG. 2B) Delay circuit (phase moving means) E1 for shifting the phase, and control pulse signal SIG1 'having the phase shifted by the delay circuit E1 (see FIG. 2C).
Edge detection circuit (detection means) E2 that detects the rising or falling timing of the above as the sampling timing and instructs the determination means J.

The edge detection circuit E2 detects the rising or falling edge of the phase-shifted control pulse signal SIG1 '. That is, since the delay circuit E1 shifts the phase of the control pulse signal SIG1 by the delay, the edge detection circuit E2 causes the edge detection circuit E2 to rise or fall the control pulse signal SIG1 ′ after the phase shift, in other words, the modulation before the phase shift processing. The timing other than the rising or falling timing in the pulse signal SIG2 (see FIG. 2A) can be detected. Here, the time of 1/4 of the cycle of one pulse included in the modulated pulse signal,
That is, the detection timing is set at the position of 90 degrees in phase.

In other words, if the duty ratio D is 0.5, the phase shift amount, that is, the sampling timing, is the time (90) of the duty ratio D × 1/2 of the period T in the modulated pulse signal. 2) (see FIG. 2C: median value of duty ON period).
In addition, when the duty ratio D is displayed in%, this value is divided by 100.

The edge detecting circuit E2 instructs the judging means J by using the detected sampling timing as a trigger signal. The determination means J includes a comparison circuit J2 to which the modulated pulse signal SIG2 and the reference level (voltage) are input. A switch J1 is provided in front of the input terminal of the modulated pulse signal SIG2 to the comparison circuit J2, and the comparison circuit J2 performs the comparison operation only when the switch J1 is connected.

When the trigger signal output from the edge detection circuit E2 is input to the switch J1, the switch J1 is in the connected state and the modulation pulse signal and the reference level are input to the comparison circuit J2. That is, the comparison circuit J2 outputs the comparison result of the modulated pulse signal and the reference level in synchronization with the sampling timing. Since the sampling timing is set to a time when no spike occurs in the modulated pulse signal, the error generated in the comparison result is suppressed (see FIGS. 2A to 2C).

The reference level is set at the center of amplitude of the modulated pulse signal whose envelope shows a sine wave, but here it is set at a voltage half the DC power supply voltage in the inverter circuit, that is, at the intermediate potential ( FIG. 2A).

The cross point between the reference level and the modulated pulse signal is the phase of 0 ° and 180 ° of the sine wave (fundamental frequency), and indirectly indicates the specific position P of the moving element R.
Assuming that the comparator circuit J2 outputs two values, a high level and a low level, a pulse signal whose repetition frequency matches the fundamental frequency of the sine wave is output. In other words, the rising or falling timing of this pulse signal indicates the specific position (specific phase) P of the mover R.

The above-mentioned control pulse generating circuit 1 and setting means E
The determining means J can be configured by an analog circuit using a logic circuit, but these may be processed as a digital signal by a computer after A / D conversion of the control pulse signal and the modulation pulse signal.
Since the electronic control unit ECU can calculate the PWM command value (control pulse signal) and control the repetition frequency (switching frequency) and duty ratio thereof, the control pulse generation circuit 1 and the setting means E and The determination means J can be composed of an ECU.

As described above, according to the above-mentioned moving element position detecting device, since the position detection is performed by excluding the portion where the spike occurs in the modulated pulse signal, the position detection error can be reduced and the control pulse signal can be reduced. Since the position detection is performed without filtering, the responsiveness can be improved.

[0030]

According to the mover position detecting device of the present invention,
It is possible to improve the responsiveness while reducing the position detection error.

[Brief description of drawings]

FIG. 1 is a block diagram of a motor control device having a mover position detection device.

FIG. 2 is a timing chart of a motor terminal voltage and a PWM control waveform.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Control pulse signal generation circuit, 2 ... Modulator, 3 ... Armature winding, E ... Setting means, E1 ... Delay circuit, E2 ... Edge detection circuit, J ... Judgment means, J1 ... Switch, J2 ... Comparison circuit, R ... mover, S ... stator, SIG1 ... control pulse signal, SIG2 ... modulation pulse signal.

Claims (2)

[Claims] 1. A stator having an armature winding to which a modulated pulse signal obtained by modulating a control pulse signal so that an envelope has a sine wave is provided, and a magnetic field formed by the armature winding. In a mover position detection device for detecting the position of the mover of a motor having a mover relatively movable with respect to the stator from the modulated pulse signal, a trailing edge of a pulse included in the control pulse signal. Alternatively, the movement is characterized by comprising setting means for setting the time excluding the rising timing as the sampling timing and determination means for determining the level of the modulated pulse signal in synchronization with the sampling timing set by the setting means. Child position detection device. 2. The setting means detects phase shift means for shifting the phase of the control pulse signal, and rising or falling timing of the control pulse signal having a phase shifted by the phase shift means as the sampling timing. The moving element position detecting device according to claim 1, further comprising: a detecting unit that instructs the determining unit.