JPH0632589B2 - Hall motor stator winding drive circuit - Google Patents

Description

The present invention relates to a hall motor stator winding drive circuit.

(Prior Art) A conventional hall motor stator winding driving circuit includes an amplifier for amplifying the output voltage of a hall element provided facing a rotating magnetic pole forming a rotor, and the output of the amplifier is used as a hall motor stator winding. Had been supplied to.

However, when the conventional Hall motor stator winding drive circuit as described above is used, since there is an offset voltage during the output of the Hall element, this offset voltage causes torque ripple at the time of rotation near the rated rotation speed of the Hall motor. However, it has a drawback that it cannot rotate smoothly.

(Object of the Invention) The present invention has been conceived in view of the above, and by canceling the offset voltage existing in the output of the hall element during rotation within a predetermined range sandwiching the rated rotation speed of the hall motor, the rated rotation speed is It is an object of the present invention to provide a Hall motor stator winding drive circuit that suppresses the occurrence of torque ripples within a predetermined range sandwiching between.

Hereinafter, the present invention will be described with reference to examples.

(Structure of One Embodiment of the Present Invention) FIG. 1 is a circuit diagram showing one embodiment of the present invention, and FIG. 1 shows one phase of a multi-phase hall motor.

Reference numeral 1 denotes a Hall element provided so as to face a rotating magnetic pole that constitutes the rotor of the Hall motor. A series circuit of a resistor 2, a hall element 1 and a resistor 3 is connected between the power source + B and ground to supply a predetermined current to the hall element 1. Reference numeral 4 is a Hall motor stator winding, one end of which is grounded.

The two outputs of the Hall element 1 are respectively supplied to the differential amplifier 5 and differentially amplified. The output voltage of the differential amplifier 5 is supplied to a phase shifter 11 including resistors 6, 7 and 8, an operational amplifier 9, and a capacitor 10. A field effect transistor 12 as an analog switch means is connected in parallel to the capacitor 10. The terminal 13 is a terminal to which a detection output for detecting that the rotation speed of the hall motor is within a predetermined range sandwiching the rated speed is supplied, and the detection output supplied to the terminal 13 is supplied to the gate of the field effect transistor 12. , When the detection output is output Field effect transistor 1
2 is turned off. Here, the detection output is, for example, a lock signal of a PLL circuit that outputs a speed control signal of the hall motor, but the rated speed detection output from the rotation speed detection means may be used instead. The resistance values of the resistors 6 and 8 are set to be equal.

The output voltage of the differential amplifier 5 and the output voltage of the phase shifter 11 are supplied to the differential amplifier 19 including the resistors 14 to 17 and the operational amplifier 18 for differential amplification, and the output voltage of the differential amplifier 19 is a hall motor. The Hall motor stator winding 4 is driven by being supplied to the other end of the stator winding 4. Here, the resistors 14 to 17 are set and the gain of the differential amplifier 19 is set to 1.

(Operation of One Embodiment of the Present Invention) In one embodiment of the present invention configured as described above, two outputs from the Hall element 1 are supplied to the differential amplifier 5 and differentially amplified. The output voltage waveform from the differential amplifier 5 is as shown in FIG. 2 (a), and ΔV is the voltage corresponding to the offset voltage existing in the output voltage of the Hall element 1, and the variation of the output waveform is If sinωt, the output voltage is s
inωt + ΔV.

On the other hand, at the rotation speed of the hall motor from when the hall motor is started to when it reaches a predetermined range between the rated rotation speeds, the field effect transistor 12 is in the ON state, the capacitor 10 is short-circuited, and the operational amplifier 9 of the operational amplifier 9 is short-circuited. The gain is "1" because the non-inverting input terminal is grounded, the phase shifter 11 acts as an inverting amplifier, and the resistances of the resistors 6 and 8 are equal. Therefore, the output voltage waveform of the phase shifter 11 becomes as shown in FIG.
inωt−ΔV.

Therefore, the output voltage of the differential amplifier 5 and the output voltage of the phase shifter 11 are differentially amplified by the differential amplifier 19 and applied to the Hall motor stator winding 4. Therefore, 2sinωt + 2ΔV [= sinωt +
A voltage of ΔV-(-sinωt-ΔV)] is supplied. In this case, since the hall motor has a rotation speed that is outside the predetermined range of the rated rotation speed, the voltage 2ΔV remains and is supplied to the hall motor stator winding 4, and there is no problem even if torque ripple occurs.

Next, when the hall motor enters a rotation speed within a predetermined range between the rated rotation speeds, the field effect transistor 12 is turned off by the voltage supplied to the terminal 13. In this state, the non-inverting input terminal of the operational amplifier 9 is grounded via the capacitor 10, and the cutoff frequency obtained by the resistor 7 and the capacitor 10 is obtained. Phase shifter 11 for AC input signals of higher frequency
Acts as an inverting amplifier having a gain of "≈1", and acts as a non-inverting amplifier having a gain of "1" with the capacitor 10 being substantially cut off from a DC input signal. In this case, the cut-off frequency c is set to a value lower than the frequency of the output signal of the hall element generated at the minimum speed within a predetermined range that encloses the rated rotation speed of the hall motor.

Therefore, the output voltage waveform of the differential amplifier 5 when the rotation speed of the hall motor falls within the predetermined range sandwiching the rated rotation speed is as shown in FIG. 2 (c), and sinω ₁ t + Δ
V. The output voltage waveform of the phase shifter 11 in this case is −sinω because the voltage ΔV is non-inverted and amplified and the AC component is inverted and amplified as shown in FIG. 2 (d). It becomes ₁ t + ΔV. As a result, the output from the differential amplifier 5 of Yotsute sinω _{1 t} + ΔV to the differential amplifier 19, such that the output from the phase shifter 11 of -sinω _{1 t} + ΔV is the differential amplifier connexion, Hall motor fixing The voltage applied to the subsidiary winding 4 is −2sinω ₁ t [= −sinω
₁ t + ΔV− (sinω ₁ t + ΔV)], and the voltage ΔV corresponding to the offset voltage during the output of the Hall element 1 is canceled.

The same applies to the hall motor stator windings of other phases. Therefore, at a rotation speed within a predetermined range that is below the rated rotation speed, torque ripple is suppressed in the hall motor, torque ripple is eliminated, and the hall motor rotates smoothly.

Next, a modification of the embodiment of the present invention will be described.

(Structure of Modified Embodiment of One Embodiment of the Present Invention) FIG. 3 is a circuit diagram showing a modified embodiment of the one embodiment of the present invention, showing one phase of the Hall motor stator winding.

In this modified embodiment, a slicer 22 formed by connecting diodes 20 and 21 in anti-parallel is connected instead of the field effect transistor 12 in the embodiment of the present invention shown in FIG. The slice level ΔS of the slicer 22 is set to be higher than the level of the voltage ΔV corresponding to the offset voltage during the output of the Hall element 1.

(Operation in Modified Embodiment of One Embodiment of the Present Invention) In the modified embodiment of the one embodiment of the present invention configured as described above, the Hall element 1 outputs the same as in the case of the one embodiment of the present invention. The two outputs are amplified by the differential amplifier 5, and the output voltage waveform of the differential amplifier 5 is as shown in FIG. 4 (a). ΔV is a voltage corresponding to the offset voltage existing in the output voltage of the Hall element 1, and the output voltage is sinωt + ΔV, where sinωt is the change in the output waveform. In FIG. 4 (a), the alternate long and short dash line indicates the slice level ΔS of the slicer 22.

On the other hand, the cutoff frequency obtained by the resistor 7 and the capacitor 10 Is set to the output signal frequency of the hall element 1 output at a predetermined rotation speed lower than the rated rotation speed of the hall motor.

Therefore, when the rotation speed of the hall motor is lower than the predetermined rotation speed, the capacitor 10 can be regarded as being substantially cut off, and the non-inverting input terminal of the operational amplifier 9 is supplied with a voltage having a waveform as shown in FIG. 4 (b ₁ ). Will be supplied. On the other hand, the output voltage of the differential amplifier 5 as shown in FIG. 4 (a) is supplied to the inverting input terminal of the operational amplifier 9. As a result, the output voltage waveform of the operational amplifier 9 becomes a waveform as shown in FIG. 4 (b ₂ ). In FIG. 4 (b ₂ ), the output voltage waveform A of the operational amplifier 9 in the section from t _{0 to} t ₁ is [−sinωt +
(ΔS−ΔV)], and the output voltage waveform C in the interval t _{1 to} t ₂ is ν = 0 in FIG. 4 (b ₁ ) ± [ΔS−Δ
V] is an output voltage waveform of the differential amplifier presenting in the range of V], and the output voltage waveform B in the section of t _{2 to} t ₃ is [sin ω
t- (ΔV + ΔS)]. The output voltage of the operational amplifier 9 having the waveform shown in FIG. 4 (b ₂ ) and the output voltage of the differential amplifier 5 having the waveform shown in FIG. 4 (a) are differentially amplified by the differential amplifier 19 and then fixed to the hall motor. It is supplied to the child winding 4. Therefore, a direct current component remains in the voltage supplied to the hall motor stator winding 4, and a tokkripple is generated in the hall motor.

When the rotation speed of the hall motor increases and the frequency of the output voltage output from the hall element 1 increases, and the rotation speed of the hall motor becomes equal to or higher than the predetermined rotation speed,
The output voltage frequency from the differential amplifier 5 becomes higher than the cut-off frequency c, the capacitor 10 becomes substantially short-circuited, the slicer 22 cannot perform its action, and the non-inverting input terminal of the operational amplifier 9 is grounded. It will be in a state of being. Therefore, the phase shifter 11 acts as an inverting amplifier having a gain "≈1" for an AC input signal having a frequency higher than the cutoff frequency c, and the capacitor 10 is substantially cut off for a DC input signal. Since it can be regarded as a state and the voltage ΔV <slice level ΔS is set, it operates as a non-inverting amplifier with a gain “≈1” for the voltage ΔV.

On the other hand, the output voltage waveform of the differential amplifier 5 when the rotation speed of the hall motor exceeds the predetermined rotation speed is shown in FIG.
As shown in (c), sin ω ₁ t + ΔV. However, in this case, the voltage ΔV is non-inverted and amplified with the gain “≈1”, and the AC component is inverted and amplified with the gain ≈1, and the output voltage waveform of the phase shifter 11 is shown in FIG. ). The output voltage from the phase shifter 11 having the waveform shown in FIG. 4 (d) is differentially amplified by the differential amplifier 19 with the output voltage from the differential amplifier 5 having the waveform shown in FIG. 4 (c). It will be. Therefore, the output voltage of the differential amplifier 19 is -2si.
nω ₁ t [= −sinω ₁ t + ΔV− (sinω ₁ t + Δ
V)], the voltage ΔV corresponding to the offset voltage during the output of the Hall element 1 is canceled and is not applied to the Hall motor stator winding. Therefore, when the hall motor rotation speed exceeds the predetermined rotation speed, the torque ripple does not occur.

In one embodiment of the present invention and its modified embodiment, a preamplifier is provided between the output terminal of the Hall element 1 and the differential amplifier 5, and a preamplifier is provided between the differential amplifier 5 and the differential amplifier 19.
A buffer amplifier may be connected between the phase shifter 11 and the differential amplifier 19, respectively.

(Effects of the Invention) As described above, according to the present invention, the inversion operation is performed with respect to the signal of the frequency higher than the set frequency lower than the output signal frequency of the hall element output when the hall motor rotates at the predetermined rotation speed. Is provided with a phase shifter that performs a non-inverting operation for low frequency signals, and an output voltage obtained by differentially amplifying the output signal of the phase shifter and the output signal of the amplifier for amplifying the output voltage of the Hall element is output. Since it is applied to the hall motor stator winding, when the rotation speed of the hall motor exceeds the predetermined rotation speed, it exceeds the set frequency lower than the output signal frequency of the hall element output when rotating at the predetermined rotation speed. The phase shifter performs an inverting operation with respect to an input signal having a different frequency, and the phase shifter performs a non-inverting operation with respect to an input signal having a frequency lower than the set frequency. The voltage corresponding to the existing offset voltage in the output is canceled, torque ripple does not occur, and the Hall motor can be smoothly rotated.

As described above, according to the present invention, the drive current of the Hall motor corresponding to the offset voltage in the output voltage of the Hall element is canceled, and the torque ripple corresponding to the offset voltage in the output voltage of the Hall element is canceled. Since the torque ripple due to the offset voltage in the output voltage of the Hall element can be reduced, the torque ripple reducing effect is great.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 2 is a waveform diagram for explaining the operation of one embodiment of the present invention. FIG. 3 is a circuit diagram showing a modification of the embodiment of the present invention. FIG. 4 is a waveform diagram for explaining the operation in a modified example of the embodiment of the present invention. 1 ... Hall element, 4 ... Hall motor stator winding, 5
And 19 ... Differential amplifier, 11 ... Phase shifter, 12 ...
Field effect transistor, 22 ... Slicer.

Claims (1)

[Claims] 1. A Hall motor stator winding drive circuit for driving a Hall motor stator winding based on an output voltage of a Hall element, an amplifier for amplifying a signal based on an output voltage of a Hall element, and an output signal of the amplifier. Input signal, and when the hall motor is rotated at a predetermined rotation speed, it performs an inversion operation for an input signal of a frequency lower than the output signal frequency of the hall element and lower than the set frequency and lower than the set frequency. A phase shifter that performs a non-inverting operation with respect to an input signal of a frequency, a control unit that selectively performs an inverting amplification operation on the phase shifter, and a difference between an output signal of the amplifier and an output signal of the phase shifter. And a differential amplifier for dynamically amplifying and supplying an output voltage to a hall motor stator winding whose one end is grounded.