JPH02188183A - Hall motor driver circuit - Google Patents

Abstract

PURPOSE:To improve torque ripple characteristics by generating a trapezoidal- waved commutating signal with a gentle inclination in rise and fall through an AGC loop and by giving an error detector amplifier a reference input voltage proportional to a supply voltage. CONSTITUTION:A trapezoidal-waved commutating signal with a gentle inclination in rise and fall is outputted from a signal processing circuit 14 by an AGC loop composed of first variable gain amplifiers 11-13, said signal processing circuit 14 and an absolute value conversion and arithmetic total means 15. Also, when the loop gain of an AGC loop composed of second variable gain amplifiers 16-18, power amplifiers 19-21, absolute converters 22-24, and an error detector amplifier 25 is set at a high value, the variation of output of power amplifiers 19-21 is suppressed. Even if a supply voltage Vcc varies, a reference input voltage Vref proportional to said supply voltage Vcc is given to the error- detector amplifier 25.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a Hall motor drive circuit implemented as a semiconductor integrated circuit (IC) for driving a two-phase or three-phase Hall motor. In particular, the present invention relates to means for processing the waveform of a Hall motor rotational origin signal and means for controlling the voltage amplitude of each phase drive coil.

(Prior art) Fig. 2 shows a three-phase Hall motor HM, three Hall elements H1 to H3 for detecting the instantaneous rotational position of the rotor magnet of this Hall motor HM, and a conventional IC-based hall motor HM. No. 3
The connection of the phase-hole motor drive circuit 20 is shown.

The Hall motor drive circuit 20 includes three Hall elements H1 to
Variable gain amplifiers (Hall amplifiers) HAI to HA3 to which each output of H3 is input, and these Hall amplifiers H
Each output of AI to HA3 is inputted to a signal processing circuit MTX for obtaining a commutation signal by performing necessary processing such as phase shift and polarity reversal for switching forward/reverse rotation, and from this signal processing circuit MTX. The three-phase AC signals to be output are manually input, amplified, and sent to the Hall motor HM.
The power amplifier PAL that supplies the stator coils of each phase of
~PA3, absolute value converters CNI~CN3 to which three-phase AC signals output from the signal processing circuit MTX are respectively input and convert the respective voltage amplitudes into absolute values, and each of these absolute value converters CNI~CN3. The voltage signal obtained by the arithmetic sum of the outputs is compared with the reference input voltage Vref to detect and amplify the error, and the amplified output controls the voltage gain of the Hall amplifiers HAI to HA3, and is applied to the input side of the power amplifiers PAI to PA3. and an error amplifier EA that provides nearly balanced three-phase signals.

It is desirable that the outputs of the three Hall elements H1 to H3 are as stable as possible in amplitude and balanced, but in many cases this is not the case, so in the Hall motor drive circuit 20, the Hall amplifier HAI ~)I
A3 → Signal processing circuit MTX = Absolute value converter CNI~CN
3 → Error amplifier EA → Hall amplifier HAI to HA3 form an automatic gain control (AGC) loop, and provide approximately balanced three-phase signals to the input sides of power amplifiers PAI to PA3, and each signal is By amplifying the power with three power amplifiers PAL to PA3 and supplying power to the stator coils of each phase, stable rotation is given to the Hall motor [M].

However, considering variations in element characteristics during mass production of ICs, variations in the balance of the final output of the Hall motor drive circuit 20 are caused by variations in the balance of the three absolute value converters CN1 to CN3 and the variations in the balance of the three absolute value converters CN1 to CN3. Power amplifier PAL~PA3
It is large because it is the composite sum of the balance variation. If there is a large variation in the balance of the final output as described above, there is a possibility that the Hall motor HM cannot be used when rotational stability (torque ripple characteristics) is particularly required. Furthermore, if the power supply voltage supplied to the power amplifiers PA1 to PA3 fluctuates, the motor drive output will fluctuate, resulting in a decrease in the stability of the rotation of the Hall motor HM.

(Issue g11 to be solved by the invention) As mentioned above, the conventional Hall motor drive circuit has large variations in the final output balance (and cannot be used when the Hall motor's torque ripple characteristics are particularly required). There is a possibility that it will not be possible.

The present invention was made to solve the above-mentioned problems, and its purpose is to prevent electromagnetic noise from being generated when the coil current of a Hall motor is commutated, and to also be used in equipment that requires a strong reduction in switching noise. The purpose of the present invention is to provide a Hall motor drive circuit that can reduce variations in the final output as much as possible, improve the torque ripple characteristics of the Hall motor, and stably rotate the Hall motor even when the power supply voltage fluctuates. .

[Structure of the Invention] (Means for Solving the Problem) The present invention provides a Hall motor drive circuit that drives a three-phase Hall motor. A variable gain amplifier, a signal processing circuit to which each output of the three first variable gain amplifiers is input and performs necessary processing including phase shift and polarity inversion, and a three-phase signal output from this signal processing circuit. The voltage amplitudes of each of the AC signals are converted into absolute values and subjected to arithmetic sum, and the voltage signal obtained thereby is used to control the first variable gain amplifier so that each output amplitude becomes a trapezoidal wave whose output amplitude is approximately constant. The absolute value conversion/arithmetic sum means and the 3-phase AC signals output from the signal processing circuit are respectively inputted.
The outputs of these three second variable gain amplifiers are respectively inputted and amplified to generate three electric powers that respectively supply power to the coils of each phase of the Hall motor. an amplifier; and absolute value conversion means for converting the absolute value of each voltage amplitude of the output of each of the power amplifiers;
The voltage signal obtained by arithmetic sum of the respective outputs of the absolute value converting means is compared with a reference input voltage proportional to the power supply voltage to detect and amplify the error, and the amplified output is used to control each of the second variable gain amplifiers. The present invention is characterized by comprising error detection/amplification means for controlling the output amplitude to be a maximum amplitude trapezoidal wave proportional to the power supply voltage.

(Function) The AGC loop formed by the first variable gain amplifier→signal processing circuit→absolute value conversion/arithmetic sum means→GSL variable gain amplifier loop allows gentle rising and falling slopes from the signal processing circuit. Since a trapezoidal wave-shaped commutation signal is output, electromagnetic noise is less likely to be generated when the coil current of the Hall motor is commutated, and it can be used even when there is a strong demand for reducing switching noise.

Furthermore, if the loop gain of the AGC loop formed by the variable gain amplifier loop in section 2 is set high, the power amplifier The variation in the balance of the output of the Hall motor is suppressed in principle, and the final variation in the balance of the output is only the variation in the balance of the second absolute value conversion means, and the variation in the balance due to circuit factors is minimized. Torque ripple characteristics can be improved.

Furthermore, even if the power supply voltage fluctuates, a reference input voltage proportional to the power supply voltage is applied to the error detection/amplification means, so the motor drive output waveform is no longer affected by fluctuations in the power supply voltage, and the trapezoidal wave amplitude remains unchanged from the reference voltage. The rotation of the Hall motor can be controlled in proportion to the input, that is, the power supply voltage.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

Figure 1 shows a three-phase hall motor HM and a three-phase hall motor HM for detecting the instantaneous rotational position of the rotor magnet of this hall motor HM.
The connection between Hall elements H1 to H3 and a three-phase hall motor drive circuit 10 formed into an IC is shown.

The Hall motor drive circuit 10 includes three Hall elements H1 to
First variable gain amplifiers (Hall amplifiers) 11 to 13 to which each output of H3 is input, and each output of these first variable gain amplifiers 11 to 13 to each input, and phase shift and forward/reverse rotation switching. Signal processing circuit 1 for obtaining a commutation signal by performing necessary processing such as polarity reversal for
4 and the three-phase AC signals output from this signal processing circuit 14 are respectively input, the respective voltage amplitudes are converted into absolute values and arithmetic summed, and the obtained voltage signals are used to input the first Hall amplifier. Absolute value conversion/arithmetic sum means 15 controls the signals 11 to 13 so that their respective output amplitudes become trapezoidal waves that are substantially constant; 2 variable gain amplifiers 16 to 18, and these three second variable gain amplifiers "a'1"
power amplifiers 19 to 21 into which each of the outputs 6 to 18 is input, amplifies each output, and supplies power to the stator coil of each phase of the Hall motor HM;
Absolute value converters 22 to 24 input each output of 1° and convert each voltage amplitude into an absolute value, and a voltage signal obtained by arithmetic sum of each output of the absolute value converters 22 to 24. is the reference input voltage Vre proportional to the power supply voltage Vcc
Error is detected and amplified by comparing with f, and the amplified output is used to control the second seasonal gain amplifiers 16 to 18 so that each output amplitude becomes a maximum amplitude trapezoidal wave proportional to the power supply voltage. It consists of an amplifier 25.

Note that it is desirable that the amplitudes of the signals input to the Hall amplifiers 11 to 13 are as stable as possible and balanced.

In the Hall motor drive circuit 10, AGC loops are formed on the front stage side and the rear stage side, respectively. That is, on the front stage side, an AGC loop is formed by a loop of first variable gain amplifiers 11 to 13 → signal processing circuit 14 → absolute value conversion/arithmetic sum means 15 → first variable gain amplifiers 11 to 13, This AGC loop allows the signal processing circuit 1
4, a trapezoidal commutation signal with gentle rising and falling slopes is output. Therefore, by amplifying the power of this commutation signal to commutate the coil current of the Hall motor HM, electromagnetic noise is less likely to be generated, and it can be used in equipment that requires a strong reduction in switching noise.

Further, on the rear stage side, second variable gain amplifiers 16 to 18-
A voltage control type AGC loop is formed by the loop of power amplifiers 19 to 21 → absolute value converters 22 to 24 → error detection/amplifier 25 → second variable gain amplifiers 16 to 18, and the power for the final stage output is Amplifiers 19 to 21 are connected to this AG
It is inside the C loop. Therefore, by setting the loop gain of this AGC loop high, variations in the balance of the outputs of the power amplifiers 19 to 21 can be theoretically suppressed, and variations in the balance of the final outputs will be reduced by the balance of the absolute value converter 22. The variation in balance due to circuit factors is minimized, and the torque ripple characteristics of the Hall motor HM can be improved.

Moreover, the power supply voltage Vc supplied to the power amplifiers 19 to 21
Even if c fluctuates, the reference input voltage Vref proportional to the power supply voltage vCC is supplied to the error detection/amplifier 25, so the motor drive output waveform is no longer affected by fluctuations in the power supply voltage vec, and only its amplitude is applied to the power supply. It can be made proportional to the voltage. That is, in the present invention, the AG on the rear stage side
The commutation signal is shaped into a trapezoidal wave in the C loop, and this is finally output as a well-balanced trapezoidal wave in the voltage-controlled AGC loop on the subsequent stage.

[Effects of the Invention] As described above, according to the Hall motor drive circuit of the present invention, a trapezoidal wave-like commutation signal with gentle rising and falling slopes is generated, so that the commutation of the coil current of the Hall motor is reduced. It is difficult for electromagnetic noise to be generated during switching, and it can also be used in equipment that requires a strong reduction in switching noise. In addition, according to the Hall motor drive circuit of the present invention, since the power amplifier for the final stage output is placed in the AGC loop, variations in the balance of the output of the power amplifier, which is ultimately desired to be stabilized, are theoretically suppressed. As a result, variations in final output are minimized, and the torque ripple characteristics of the Hall motor can be improved. Furthermore, according to the Hall motor drive circuit of the present invention, a reference input voltage proportional to the power supply voltage is applied to the error detection/amplifier, so even if the power supply voltage fluctuates, the motor drive output is not affected by the fluctuations in the power supply voltage. The hall motor can be rotated stably.

[Brief explanation of the drawing]

Fig. 1 is a block circuit diagram showing an embodiment of the Hall motor drive circuit of the present invention and the connection relationship between the Hall motor and the Hall element, and Fig. 2 is a conventional Hall motor drive circuit and the connection between the Hall motor and the Hall element. FIG. 3 is a block circuit diagram showing the relationship. HM...3-phase Hall motor, I (1~H3...
... Hall element, 10 ... Hall motor drive circuit, 11 to 13 ... First variable gain amplifier (Hall amplifier) 14 ... Signal processing circuit, 15
...Absolute value conversion/arithmetic sum means, 16-18...
...Second variable gain amplifier, 19-21...
・Power amplifier, 22-24...Absolute value converter,
25...Error amplifier. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In a Hall motor drive circuit that drives a three-phase Hall motor, three first variable gain amplifiers to which respective outputs of three Hall elements are respectively input; A signal processing circuit receives each output of the variable gain amplifier and performs necessary processing including phase shift and polarity inversion, and converts the voltage amplitude of each of the three-phase AC signals output from this signal processing circuit into absolute values. absolute value conversion/arithmetic sum means for controlling the first variable gain amplifier so that each output amplitude becomes a substantially constant trapezoidal wave using the voltage signal obtained by the arithmetic sum; Three second variable gain amplifiers to which the three-phase AC signals output from the processing circuit are respectively input;
There are three power amplifiers into which each output of the variable gain amplifier is input, amplified respectively, and supplies power to the coils of each phase of the Hall motor. Absolute value conversion means for converting values, and a voltage signal obtained by arithmetic sum of each output of this absolute value conversion means, is compared with a reference input voltage proportional to the power supply voltage to detect and amplify the error, and the amplified output is used to detect and amplify the error. A Hall motor drive circuit comprising error detection/amplification means for controlling the second variable gain amplifier so that each output amplitude becomes a maximum amplitude trapezoidal wave proportional to the power supply voltage.