CN116317728A - Motor counter electromotive force filtering detection method and circuit - Google Patents
Motor counter electromotive force filtering detection method and circuit Download PDFInfo
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- CN116317728A CN116317728A CN202111565305.3A CN202111565305A CN116317728A CN 116317728 A CN116317728 A CN 116317728A CN 202111565305 A CN202111565305 A CN 202111565305A CN 116317728 A CN116317728 A CN 116317728A
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- 238000001914 filtration Methods 0.000 title claims abstract description 130
- 238000001514 detection method Methods 0.000 title claims abstract description 40
- 238000005070 sampling Methods 0.000 claims abstract description 30
- 230000001960 triggered effect Effects 0.000 claims description 11
- 230000000630 rising effect Effects 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 238000012986 modification Methods 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 230000005355 Hall effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 241001391944 Commicarpus scandens Species 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/18—Circuit arrangements for detecting position without separate position detecting elements
- H02P6/182—Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P2203/00—Indexing scheme relating to controlling arrangements characterised by the means for detecting the position of the rotor
- H02P2203/03—Determination of the rotor position, e.g. initial rotor position, during standstill or low speed operation
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
- Control Of Electric Motors In General (AREA)
Abstract
The invention provides a motor back electromotive force filtering detection method and a motor back electromotive force filtering detection circuit. Receiving a back electromotive force signal of a motor; setting a reference voltage based on the back electromotive force signal, comparing the back electromotive force signal with the reference voltage in a non-driving interval of the motor to output a sampling signal, and judging the rotating speed of the motor according to the slope of the back electromotive force signal in the non-driving interval; adjusting a filtering frequency range according to the rotating speed of the motor, filtering the sampling signal based on a filtering clock signal, and outputting a filtering result; and detecting a zero crossing event of the filtering result, and generating a control signal of the motor. The invention does not use an external sensor and an external comparison circuit, and reduces the cost. The motor-based speed regulation device is convenient to operate, simple in overall structure, low in power consumption, small in occupied computing resources, flexible and controllable to realize.
Description
Technical Field
The invention relates to the field of motor control, in particular to a motor back electromotive force filtering detection method and a circuit.
Background
In the brushless dc motor BLDC (Brushless Direct Current) control scheme with sensors, an external sensor is typically used to determine the position of the motor rotor relative to the motor stator, which can make the motor control quite simple, the processor only needs to wait for the hall effect sensors to change state, then determine the interval where the rotor is located according to the outputs of the three hall effect sensors, and commutate the motor windings accordingly, but the sensor is expensive, and needs to be installed when the motor is manufactured, and the sensor is prone to failure, and the use environment is limited. In sensorless BLDC control, the motor winding commutation time is typically determined using an external comparator plus internal IIR (Infinite Impulse Response) or FIR (Finite Impulse Response) digitally filtered back emf. External comparators also increase external circuit cost, IIR or FIR digital filtering increases circuit complexity, increases chip power consumption, and consumes excessive chip computing resources and memory.
The existing motor back electromotive force detection technology comprises the following steps:
1) In sensored BLDC control, an external hall sensor is used to determine motor winding commutation time.
2) In sensorless BLDC control, the back emf is signal processed using an external comparator plus an internal chip IIR or FIR digital filter circuit to determine the motor winding commutation time.
The limitations of the prior art are: in the prior art 1), the sensor is expensive, the use environment is limited, and the sensor is easy to break down. In the prior art 2), the circuit is complex, the power consumption of the chip is increased, and a large amount of operation resources are occupied.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an objective of the present invention is to provide a method and a circuit for detecting back electromotive force filtering of a motor, which are used for solving the problems of increased circuit cost, increased circuit complexity and increased digital filtering operation resources caused by the addition of an external sensor and an external comparator in the prior art for signal processing of back electromotive force.
To achieve the above and other related objects, the present invention provides a motor back electromotive force filtering detection method, which at least includes:
receiving a back electromotive force signal of a motor;
setting a reference voltage based on the back electromotive force signal, and comparing the back electromotive force signal with the reference voltage in a non-driving interval of a motor to output a sampling signal;
adjusting a filtering frequency range according to the rotating speed of the motor, filtering the sampling signal based on a filtering clock signal, and outputting a filtering result;
and detecting a zero crossing event of the filtering result, and generating a control signal of the motor.
Optionally, the reference voltage is equal to half of the amplitude interval of the back emf signal.
Optionally, when the motor rotation speed is greater than 2000 revolutions, the filtering frequency range is set to be greater than the frequency range of the sampling signal, so as to filter out voltage spike noise of the sampling signal.
Optionally, the filtering operation is performed on a rising or falling edge of a filtering clock.
Optionally, the rotating speed of the motor is less than or equal to 2000 rpm, when the sampling signal is triggered to a high level in five continuous filtering clocks, the filtering result starts to output the high level from a sixth filtering clock; when the sampling signal is triggered to a low level in five consecutive filter clocks, the filter result outputs a low level from the sixth filter clock.
Optionally, the rotation speed of the motor is greater than 2000 rpm, and when the sampling signal is triggered to a high level in two continuous filtering clocks, the filtering result starts to output the high level from a third filtering clock; when the sampling signal is triggered to a low level in two consecutive filter clocks, the filter result outputs a low level from the third filter clock.
The invention provides a motor back electromotive force filtering detection circuit, which is used for realizing the motor back electromotive force filtering detection method, and comprises the following steps: comparison unit, filtering module, detection module and modulation module, wherein:
the comparison unit receives a back electromotive force signal of the motor, samples the back electromotive force signal, and judges the rotating speed of the motor according to the slope of the back electromotive force signal in a non-driving interval;
the filtering module is connected to the output end of the comparing unit, adjusts the filtering frequency range according to the rotating speed of the motor, and performs filtering operation to output a filtering result;
the detection module is connected with the output end of the filtering module and is used for detecting a zero crossing event of the filtering result;
the modulation module is connected to the output end of the detection module and is used for generating a control signal of the motor.
Optionally, the modulation module is a pulse code modulation module.
As described above, the motor back electromotive force filtering detection method and circuit have the following beneficial effects:
1. compared with the prior art 1), the invention does not use an external sensor and an external comparison circuit, and reduces the cost.
2. Compared with the prior art 2), the back electromotive force filtering detection method and circuit are convenient to operate, simple in overall structure, low in power consumption, small in occupied computing resources, flexible and controllable to realize based on speed adjustment of the motor.
Drawings
Fig. 1 is a schematic flow chart of a motor back electromotive force filtering detection method according to a first embodiment of the present application.
Fig. 2 is a timing diagram of a motor back electromotive force filtering detection method according to a first embodiment of the present application.
Fig. 3 is a schematic diagram of a motor back electromotive force filtering detection circuit according to a second embodiment of the present application.
Description of element reference numerals
110. Triggering to high level in two continuous filtering clocks
120. Outputting a high level from the third filter clock
130. Triggering to low level in two consecutive filter clocks
140. Outputting a low level from the third filter clock
210. Comparison unit
220. Filtering module
230. Detection module
240. Modulation module
S1 to S4 steps
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present invention, which is described by the following specific examples.
Please refer to fig. 1 to 3. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that it can be practiced, since modifications, changes in the proportions, or otherwise, used in the practice of the invention, are not intended to be critical to the essential characteristics of the invention, but are intended to fall within the spirit and scope of the invention. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like recited in the present specification are merely for descriptive purposes and are not intended to limit the scope of the invention, but are intended to provide relative positional changes or modifications without materially altering the technical context in which the invention may be practiced.
Example 1
As shown in fig. 1 to 3, the present embodiment provides a motor back electromotive force filtering detection method, which at least includes:
s1: as shown in fig. 1, a back emf signal of the motor is received.
In particular, according to the basic principle of the motor, the back emf signal is not a smooth signal and the back emf signal couples noise disturbances, thus resulting in an inaccurate detection of zero crossing events. In actual back emf detection, the ideal back emf signal and the actual back emf signal have a phase difference, so that zero-crossing events cannot be accurately detected in the non-driving section, and therefore, optimization processing is required for the back emf signal.
S2: as shown in fig. 1, a reference voltage is set based on the back electromotive force signal, and then the back electromotive force signal and the reference voltage are compared in a non-driving section of the motor, and a sampling signal is outputted, wherein a slope of the back electromotive force signal in the non-driving section is proportional to a rotational speed of the motor.
Specifically, as an example, in the present embodiment, the reference voltage is equal to half of the amplitude interval of the counter electromotive force signal. It should be noted that the reference voltage should be set according to a specific debug environment, and is not limited to this embodiment. Since the slope of the back emf signal in the non-drive interval is proportional to the rotational speed of the motor, if the back emf and reference voltage are not compared, it may result in a detected zero crossing event that lags the actual zero crossing event. When the rotating speed of the motor is less than or equal to 2000 revolutions per minute, the comparison operation can effectively reduce noise, so that the workload of the next step is reduced; when the motor speed is greater than 2000 rpm, since the back emf signal has significant voltage spike noise in the non-driving interval, although the voltage spike noise is not completely filtered by the comparison operation, the residual voltage spike noise still causes the detected zero crossing time to lag behind the actual zero crossing event, and thus further processing of the residual voltage spike noise is required to improve accuracy.
S3: as shown in fig. 1, the filtering frequency range is adjusted according to the rotation speed of the motor, filtering operation is performed on the sampling signal based on the filtering clock signal, and a filtering result is output.
Specifically, as an example, in the present embodiment, when the motor rotation speed is greater than 2000 rpm, the filtering frequency range is set to be greater than the frequency range of the sampling signal to filter out the voltage spike noise of the sampling signal. When the motor rotation speed is less than or equal to 2000 rpm, the comparing operation in step S2 has reduced a lot of noise, so the filtering operation requirement is relatively relaxed, and the filtering frequency range should be adjusted according to the actual use situation, which is not limited by the embodiment.
Further, as an example, as shown in fig. 2, the filtering operation is performed on a rising edge of the filtering clock or a falling edge of the filtering clock; as can be seen from step S2, the motor rotation speed is greater than 2000 rpm, and when the sampling signal is triggered to a high level in two continuous filter clocks, namely 110 in fig. 2; the filtering result outputs a high level starting from the third filtering clock, indicated as 120 in fig. 2. If the sample signal toggles low in two consecutive filter clocks, shown as 130 in fig. 2; the filtering result outputs a low level starting from the third filtering clock, indicated as 140 in fig. 2. It should be noted that the filtering operation time includes, but is not limited to, a rising edge of the filtering clock or a falling edge of the filtering clock, and should be set according to an actual operating environment, and the number of high-level triggering and the number of low-level triggering of the sampling signal should be set according to an actual operating environment, especially, an operating condition of the motor, not limited to the embodiment.
Further, as an example, as shown in step S2, the motor rotation speed is 2000 rpm or less, and when the sampling signal is triggered to a high level in five continuous filter clocks; the filtering result outputs a high level from the sixth filtering clock. If the sampling signal is triggered to a low level in five continuous filtering clocks; the filtering result outputs a low level from the sixth filtering clock. It should be noted that the filtering operation time includes, but is not limited to, a rising edge of the filtering clock or a falling edge of the filtering clock, the setting should be performed according to an actual operating environment, and the number of the high-level triggering signals and the number of the low-level triggering signals should be set according to an actual operating environment, especially, an operating condition of the motor, and the setting should be performed according to an actual operating environment, especially, an operating condition of the motor, not limited to the embodiment.
S4: as shown in fig. 1, a zero crossing event of the filtering result is detected, and a control signal of the motor is generated.
Specifically, as shown in fig. 1 and fig. 2, the filtering result obtained by the filtering operation is close to an ideal counter electromotive force signal, and the zero crossing event is detected to be almost the same as the actual zero crossing event, so as to generate a control signal of the motor.
Example two
As shown in fig. 3, the present embodiment provides a motor back electromotive force filtering detection circuit for implementing the motor back electromotive force filtering detection method provided in the first embodiment, where the motor back electromotive force filtering detection circuit includes:
the comparing unit 210, the filtering module 220, the detecting module 230 and the modulating module 240;
as shown in fig. 3, the comparing unit 210 is configured to receive a back electromotive force signal of the motor, sample the back electromotive force signal, and determine a rotation speed of the motor according to a slope of the back electromotive force signal in a non-driving interval.
It should be noted that, as shown in fig. 3, according to the description in the first embodiment, the comparing unit 210 sets half of the amplitude interval of the back electromotive force signal as the reference signal, and then compares the back electromotive force signal with the reference signal to output the sampling signal, and it should be noted that the setting of the reference voltage should be set according to the actual use environment, and is not limited to this embodiment. The comparing unit 210 includes, but is not limited to, an analog-to-digital converter and a digital signal processor, and any device capable of implementing the comparing function is suitable, and will not be described in detail herein.
As shown in fig. 3, the filtering module 220 is connected to the output end of the comparing unit, adjusts the filtering frequency range according to the rotation speed of the motor, and then performs filtering operation to output the filtering result.
It should be noted that, as an example, as shown in fig. 3, according to the description in the first embodiment, the filtering module 220 performs a filtering operation on the sampling signal output by the comparing unit 210 based on the filtering clock, and then outputs a filtering result. The filtering module 220 includes, but is not limited to, a programmable gate array, and any device capable of implementing a filtering operation is suitable, which is not described herein in detail.
As shown in fig. 3, the detection module 230 is connected to the output of the filtering module 220, and detects the zero crossing event of the filtering result.
As shown in fig. 3, the modulation module 240 is connected to the output end of the detection module 230, and is configured to generate a control signal of the motor.
Specifically, as shown in fig. 3, the modulation module 240 is a pulse code modulation module. As shown in fig. 2, the filtering result represents a control signal for generating the motor, and according to the description in the first embodiment, the filtering result approximates to an ideal back electromotive force signal, and the zero-crossing event is detected to be almost the same as the actual zero-crossing event. And the filtering result drives the motor to operate. It should be noted that, the modulation module 240 includes, but is not limited to, a pulse code modulation module, and any module capable of driving a motor to operate is applicable and not limited to the present embodiment.
In summary, the method and circuit for detecting the back electromotive force filtering of the motor according to the present invention include: receiving a back electromotive force signal of a motor; setting a reference voltage based on the back electromotive force signal, comparing the back electromotive force signal with the reference voltage in a non-driving interval of the motor, outputting a sampling signal, and judging the rotating speed of the motor according to the slope of the back electromotive force signal in the non-driving interval; adjusting a filtering frequency range according to the rotating speed of the motor, filtering the sampling signal based on a filtering clock signal, and outputting a filtering result; and detecting a zero crossing event of the filtering result, and generating a control signal of the motor. The motor back electromotive force filtering detection method and circuit provided by the invention have the advantages that an external sensor and an external comparison circuit are not used, and the cost is reduced. The back electromotive force filtering detection method and the circuit are convenient to operate, simple in overall structure, low in power consumption, small in occupied computing resources, flexible and controllable to realize based on speed adjustment of the motor. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (8)
1. A method for detecting back emf filtering of a motor, the method comprising:
receiving a back electromotive force signal of a motor;
setting a reference voltage based on the back electromotive force signal, and comparing the back electromotive force signal with the reference voltage in a non-driving interval of a motor to output a sampling signal;
adjusting a filtering frequency range according to the rotating speed of the motor, filtering the sampling signal based on a filtering clock signal, and outputting a filtering result;
and detecting a zero crossing event of the filtering result, and generating a control signal of the motor.
2. The motor back emf filtering detection method of claim 1, wherein: the reference voltage is equal to half the amplitude interval of the back emf signal.
3. The motor back emf filtering detection method of claim 1, wherein: when the motor rotation speed is greater than 2000 revolutions, the filtering frequency range is set to be greater than the frequency range of the sampling signal so as to filter the voltage peak noise of the sampling signal.
4. The motor back emf filtering detection method of claim 1, wherein: the filtering operation is performed on either the rising or falling edge of the filter clock.
5. The motor back emf filtering detection method of claim 1, wherein: the rotating speed of the motor is less than or equal to 2000 rpm, and when the sampling signal is triggered to a high level in five continuous filtering clocks, the filtering result starts to output the high level from a sixth filtering clock; when the sampling signal is triggered to a low level in five consecutive filter clocks, the filter result outputs a low level from the sixth filter clock.
6. The motor back emf filtering detection method of claim 1, wherein: the rotating speed of the motor is more than 2000 rpm, and when the sampling signal is triggered to a high level in two continuous filtering clocks, the filtering result starts to output the high level from a third filtering clock; when the sampling signal is triggered to a low level in two consecutive filter clocks, the filter result outputs a low level from the third filter clock.
7. A motor back electromotive force filtering detection circuit for implementing the motor back electromotive force filtering detection method according to any one of claims 1 to 6, characterized in that: the motor back electromotive force filtering detection circuit at least comprises: comparison unit, filtering module, detection module and modulation module, wherein:
the comparison unit receives a back electromotive force signal of the motor, samples the back electromotive force signal, and judges the rotating speed of the motor according to the slope of the back electromotive force signal in a non-driving interval;
the filtering module is connected to the output end of the comparing unit, adjusts the filtering frequency range according to the rotating speed of the motor, and performs filtering operation to output a filtering result;
the detection module is connected with the output end of the filtering module and is used for detecting a zero crossing event of the filtering result;
the modulation module is connected to the output end of the detection module and is used for generating a control signal of the motor.
8. The motor back emf filtering detection circuit of claim 7, wherein: the modulation module is a pulse code modulation module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111565305.3A CN116317728A (en) | 2021-12-20 | 2021-12-20 | Motor counter electromotive force filtering detection method and circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111565305.3A CN116317728A (en) | 2021-12-20 | 2021-12-20 | Motor counter electromotive force filtering detection method and circuit |
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| Publication Number | Publication Date |
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| CN116317728A true CN116317728A (en) | 2023-06-23 |
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| CN202111565305.3A Pending CN116317728A (en) | 2021-12-20 | 2021-12-20 | Motor counter electromotive force filtering detection method and circuit |
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| CN (1) | CN116317728A (en) |
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- 2021-12-20 CN CN202111565305.3A patent/CN116317728A/en active Pending
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