CN104730318B - The current sampling circuit and method of hall device under periodically strong variation magnetic field - Google Patents
The current sampling circuit and method of hall device under periodically strong variation magnetic field Download PDFInfo
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- CN104730318B CN104730318B CN201510173707.7A CN201510173707A CN104730318B CN 104730318 B CN104730318 B CN 104730318B CN 201510173707 A CN201510173707 A CN 201510173707A CN 104730318 B CN104730318 B CN 104730318B
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Abstract
The invention discloses the current sampling circuit and method of hall device under a kind of strong variation magnetic field of periodicity, its circuital point sensor, Hall current sample circuit, midget relay switching circuit and MCU process circuits, union of being sampled first in direct current permanent magnetic brushless motor goes out the interference signal rule that the external magnetic field change being superimposed on reference current is produced, re-sampling is tested electric current, calculate interference signal rule and filter the interference being attached on current sampling signal, the interference that extraneous strong variation magnetic field is sampled to Hall current in direct current permanent magnetic brushless motor is eliminated using switching and computing, it is the feasible method of accurate measurement current of electric in direct current permanent magnetic brushless motor, this invention applies also for the Hall current sampling under periodically strong variation magnetic field environment, have a good application prospect.
Description
Technical field
The present invention relates to current sampling technique field, and in particular to the electricity of hall device under a kind of strong variation magnetic field of periodicity
Stream sample circuit and method, it is adaptable to direct current permanent magnetic brushless motor.
Background technology
With the fast development of electronic metering equipment, Hall current Sampling device obtains widely should in current sampling circuit
With, by taking the Hall current Sampling device of Allegro companies as an example, the main electric current made of copper by near chip surface of such device
The composition such as path and accurate low biasing linear hall sensor circuit, path that tested electric current is flowed through (pin l and 2,3 and 4 it
Between circuit) interior resistance be typically 1.2m Ω, with relatively low power consumption.Tested current path and sensor pin (pin 5~
8) insulation voltage ＞ 2.1kVRMS, almost insulate, as shown in figure 1, flowing through produced by the electric current of copper current path
Magnetic field, can be sensed by the Hall IC in piece and be translated into proportional voltage, as shown in Fig. 2 by by magnetic signal
The optimization of device accuracy is realized close proximity to Hall sensor, such Hall current Sampling device has low noise, rung
(correspondence stepping input current, the output rise time is 5S) fast between seasonable, 50 kilo hertzs of bandwidth, total output error is 4%, height to the maximum
Output sensitivity (66mV/A~185mV/A), the features such as easy to use, cost performance is high, insulation voltage is high, is mainly used in electronic
Machine control, load detection and the protection of management, switch mode power and overcurrent fault etc., particularly those require electric insulation but not
Use optoelectronic insulation.
But Hall current Sampling device is easily disturbed by external magnetic field, when the magnetic interference changed around Hall chip
In the case of, often it is superimposed interference signal on its output voltage signal, it is impossible to which accurate output is believed with the voltage of tested current in proportion
Number, when Hall current sampling A/D chip is used in direct current permanent magnetic brushless motor close beta current of electric, due to motor internal magnetic field
Be with the difference saltus step of its corner thus cannot signal that accurately output-response current of electric changes, thus cannot draw accurate
Current sampling data.
Existing some researchs and patent in terms of the diamagnetic interference of Hall circuit, have such as been published as CN 101915867 at present
The patent of A, its solution for using and circuit are parallel to each other and method as shown in figure 3, be that two Hall elements are placed side by side
To conversely, two Hall elements recycle operation amplifier circuit to two-way Hall output signal by the tested electric current of identical
Computing is carried out, the interference signal that external magnetic field is produced is offset, the feature of this method describes to be based in the patent such as it
Magnetic field is gradual in whole spatial distribution, and two Hall elements are approximately considered as a point in magnetic field, therefore, by two Hall elements
It is identical that magnetic interference signal in output signal is considered as amplitude, and can be offset by computing.But, this method is obviously uncomfortable
For this kind of occasion of non-brush permanent-magnet DC motor, in direct current generator magnetic field be according to corner is different saltus step as shown in figure 4,
The distance that two Hall elements are not to be regarded as between same point, device in magnetic field space can cause external magnetic field in two Hall elements
The interference signal of upper generation is different, so what cannot be produced by the circuit described in its patent and computing offset magnetic field is dry
Signal is disturbed, therefore, to find new Method and circuits and go to solve, accurate current sample asks inside direct current permanent magnetic brushless motor
Topic.
The content of the invention
Technical problem solved by the invention is to overcome existing under periodically strong variation magnetic field environment, and Hall current is adopted
The sampling of sample device current is inaccurate, especially for the problem of direct current permanent magnetic brushless motor inner utilization Hall current Sampling device.
In order to solve the above-mentioned technical problem, the technical solution adopted in the present invention is：
The current sampling circuit of hall device under a kind of strong variation magnetic field of periodicity, it is characterised in that：It is arranged on direct current forever
The inside of magnetic brushless electric machine, including angular transducer, Hall current sample circuit, midget relay switching circuit and MCU treatment
Circuit,
The angular transducer is used to measure the corner of direct current permanent magnetic brushless motor, and angle signal is transferred at MCU
Reason circuit；
The electric current that the Hall current sample circuit is used to flow through Hall current device is converted into corresponding voltage signal,
It is transferred to MCU process circuits；
The midget relay switching circuit is used for the switching between reference current source and tested electric current, makes the electricity after switching
Stream flows to Hall current device and is detected；
The MCU process circuits are used to sample the voltage signal of Hall current device transmission through MCU inside AD conversion, and
Computing is carried out according to the angle signal that angular transducer is transmitted, the current value of direct current permanent magnetic brushless motor is drawn.
The method of sampling of the current sampling circuit of hall device under the strong variation magnetic field of foregoing periodicity, it is characterised in that：
Comprise the following steps,
Step (1), direct current permanent magnetic brushless motor start rotation when 10 cycles in midget relay switching circuit make
Reference current flows through Hall Sampling device；
Step (2), rotor is rotated in direct current permanent magnetic brushless motor by angular transducer 360 ° are divided into some
Fixed corner, and each fixation corner carries out current sample under reference current；
Step (3), when calculating each fixation corner, the reference voltage signal V of hall device outputI1,
VI1=K*IBenchmark+V1’ (1)
Wherein, V1' on the basis of changes of magnetic field is produced under electric current interference signal, IBenchmarkOn the basis of electric current, K is hall device
Output voltage and tested current ratio value, unit mV/A；
Step (4), MCU process circuits are calculated and started in 10 cycles of rotation, and carrying out each fixation corner carries out electric current
Sampling, and calculate the voltage signal V of hall device output under reference currentI1Root-mean-square value VI1’；
Step (5), after 10 cycles of the direct current permanent magnetic brushless motor when rotation is started, midget relay switching circuit makes
Tested direct current permanent magnetic brushless motor electric current flows through Hall Sampling device；
Step (6), and carry out current sample in each the fixation corner sampled with reference current；
Step (7), when calculating each fixation corner, the tested voltage signal V of hall device outputI2,
VI2=K*IIt is tested+V2’ (2)
Wherein, V2' it is changes of magnetic field is produced under tested direct current permanent magnetic brushless motor electric current interference signal, IIt is testedIt is tested
Direct current permanent magnetic brushless motor electric current, K is the output voltage and tested current ratio value, unit mV/A of hall device, and the value is by suddenly
The characteristic of your device determines that the model of hall device determines the numerical value of the coefficient.
Step (8), MCU process circuits are calculated and rotated in 10-20 cycle, and carrying out each fixation corner carries out electric current and adopt
Sample, and calculate the voltage signal V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2Root-mean-square value
VI2’；
Step (9), by the voltage signal root-mean-square value V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2’
The voltage signal root-mean-square value V exported with hall device under reference currentI1' subtract each other, filtering interference signals,
VI2’-VI1'=K*IIt is tested-K*IBenchmark+V2’–V1’ (3)
Wherein, interference signal V1 ', V2 ' are identicals in same fixed corner, i.e.
VI2’-VI1'=K*IIt is tested-K*IBenchmark (4)
Step (10), according to formula (5), is tested direct current permanent magnetic brushless motor current value IIt is tested,
IIt is tested=(VI2’-VI1’)/K+IBenchmark (5)。
Current sample method of the foregoing hall device under periodically strong variation magnetic field, it is characterised in that：Step (2),
Rotor is rotated in direct current permanent magnetic brushless motor by angular transducer 360 ° are divided into six fixed corners, and each is fixed
The angle of corner is 60 °.
The beneficial effects of the invention are as follows：Under the strong variation magnetic field of periodicity of the invention the current sampling circuit of hall device and
Method, the interference that magnetic field is sampled to Hall current in direct current permanent magnetic brushless motor is eliminated using switching and computing, is solved suddenly
Your current sampling circuit in the case where strong variation magnetic field is disturbed cannot the tested current value of accurate measurement problem, be permanent-magnetic brush-less DC electricity
Accurate measurement current of electric provides feasible method in machine, and this invention is applied also under other periodically strong variation magnetic field environment
Hall current sampling, have a good application prospect.
Brief description of the drawings
Fig. 1 is Hall current sampling A/D chip internal structure.
Fig. 2 is Hall current sampling A/D chip output voltage signal and tested current signal graph of a relation.
The circuit diagram that Fig. 3 is used by the A of patent CN 101915867.
Fig. 4 is the motor internal changes of magnetic field diagram by taking 0~180 degree corner as an example.
Fig. 5 is the system block diagram of the current sampling circuit of hall device under the strong variation magnetic field of periodicity of the invention.
Fig. 6 is the validation test curve of the current sample method of hall device under the strong variation magnetic field of periodicity of the invention.
Specific embodiment
Below in conjunction with Figure of description, the present invention is further illustrated.
As shown in figure 5, under the strong variation magnetic field of periodicity of the invention hall device current sampling circuit, be arranged on direct current
The inside (applying also for the Hall current sampling under other periodically strong variation magnetic field environment) of permanent magnetic brushless, including angle
Degree sensor, Hall current sample circuit, midget relay switching circuit and MCU process circuits, in direct current permanent magnetic brushless motor
Inside sampling union goes out the interference signal rule that the external magnetic field change being superimposed on reference current is produced, the tested electricity of re-sampling first
Stream, is calculated interference signal rule and filters the interference being attached on current sampling signal, and eliminated directly using switching and computing
The interference that extraneous strong variation magnetic field is sampled to Hall current in stream permanent magnetic brushless, is accurately surveyed in direct current permanent magnetic brushless motor
The feasible method of current of electric is measured, this invention applies also for the Hall current sampling under periodically strong variation magnetic field environment, its
In,
The angular transducer is used to measure the corner of direct current permanent magnetic brushless motor, and angle signal is transferred at MCU
Reason circuit；
The electric current that the Hall current sample circuit is used to flow through Hall current device is converted into corresponding voltage signal,
It is transferred to MCU process circuits；
The midget relay switching circuit is used for the switching between reference current source and tested electric current, makes the electricity after switching
Stream flows to Hall current device and is detected；
The MCU process circuits are used to sample the voltage signal of Hall current device transmission through MCU inside AD conversion, and
Computing is carried out according to the angle signal that angular transducer is transmitted, the current value of direct current permanent magnetic brushless motor is drawn.
Based on the method for sampling of the current sampling circuit of hall device under the above-mentioned strong variation magnetic field of periodicity, its feature exists
In：Comprise the following steps,
Step (1), in 10 cycles when rotation is started, midget relay switching circuit makes direct current permanent magnetic brushless motor
Reference current flows through Hall Sampling device；
Step (2), rotor is rotated in direct current permanent magnetic brushless motor by angular transducer 360 ° are divided into some
Fixed corner, and each fixation corner carries out current sample under reference current, is divided into six fixed corners, each is fixed and turns
The angle at angle is the periodic sampling of 60 °, i.e., 16 times.
Step (3), when calculating each fixation corner, the reference voltage signal V of hall device outputI1,
VI1=K*IBenchmark+V1’ (1)
Wherein, V1' on the basis of changes of magnetic field is produced under electric current interference signal, IBenchmarkOn the basis of electric current, K is hall device
Output voltage is determined that the model of hall device is determined with tested current ratio value, unit mV/A, the value by the characteristic of hall device
The numerical value of the coefficient；
Step (4), MCU process circuits are calculated and started in 10 cycles of rotation, and carrying out each fixation corner carries out electric current
Sampling, and calculate the voltage signal V of hall device output under reference currentI1Root-mean-square value VI1’；
Step (5), after 10 cycles of the direct current permanent magnetic brushless motor when rotation is started, midget relay switching circuit makes
Tested direct current permanent magnetic brushless motor electric current flows through Hall Sampling device；
Step (6), and carry out current sample in each the fixation corner sampled with reference current；
Step (7), when calculating each fixation corner, the tested voltage signal V of hall device outputI2,
VI2=K*IIt is tested+V2’ (2)
Wherein, V2' it is changes of magnetic field is produced under tested direct current permanent magnetic brushless motor electric current interference signal, IIt is testedIt is tested
Direct current permanent magnetic brushless motor electric current, K is hall device output voltage and tested current ratio value, unit mV/A, and the value is by Hall
The characteristic of device determines that the model of hall device determines the numerical value of the coefficient.
Step (8), MCU process circuits were calculated within the 10-20 cycles, and carrying out each fixation corner carries out current sample, and
Calculate the voltage signal V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2Root-mean-square value VI2’；
Step (9), by the voltage signal root-mean-square value V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2’
The voltage signal root-mean-square value V exported with hall device under reference currentI1' subtract each other, filtering interference signals,
VI2’-VI1'=K*IIt is tested-K*IBenchmark+V2’–V1’ (3)
Wherein, interference signal V1 ', V2 ' are identicals in same fixed corner, i.e.
VI2’-VI1'=K*IIt is tested-K*IBenchmark (4)
Step (10), according to formula (5), is tested direct current permanent magnetic brushless motor current value IIt is tested,
IIt is tested=(VI2’-VI1’)/K+IBenchmark (5)。
The method of the present invention is arranged in direct current permanent magnetic brushless motor Hall current when sampling, the circuit of anti-magnetic interference and
Method, the method and circuit are applied and verify in real electrical machinery parameter acquisition integral system, validation test curve, such as
Shown in Fig. 6.
General principle of the invention and principal character and advantages of the present invention has been shown and described above.The technology of the industry
Personnel it should be appreciated that the present invention is not limited to the above embodiments, simply explanation described in above-described embodiment and specification this
The principle of invention, without departing from the spirit and scope of the present invention, various changes and modifications of the present invention are possible, these changes
Change and improvement all fall within the protetion scope of the claimed invention.The claimed scope of the invention by appending claims and its
Equivalent thereof.
Claims (3)
1. under a kind of strong variation magnetic field of periodicity hall device current sampling circuit, it is characterised in that：It is arranged on AC permanent magnet
The inside of brushless electric machine, including angular transducer, Hall current sample circuit, midget relay switching circuit and MCU treatment electricity
Road,
The angular transducer is used to measure the corner of direct current permanent magnetic brushless motor, and angle signal is transferred into MCU treatment electricity
Road；
The electric current that the Hall current sample circuit is used to flow through Hall current device is converted into corresponding voltage signal, transmits
To MCU process circuits；
The midget relay switching circuit is used for the switching between reference current source and tested electric current, makes the electric current stream after switching
Detected to Hall current device；
The MCU process circuits are used to sample the voltage signal of Hall current device transmission through MCU inside AD conversion, and according to
The angle signal of angular transducer transmission carries out computing, draws the current value of direct current permanent magnetic brushless motor.
2. the method for sampling of the current sampling circuit of hall device under the strong variation magnetic field of periodicity described in claim 1 is based on,
It is characterized in that：Comprise the following steps,
Step (1), direct current permanent magnetic brushless motor start rotation when 10 cycles in midget relay switching circuit make benchmark
Electric current flows through Hall Sampling device；
Step (2), rotor is rotated in direct current permanent magnetic brushless motor by angular transducer 360 ° are divided into some fixations
Corner, and each fixation corner carries out current sample under reference current；
Step (3), when calculating each fixation corner, the reference voltage signal V of hall device outputI1,
VI1=K*IBenchmark+V1’ (1)
Wherein, V1' on the basis of changes of magnetic field is produced under electric current interference signal, IBenchmarkOn the basis of electric current, K for hall device output
Voltage and tested current ratio value, unit mV/A；
Step (4), MCU process circuits are calculated and started in 10 cycles of rotation, and carrying out each fixation corner carries out current sample,
And calculate the voltage signal V of hall device output under reference currentI1Root-mean-square value VI1’；
Step (5), after 10 cycles of the direct current permanent magnetic brushless motor when rotation is started, midget relay switching circuit makes to be tested
Direct current permanent magnetic brushless motor electric current flows through Hall Sampling device；
Step (6), and carry out current sample in each the fixation corner sampled with reference current；
Step (7), when calculating each fixation corner, the tested voltage signal V of hall device outputI2,
VI2=K*IIt is tested+V2’ (2)
Wherein, V2' it is changes of magnetic field is produced under tested direct current permanent magnetic brushless motor electric current interference signal, IIt is testedFor tested direct current forever
Magnetic brushless electric machine electric current, K is the output voltage and tested current ratio value, unit mV/A of hall device；
Step (8), MCU process circuits are calculated and rotated in 10-20 cycle, and carrying out each fixation corner carries out current sample,
And calculate the voltage signal V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2Root-mean-square value VI2’；
Step (9), by the voltage signal root-mean-square value V of hall device output under tested direct current permanent magnetic brushless motor electric currentI2' and base
The voltage signal root-mean-square value V of hall device output under quasi- electric currentI1' subtract each other, filtering interference signals,
VI2’-VI1'=K*IIt is tested-K*IBenchmark+V2’–V1’ (3)
Wherein, interference signal V1 ', V2 ' are identicals in same fixed corner, i.e.
VI2’-VI1'=K*IIt is tested-K*IBenchmark (4)
Step (10), according to formula (5), is tested direct current permanent magnetic brushless motor current value IIt is tested,
IIt is tested=(VI2’-VI1’)/K+IBenchmark (5)。
3. current sample method of the hall device according to claim 2 under periodically strong variation magnetic field, its feature exists
In：Step (2), rotor is rotated in direct current permanent magnetic brushless motor by angular transducer 360 ° are divided into six fixations and turned
Angle, each angle for fixing corner is 60 °.
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