CN107834917B - Back electromotive force phase change point detection circuit and method of direct current brushless motor - Google Patents
Back electromotive force phase change point detection circuit and method of direct current brushless motor Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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- G01R19/175—Indicating the instants of passage of current or voltage through a given value, e.g. passage through zero
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- H—ELECTRICITY
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Abstract
The invention relates to the technical field of brushless motors, in particular to a counter electromotive force phase change point detection circuit and a counter electromotive force phase change point detection method of a direct current brushless motor, wherein the direct current brushless motor adopts a six-step phase change driving mode and comprises the following steps: connecting a direct current power supply with a three-phase winding of the motor, so that conducting current exists in two phases of the three phases in each step; a zero crossing point detection circuit is adopted to collect voltage signals of the opposite ends of non-conductive phases in the three-phase winding and output the voltage signals to the single chip microcomputer; the single chip microcomputer calculates and processes the acquired terminal voltage signals based on a theoretical model of the direct current brushless motor to obtain a functional relation between back electromotive force and sampling time; and calculating to obtain the zero crossing point of the back electromotive force and the phase change point through the functional relation. The counter electromotive force phase change point detection circuit and the counter electromotive force phase change point detection method provided by the invention can be used for rapidly and accurately detecting the zero crossing point of the counter electromotive force of the direct current brushless motor under the condition of not using a comparator, have high reliability, save the cost and improve the running stability of the motor.
Description
Technical Field
The invention relates to the technical field of brushless motors, in particular to a back electromotive force phase change point detection circuit and method of a direct-current brushless motor.
Background
The brushless motor is a direct current motor developed along with the development of microprocessor technology, the continuous application of high-frequency low-power-consumption power devices and the continuous progress of a motor drive control method, overcomes the defects of complex structure, noise, spark and difficult maintenance of a brush motor, and is widely applied by the advantages of simple structure, reliable operation, high efficiency, energy conservation and easy control. In the sensorless control of the brushless motor, the back electromotive force of the motor needs to be detected to extract a zero crossing point signal of the back electromotive force for motor phase change operation, a hardware comparator is usually adopted to compare the back electromotive force of the motor with a central point signal to obtain the inversion of the zero crossing point signal of the comparator, the method needs to be externally connected with the comparator, the interference of PWM modulation noise waves and other noises is easily caused, a certain phase lag is generated on the signal, when the phase lag angle exceeds 30 degrees, the phase change lag of the motor is caused, the normal operation of the motor is not facilitated, and the cost is high by adopting the comparator.
Disclosure of Invention
In order to solve the technical problems, the invention provides a back electromotive force phase change point detection circuit and a back electromotive force phase change point detection method for a brushless direct current motor, which can quickly and accurately detect the zero crossing point of the back electromotive force of the brushless direct current motor at lower cost.
In order to achieve the technical effects, the invention comprises the following technical scheme: a counter electromotive force phase change point detection method of a direct current brushless motor, the direct current brushless motor adopts a six-step phase change driving mode, and the method comprises the following steps:
(1) connecting a direct current power supply with a three-phase winding of the motor, so that conducting current exists in two phases of the three phases in each step;
(2) a zero crossing point detection circuit is adopted to collect voltage signals of the opposite ends of non-conductive phases in the three-phase winding and output the voltage signals to the single chip microcomputer;
(3) the single chip microcomputer calculates and processes the acquired terminal voltage signals based on a theoretical model of the direct current brushless motor to obtain a functional relation between back electromotive force and sampling time; and calculating to obtain the zero crossing point of the back electromotive force and the phase change point through the functional relation.
Furthermore, the number of the zero crossing point detection circuits in the step (2) is three, the input ends of the three zero crossing point detection circuits are respectively connected with the three-phase winding of the brushless motor, and the output ends of the three zero crossing point detection circuits are connected with the single chip microcomputer.
Further, the step (3) is specifically:
the single chip microcomputer collects terminal voltages at a plurality of moments in each step period;
calculating the back electromotive force corresponding to each sampling moment according to the acquired terminal voltage; wherein,
Vnterminal voltage V for three-phase windinga、VbOr Vc，enBeing back electromotive force e of three-phase windingsa、ebOr ec；
Obtaining a functional relation e between the sampling time and the back electromotive forcen＝f(t)；
And calculating the zero crossing point of the back electromotive force and the phase change point based on the functional relation.
Further, the step (3) further comprises: said function en(t) is a linear function; starting from any commutation point, marking the commutation point as the initial point of the first step, and counting time to zero; the commutation point required to be calculated in each step is the initial point of the next step;
fitting the obtained back electromotive force at each sampling moment by adopting a least square method to obtain a linear function relation e between the back electromotive force and the sampling momentn＝f(t)；
Calculating the zero crossing point of the back electromotive force according to the acquired linear function relation, namely enThe sampling time corresponding to the zero position;
and obtaining a phase change point according to the initial point and the counter electromotive force zero crossing point.
In this embodiment, the step (3) further includes: in each step, the single chip microcomputer detects the back electromotive force at each sampling moment, judges whether positive and negative changes occur or not, and stops sampling when the positive and negative changes occur.
On the other hand, the invention provides a counter electromotive force phase change point detection circuit of a direct current brushless motor, which comprises a single chip microcomputer, a driving circuit and a zero crossing point detection circuit, wherein the driving circuit is connected between the single chip microcomputer and a three-phase winding of the brushless motor; the input end of the zero-crossing detection circuit is connected with a three-phase winding of the brushless motor to detect the terminal voltage of each phase winding, the output end of the zero-crossing detection circuit is connected with the single chip microcomputer, the single chip microcomputer calculates the back electromotive force zero-crossing point and the phase change point according to the detected terminal voltage, and the drive circuit drives the brushless motor according to the calculated phase change point.
Furthermore, the zero crossing point detection circuit comprises a first detection circuit, a second detection circuit and a third detection circuit, and the three detection circuits are respectively connected with the three-phase winding; the first detection circuit comprises a first resistor and a second resistor, the first resistor and the second resistor are connected between the A-phase winding and the ground in series, an output end is arranged between the first resistor and the second resistor, and the output end is connected with the single chip microcomputer;
one end of the first resistor is an input end and is connected with the A-phase winding, the other end of the first resistor is connected with the second resistor in series, and the other end of the second resistor is grounded; an output end is arranged between the first resistor and the second resistor, and the output end is connected with the singlechip;
the second detection circuit comprises a third resistor and a fourth resistor, the third resistor and the fourth resistor are connected between the B-phase winding and the ground in series, an output end is arranged between the third resistor and the fourth resistor, and the output end is connected with the single chip microcomputer;
one end of the third resistor is an input end and is connected with the B-phase winding, the other end of the third resistor is connected with the fourth resistor in series, and the other end of the fourth resistor is grounded;
the third detection circuit comprises a fifth resistor and a sixth resistor, the fifth resistor and the sixth resistor are connected between the C-phase winding and the ground in series, an output end is arranged between the fifth resistor and the sixth resistor, and the output end is connected with the single chip microcomputer.
One end of the fifth resistor is an input end and is connected with the C-phase winding, the other end of the fifth resistor is connected with the sixth resistor in series, and the other end of the sixth resistor is grounded;
furthermore, the first detection circuit, the second detection circuit and the third detection circuit respectively comprise a first capacitor, a second capacitor and a third capacitor, one end of the first capacitor is connected with the output end of the first detection circuit, and the other end of the first capacitor is grounded; one end of the second capacitor is connected with the output end of the second detection circuit, and the other end of the second capacitor is grounded; and one end of the third capacitor is connected with the output end of the third detection circuit, and the other end of the third capacitor is grounded.
Further, the driving circuit includes a driver and a switching circuit.
The invention also provides a direct current brushless motor which comprises the counter electromotive force phase change point detection circuit.
By adopting the technical scheme, the method has the following beneficial effects: the counter electromotive force phase change point detection circuit and method of the direct current brushless motor provided by the invention can quickly and accurately detect the zero crossing point of the counter electromotive force of the direct current brushless motor under the condition of not using a comparator, have high reliability, save the cost and improve the running stability of the motor.
Drawings
Fig. 1 is a waveform diagram of back electromotive force of a brushless dc motor according to an embodiment of the present invention;
fig. 2 is a circuit diagram of a back emf commutation point detection circuit according to an embodiment of the present invention;
FIG. 3 is an enlarged view taken at 100 in FIG. 2;
FIG. 4 is an enlarged view of FIG. 2 at 200;
fig. 5 is an enlarged view at 300 of fig. 2.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the present invention, the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "center", "vertical", "horizontal", "lateral", "longitudinal", and the like indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are used primarily to better describe the invention and its embodiments and are not intended to limit the indicated devices, elements or components to a particular orientation or to be constructed and operated in a particular orientation.
Moreover, some of the above terms may be used to indicate other meanings besides the orientation or positional relationship, for example, the term "on" may also be used to indicate some kind of attachment or connection relationship in some cases. The specific meanings of these terms in the present invention can be understood by those skilled in the art as appropriate.
Furthermore, the terms "mounted," "disposed," "provided," "connected," and "coupled" are to be construed broadly. For example, it may be a fixed connection, a removable connection, or a unitary construction; can be a mechanical connection, or an electrical connection; may be directly connected, or indirectly connected through intervening media, or may be in internal communication between two devices, elements or components. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.
"plurality" means two or more unless otherwise specified.
The present invention will be described in further detail below with reference to specific embodiments and with reference to the attached drawings.
Example 1:
the brushless DC motor is a permanent magnet synchronous motor, and the rotor is provided with a permanent magnet and trapezoidal back electromotive force. The brushless dc motor is controlled by switching phases of a dc power supply in a stator coil, and a switching timing is determined by a rotor position. The current phase of the brushless direct current motor is a rectangular wave in standard and is synchronous with the counter electromotive force which provides constant torque under constant rotating speed; in the sensorless control of the brushless motor, the back electromotive force of the motor needs to be detected to extract a zero crossing point signal of the back electromotive force for motor phase change operation, a hardware comparator is usually adopted to compare the back electromotive force of the motor with a central point signal to obtain the inversion of the zero crossing point signal of the comparator, the method needs to be externally connected with the comparator, the interference of PWM modulation noise waves and other noises is easily caused, a certain phase lag is generated on the signal, when the phase lag angle exceeds 30 degrees, the phase change lag of the motor is caused, the normal operation of the motor is not facilitated, and the cost is high by adopting the comparator.
In order to overcome this drawback, this embodiment provides a method for detecting a back electromotive force commutation point of a dc brushless motor, where the dc brushless motor adopts a six-step commutation driving mode, and the method includes the following steps:
s1, connecting a direct current power supply with a three-phase winding of the motor, so that conducting current exists in two phases of the three phases in each step;
the three-phase brushless direct current motor is driven by adopting a six-step 120-degree phase change mode, and only two phases of three phases are electrified at the same moment. For example, when phase a and phase B are electrically connected, phase C is floating, and this conductive connection interval lasts 60 degrees in electrical degrees, called a step. The conventional way of jumping from one step to the next is called commutation, so there are a total of 6 steps in one cycle. For optimum control and maximum torque/amperage, the current mode is switched as follows: keeping the current in phase with the opposing emf and the switching time is determined by the rotor position. Since the waveform of the back emf is determined by the rotor position, which makes it possible to determine the commutation time with the back emf known, the phase current is in phase with the back emf, and the time to switch the current can be obtained by measuring the back emf at the zero crossing.
S2, collecting voltage signals of the opposite ends of the non-conducting phases in the three-phase winding by adopting a zero crossing point detection circuit and outputting the voltage signals to the single chip microcomputer;
each phase change has one winding connected to the positive pole of the DC power supply, the current enters the winding, the second winding is connected to the negative pole of the DC power supply, the current flows out from the winding, the third winding is in an open circuit state, the phase voltage of the phase winding in the open circuit state is the counter electromotive force, the brushless DC motor needs to change the phase for six times when rotating for one circle, the counter electromotive force of each phase crosses zero twice, and the counter electromotive force can only be obtained by measuring the end voltage because the counter electromotive force can not be directly measured.
S3, the single chip microcomputer calculates and processes the acquired terminal voltage signals based on a theoretical model of the direct current brushless motor to obtain a functional relation between the back electromotive force and the sampling time; and calculating to obtain the zero crossing point of the back electromotive force and the phase change point through the functional relation.
As can be seen from the theoretical model of a brushless motor,
wherein VnTo disconnect terminal voltage of phase, VxnIs the motor neutral voltage.
In a circuit theory model of the motor, when the upper switch of the A phase is closed, current flows through the switch to the coil of the AB. When the upper transistor of the half bridge is turned off, current freewheels through the diode through the a-phase lower switch. In the free-wheeling device, under the condition that the C phase has no current, the terminal voltage Vc is applied to the C phaseThe generated counter electromotive force is detected. By means of an electric circuit, obtain Vc＝ec+VXnVc is the terminal voltage of the C phase of the suspension terminal, ecIs a counter electromotive force, VXnIs the motor neutral voltage.
Phase a, the diode voltage drop at the front end is neglected,
for phase B, the front end voltage drop of the switch is ignored,
adding (1.1) and (1.2) to obtain:
assuming this is a balanced three-phase system, third harmonics are ignored,
ea+eb+ec＝0 (1.4)
ignoring the third harmonic, we have by 1.3 and 1.4:
therefore, the terminal voltage Vc:
during the PWM closing period, namely the current freewheeling device, the terminal voltage of the suspended phase is directly proportional to the back electromotive voltage without any superimposed switching noise, and the back electromotive force can be obtained by detecting the terminal voltage of the suspended phase of the terminal.
In this embodiment, specifically, the following steps are included:
s31, the single chip microcomputer collects terminal voltages at a plurality of moments in each step period;
s32, calculating the counter electromotive force corresponding to each sampling moment according to the obtained terminal voltage; wherein,
Vnterminal voltage V for three-phase windinga、VbOr Vc，enBeing back electromotive force e of three-phase windingsa、ebOr ec；
S33, obtaining a functional relation e between the sampling time and the back electromotive forcen＝f(t)；
And S34, calculating the zero crossing point of the back electromotive force and the phase conversion point based on the functional relation.
In particular, the function en(t) is a linear function; starting from any commutation point, marking the commutation point as the initial point of the first step, and counting time to zero; the commutation point required to be calculated in each step is the initial point of the next step; fitting the obtained back electromotive force at each sampling moment by adopting a least square method to obtain a linear function relation e between the back electromotive force and the sampling momentn＝f(t)；
Calculating the zero crossing point of the back electromotive force according to the acquired linear function relationship, namely the position where the back electromotive force is zero;
and obtaining a phase change point according to the initial point and the counter electromotive force zero crossing point.
Referring to fig. 1, a partial waveform diagram of the back electromotive force of the motor is specifically described, the motor rotates for a circle and changes phases for six times in the rotating process, a-B-C-D-E-F-G represents a waveform diagram of the back electromotive force detected in a period, in this embodiment, a-B is used as a first step, point a is an initial point of the first step, and the back electromotive force at multiple moments is collected from point a; when the first step enters the second step, the specific time point of the phase change point B needs to be obtained, and the collected back electromotive force data is fitted by adopting a least square method to obtain a linear function e between the ABnF (t), calculating e according to the obtained linear function relationnThe time corresponding to zero is calculated, and the time corresponding to the phase change point, t, can be calculated because the initial time and the zero crossing point time in the first step are knownPhase 1＝tBeginning 1+2(tZero 1-tBeginning 1),tPhase 1For the moment of commutation point at which the first step is switched to the second step, tBeginning 1Initial time of the first step, tZero 1For the zero-crossing point in the first step corresponding to the moment, tPhase 1And the time corresponding to the starting point C in the second step can be obtained by the same method, and the second step is switched to the commutation point C in the third step.
In this embodiment, in order to improve the accuracy of measurement, in each step, the single chip detects the back electromotive force at each sampling time, determines whether positive and negative changes occur, and stops sampling when the positive and negative changes occur. Specifically, when sampling is performed in each step, sampling is performed only for the first half period in each step, that is, sampling is performed on the side of the back electromotive force zero crossing point, so that the accuracy of measurement is ensured, and once it is determined that the positive and negative of the back electromotive force corresponding to the sampling point change, sampling is stopped, and the point is not used as a sampling point.
Example 2:
on the basis of embodiment 1, the present embodiment provides a back electromotive force phase change point detection circuit for a dc brushless motor, including a single chip microcomputer, a driving circuit and a zero crossing point detection circuit, where the driving circuit is connected between the single chip microcomputer and a three-phase winding of the brushless motor; the input end of the zero-crossing detection circuit is connected with a three-phase winding of the brushless motor to detect the terminal voltage of each phase winding, the output end of the zero-crossing detection circuit is connected with the single chip microcomputer, the single chip microcomputer calculates the back electromotive force zero-crossing point and the phase change point according to the detected terminal voltage, and the drive circuit drives the brushless motor according to the calculated phase change point.
Referring to fig. 2 to 5, the zero-crossing detection circuit in this embodiment includes a first detection circuit 101, a second detection circuit 201, and a third detection circuit 301, where the three detection circuits are respectively connected to the three-phase windings;
the first detection circuit 101 comprises a first resistor R9 and a second resistor R19, the first resistor R9 and the second resistor R19 are connected between the A-phase winding and the ground in series, an output end is arranged between the first resistor R9 and the second resistor R19, and the output end is connected with the single chip microcomputer;
one end of the first resistor R9 is an input end and is connected with the A-phase winding, the other end of the first resistor R9 is connected with the second resistor R19 in series, and the other end of the second resistor R19 is grounded; an output end is arranged between the first resistor R9 and the second resistor R19, and the output end is connected with the single chip microcomputer;
the first detection circuit 101 adopts two divider resistors, a first resistor R9 and a second resistor R19 to collect the terminal voltage of the A-phase winding, and feeds the terminal voltage back to the single chip microcomputer.
The second detection circuit 201 comprises a third resistor R10 and a fourth resistor R20, the third resistor R10 and the fourth resistor R20 are connected between the B-phase winding and the ground in series, an output end is arranged between the third resistor R10 and the fourth resistor R20, and the output end is connected with the single chip microcomputer;
one end of the third resistor R10 is an input end and is connected with the B-phase winding, the other end of the third resistor R10 is connected with the fourth resistor R20 in series, and the other end of the fourth resistor R20 is grounded;
the second detection circuit 201 adopts two voltage dividing resistors, namely a first resistor R10 and a second resistor R20 to acquire the terminal voltage of the B-phase winding, and feeds the terminal voltage back to the single chip microcomputer.
The third detection circuit comprises a fifth resistor R26 and a sixth resistor R31, the fifth resistor R26 and the sixth resistor are connected between the C-phase winding and the ground in series, an output end is arranged between the fifth resistor R26 and the sixth resistor, and the output end is connected with the single chip microcomputer.
One end of the fifth resistor R26 is an input end and is connected with the C-phase winding, the other end of the fifth resistor R26 is connected with the sixth resistor R31 in series, and the other end of the sixth resistor R31 is grounded;
the third detection circuit 301 adopts two voltage dividing resistors, namely a first resistor R26 and a second resistor R31, to collect the terminal voltage of the C-phase winding, and feeds the terminal voltage back to the single chip microcomputer.
Generally speaking, a three-phase winding of a brushless motor respectively outputs terminal voltages to an input end of a corresponding zero-crossing detection circuit, a divider resistor acquires the terminal voltages of the corresponding winding and then inputs the terminal voltages to a single chip microcomputer, the single chip microcomputer calculates the acquired terminal voltages to obtain back electromotive force, fitting is carried out on data groups acquired by a least square method to obtain a linear function relation between the back electromotive force and time, a back electromotive force zero-crossing point is calculated based on the linear function relation to obtain a phase-changing point, and a driving circuit drives the three-phase winding according to a control signal of the single chip microcomputer. The driving circuit comprises a driver and a switch circuit, wherein in fig. 2-5, 102, 202 and 302 are all switch circuits, and the switch circuit is controlled to be on or off according to a signal of a single chip microcomputer, so that one of A, B and C is connected to the positive pole of a direct current power supply, the other is connected to the negative pole of the direct current power supply, and the third is in a power-off state during each phase change.
In order to filter interference noise in the back electromotive force detection circuit and enable the output voltage to be stable and reliable, the first detection circuit, the second detection circuit and the third detection circuit respectively comprise a first capacitor C6, a second capacitor C7 and a third capacitor C11, one end of the first capacitor C6 is connected with the output end of the first detection circuit, and the other end of the first capacitor C6 is grounded; one end of the second capacitor C7 is connected with the output end of the second detection circuit, and the other end of the second capacitor C7 is grounded; one end of the third capacitor C11 is connected with the output end of the third detection circuit, and the other end is grounded.
In addition, the embodiment also provides a brushless direct current motor which comprises the counter electromotive force phase change point detection circuit.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (2)
1. A counter electromotive force phase change point detection method of a direct current brushless motor is characterized in that the direct current brushless motor adopts a six-step phase change driving mode, and comprises the following steps:
(1) connecting a direct current power supply with a three-phase winding of the motor, so that conducting current exists in two phases of the three phases in each step;
(2) a zero crossing point detection circuit is adopted to collect voltage signals of the opposite ends of non-conductive phases in the three-phase winding and output the voltage signals to the single chip microcomputer; the zero crossing point detection circuits are three in number, the input ends of the three zero crossing point detection circuits are respectively connected with a three-phase winding of the brushless motor, and the output ends of the three zero crossing point detection circuits are connected with the single chip microcomputer;
(3) the single chip microcomputer calculates and processes the acquired terminal voltage signals based on a theoretical model of the direct current brushless motor to obtain a functional relation between back electromotive force and sampling time; calculating to obtain a back electromotive force zero crossing point and a phase inversion point through the functional relation;
the step (3) is specifically as follows:
the single chip microcomputer collects terminal voltages at a plurality of moments in each step period;
calculating the back electromotive force corresponding to each sampling moment according to the acquired terminal voltage; wherein,
Vnterminal voltage V for three-phase windinga、VbOr Vc，enBeing back electromotive force e of three-phase windingsa、ebOr ec；
Obtaining a functional relation e between the sampling time and the back electromotive forcen＝f(t)；
Calculating a back electromotive force zero crossing point and a phase inversion point based on the functional relation;
said function en(t) is a linear function;
fitting the obtained back electromotive force at each sampling moment by adopting a least square method to obtain a linear function relation e between the back electromotive force and the sampling momentn＝f(t)；
Calculating the zero crossing point of the back electromotive force according to the acquired linear function relation, namely enThe sampling time corresponding to the zero position;
and obtaining a phase change point according to the initial point and the counter electromotive force zero crossing point.
2. The method of claim 1, wherein step (3) further comprises: in each step, the single chip microcomputer detects the back electromotive force at each sampling moment, judges whether positive and negative changes occur or not, and stops sampling when the positive and negative changes occur.
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| CN112327157A (en) * | 2020-11-02 | 2021-02-05 | 深圳市朗科智能电气股份有限公司 | Device and method for detecting counter electromotive force zero crossing point of motor |
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| CN113411013B (en) * | 2021-07-14 | 2022-06-10 | 北京航空航天大学 | Brushless direct current motor control system and method for back electromotive force function integral prediction |
| CN114900079A (en) * | 2022-05-11 | 2022-08-12 | 珠海隆华直升机科技有限公司 | Asynchronous detection method for zero crossing point of model airplane brushless motor |
| CN118137894A (en) * | 2024-03-20 | 2024-06-04 | 深圳市航顺芯片技术研发有限公司 | Square wave control method and system for brushless direct current motor |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202334417U (en) * | 2011-11-28 | 2012-07-11 | 深圳市博巨兴实业发展有限公司 | Direct-current brushless motor and counter-electromotive-force zero-crossing detecting circuit thereof |
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| CN105897085B (en) * | 2014-12-23 | 2019-07-12 | 恩智浦美国有限公司 | Zero cross detection circuit and its method for electric machine controller |
| CN106374794B (en) * | 2016-11-09 | 2018-07-27 | 中国工程物理研究院机械制造工艺研究所 | A kind of BLDC motor phase detection methods based on back-emf Wave crest and wave trough |
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