CN109713949B - Method and system for suppressing torque ripple of brushless direct current motor - Google Patents
Method and system for suppressing torque ripple of brushless direct current motor Download PDFInfo
- Publication number
- CN109713949B CN109713949B CN201811625292.2A CN201811625292A CN109713949B CN 109713949 B CN109713949 B CN 109713949B CN 201811625292 A CN201811625292 A CN 201811625292A CN 109713949 B CN109713949 B CN 109713949B
- Authority
- CN
- China
- Prior art keywords
- phase
- conduction
- circuit
- direct current
- switching
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
The invention relates to a method and a system for inhibiting torque ripple of a brushless direct current motor, wherein the method comprises the steps of acquiring Hall signals acquired by a Hall sensor in the brushless direct current motor and three-phase current in the running process of the brushless direct current motor, judging whether the brushless direct current motor is in a phase change state according to the Hall signals and the three-phase current, and if not, controlling a voltage type inverter by adopting a pairwise conduction control mode; if yes, the voltage type inverter is controlled by adopting a two-to-two conduction and three-to-three conduction switching control mode. In the phase change stage, only one switching tube changes through a pairwise conduction and three-to-three conduction switching control mode, so that torque pulsation generated by the brushless direct current motor during phase change is effectively inhibited; and because two conduction control modes and three conduction control modes are mutually matched, a dead zone does not need to be set, the suppression effect of torque pulsation is better, the detection method and the control algorithm are simpler, the calculation difficulty is lower, the cost is lower, and the control efficiency is higher.
Description
Technical Field
The invention relates to the technical field of motor control, in particular to a method and a system for inhibiting torque pulsation of a brushless direct current motor.
Background
Electrical machines have been used in all aspects of modern society through many years of development. Dc motors are increasingly used in electric traction systems because of their excellent regulation capability and starting performance. Brushless dc motors have been developed on the basis of brushed dc motors. The reserves of the permanent magnet materials in China are quite abundant, so that a good material foundation is laid for the development of the brushless direct current motor. Due to the growing maturity of the processing level of permanent magnet materials and the increasing progress of control circuit technology, brushless direct current motors have been spread in various fields and links of modern society and national economy. The brushless direct current motor has the advantages of simple structure, high power density, long service life and the like, and is widely applied to the fields of national defense, industrial process control, robots, automotive electronics, household appliances, office automation and the like.
However, brushless dc motors also have a significant disadvantage, namely large torque ripple. The torque ripple of the motor is mainly divided into: torque ripple caused by current commutation and torque ripple caused by cogging. Because the torque ripple problem of the brushless dc motor causes its use to be hindered in the field where the requirement for output torque performance is high. The torque ripple caused by the current commutation has a lower frequency and a larger amplitude than the cogging torque ripple, and is a main component of the torque ripple of the brushless dc motor. Therefore, it is very important to effectively suppress torque ripple caused by current commutation.
There are many methods for suppressing the torque ripple caused by current commutation, and the core of suppression is to try to reduce the electromagnetic torque ripple by controlling the current rising and falling rates of the motor winding of the brushless dc motor to be equal when the commutation, among which, the most common one is the Pulse Width Modulation (PWM) chopping method, and the principle of the method is: the switching device performs chopping with a certain frequency before switching off and after switching on, and controls the terminal voltage of the winding in the phase change process, so that the rising and falling rates of all commutation currents are equal, the change of the amplitude value of the total current is compensated, and the torque pulsation is suppressed. However, the existing PWM chopping method has the following disadvantages: the control efficiency is low, dead time needs to be added, the suppression of torque ripple is not obvious due to the fact that the dead time needs to be added, different duty ratios need to be calculated according to different PWM modulation modes, the detection method and the control algorithm are complex, the calculation difficulty is high, and the cost is high.
Disclosure of Invention
The present invention provides a method and a system for suppressing torque ripple of a brushless dc motor, which are directed to overcome the above-mentioned shortcomings in the prior art.
The technical scheme for solving the technical problems is as follows:
a suppression system of torque ripple of a brushless direct current motor comprises a voltage type inverter, a controller and a sampling circuit;
the voltage type inverter is used for controlling the three-phase on and off of the brushless direct current motor;
the sampling circuit is used for collecting three-phase current in the running process of the brushless direct current motor and sending the collected three-phase current to the controller;
the controller is used for receiving the three-phase current and Hall signals collected by a Hall sensor of the brushless direct current motor; and the brushless direct current motor is also used for judging whether the brushless direct current motor is in a phase change state or not according to the three-phase current and the Hall signal, when the judgment result is negative, the voltage type inverter is controlled by adopting a pairwise conduction control mode, and when the judgment result is positive, the voltage type inverter is controlled by adopting a pairwise conduction and three-to-three conduction switching control mode.
The invention has the beneficial effects that: the two-by-two conduction control mode means that the brushless direct current motor works in a 120-degree conduction mode, the working process of the brushless direct current motor can be divided into two sections, one section is a phase commutation section in which the conduction phase current is increased and the turn-off phase current is reduced, and each group of windings has current flowing through, and the other section is a non-phase commutation section; the three-three conduction control mode means that the brushless direct current motor works in a 180-degree conduction mode, namely, at each moment, current flows through the three-phase winding, and the upper and lower tubes of each phase of winding cannot be conducted simultaneously; the two-to-two conduction and three-to-three conduction switching control mode refers to a conduction mode in which the two-to-two conduction control mode and the three-to-three conduction control mode are switched with each other, for example, when the two-to-two conduction control mode is a conduction mode of an A-phase upper tube and a B-phase lower tube, the next step of switching the conduction mode of the A-phase upper tube and the conduction mode of a C-phase lower tube, when the two-to-three conduction switching control mode is adopted, a three-to-three conduction state is required to be inserted between the two states of the conduction mode of the A-phase upper tube and the conduction mode of the B-phase lower tube, namely the conduction mode of the A;
after the controller judges whether the brushless direct current motor is in a phase change state or not according to the Hall signal, if the brushless direct current motor is in a non-phase change state, the voltage type inverter is controlled by adopting a pairwise conduction control mode to realize the control of switching off and on each phase of the brushless direct current motor, and if the brushless direct current motor is in the phase change state, the voltage type inverter is controlled by adopting a pairwise conduction and three-to-three conduction switching control mode to realize the control of switching off and on each phase of the brushless direct current motor. The principle of the control mode is as follows: in the phase change stage, firstly, a control mode of two-to-two conduction is adopted, because the current existing in the inductor can not change suddenly under the condition of high-speed operation, the change rate of the off-phase current is higher than that of the on-phase current, the non-phase-change current inevitably has a falling trend and generates torque ripple, and when the non-phase-change current generates a falling trend, the control mode is switched to a three-to-three conduction control mode, and the off-phase in the three-to-three conduction is continuously conducted in the phase change stage, so that the change rate of the off-phase current can be reduced, and the change rate of the off-phase current is equal to that of the on-phase current, thereby inhibiting the generation of the torque ripple;
compared with the traditional closed-loop control, the suppression system has the advantages that only one switching tube changes in the phase change stage through the two-to-two conduction and three-to-three conduction switching control mode, so that the torque pulsation generated by the brushless direct current motor during phase change is effectively suppressed; and because two conduction control modes and three conduction control modes are mutually matched, a dead zone does not need to be set, the suppression effect of torque pulsation is better, the detection method and the control algorithm are simpler, the calculation difficulty is lower, the cost is lower, and the control efficiency is higher.
On the basis of the technical scheme, the invention can be further improved as follows:
further: three input ends of the sampling circuit are respectively and correspondingly electrically connected with a three-phase winding of the brushless direct current motor, and an output end of the sampling circuit is electrically connected with an input end of the controller; the sampling circuit is further specifically used for collecting three-phase stator terminal voltage in the operation process of the brushless direct current motor and sending the collected three-phase stator terminal voltage to the controller.
The beneficial effects of the further scheme are as follows: through the collected three-phase stator terminal voltage, the turn-off phase duty ratio of three-three conduction under the control mode of two-two conduction and three-three conduction switching is convenient to calculate according to the three-phase stator terminal voltage, PWM chopping is convenient to be carried out on the brushless direct current motor according to the turn-off phase duty ratio, and therefore a proper modulation signal is provided to effectively suppress torque pulsation generated by the brushless direct current motor in a phase change stage.
Further: the controller comprises an A/D conversion circuit, a calculation circuit, a phase change control circuit, a PI D control circuit and a PWM signal circuit;
the input end of the A/D conversion circuit is electrically connected with the output end of the sampling circuit and the Hall signal output end of the brushless direct current motor respectively, and the A/D conversion circuit is used for performing analog-to-digital conversion on the three-phase current, the three-phase stator end voltage and the Hall signal respectively;
the input end of the computing circuit is electrically connected with the output end of the A/D conversion circuit, the output end of the computing circuit is electrically connected with the input end of the PID control circuit and the input end of the commutation control circuit respectively, the computing circuit is used for computing the rotating speed of the brushless direct current motor according to the result of the Hall signal after analog-to-digital conversion, judging whether the brushless direct current motor is in a commutation state according to the rotating speed and the result of the three-phase current after analog-to-digital conversion, and taking the judgment result as the input of the commutation control circuit; the computing circuit is also used for computing the turn-off phase duty ratio of the brushless direct current motor in the three-three conduction process under the two-two conduction and three-three conduction switching control mode according to the result of analog-to-digital conversion of the three-phase current and the three-phase stator end voltage, and taking the turn-off phase duty ratio as the input of the PID control circuit;
the specific formula of the off-phase duty ratio is as follows:
d2for the off-phase duty cycle, UdcIs of the voltage typeVoltage at the DC input of the inverter, ex、eyAnd ezRespectively under the two-to-two conduction and three-to-three conduction switching control modes, calculating non-commutation opposite electromotive force, on-state opposite electromotive force and off-state opposite electromotive force according to the three-phase current and the three-phase stator terminal voltage, d and d1Respectively obtaining a non-commutation phase duty ratio and a switching-on phase duty ratio according to the three-phase current and the three-phase stator terminal voltage under the two-to-two conduction and three-to-three conduction switching control modes;
the input end of the commutation control circuit is electrically connected with the output end of the computing circuit, the output end of the commutation control circuit is electrically connected with the input end of the voltage type inverter, and the commutation control circuit is used for controlling the generation of commutation control signals corresponding to the voltage type inverter according to the judgment result of whether the brushless direct current motor is in a commutation state or not judged by the computing circuit;
the input end of the PID control circuit is electrically connected with the output end of the computing circuit, the output end of the PID control circuit is electrically connected with the input end of the PWM signal circuit, and the PID control circuit is used for controlling the generation of the PWM signal corresponding to the voltage type inverter according to the duty ratio;
the input end of the PWM signal circuit is electrically connected with the output end of the PID controller, the output end of the PWM signal circuit is electrically connected with the input end of the voltage type inverter, and the PWM signal circuit is used for modulating the three-phase full-bridge inverter according to the PWM signal.
The beneficial effects of the further scheme are as follows: the A/D conversion circuit is used for carrying out analog-to-digital conversion on the collected Hall signal, the three-phase current and the three-phase stator end voltage, so that a calculation circuit can calculate and judge whether the brushless direct current motor is in a phase change state or not and calculate the off-phase duty ratio, and therefore the corresponding phase change control signal and the input signal of the PID control circuit are obtained respectively; the commutation control of the voltage-type inverter and the control of the PWM signal are respectively realized by a commutation control circuit and a PID control circuit, for example, according to the Hall signal and the three-phase current converted by an A/D conversion circuitIf the phase-change state is judged after calculation by the calculation circuit, a pairwise conduction and triple conduction switching control mode corresponding to the current state is generated and sent to the phase-change control circuit to control the on and off of each corresponding phase, and meanwhile, the off-phase duty ratio D under the corresponding triple conduction is obtained after calculation by the calculation circuit according to the three-phase current and the three-phase stator terminal voltage converted by the A/D conversion circuit2The off-phase duty ratio is sent to a PI D control circuit to control the generation of a corresponding PWM signal, and the PWM signal circuit modulates a voltage type inverter by adopting the corresponding PWM signal, so that the torque pulsation in the phase commutation stage is effectively inhibited; the calculated off-phase duty ratio can enable the change rate of the off-phase current to be just equal to the change rate of the on-phase current, so that the situation of over-compensation is avoided while torque pulsation is inhibited, the off-phase duty ratio is suitable for all current common PWM modulation modes, different duty ratio calculation methods do not need to be switched according to different PWM modulation modes, and the calculation process is simplified.
Further: the phase-change protection circuit comprises a PWM signal circuit, a phase-change control circuit and a drive protection circuit, wherein the phase-change control circuit is used for controlling the phase-change of the PWM signal circuit, the phase-change control circuit is used for controlling the phase-change of the phase-change control circuit, and the drive protection circuit is used for protecting the phase-change control circuit.
The beneficial effects of the further scheme are as follows: the driving protection circuit has better electrical isolation performance, and can protect the voltage type inverter on the one hand and enhance the driving capability of the controller to the voltage type inverter on the other hand through the driving protection circuit.
Further: the three-terminal input end of the filter circuit is electrically connected with the three-phase winding corresponding to the brushless direct current motor, and the three-terminal output end of the filter circuit is electrically connected with the three-terminal input end of the sampling circuit and used for filtering the acquisition process of the sampling circuit.
The beneficial effects of the further scheme are as follows: the filtering circuit is used for filtering the sampling process, so that more accurate data such as Hall signals, three-phase current, three-phase stator terminal voltage and the like can be obtained, the calculation precision and the control algorithm precision are improved, and the torque pulsation is accurately inhibited.
Further: the brushless direct current motor is characterized by further comprising a power supply, wherein the power supply is used for providing direct current input end voltage for the voltage type inverter, the voltage type inverter is specifically a three-phase full-bridge inverter, the input end of the three-phase full-bridge inverter is respectively and electrically connected with the power supply and the output end of the controller, and three output ends of the three-phase full-bridge inverter are respectively and correspondingly and electrically connected with three-phase windings of the brushless direct current motor;
the three-phase full-bridge inverter comprises six switching tubes which are respectively a first switching tube VT1A second switching tube VT2And a third switching tube VT3And a fourth switching tube VT4The fifth switch tube VT5And a sixth switching tube VT6(ii) a The six switch tubes are all triodes, and a diode is reversely connected in parallel between a collector and an emitter of each switch tube; the first switch tube VT1And the fourth switching tube VT4A phase A connected to form the three-phase full-bridge inverter, and the first switching tube VT1Is an A phase tube, the fourth switch tube VT1Is phase A lower tube; the third switching tube VT3And the sixth switching tube VT6A B phase connected to form the three-phase full-bridge inverter, and a third switching tube VT3For phase B tubes, the sixth switching tube VT6Is a B phase lower tube; the fifth switching tube VT5And the second switching tube VT2A C phase connected to form the three-phase full-bridge inverter, and the fifth switching tube VT5Is a C phase tube, the second switch tube VT2Is C phase lower tube; the first switch tube VT1The third switching tube VT3And the fifth switching tube VT5And a collector electrode of the second switching tube VT is connected with the positive electrode of the power supply in a tandem manner2The fourth switching tube VT4And the sixth switching tube VT6OfThe emitter is connected in a junction manner, is electrically connected with the negative electrode of the power supply and then is grounded; and the first switching tube VT1And the fourth switching tube VT4After the collectors are connected together, the third switching tube VT3And the sixth switching tube VT6After the collector is connected in a junction manner, and the fifth switching tube VT5And the second switching tube VT2After the collectors are connected in a junction mode, the collectors are respectively gathered at the motor midpoint of the brushless direct current motor through a resistor and an inductor. The beneficial effects of the further scheme are as follows: through the three-phase full-bridge inverter adopting the connection mode, the on and off of each phase of the brushless direct current motor can be controlled conveniently according to the judgment result of the controller for judging whether the brushless direct current motor is in the phase change state, so that the torque pulsation of the brushless direct current motor in the phase change stage can be restrained conveniently, and the six switching tubes can also be MOS tubes.
According to another aspect of the present invention, there is provided a method for suppressing torque ripple of a brushless dc motor, which employs the system for suppressing torque ripple of a brushless dc motor of the present invention, including the steps of:
step 1: acquiring the Hall signal acquired by the Hall sensor in the brushless direct current motor and the three-phase current in the running process of the brushless direct current motor, and judging whether the brushless direct current motor is in a phase change state or not according to the Hall signal and the three-phase current, if not, entering step 2, and if so, entering step 3;
step 2: controlling the voltage type inverter by adopting the pairwise conduction control mode;
and step 3: and controlling the voltage type inverter by adopting a pairwise conduction and three-to-three conduction switching control mode.
The invention has the beneficial effects that: in the phase change stage, firstly, a control mode of two-to-two conduction is adopted, because the current existing in the inductor can not change suddenly under the condition of high-speed operation, the change rate of the off-phase current is higher than that of the on-phase current, the non-phase-change current inevitably has a falling trend and generates torque ripple, and when the non-phase-change current generates a falling trend, the control mode is switched to a three-to-three conduction control mode, and the off-phase in the three-to-three conduction is continuously conducted in the phase change stage, so that the change rate of the off-phase current can be reduced, and the change rate of the off-phase current is equal to that of the on-phase current, thereby inhibiting the generation of the torque ripple;
compared with the traditional closed-loop control, the suppression method has the advantages that only one switching tube changes in the phase change stage through the two-to-two conduction and three-to-three conduction switching control mode, and the torque pulsation generated by the brushless direct current motor during the phase change is effectively suppressed; and because two conduction control modes and three conduction control modes are mutually matched, a dead zone does not need to be set, the suppression effect of torque pulsation is better, the detection method and the control algorithm are simpler, the calculation difficulty is lower, the cost is lower, and the control efficiency is higher.
On the basis of the technical scheme, the invention can be further improved as follows:
further: in the step 1, judging whether the brushless dc motor is in a phase-change state according to the hall signal and the three-phase current specifically includes the following steps:
step 11: determining the rotor speed of the brushless direct current motor according to the Hall signal;
step 12: and judging whether the brushless direct current motor is in a phase change state or not according to the rotor rotating speed and the three-phase current.
The beneficial effects of the further scheme are as follows: because the Hall signals respectively comprise an on signal and an off signal, and the brushless direct current motor generally comprises three Hall sensors, six different Hall signals are provided, each Hall signal corresponds to the beginning of one phase change stage, one phase change stage is from the beginning of phase change to the end of phase change, and the off phase current is 0 when the phase change is finished; the rotor speed of the brushless direct current motor can be judged through the Hall signals, so that the position of the rotor of the motor is determined, and whether the phase change stage of the current state is finished or not and whether the phase change stage enters the next phase change stage or not can be judged by combining the position of the rotor of the motor in the current state and the phase current.
Further: in the step 1, a three-phase stator terminal voltage in the operation process of the brushless direct current motor is obtained.
The beneficial effects of the further scheme are as follows: the obtained three-phase stator terminal voltage is convenient for subsequent calculation of the turn-off phase duty ratio in the three-three conduction process in the two-two conduction and three-three conduction switching control mode, and the control of the voltage type inverter is conveniently realized according to the turn-off phase duty ratio to inhibit the torque pulsation of the brushless direct current motor.
Further: the step 3 specifically comprises the following steps:
step 31: calculating non-commutation opposite electromotive force, switching-on opposite electromotive force and switching-off opposite electromotive force of the brushless direct current motor in a pairwise conduction and triplex conduction switching control mode according to the three-phase stator terminal voltage and the three-phase current;
step 32: acquiring a non-commutation phase duty ratio and a switching phase duty ratio corresponding to the brushless direct current motor under the control mode of pairwise conduction and triplex conduction switching according to the three-phase current and the three-phase stator terminal voltage;
step 33: calculating a turn-off phase duty ratio in a three-three conduction process under the two-two conduction and three-three conduction switching control mode according to the non-commutation phase counter electromotive force, the turn-on phase counter electromotive force and the turn-off phase counter electromotive force, and the corresponding non-commutation phase duty ratio and the turn-on phase duty ratio;
the specific formula of the off-phase duty ratio is as follows:
d2for the off-phase duty cycle, UdcAt the DC input terminal voltage of the voltage-type inverter, exFor said non-commutation counter electromotive force, eyFor said switching on of counter electromotive force, ezD is the off-phase back EMF, d is the non-commutation phase duty cycle, d1Is the on-phase duty cycle;
step 34: and controlling the voltage type inverter according to the off-phase duty ratio.
The beneficial effects of the further scheme are as follows: the off-phase duty ratio calculated by the method for calculating the off-phase duty ratio is suitable for all current common PWM modulation modes, different duty ratio calculation methods do not need to be switched according to different PWM modulation modes, the calculation process is simplified, the change rate of the off-phase current is just equal to the change rate of the on-phase current, and the situation of over-compensation is avoided while torque pulsation is inhibited.
Drawings
Fig. 1 is a schematic structural diagram of a system for suppressing torque ripple of a brushless dc motor according to the present invention;
fig. 2 is a schematic structural diagram of a voltage-type inverter according to an embodiment of the invention;
FIG. 3 is a first schematic structural diagram of a system for suppressing torque ripple of a brushless DC motor according to the present invention;
FIG. 4 is a waveform diagram of Hall signals and three-phase current according to one embodiment of the present invention;
fig. 5 is a schematic diagram of driving of each switching tube in a two-to-two conduction and three-to-three conduction switching control manner according to an embodiment of the present invention;
fig. 6 is a schematic diagram of PWM signals of each phase in a two-to-two conduction and three-to-three conduction switching control manner according to an embodiment of the present invention;
FIG. 7 is a flow chart illustrating a method for suppressing torque ripple of a brushless DC motor according to the present invention;
FIG. 8 is a waveform diagram of non-commutation phase current and torque using conventional control in accordance with a second embodiment of the present invention;
FIG. 9 is a waveform diagram of non-commutation phase current and torque in the commutation phase by two-conduction and three-conduction switching control according to the second embodiment of the present invention;
FIG. 10 is a torque waveform diagram of a second embodiment of the present invention under a sudden load condition using a conventional control scheme;
fig. 11 is a torque waveform diagram of the second embodiment of the present invention adopting the two-to-two conduction and three-to-three conduction switching control method under the condition of sudden load.
In the drawings, the components represented by the respective reference numerals are listed below:
1. the device comprises a power supply, 2, a voltage-type inverter, 3, a brushless direct current motor, 4, a controller, 5, a sampling circuit, 6, a driving protection circuit, 7, a filter circuit, 41, an A/D conversion circuit, 42, a calculation circuit, 43, a commutation control circuit, 44, a PID control circuit, 45 and a PWM signal circuit.
Detailed Description
The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.
The present invention will be described with reference to the accompanying drawings.
In one embodiment, as shown in fig. 1, a system for suppressing torque ripple of a brushless dc motor includes a voltage-type inverter 2, a controller 4, and a sampling circuit 5;
the voltage type inverter 2 is used for controlling the on and off of each phase of the brushless direct current motor 3;
the sampling circuit 5 is configured to collect three-phase current in the operation process of the brushless dc motor 3, and send the collected three-phase current to the controller 4;
the controller 4 is configured to receive the three-phase current and a hall signal acquired by a hall sensor of the brushless dc motor 3; and the brushless direct current motor is also used for judging whether the brushless direct current motor 3 is in a phase change state or not according to the three-phase current and the Hall signal, when the judgment result is negative, the voltage type inverter is controlled by adopting a two-to-two conduction control mode, and when the judgment result is positive, the voltage type inverter is controlled by adopting a two-to-two conduction and three-to-three conduction switching control mode.
Specifically, as shown in fig. 2 and fig. 3, the brushless dc motor further includes a power supply 1, where the power supply 1 is configured to provide a dc input end voltage for the voltage-type inverter 2, the voltage-type inverter 2 is specifically a three-phase full-bridge inverter, an input end of the three-phase full-bridge inverter is electrically connected to the power supply 1 and an output end of the controller 4, respectively, and three output ends of the three-phase full-bridge inverter are electrically connected to three-phase windings of the brushless dc motor 3, respectively;
the three-phase full-bridge inverter 2 comprises six switching tubes which are respectively a first switching tube VT1A second switching tube VT2And a third switching tube VT3And a fourth switching tube VT4The fifth switch tube VT5And a sixth switching tube VT6(ii) a The six switch tubes are all triodes, and a diode is reversely connected in parallel between a collector and an emitter of each switch tube; the first switch tube VT1And the fourth switching tube VT4The A phase of the three-phase full-bridge inverter 2 is connected and formed, and the first switch tube VT1Is an A phase tube, the fourth switch tube VT1Is phase A lower tube; the third switching tube VT3And the sixth switching tube VT6The phase B of the three-phase full-bridge inverter 2 is connected and formed, and the third switching tube VT3For phase B tubes, the sixth switching tube VT6Is a B phase lower tube; the fifth switching tube VT5And the second switching tube VT2A C phase connected to form the three-phase full-bridge inverter 2, and the fifth switching tube VT5Is a C phase tube, the second switch tube VT2Is C phase lower tube; the first switch tube VT1The third switching tube VT3And the fifth switching tube VT5And the collector electrode of the second switching tube VT is connected with the positive electrode of the power supply 1 in a junction way and is electrically connected with the positive electrode of the power supply 12The fourth switching tube VT4And the sixth switching tube VT6The emitting electrodes of the power supply 1 are connected in a junction manner, are electrically connected with the negative electrode of the power supply 1 and then are grounded; and the first switching tube VT1And the fourth switching tube VT4After the collectors are connected together, the third switching tube VT3And the sixth switching tube VT6After the collector is connected in a junction manner, and the fifth switching tube VT5And the second switching tube VT2After the collectors are connected in a junction mode, the collectors are respectively gathered at the motor midpoint of the brushless direct current motor 3 through a resistor and an inductor.
In this embodiment, the three-phase full-bridge inverter 2 further includes a capacitor, one end of the capacitor is electrically connected to the positive electrode of the power supply 1, and the other end of the capacitor is electrically connected to the negative electrode of the power supply 1 and grounded.
In this embodiment, U in FIG. 2dcThe voltage at the DC input end of the three-phase full-bridge inverter of this embodiment is controlled by the switch tube VT1～VT6Completing electronic phase-change and inversion output, anti-parallel diode VD1-VD6Follow current, R, L and ea、eb、ecThe three-phase motor is characterized by comprising a motor equivalent resistor, an inductor and back electromotive force corresponding to a three-phase stator winding respectively, wherein a star-shaped connection point n of the three-phase winding is a motor midpoint, and g is a direct-current bus voltage ground.
Preferably, three input ends of the sampling circuit 5 are respectively and electrically connected with three-phase windings of the brushless dc motor 3, and an output end is electrically connected with an input end of the controller 4; the sampling circuit 5 is further specifically configured to collect three-phase stator terminal voltages during an operation process of the brushless dc motor 3, and send the collected three-phase stator terminal voltages to the controller 4.
The voltages of the three-phase stator terminals collected in the embodiment are respectively ua、ub、ucThree phase currents are ia、ib、icIn the present embodiment equal to the three-phase stator current. The mathematical equivalent model of the brushless dc motor obtained according to fig. 2 is:
wherein u isnAnd p is a differential operator for the motor midpoint voltage.
Specifically, as shown in fig. 3, the controller 4 includes an a/D conversion circuit 41, a calculation circuit 42, a commutation control circuit 43, a PID control circuit 44, and a PWM signal circuit 45; the input end of the a/D conversion circuit 41 is electrically connected with the output end of the sampling circuit 5 and the hall signal output end of the brushless dc motor 3, respectively; the input end of the computing circuit 42 is electrically connected with the output end of the a/D conversion circuit 41, and the output end of the computing circuit 42 is electrically connected with the input end of the PID control circuit 44 and the input end of the commutation control circuit 43 respectively; the input end of the commutation control circuit 43 is electrically connected with the output end of the computing circuit 42, and the output end of the commutation control circuit 43 is electrically connected with the input end of the three-phase full-bridge inverter; the input end of the PID control circuit 44 is electrically connected with the output end of the computing circuit 42, and the output end of the PID control circuit 44 is electrically connected with the input end of the PWM signal circuit 45; the input end of the PWM signal circuit 45 is electrically connected to the output end of the PID controller 44, and the output end of the PWM signal circuit 45 is electrically connected to the input end of the three-phase full-bridge inverter.
The controller of the embodiment adopts a DSP chip dsPIC30F6010 manufactured by Microchip company, and is mainly used for calculating the current speed of the motor, generating a PWM signal, generating a commutation control signal and the like. The voltage sensor and the current sensor are used for respectively detecting the voltage of a three-phase stator end and the phase current of a three-phase stator of the motor, three Hall signals detected by the Hall sensors can be used for calculating the current rotor rotating speed of the motor, and the three Hall signals are sent to the controller to obtain a phase change control signal of the three-phase full-bridge inverter. The three-phase stator terminal voltage and the three-phase current are used for calculating different duty ratios required by the motor at the current rotor rotating speed, so that the functions of controlling the motor to operate and inhibiting torque pulsation are achieved.
In this embodiment, whether the brushless dc motor is in the phase-change state is determined according to the hall signal and the three-phase current, and a specific waveform diagram is shown in fig. 4. When the brushless DC motor is judged to be in a phase-change state, a two-to-two conduction and three-to-three conduction switching control mode is adopted, taking A + B-to-A + C-as an example under a PWM-ON modulation mode, and a three-to-three conduction control mode of A + B-C-is inserted in a phase-change stage, wherein A + represents conduction of a tube ON the A phase, namely a first switching tube VT1Conduction, B-represents conduction of the B-phase lower tube, i.e. the sixth switching tube VT6And so on, for convenience of description, the switching tube and the diode of the present embodiment will be directly indicated by the letter of each switching tube.
When the phase change starts, a control method of two-to-two conduction is adopted, and the tube VT is arranged under the B phase6Cut off, the current passes through VD3Freewheeling by neglecting the voltage drop of the diode, thisTime ua＝Udc，ub＝UdcC phase lower tube VT2Switching on and chopping. During chopping, if VT2Duty cycle of the tube
Current passing VT2To the negative terminal of the power supply, u c0; if VT2Duty cycle of the tube
Current passing through VD2Follow current at this time uc＝UdcIn conclusion, the following results
(
Is VT2Duty cycle of the tube). The three-point potentials of a, b and c are substituted into an equivalent mathematical model of the brushless direct current motor to obtain:
finishing to obtain:
the time corresponding to one PWM period is TsThen, the torque variation in one PWM period is:
wherein, Δ Pe＝eaΔia+ebΔib+ecΔic，ωmThe rotor speed of the brushless DC motor.
Due to VT2Duty ratio of tube is not less than 0 and not more than dVT2When the value is less than or equal to 1, obtaining the delta TeThe range of (A):
when the motor is operating at high speed, let 2ea-eb-ecThe variation interval within the commutation interval is [ e ]min,emax]Within this interval ea＞0、eb< 0 and ec< 0, from which 0 < emin＜emax. Since the back electromotive force is proportional to the motor speed, U isdc＜eminMust have Udc＜2ea-eb-ecThe following can be obtained:
2(eaeb+eaec+eceb-ea 2-eb 2-ec 2)+(ea+eb-2ec)Udc＜
2(eaeb+eaec+eceb-ea 2-eb 2-ec 2)+(ea+eb-2ec)(2ea-eb-ec)＝3(ec-eb)(eb-ea)；
due to e in the commutation intervalc≤eb＜0＜eaObtaining 3 (e)c-eb)(eb-ea) Is 0, then:
2(eaeb+eaec+eceb-ea 2-eb 2-ec 2)+(ea+eb-2ec)Udc＜0；
get Delta TeLess than 0; in the case of high-speed operation of the motor, the two-two conduction inevitably generates torque pulsation, and the torque tends to be reduced.
When the generated torque is in a descending trend, the mode is switched to a three-three conduction control mode, the conduction mode of each tube is A + B-C-, and the potentials of the three points a, B and C are respectively ua＝Udc，ub＝0，ucAnd (5) similarly substituting the equivalent mathematical model of the brushless direct current motor into 0 to obtain:
finishing to obtain:
the torque variation in one PWM period at this time is:
similarly, it is calculated that Δ T 'when the mode of opening is A + B-C'eIf the motor runs at high speed, the three-three conduction state can generate rising torque pulsation. Therefore, during the phase change, the torque drop generated by two-to-three conduction can be restrained by inserting the proper three-to-three conduction, and the torque pulsation generated during the phase change can be reduced.
The driving of each switch tube under the two-to-two conduction and three-to-three conduction switching control manner in this embodiment is shown in fig. 5, wherein the dotted line corresponds to the two-to-two conduction and three-to-three conduction switching process, VT1The tubes being non-phase-shifting, VT2Tube open phase, VT6The tube is in a turn-off phase; in the two-to-two conduction and three-to-three conduction switching control modes, the on phase and the off phase both adopt a PWM (pulse-width modulation) mode, and the modulation duty ratio of the off phase is smaller than that of the on phase. In order to ensure the stability of the control, the PWM signals of the on-phase and the off-phase are generated by using the same carrier wave with the amplitude D, as shown in fig. 6, the non-inverting phase VT1 is normally on, and the on-phase VT is6The tube is chopped and given an amplitude of D1Comparing the modulated wave with the carrier wave to obtain VT6Turn-off phase VT2The tube is also chopped and given an amplitude D2Comparing the modulated wave with the carrier wave to obtain VT2And all drive signals of the three-phase drive circuit are controlled by a PWM signal circuitA full bridge inverter.
Therefore, one PWM period T of the control mode is switched between two conduction modes and three conduction modessThree switching tube switching-on modes are provided, only one switching tube is switched on A +, two switching tubes are simultaneously switched on A + C-, and three switching tubes are simultaneously switched on A + B-C-, so that the non-commutation phase VT1The rate of change of current for the tube in these three cases is:
in a PWM period TsNon-commutation phase VT under three opening modes of internal, A + C-and A + B-C-1The tube is applied for a time of (1-d)1)Ts、(d1-d2)TsAnd d2TsWherein d is1Duty ratio of on phase, d2Substituting into the non-commutation phase VT under the three turn-on modes for the duty ratio of the turn-off phase1In the current change rate corresponding to the tube, the current change amount corresponding to one PWM period is obtained as follows:
in order to effectively suppress torque ripple, if the current change rates of the on-phase and the off-phase must be equal to each other, the following are necessary:
Δi＝Δia1+Δia2+Δia3＝0
the calculation of the equation set of the simultaneous current variation obtains that the off-phase duty ratio of the three-three conduction stage in the two-two conduction and three-three conduction switching control mode in the embodiment is as follows:
because the brushless direct current motor has six commutation processes in one electric cycle, in the PWM-ON modulation mode, only the ON-phase, the off-phase and the non-commutation phase in the six commutation processes are different, and the other five commutation processes are equivalent to the commutation process of this embodiment, so the off-phase duty ratio of the three-conduction stage can be generalized in the whole electric cycle, and the off-phase duty ratio of the three-conduction stage in the whole electric cycle is obtained as follows:
wherein e isx、eyAnd ezRespectively a non-commutation counter electromotive force, an on counter electromotive force and an off counter electromotive force.
In this embodiment, a PWM-ON modulation method is taken as an example, and the brushless dc motor control system further includes four modulation methods, i.e., ON-PWM, HPWM-L _ ON, H _ ON-L _ PWM and H _ PWM-L _ PWM, and the five PWM modulation methods are different in that:
1. h _ PWM-L _ PWM: the upper and lower bridge arm switch tubes are both subjected to PWM signal modulation (the two-phase switch tubes are conducted and simultaneously subjected to PWM modulation);
2. ON-PWM: during the period of 120 degrees of conduction of the switching tubes, the front 60-degree electrical angle of each tube is kept constant, and the rear 60-degree electrical angle is subjected to PWM signal modulation;
3. PWM-ON: PWM signal modulation is carried out on the front 60-degree electrical angle of each tube, and the rear 60-degree electrical angle is kept constant;
4. HPWM-L _ ON: the upper bridge arm switching tube is modulated by a PWM signal, and the lower bridge arm switching tube is kept in constant connection;
5. h _ ON-L _ PWM: the upper bridge arm switching tube is kept constant, and the lower bridge arm switching tube carries out PWM signal modulation.
Assuming that the duty ratio of the non-commutation phase is d, and the non-commutation phase duty ratio d of the three-three conduction phases in the case of the PWM-ON modulation method of this embodiment is 1, the off-phase duty ratio
Can be expressed as:
under the ON-PWM modulation mode, the off-phase duty ratio at three ON-phases can be obtained by the same method of this embodiment as follows:
ON-phase duty ratio d in ON-PWM modulation mode1When the duty ratio of the off phase in the three-three on phase is 1:
similarly, the off-phase duty ratios of the three on-phases in the other modulation modes can be obtained:
therefore, under different modulation modes of the brushless DC motor, the same formula can be used
Compared with the traditional closed-loop control, the suppression system of the embodiment suppresses the torque pulsation generated by the brushless direct current motor during phase commutation by switching control modes of two-to-two conduction and three-to-three conduction in the phase commutation stage; in the switching system, due to the mutual matching of two-to-two conduction and three-to-three conduction, no dead zone needs to be set; for the calculation mode of the off-phase duty ratio in the three-three conduction, the change rate of the off-phase current can be just equal to that of the on-phase current, so that the over-compensation condition is avoided while the torque ripple is inhibited, the method is suitable for all the current common PWM modulation modes, different duty ratio calculation methods do not need to be switched according to different PWM modulation modes, and the calculation process is simplified; the algorithm has less calculation process and low calculation difficulty, and can ensure the real-time performance of motor control to a great extent.
Preferably, as shown in fig. 3, the inverter further includes a driving protection circuit 6, an input end of the driving protection circuit 6 is electrically connected to an output end of the PWM signal circuit 45 and an output end of the commutation control circuit 43, an output end of the driving protection circuit 6 is electrically connected to an input end of the three-phase full-bridge inverter, and the driving protection circuit 6 is configured to protect the three-phase full-bridge inverter according to the PWM signal and the commutation control signal.
The drive protection circuit has better electrical isolation performance, through the drive protection circuit, can protect the three-phase full-bridge inverter on the one hand, and on the other hand can also strengthen the driving capability of the controller to the three-phase full-bridge inverter, and the ACPL-33XJ series drive optocoupler of AVAGO can be selected for use to the drive protection circuit of this embodiment.
Preferably, the system further comprises a filter circuit 7, three-terminal input ends of the filter circuit 7 are respectively and electrically connected with three-phase windings corresponding to the brushless dc motor 3, and three-terminal output ends of the filter circuit 7 are respectively and electrically connected with three-terminal input ends of the sampling circuit 5, and are used for performing filtering processing on the acquisition process of the sampling circuit 5.
The filtering circuit is used for filtering the sampling process, so that more accurate data such as Hall signals, three-phase current, three-phase stator terminal voltage and the like can be obtained, the calculation precision and the control algorithm precision are improved, and the torque pulsation is accurately inhibited.
In a second embodiment, as shown in fig. 7, a method for suppressing torque ripple of a brushless dc motor, which employs the system for suppressing torque ripple of a brushless dc motor according to the present invention, includes the following steps:
s1: acquiring the Hall signal acquired by the Hall sensor in the brushless direct current motor and the three-phase current in the running process of the brushless direct current motor, and judging whether the brushless direct current motor is in a phase change state or not according to the Hall signal and the three-phase current, if not, entering S2, and if so, entering S3;
s2: controlling the voltage type inverter by adopting the pairwise conduction control mode;
s3: and controlling the voltage type inverter by adopting a pairwise conduction and three-to-three conduction switching control mode.
In the phase change stage, firstly, a control mode of two-to-two conduction is adopted, because the current existing in the inductor can not change suddenly under the condition of high-speed operation, the change rate of the off-phase current is higher than that of the on-phase current, the non-phase-change current inevitably has a falling trend and generates torque ripple, and when the non-phase-change current generates a falling trend, the control mode is switched to a three-to-three conduction control mode, and the off-phase in the three-to-three conduction is continuously conducted in the phase change stage, so that the change rate of the off-phase current can be reduced, and the change rate of the off-phase current is equal to that of the on-phase current, thereby inhibiting the generation of the torque ripple;
compared with the traditional closed-loop control, the suppression method has the advantages that only one switching tube changes in the phase change stage through the two-to-two conduction and three-to-three conduction switching control mode, and the torque pulsation generated by the brushless direct current motor during the phase change is effectively suppressed; and because two conduction control modes and three conduction control modes are mutually matched, a dead zone does not need to be set, the suppression effect of torque pulsation is better, the detection method and the control algorithm are simpler, the calculation difficulty is lower, the cost is lower, and the control efficiency is higher.
Preferably, in S1, the step of determining whether the brushless dc motor is in the phase-change state according to the hall signal and the three-phase current specifically includes the steps of:
s11: determining the rotor speed of the brushless direct current motor according to the Hall signal;
s12: and judging whether the brushless direct current motor is in a phase change state or not according to the rotor rotating speed and the three-phase current.
Because the Hall signals respectively comprise an on signal and an off signal, and the brushless direct current motor generally comprises three Hall sensors, six different Hall signals are provided, each Hall signal corresponds to the beginning of one phase change stage, one phase change stage is from the beginning of phase change to the end of phase change, and the off phase current is 0 when the phase change is finished; the rotor speed of the brushless direct current motor can be judged through the Hall signals, so that the position of the rotor of the motor is determined, and whether the phase change stage of the current state is finished or not and whether the phase change stage enters the next phase change stage or not can be judged by combining the position of the rotor of the motor in the current state and the phase current.
Preferably, in S1, the method further includes acquiring terminal voltages of the three-phase stator during the operation of the brushless dc motor.
The obtained three-phase stator terminal voltage is convenient for subsequent calculation of the turn-off phase duty ratio in the three-three conduction process in the two-two conduction and three-three conduction switching control mode, and the control of the three-phase full-bridge inverter is conveniently realized according to the turn-off phase duty ratio to inhibit the torque pulsation of the brushless direct current motor.
Preferably, S3 specifically includes the following steps:
s31: calculating non-commutation opposite electromotive force, switching-on opposite electromotive force and switching-off opposite electromotive force of the brushless direct current motor in a pairwise conduction and triplex conduction switching control mode according to the three-phase stator terminal voltage and the three-phase current;
s32: acquiring a non-commutation phase duty ratio and a switching phase duty ratio corresponding to the brushless direct current motor under the control mode of pairwise conduction and triplex conduction switching according to the three-phase current and the three-phase stator terminal voltage;
s33: calculating a turn-off phase duty ratio in a three-three conduction process under the two-two conduction and three-three conduction switching control mode according to the non-commutation phase counter electromotive force, the turn-on phase counter electromotive force and the turn-off phase counter electromotive force, and the corresponding non-commutation phase duty ratio and the turn-on phase duty ratio;
the specific formula of the off-phase duty ratio is as follows:
d2for the off-phase duty cycle, UdcIs the voltage of the DC power supply, exFor said non-commutation counter electromotive force, eyFor said switching on of counter electromotive force, ezFor said switching off to reverse motoringPotential, d is the non-commutation phase duty cycle, d1Is the on-phase duty cycle;
s34: and controlling the voltage type inverter according to the off-phase duty ratio.
The off-phase duty ratio calculated by the method for calculating the off-phase duty ratio is suitable for all current common PWM modulation modes, different duty ratio calculation methods do not need to be switched according to different PWM modulation modes, the calculation process is simplified, the change rate of the off-phase current is just equal to the change rate of the on-phase current, and the situation of over-compensation is avoided while torque pulsation is inhibited.
The parameters of the brushless dc motor selected in this embodiment are: the stator resistance R is 2.875 omega, the stator self-inductance L is 8.5mH, the mutual inductance between the stators is 1.6mH, the number of pole pairs of the motor is 5, the switching frequency is 20kHz, and the rotor rotating speed omega ismAt 2300r/min, the load is 8Nm, wherein the specific modulation method adopts the modulation method described in the first embodiment, refer to the detailed description of the first embodiment and fig. 1 to 6, and will not be described herein again.
The waveforms of the non-commutation phase current and the torque under the condition of entering the steady-state operation are shown in fig. 8 and 9, respectively, under the conventional control manner and the suppression method of the present embodiment, respectively. Comparing fig. 8 and fig. 9, it can be seen that the non-commutation phase current is more stable in the phase-change phase by using the two-conduction and three-conduction switching control method of the present embodiment; and the peak value difference of the torque under the traditional control mode is 3.98Nm, while the peak value difference of the torque under the two-two conduction and three-three conduction switching control mode is 2.32Nm, and the torque ripple is reduced by 41.7 percent compared with the torque ripple under the traditional control mode.
In this embodiment, under the no-load operation at the given rotation speed 2300r/mi n, a load of 8Nm is applied, and the conventional control method and the suppression method of this embodiment are respectively adopted to control, and the obtained torque waveforms are respectively shown in fig. 10 and fig. 11. Comparing fig. 10 and fig. 11, it can be seen that, for the case of sudden load, the two-conduction and three-conduction switching control method of the present embodiment is adopted in the phase-change stage, and the torque fluctuation is significantly lower than that of the conventional control method.
Therefore, the embodiment has good dynamic performance and static performance under the condition of adopting a two-to-two conduction and three-to-three conduction switching control mode in the phase change stage, can effectively inhibit torque pulsation in the phase change stage, and has high operation precision.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (6)
1. The suppression system of the torque ripple of the brushless direct current motor is characterized by comprising a voltage type inverter (2), a controller (4) and a sampling circuit (5);
the voltage type inverter (2) is used for controlling the three-phase on and off of the brushless direct current motor (3);
the sampling circuit (5) is used for acquiring three-phase current in the running process of the brushless direct current motor (3) and sending the acquired three-phase current to the controller (4);
the controller (4) is used for receiving the three-phase current and Hall signals collected by a Hall sensor of the brushless direct current motor (3); the brushless direct current motor is also used for judging whether the brushless direct current motor (3) is in a phase change state or not according to the three-phase current and the Hall signal, when the judgment result is negative, the voltage type inverter (2) is controlled by adopting a pairwise conduction control mode, and when the judgment result is positive, the voltage type inverter (2) is controlled by adopting a pairwise conduction and three-to-three conduction switching control mode;
three input ends of the sampling circuit (5) are respectively and correspondingly electrically connected with a three-phase winding of the brushless direct current motor (3), and an output end of the sampling circuit is electrically connected with an input end of the controller (4); the sampling circuit (5) is further specifically used for collecting three-phase stator terminal voltage in the operation process of the brushless direct current motor (3) and sending the collected three-phase stator terminal voltage to the controller (4);
the controller (4) comprises an A/D conversion circuit (41), a calculation circuit (42), a commutation control circuit (43), a PID control circuit (44) and a PWM signal circuit (45);
the input end of the A/D conversion circuit (41) is respectively and electrically connected with the output end of the sampling circuit (5) and the Hall signal output end of the brushless direct current motor (3), and the A/D conversion circuit (41) is used for respectively carrying out analog-to-digital conversion on the three-phase current, the three-phase stator end voltage and the Hall signal;
the input end of the computing circuit (42) is electrically connected with the output end of the A/D conversion circuit (41), the output end of the computing circuit (42) is respectively electrically connected with the input end of the PID control circuit (44) and the input end of the commutation control circuit (43), the computing circuit (42) is used for computing the rotating speed of the brushless direct current motor (3) according to the result of the Hall signal after analog-to-digital conversion, judging whether the brushless direct current motor (3) is in a commutation state according to the rotating speed and the result of the three-phase current after analog-to-digital conversion, and taking the judgment result as the input of the commutation control circuit (43); the calculation circuit (42) is further configured to calculate, according to a result of analog-to-digital conversion performed on the three-phase current and the three-phase stator terminal voltage, an off-phase duty ratio of the brushless dc motor (3) in a three-to-three switching process in the two-to-two switching control mode and the three-to-three switching control mode, and use the off-phase duty ratio as an input of the PID control circuit (44);
the specific formula of the off-phase duty ratio is as follows:
d2for the off-phase duty cycle, UdcIs the voltage at the DC input of the voltage-type inverter (2), ex、eyAnd ezRespectively under the two-to-two conduction and three-to-three conduction switching control modes, calculating non-commutation opposite electromotive force, on-state opposite electromotive force and off-state opposite electromotive force according to the three-phase current and the three-phase stator terminal voltage, d and d1Under the control mode of switching between the two-phase conduction mode and the three-phase conduction mode respectively, according to the three-phase current and the three-phase currentAcquiring a non-commutation phase duty ratio and a switching-on phase duty ratio at the voltage of the three-phase stator terminal;
the input end of the commutation control circuit (43) is electrically connected with the output end of the computing circuit (42), the output end of the commutation control circuit (43) is electrically connected with the input end of the voltage-type inverter (2), and the commutation control circuit (43) is used for controlling the generation of commutation control signals corresponding to the voltage-type inverter (2) according to the judgment result that whether the brushless direct current motor (3) is in a commutation state or not by the computing circuit (42);
the input end of the PID control circuit (44) is electrically connected with the output end of the computing circuit (42), the output end of the PID control circuit (44) is electrically connected with the input end of the PWM signal circuit (45), and the PID control circuit (44) is used for controlling the generation of the PWM signal corresponding to the voltage-type inverter (2) according to the duty ratio;
the input end of the PWM signal circuit (45) is electrically connected with the output end of the PID controller (44), the output end of the PWM signal circuit (45) is electrically connected with the input end of the voltage type inverter (2), and the PWM signal circuit (45) is used for modulating the voltage type inverter (2) according to the PWM signal.
2. The suppression system of torque ripple of brushless dc motor according to claim 1, further comprising a driving protection circuit (6), wherein an input terminal of the driving protection circuit (6) is electrically connected to the output terminal of the PWM signal circuit (45) and the output terminal of the commutation control circuit (43), respectively, an output terminal of the driving protection circuit (6) is electrically connected to an input terminal of the voltage-type inverter (2), and the driving protection circuit (6) is configured to protect the voltage-type inverter (2) according to the PWM signal and the commutation control signal.
3. The suppression system for the torque ripple of the brushless dc motor according to claim 1, further comprising a filter circuit (7), wherein three-terminal input terminals of the filter circuit (7) are electrically connected to the corresponding three-phase windings of the brushless dc motor (3), respectively, and three-terminal output terminals of the filter circuit (7) are electrically connected to three-terminal input terminals of the sampling circuit (5), respectively, for performing a filtering process on the acquisition process of the sampling circuit (5).
4. The suppression system of torque ripple of brushless dc motor according to any one of claims 1-3, further comprising a power supply (1), wherein the power supply (1) is configured to provide dc input voltage to the voltage-type inverter (2), the voltage-type inverter (2) is specifically a three-phase full-bridge inverter, the input of the three-phase full-bridge inverter is electrically connected to the power supply (1) and the output of the controller (4), and the three outputs of the three-phase full-bridge inverter are electrically connected to the three-phase windings of the brushless dc motor (3);
the three-phase full-bridge inverter comprises six switching tubes which are respectively a first switching tube VT1A second switching tube VT2And a third switching tube VT3And a fourth switching tube VT4The fifth switch tube VT5And a sixth switching tube VT6(ii) a The six switch tubes are all triodes, and a diode is reversely connected in parallel between a collector and an emitter of each switch tube; the first switch tube VT1And the fourth switching tube VT4A phase A connected to form the three-phase full-bridge inverter, and the first switching tube VT1Is an A phase tube, the fourth switch tube VT1Is phase A lower tube; the third switching tube VT3And the sixth switching tube VT6A B phase connected to form the three-phase full-bridge inverter, and a third switching tube VT3For phase B tubes, the sixth switching tube VT6Is a B phase lower tube; the fifth switching tube VT5And the second switching tube VT2A C phase connected to form the three-phase full-bridge inverter, and the fifth switching tube VT5Is a C phase tube, the second switch tube VT2Is C phase lower tube; the first switch tube VT1The third switching tube VT3And the fifth switching tube VT5And the collector electrode of the second switching tube VT is connected with the positive electrode of the power supply (1) in a junction way and is electrically connected with the positive electrode of the power supply (1)2The fourth switch tube VT4And the sixth switching tube VT6The emitter of the power supply is connected in a junction way, is electrically connected with the cathode of the power supply (1) and then is grounded; and the first switching tube VT1And the fourth switching tube VT4After the collectors are connected together, the third switching tube VT3And the sixth switching tube VT6After the collector is connected in a junction manner, and the fifth switching tube VT5And the second switching tube VT2After the collectors are connected in a junction mode, the collectors are respectively gathered at the motor midpoint of the brushless direct current motor (3) through a resistor and an inductor.
5. A method for suppressing torque ripple of a brushless dc motor, which employs the system for suppressing torque ripple of a brushless dc motor according to any one of claims 1 to 4, comprising the steps of:
step 1: acquiring the Hall signal acquired by the Hall sensor in the brushless direct current motor and the three-phase current in the running process of the brushless direct current motor, and judging whether the brushless direct current motor is in a phase change state or not according to the Hall signal and the three-phase current, if not, entering step 2, and if so, entering step 3;
step 2: controlling the voltage type inverter by adopting the pairwise conduction control mode;
and step 3: controlling the voltage type inverter by adopting the two-to-two conduction and three-to-three conduction switching control mode;
in the step 1, a three-phase stator terminal voltage in the running process of the brushless direct current motor is obtained;
the step 3 specifically comprises the following steps:
step 31: calculating non-commutation opposite electromotive force, switching-on opposite electromotive force and switching-off opposite electromotive force of the brushless direct current motor in a pairwise conduction and triplex conduction switching control mode according to the three-phase stator terminal voltage and the three-phase current;
step 32: acquiring a non-commutation phase duty ratio and a switching phase duty ratio corresponding to the brushless direct current motor under the control mode of pairwise conduction and triplex conduction switching according to the three-phase current and the three-phase stator terminal voltage;
step 33: calculating a turn-off phase duty ratio in a three-three conduction process under the two-two conduction and three-three conduction switching control mode according to the non-commutation phase counter electromotive force, the turn-on phase counter electromotive force and the turn-off phase counter electromotive force, and the corresponding non-commutation phase duty ratio and the turn-on phase duty ratio;
the specific formula of the off-phase duty ratio is as follows:
d2for the off-phase duty cycle, UdcAt the DC input terminal voltage of the voltage-type inverter, exFor said non-commutation counter electromotive force, eyFor said switching on of counter electromotive force, ezD is the off-phase back EMF, d is the non-commutation phase duty cycle, d1Is the on-phase duty cycle;
step 34: and controlling the voltage type inverter according to the off-phase duty ratio.
6. The method for suppressing torque ripple of a brushless dc motor according to claim 5, wherein in the step 1, determining whether the brushless dc motor is in a phase-change state according to the hall signal and the three-phase current specifically includes:
step 11: determining the rotor speed of the brushless direct current motor according to the Hall signal;
step 12: and judging whether the brushless direct current motor is in a phase change state or not according to the rotor rotating speed and the three-phase current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811625292.2A CN109713949B (en) | 2018-12-28 | 2018-12-28 | Method and system for suppressing torque ripple of brushless direct current motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811625292.2A CN109713949B (en) | 2018-12-28 | 2018-12-28 | Method and system for suppressing torque ripple of brushless direct current motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109713949A CN109713949A (en) | 2019-05-03 |
| CN109713949B true CN109713949B (en) | 2020-05-22 |
Family
ID=66258143
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811625292.2A Active CN109713949B (en) | 2018-12-28 | 2018-12-28 | Method and system for suppressing torque ripple of brushless direct current motor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109713949B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113014155B (en) * | 2019-12-18 | 2023-01-24 | 珠海格力电器股份有限公司 | Motor control method and device, motor controller and motor |
| CN115603633B (en) * | 2021-07-09 | 2024-01-19 | 南京泉峰科技有限公司 | Electric tool and control method thereof |
| CN114006556A (en) * | 2021-11-04 | 2022-02-01 | 江苏科技大学 | Control system for reducing square wave operation torque pulsation of brushless direct current motor |
| CN114362603A (en) * | 2021-11-09 | 2022-04-15 | 江苏科技大学 | Control method for suppressing starting torque pulsation of brushless direct current motor |
| CN114244197A (en) * | 2021-11-18 | 2022-03-25 | 江苏科技大学 | Brushless direct current motor dual-mode control low-noise operation control method and system |
| WO2023124865A1 (en) * | 2021-12-27 | 2023-07-06 | 南京泉峰科技有限公司 | Electric tool and control method therefor |
| CN114070137B (en) * | 2022-01-17 | 2022-04-29 | 浙江大学 | Electric tricycle motor commutation torque ripple suppression system |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102025305A (en) * | 2010-12-07 | 2011-04-20 | 南京邮电大学 | Hall phase sequence detecting method and device of brushless direct-current motor |
| CN103078570A (en) * | 2013-02-04 | 2013-05-01 | 上海理工大学 | Torque pulsation restraining system and method of permanent magnet brushless direct current motor |
| CN203135771U (en) * | 2012-12-28 | 2013-08-14 | 重庆川仪自动化股份有限公司 | Three-to-three conduction brushless direct-current motor control system |
| CN103501146A (en) * | 2013-10-17 | 2014-01-08 | 中南林业科技大学 | Commutation torque ripple restraining method and system for brushless DC (Direct Current) motor driving system |
| JP2014087078A (en) * | 2012-10-19 | 2014-05-12 | Panasonic Corp | Motor drive unit and refrigerator using the same |
| CN106533275A (en) * | 2016-12-01 | 2017-03-22 | 西北工业大学 | Control method for suppressing commutation torque ripple of brushless DC motor |
| CN106602941A (en) * | 2016-12-06 | 2017-04-26 | 南京邮电大学 | Control device and method for reducing commutation torque ripple of brushless direct-current motor |
| CN106655911A (en) * | 2016-09-30 | 2017-05-10 | 天津大学 | PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of brushless DC motor |
| CN106712599A (en) * | 2017-01-23 | 2017-05-24 | 哈尔滨工程大学 | Commutation torque ripple suppression device and suppression method for brushless DC motor |
| CN107070317A (en) * | 2017-04-28 | 2017-08-18 | 燕山大学 | A kind of brshless DC motor PWM method based on two or three mixing conductings |
| CN107070318A (en) * | 2017-05-09 | 2017-08-18 | 天津大学 | A kind of harmonic analysis method of permanent-magnet brushless DC electric machine commutation torque ripple |
| CN107171605A (en) * | 2017-05-19 | 2017-09-15 | 燕山大学 | A kind of conductings of BLDCM bis- or two and three or three conducting switching methods |
-
2018
- 2018-12-28 CN CN201811625292.2A patent/CN109713949B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102025305A (en) * | 2010-12-07 | 2011-04-20 | 南京邮电大学 | Hall phase sequence detecting method and device of brushless direct-current motor |
| JP2014087078A (en) * | 2012-10-19 | 2014-05-12 | Panasonic Corp | Motor drive unit and refrigerator using the same |
| CN203135771U (en) * | 2012-12-28 | 2013-08-14 | 重庆川仪自动化股份有限公司 | Three-to-three conduction brushless direct-current motor control system |
| CN103078570A (en) * | 2013-02-04 | 2013-05-01 | 上海理工大学 | Torque pulsation restraining system and method of permanent magnet brushless direct current motor |
| CN103501146A (en) * | 2013-10-17 | 2014-01-08 | 中南林业科技大学 | Commutation torque ripple restraining method and system for brushless DC (Direct Current) motor driving system |
| CN106655911A (en) * | 2016-09-30 | 2017-05-10 | 天津大学 | PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of brushless DC motor |
| CN106533275A (en) * | 2016-12-01 | 2017-03-22 | 西北工业大学 | Control method for suppressing commutation torque ripple of brushless DC motor |
| CN106602941A (en) * | 2016-12-06 | 2017-04-26 | 南京邮电大学 | Control device and method for reducing commutation torque ripple of brushless direct-current motor |
| CN106712599A (en) * | 2017-01-23 | 2017-05-24 | 哈尔滨工程大学 | Commutation torque ripple suppression device and suppression method for brushless DC motor |
| CN107070317A (en) * | 2017-04-28 | 2017-08-18 | 燕山大学 | A kind of brshless DC motor PWM method based on two or three mixing conductings |
| CN107070318A (en) * | 2017-05-09 | 2017-08-18 | 天津大学 | A kind of harmonic analysis method of permanent-magnet brushless DC electric machine commutation torque ripple |
| CN107171605A (en) * | 2017-05-19 | 2017-09-15 | 燕山大学 | A kind of conductings of BLDCM bis- or two and three or three conducting switching methods |
Non-Patent Citations (1)
| Title |
|---|
| 电动汽车用永磁无刷驱动电动机高性能控制技术;李岩 等;《2014中国汽车工程学会年会论文集》;20161027;第96-99页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109713949A (en) | 2019-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109713949B (en) | Method and system for suppressing torque ripple of brushless direct current motor | |
| CN101789737B (en) | Method and device for inhibiting electromagnetic torque pulsation of brushless direct-current motor | |
| CN106849779B (en) | Switched reluctance machines dead-beat current PWM duty cycle control method | |
| CN109167539B (en) | Commutation error compensation method and control system for brushless direct current motor without position sensor under heavy load condition | |
| CN107222135A (en) | A kind of D-C brushless electric machine no-position sensor control system phase change control method | |
| CN107834917A (en) | The counter electromotive force commutation point detection circuit and method of a kind of DC brushless motor | |
| CN108400730A (en) | A kind of square-wave motor control system and use its square-wave motor | |
| CN108023473A (en) | Pfc circuit, electric machine control system and transducer air conditioning | |
| CN109088567B (en) | Follow current interference compensation method for brushless direct current motor without position sensor | |
| CN105915130B (en) | A kind of pump control method and its device of position-sensor-free magneto | |
| CN113992075B (en) | Compensation circuit and control method for phase delay of brushless direct current motor | |
| CN109861616B (en) | Two-three phase mixed conduction control system and control method for permanent magnet brushless direct current motor | |
| CN108206651B (en) | Nine-switch inverter double-motor driving system and control method thereof | |
| CN114487917B (en) | Power tube of electro-magnetic doubly salient motor converter and winding open-circuit fault diagnosis method | |
| CN115800829A (en) | Feedback boost inverter for inhibiting torque ripple of brushless direct current motor and control method | |
| Wang et al. | A commutation optimization strategy for high speed brushless DC drives with inaccurate rotor position signals | |
| CN112436763A (en) | Switched reluctance motor brake control system and control method | |
| Niasar et al. | A low-cost sensorless BLDC motor drive using one-cycle current control strategy | |
| CN112311267B (en) | Feedback voltage regulation four-level inverter topology and BLDCM torque ripple suppression method driven by same | |
| Bian et al. | Research on regenerative braking torque ripple suppression of brushless DC motor | |
| CN116247998B (en) | Current setting control method for electro-magnetic doubly salient motor based on H-bridge power circuit | |
| CN212572306U (en) | DC brushless motor without position sensor | |
| Liu et al. | The Influence of PWM Modulation Mode on the Commutation Performance of Brushless DC Motor | |
| Yue et al. | Design of Control System for BLDCM without Position Sensor | |
| CN114204862B (en) | Device and method for improving low-speed performance of brushless direct current motor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |