CN116317731A - Brushless DC motor energy feedback control method and system - Google Patents

Brushless DC motor energy feedback control method and system Download PDF

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Publication number
CN116317731A
CN116317731A CN202310210037.6A CN202310210037A CN116317731A CN 116317731 A CN116317731 A CN 116317731A CN 202310210037 A CN202310210037 A CN 202310210037A CN 116317731 A CN116317731 A CN 116317731A
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motor
circuit
phase
power
state
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Inventor
蔡志端
沈佳浩
秦陈威
徐静云
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Huzhou University
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Huzhou University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/24—Arrangements for stopping
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
    • H02M3/1582—Buck-boost converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
    • H02P27/08—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters with pulse width modulation
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/10—Arrangements for controlling torque ripple, e.g. providing reduced torque ripple
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/14—Electronic commutators
    • H02P6/16—Circuit arrangements for detecting position
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
    • H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
    • H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
    • H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P2203/00—Indexing scheme relating to controlling arrangements characterised by the means for detecting the position of the rotor
    • H02P2203/03—Determination of the rotor position, e.g. initial rotor position, during standstill or low speed operation

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)

Abstract

The invention discloses a brushless DC motor energy feedback control method and system, wherein the system comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit; the method comprises the steps of obtaining the operation instruction and the Hall state of a motor in a three-phase motor circuit; when the operation command is a braking command, encoding three-phase Hall values and judging the commutation state of the motor; and switching on and switching off the preset power switch tube according to the phase change state, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with a power supply to feed back energy generated during motor braking to the power supply. Compared with the traditional conversion circuit, the invention directly connects the power supply with the three-phase motor circuit through the preset power switch tube in the switch selection circuit, realizes energy feedback braking control while realizing voltage regulation and phase conversion torque inhibition of the front-end buck-boost conversion circuit, and improves the cruising ability of the power supply.

Description

Brushless DC motor energy feedback control method and system
Technical Field
The invention relates to the technical field of motor control, in particular to a brushless direct current motor energy feedback control method and system.
Background
Along with the rapid development of power electronics technology, microelectronics technology, novel control theory and rare earth permanent magnet materials, the rare earth permanent magnet brushless motor can be rapidly popularized and applied due to the advantages of simple structure, high power density, high efficiency, reliable operation and the like. However, in some cases where the control requirement is high, there is a high requirement on the accuracy and output performance of the brushless dc motor, for example, the torque ripple problem is one of the inherent problems of the brushless dc motor. The larger torque ripple can cause vibration and noise problems to the device, and can also reduce the control accuracy and the service life of the device.
In the existing torque ripple suppression strategy, the bus voltage is regulated through the front-end buck-boost conversion circuit to effectively suppress torque ripple, but the traditional conversion circuit cannot realize energy feedback in a brushless direct current motor braking state.
The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.
Disclosure of Invention
The invention mainly aims to provide a brushless direct current motor energy feedback control method and system, and aims to solve the technical problem that the traditional conversion circuit in the prior art cannot realize energy feedback in a braking state of a brushless direct current motor.
In order to achieve the above object, the present invention provides a brushless dc motor energy feedback control method, which is applied to a control system, the system includes a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit, and a three-phase motor circuit; the method comprises the following steps:
acquiring an operation instruction and a Hall state of a motor in the three-phase motor circuit;
when the operation instruction is a braking instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values;
and switching on and switching off a preset power switch tube in the switch selection circuit according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit, and enabling the three-phase motor circuit to be connected with the power supply so as to feed back energy generated during motor braking to the power supply.
Optionally, the first end of the power supply is connected with the first end of the front-end buck-boost conversion circuit, the second end of the power supply is connected with the second end of the front-end buck-boost conversion circuit, the first end of the switch selection circuit is connected with the first end of the power supply, the second end of the switch selection circuit is connected with the third end of the front-end buck-boost conversion circuit, the third end of the switch selection circuit is connected with the first end of the three-phase motor circuit, and the second end of the three-phase motor circuit is connected with the fourth end of the front-end buck-boost conversion circuit.
Optionally, the switch selection circuit includes ninth to eleventh power switching transistors;
the source electrode of the ninth power switch tube is connected with the first end of the power supply, the drain electrode of the ninth power switch tube is connected with the source electrode of the tenth power switch tube, the source electrode of the tenth power switch tube is connected with the first end of the three-phase motor circuit, the drain electrode of the tenth power switch tube is connected with the third end of the front-end buck-boost conversion circuit, the source electrode of the eleventh power switch tube is connected with the drain electrode of the ninth power switch tube, and the drain electrode of the eleventh power switch tube is connected with the source electrode of the ninth power switch tube.
Optionally, the step of switching on and off a preset power switching tube in the switch selection circuit according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit, and the three-phase motor circuit is connected with the power supply to feed back energy generated when the motor is braked to the power supply, includes:
turning off the tenth power switching tube according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit;
And turning off the eleventh power switching tube and turning on the ninth power switching tube so as to enable the three-phase motor circuit to be connected with the power circuit and feed back energy generated during motor braking to the power circuit.
Optionally, the step of obtaining the operation instruction and the hall state of the motor in the three-phase motor circuit further includes:
when the operation instruction is an electric instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values;
when the commutation state is commutation, the ninth power switching tube and the eleventh power switching tube are turned off, so that the power supply is disconnected with the three-phase motor circuit;
and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
Optionally, when the operation instruction is an electric instruction, the step of encoding three-phase hall values in the hall state and judging the commutation state of the motor according to the encoded three-phase hall values further includes:
When the commutation state is non-commutation, current rotation speed data of the motor are obtained;
turning off the ninth power switching tube and the tenth power switching tube so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit;
and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
In addition, in order to achieve the above purpose, the invention also provides a brushless DC motor energy feedback control system, which comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit;
the controller is used for acquiring the operation instruction and the Hall state of the motor in the three-phase motor circuit;
the controller is further used for encoding three-phase Hall values in the Hall state when the operation instruction is a braking instruction, and judging the phase change state of the motor according to the encoded three-phase Hall values;
the controller is further used for conducting and switching off a preset power switch tube in the switch selection circuit according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with the power supply to feed back energy generated during motor braking to the power supply.
Optionally, the switch selection circuit includes ninth to eleventh power switch tubes, wherein a source electrode of the ninth power switch tube is connected with a first end of the power supply, a drain electrode of the ninth power switch tube is connected with a source electrode of the tenth power switch tube, a source electrode of the tenth power switch tube is connected with a first end of the three-phase motor circuit, a drain electrode of the tenth power switch tube is connected with a third end of the front-end buck-boost conversion circuit, a source electrode of the eleventh power switch tube is connected with a drain electrode of the ninth power switch tube, and a drain electrode of the eleventh power switch tube is connected with a source electrode of the ninth power switch tube;
the controller is further configured to turn off the tenth power switching tube according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit;
the controller is further configured to turn off the eleventh power switch tube and turn on the ninth power switch tube, so that the three-phase motor circuit is connected with the power circuit, and feedback energy generated when the motor is braked to the power circuit.
Optionally, the controller is further configured to encode three-phase hall values in the hall state when the operation instruction is an electric instruction, and determine a commutation state of the motor according to the encoded three-phase hall values;
the controller is further configured to turn off the ninth power switching tube and the eleventh power switching tube when the commutation state is commutation, so that the power supply is disconnected from the three-phase motor circuit; and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
Optionally, the controller is further configured to obtain current rotation speed data of the motor when the commutation state is non-commutation;
the controller is further configured to turn off the ninth power switching tube and the tenth power switching tube, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit; and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
The invention provides a brushless DC motor energy feedback control method which is applied to a control system, wherein the system comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit; the method comprises the following steps: acquiring an operation instruction and a Hall state of a motor in the three-phase motor circuit; when the operation instruction is a braking instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values; and switching on and switching off a preset power switch tube in the switch selection circuit according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit, and enabling the three-phase motor circuit to be connected with the power supply so as to feed back energy generated during motor braking to the power supply. Compared with the traditional conversion circuit, the invention enables the switch selection circuit to be switched on and off under different conditions by judging the operation instruction and the Hall state of the motor, when the operation instruction is a braking instruction, the preset power switch tube in the switch selection circuit is used for directly connecting the power supply with the three-phase motor circuit, so that the front-end buck-boost conversion circuit is used for regulating the bus voltage to inhibit the commutation torque, and meanwhile, the energy feedback braking control is realized, and the cruising ability of the power supply is improved.
Drawings
FIG. 1 is a schematic flow chart of a brushless DC motor feedback control method according to a first embodiment of the invention;
FIG. 2 is a schematic circuit diagram of a brushless DC motor energy feedback control system according to a second embodiment of the present invention;
FIG. 3 is a schematic circuit diagram of a front-end buck-boost converter circuit in a second embodiment of a brushless DC motor feedback control method according to the present invention;
FIG. 4 is a flow chart of a second embodiment of a brushless DC motor feedback control method according to the present invention;
FIG. 5 is a schematic circuit diagram of a brushless DC motor in an energy feedback braking state according to a second embodiment of the present invention;
fig. 6 is a schematic circuit diagram of a brushless dc motor in a torque ripple suppression state according to a second embodiment of the present invention;
FIG. 7 is a schematic circuit diagram of a brushless DC motor according to a second embodiment of the invention in a rotational speed control mode;
fig. 8 is a flow chart of a system control amplifier in a second embodiment of the brushless dc motor feedback control method according to the present invention.
The achievement of the objects, functional features and advantages of the present invention will be further described with reference to the accompanying drawings, in conjunction with the embodiments.
Detailed Description
It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
An embodiment of the invention provides a brushless dc motor energy feedback control method, referring to fig. 1, fig. 1 is a flow chart of a first embodiment of the brushless dc motor energy feedback control method of the invention.
In this embodiment, the brushless dc motor energy feedback control method is applied to a control system, where the system includes a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit, and a three-phase motor circuit; the method comprises the following steps:
step S10: and acquiring an operation instruction and a Hall state of a motor in the three-phase motor circuit.
It should be noted that, the execution body of the method of the present embodiment may be a computing device having functions of data processing and program operation, for example, a controller in the above-mentioned control system, where the controller obtains information of each circuit in the system, controls the operation of the circuits in the system based on the current status of the circuits, and implements the brushless dc motor energy feedback control method of the present embodiment, and the controller may be a computer or a circuit controller, or may be other electronic devices capable of implementing the same or similar functions, which is not limited in this embodiment. The controller in the control system is used to specifically explain the brushless dc motor energy feedback control method provided in this embodiment and the following embodiments.
It can be understood that the three-phase motor circuit is a short term of a brushless direct current motor and a three-phase inverter circuit, and the three-phase inverter circuit converts direct current provided by a power supply into three-phase alternating current for the brushless direct current motor to operate.
It is understood that the operating command refers to a command in an operating state of the motor, for example, an electric command and a braking command for the controller in an electric state of the motor and in a braking state of the motor, respectively.
The Hall state is a commutation state of the motor, the Hall element is realized based on the Hall element of the motor, the Hall element is a magnetic field sensor, and the Hall element is used for detecting the position of a magnetic pole and can play a role in controlling the speed of the brushless motor.
Step S20: and when the running instruction is a braking instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values.
The braking command is a command collected by a deceleration braking mode adopted by the motor in a normal operation process.
In a specific implementation, when the controller receives the operation instruction as a braking instruction, the controller encodes three-phase Hall values in the collected Hall states, and judges the phase change state of the motor according to the encoded three-phase Hall values.
Step S30: and switching on and switching off a preset power switch tube in the switch selection circuit according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit, and enabling the three-phase motor circuit to be connected with the power supply so as to feed back energy generated during motor braking to the power supply.
The commutation state is a state in which the motor changes the phase sequence or phase of connection during the operation of the motor, and is used for balancing a three-phase load or changing the steering direction of the motor, and includes two states of commutation and non-commutation.
It can be understood that the preset power switching tube is a plurality of preset power switching tubes in the switch selection circuit, and the switch selection circuit can realize the integral fusion and function switching of functions of power supply, bus voltage lifting, energy feedback, torque pulsation suppression, motor speed regulation and the like of the annual control system based on the preset power switching tube.
In a specific implementation, the controller judges whether a preset power switch tube in the switch selection circuit is turned on or off according to the commutation state of the motor, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with a power supply to feed back energy generated during motor braking to the power supply, thereby realizing energy feedback braking of the motor.
The embodiment provides a brushless DC motor energy feedback control method which is applied to a control system, wherein the system comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit; acquiring an operation instruction and a Hall state of a motor in a three-phase motor circuit in advance, then encoding three-phase Hall values in the acquired Hall state when the operation instruction is received as a braking instruction, and judging a phase change state of the motor according to the encoded three-phase Hall values; and finally, the controller judges whether a preset power switch tube in the switch selection circuit is turned on or off according to the commutation state of the motor, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with a power supply to feed back energy generated during motor braking to the power supply, thereby realizing energy feedback braking of the motor. Compared with the traditional conversion circuit, the invention enables the switch selection circuit to be switched on and off under different conditions by judging the running instruction and the Hall state of the motor, realizes the control of energy feedback braking while realizing the regulation of bus voltage by the front-end buck-boost conversion circuit to inhibit the commutation torque, and improves the cruising ability of the power supply.
Based on the above-mentioned first embodiment, in this embodiment, considering that the conventional conversion circuit cannot realize energy feedback in the braking state of the brushless dc motor, a specific circuit schematic diagram of a control system capable of achieving both torque ripple suppression and energy feedback is now proposed, as shown in fig. 2, and fig. 2 is a circuit schematic diagram of the brushless dc motor energy feedback control system in the second embodiment of the brushless dc motor energy feedback control method of the present invention.
The first end of the power supply 10 is connected to the first end of the front-end buck-boost conversion circuit 20, the second end of the power supply 10 is connected to the second end of the front-end buck-boost conversion circuit 20, the first end of the switch selection circuit 30 is connected to the first end of the power supply 10, the second end of the switch selection circuit 30 is connected to the third end of the front-end buck-boost conversion circuit 20, the third end of the switch selection circuit 30 is connected to the first end of the three-phase motor circuit 40, and the second end of the three-phase motor circuit 40 is connected to the fourth end of the front-end buck-boost conversion circuit 20.
It will be appreciated that, as shown in FIG. 2, the power supply U dc The positive terminal of (a) is the first terminal of the power supply, the power supply U dc The negative end of the battery is the second end of the power supply, and the battery is used as the power supply of the system, and a lithium ion power battery module can be used as a storage battery.
Further, as shown in fig. 2, the switch selection circuit 30 includes ninth to eleventh power switching transistors (T9 to T11); the source of the ninth power switch tube T9 is connected to the first end of the power supply 10, the drain of the ninth power switch tube T9 is connected to the source of the tenth power switch tube T10, the source of the tenth power switch tube T10 is connected to the first end of the three-phase motor circuit 40, the drain of the tenth power switch tube T10 is connected to the third end of the front-end buck-boost converter circuit 20, the source of the eleventh power switch tube T11 is connected to the drain of the ninth power switch tube T9, and the drain of the eleventh power switch tube T11 is connected to the source of the ninth power switch tube T9.
It should be noted that, the power switch tube may be a MOS tube or a transistor, and is selected according to practical situations, which is not limited in this embodiment.
It should be understood that the switch selection circuit can realize the integral fusion and function switching of the functions of power supply, bus voltage rise and fall, energy feedback, torque ripple suppression, motor speed regulation and the like of the system.
Further, as shown in fig. 2 and 3, fig. 3 is a schematic circuit diagram of a front-end buck-boost converter circuit in a second embodiment of the brushless dc motor energy feedback control method of the present invention, and the front-end buck-boost converter circuit 20 includes: the front-end buck-boost conversion circuit comprises a seventh power switch tube T7, an eighth power switch tube T8, a seventh diode D7, an eighth diode D8, a first inductor L1 and a first capacitor C1; the drain of the seventh power switch tube T7 is connected to the first end of the power supply 10, the source of the seventh power switch tube T7 is connected to the cathode of the seventh diode D7, the anode of the seventh diode D7 is connected to the second end of the power supply 10, the first end of the first inductor L1 is connected to the source of the seventh power switch tube T7, the second end of the first inductor L1 is connected to the drain of the eighth power switch tube T8, the source of the eighth power switch tube T8 is connected to the anode of the seventh diode D7, the anode of the eighth diode D8 is connected to the second end of the first inductor L1, the cathode of the eighth diode D8 is connected to the drain of the tenth power switch tube T10, the first end of the first capacitor C1 is connected to the cathode of the eighth diode D8, the second end of the first capacitor C1 is connected to the second end of the second capacitor C8, and the third end of the third capacitor C1 is connected to the third power switch tube 40.
As shown in fig. 3, the front-end buck-boost converter circuit may convert the buck-boost voltage of the power supply to change the bus voltage of the system, and the front-end buck-boost converter circuit may be controlled by the PWM control technique to output the voltage U o In a step-up or step-down state, U when operating in the step-up state o >U dc At this time, U o ＝U dc ·D 1 Wherein D is 1 Is the duty cycle of the PWM signal. When working in a step-down state, U o <U dc At this time, the first and second electrodes are connected,
Figure BDA0004112405120000091
wherein D is 2 Is the duty cycle of the PWM signal. Thus realizing the function of regulating the output voltage.
Further, as shown in fig. 2, the three-phase motor circuit 40 includes a three-phase inverter circuit 41 and a brushless dc motor 42, the brushless dc motor 42 is an equivalent model of the three-phase motor, the equivalent voltage is Un, the equivalent motors are ea, eb and ec, the negative terminals of the three equivalent motors are commonly connected, the positive terminals of the three equivalent motors are connected with series groups of resistors and inductors, the three series groups are equivalent models, the resistance and the inductance of the three series groups are consistent, the positive terminal of the motor ea is connected with one end of a second inductor L2, the other end of the second inductor L2 is connected with one end of a first resistor R1, the positive terminal of the motor eb is connected with one end of a third inductor L3, the other end of the third inductor L3 is connected with one end of the second resistor R2, the positive terminal of the motor ec is connected with one end of a fourth inductor L4, and the other end of the fourth inductor L4 is connected with one end of the third resistor R3.
The three-phase inverter circuit 41 further comprises first to sixth diodes (D1-D6) and first to sixth power switches (T1-T6), wherein the source of the first power switch T1 is connected to the anode of the first diode D1, the drain of the first power switch T1 is connected to the cathode of the first diode D1, the source of the second power switch T2 is connected to the anode of the second diode D2, the drain of the second power switch T2 is connected to the cathode of the second diode D2, the source of the third power switch T3 is connected to the anode of the third diode D3, the drain of the third power switch T3 is connected to the cathode of the third diode D3, the source of the fourth power switch T4 is connected to the anode of the fourth diode D4, the drain of the fourth power switch T4 is connected to the drain of the fifth diode T6, the drain of the fourth power switch T4 is connected to the drain of the fifth diode T5 is connected to the drain of the fourth diode T6, the drain of the third power switch T3 is connected to the cathode of the third diode D3, the source of the third power switch tube T3 is connected with the drain of the sixth power switch tube T6, the source of the sixth power switch tube T6 is connected with the source of the fourth power switch tube T4, the drain of the fifth power switch tube T5 is connected with the drain of the third power switch tube T3, the source of the fifth power switch tube T5 is connected with the drain of the second power switch tube T2, the source of the second power switch tube T2 is connected with the source of the sixth power switch tube T6, the other end of the first resistor R1 is connected with the source of the first power switch tube T1, the other end of the second resistor R2 is connected with the source of the third power switch tube T3, and the other end of the third resistor R3 is connected with the source of the fifth power switch tube T5.
It is understood that the controller can perform commutation control of the brushless dc motor through the three-phase inverter circuit. In an electric state, the three-phase inverter circuit adopts a modulation mode of H_ON-L_ON; in the braking state, the three-phase inverter circuit adopts a PWM_OFF modulation mode.
The power supply is used for providing voltage and current for the brushless direct current motor, the switch selection circuit is used for controlling the current flow direction of the control system through the on-off of the power switch tube, the front-end buck-boost conversion circuit is used for regulating the voltage and transmitting the regulated voltage to the three-phase inverter circuit, and the three-phase inverter circuit is used for converting the direct current voltage provided by the power supply into three-phase alternating current voltage.
Further, the circuit schematic diagram based on the control system further realizes the brushless dc motor energy feedback control method, so that the energy feedback control function can be conveniently realized, as shown in fig. 4, fig. 4 is a flow schematic diagram of a second embodiment of the brushless dc motor energy feedback control method of the present invention;
step S31: and switching off the tenth power switching tube according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit.
Step S32: and turning off the eleventh power switching tube and turning on the ninth power switching tube so as to enable the three-phase motor circuit to be connected with the power circuit and feed back energy generated during motor braking to the power circuit.
When the brushless DC motor works in a braking state, the three-phase inverter circuit adopts an OFF_PWM modulation mode, and in a feedback braking process, the motor can pass through an energy storage state and an energy feedback state, and in the energy storage state, the mechanical energy of the motor can be converted into electric energy and stored in a stator winding of the motor, and in the energy feedback state, the energy feedback can be carried out on the power supply.
In a specific implementation, the circuit state and the current flow direction are shown in fig. 5, fig. 5 is a schematic circuit diagram of the brushless dc motor in the energy feedback braking state in the second embodiment of the present invention, when energy is fed back, T9 is turned on and T10 and T11 are turned off, so that the front-end buck-boost conversion circuit is disconnected from the three-phase inverter circuit, so that the three-phase inverter circuit is connected with the power supply and the energy generated when the motor is braked is fed back to the power supply circuit, and at this time, the current I of the circuit is conducted in a direction that the three-phase inverter circuit is conducted to the power supply in a unidirectional manner, so that the reverse charging of the power supply can be implemented, and the endurance of the power supply is improved.
Further, considering that in a non-braking state, namely an electric state, during commutation, the front-end step-up and step-down circuit of the control system can adjust the bus voltage of the three-phase inverter circuit to inhibit commutation torque ripple, so that a motor torque ripple control function during commutation is conveniently realized. The step S10 further includes: when the operation instruction is an electric instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values; when the commutation state is commutation, the ninth power switching tube and the eleventh power switching tube are turned off, so that the power supply is disconnected with the three-phase motor circuit; and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
During the phase change, the front-end step-up and step-down circuit adjusts the bus voltage of the three-phase inverter circuit to inhibit the phase change torque ripple, and the PWM duty ratio of the front-end step-up and step-down circuit is controlled to calculate as follows:
when the motor operates in a low-speed state, the following conditions are satisfied: u (U) dc Not less than 4E, the front-end buck-boost conversion circuit works in a buck state at the moment, and the target output voltage U is used o =4e, then there is:
U o ＝D 1 ·U dc ＝4E
thereby obtaining the PWM duty ratio D of the control front-end buck-boost conversion circuit 1 The method comprises the following steps:
Figure BDA0004112405120000111
according to a rated counter electromotive force calculation formula, obtaining:
Figure BDA0004112405120000112
when the motor operates in a high-speed state, the following conditions are satisfied: u (U) dc <4E, at this time, the front-end buck-boost conversion circuit is operated in a boost state, and since the target output voltage uo=4e, there is:
Figure BDA0004112405120000113
thereby obtaining the PWM duty ratio D of the control front-end buck-boost conversion circuit 2 The method comprises the following steps:
Figure BDA0004112405120000114
according to a rated counter electromotive force calculation formula, obtaining:
Figure BDA0004112405120000115
in a specific implementation, the circuit state and the current flow are shown in fig. 6, and fig. 6 is a schematic circuit diagram of the second embodiment of the brushless dc motor energy feedback control method according to the present invention in the torque ripple suppression state. The controller judges the running interval of the motor rotor according to the real-time rotor position information provided by the Hall position sensor, thereby obtaining the commutation moment. During the phase change in the electric state, the bus voltage of the three-phase inverter circuit is regulated through the front-end buck-boost circuit to inhibit the phase change torque ripple, the PWM duty ratio of the front-end buck-boost circuit is controlled, at the moment, T10 is turned on, T9 and T11 are turned off, so that the power supply is disconnected from the three-phase motor circuit, the front-end buck-boost circuit is connected with the three-phase motor circuit, and the torque ripple generated during the phase change of the motor is inhibited; the controller can quickly adjust the bus voltage of the three-phase inverter circuit to realize the suppression of commutation torque ripple, and the current I of the circuit is conducted in the direction shown in fig. 6. The voltage regulation time of the buck-boost conversion circuit used in the embodiment is longer, but the phase change time interval of the brushless direct current motor is very short and even smaller than the voltage regulation time of the conversion circuit, so as to ensure the rapid response of the bus voltage during the phase change of the motor, the switch selection circuit adopted in the embodiment can be used for rapidly switching during the phase change of the motor. And the busbar voltage regulation is realized during the commutation period of the motor, so that the rising rate of the on-phase current and the falling rate of the off-phase current are ensured to be the same during the commutation, and the commutation torque pulsation problem of the brushless direct current motor is solved.
Further, considering the rotation speed control of the motor in the phase change period under the electric state, the motor speed regulation can be conveniently realized through a control system. When the operation instruction is an electric instruction, the method encodes three-phase Hall values in the Hall state, and judges the phase change state of the motor according to the encoded three-phase Hall values, and then the method further comprises the following steps: when the commutation state is non-commutation, current rotation speed data of the motor are obtained; turning off the ninth power switching tube and the tenth power switching tube so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit; and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
The preset threshold is a threshold of a rotation speed range of the motor in a working state, and the motor can work normally.
In a specific implementation, the circuit state and the current flow direction I are shown in fig. 7, and fig. 7 is a circuit principle of the brushless dc motor energy feedback control method according to the second embodiment of the present invention in the rotational speed control state. When the brushless direct current motor works in a normal electric running state, the three-phase inverter circuit only needs to adopt a modulation mode of H_ONL_ON, so that the three-phase inverter circuit realizes an inverter function and outputs alternating current without complex voltage regulation control. At this time, during the non-commutation period, the T9 and the T10 are turned off, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit, the T11 is subjected to PWM modulation, the speed regulation of the motor is realized by adjusting the duty ratio of the PWM to the T11, and the circuit conduction direction is the unidirectional conduction from the power supply to the three-phase inversion circuit.
For the control system, the overall control process is shown in fig. 8, and fig. 8 is a schematic flow chart of the system control in the second embodiment of the brushless dc motor energy feedback control method of the present invention; the functions of motor speed regulation, energy feedback, torque pulsation suppression and the like can be effectively realized, and as shown in fig. 8, the specific realization process is as follows:
s1) starts first, and it is determined whether the motor is braked. The controller acquires an electric or braking instruction of the motor, and then performs electric or braking control.
S2) if the brake is not performed (NO), the operation instruction is electric, a Hall state is obtained, and three-phase Hall values are encoded; and judging whether to commutate according to the Hall state.
And S3) if the phase change is not carried out (NO), detecting the rotation speed of the motor, turning off T9 and T10 according to the rotation speed condition, carrying out PWM modulation on T11 according to the target speed, realizing motor speed regulation, and finally ending.
S4) if the phase change is carried out (yes), the duty ratio of the front-end buck-boost conversion circuit when the output voltage is 4E is calculated before the phase change, the voltage with the duty ratio of 4E is obtained through calculation, E is the back electromotive force amplitude, the phase change is carried out according to the Hall state through the three-phase inverter circuit, meanwhile, the T10 is conducted, the T9 and the T11 are turned off, the phase change torque pulsation suppression is carried out, and finally the phase change is finished.
S5) if the operation instruction is braking (yes), acquiring a Hall state and encoding three-phase Hall values. And judging whether to commutate according to the Hall state.
S6) if the phase change is carried out (yes), the phase change is carried out through a three-phase inverter circuit according to the Hall state, and meanwhile, T9 is conducted and T10 and T11 are turned off; if the commutation is not carried out (NO), directly switching on T9 and switching off T10 and T11; and then energy feedback braking control is carried out, and finally the process is finished.
In the non-commutation period of the motor in an electric state, the embodiment only carries out PWM modulation on T11 in the switch selection circuit, and the three-phase inverter circuit only carries out commutation and does not carry out PWM modulation on bus voltage, so that the diodes in the circuit do not carry out freewheeling in the non-commutation period, the freewheeling loss and the switching loss can be reduced, the service life of the system is prolonged, and simultaneously, torque pulsation caused by freewheeling of the non-conductive phase diodes in the non-commutation period is restrained. Further, during the phase conversion of the motor in an electric state, the front-end buck-boost converter is used for regulating the bus voltage, so that torque pulsation of the brushless direct current motor during the phase conversion is restrained, and during the phase conversion, the T10 in the switch selection circuit is used for directly controlling the on or off of the front-end buck-boost converter, so that the response speed of the bus voltage regulation of the three-phase inverter circuit is accelerated. Further, when the motor is in a braking state, the power supply is directly connected with the three-phase inverter circuit through T9 in the switch selection circuit, so that the front-end buck-boost converter is used for regulating the bus voltage to inhibit the commutation torque, the energy feedback braking control is realized, and the cruising ability of the power supply is improved.
In addition, the embodiment of the invention also provides a brushless DC motor energy feedback control system which is realized based on the brushless DC motor energy feedback control method.
Based on the above embodiments, in this embodiment, a brushless dc motor energy feedback control system is provided, and the system provided by the embodiment of the present invention includes a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit, and a three-phase motor circuit;
the controller is used for acquiring the operation instruction and the Hall state of the motor in the three-phase motor circuit;
the controller is further used for encoding three-phase Hall values in the Hall state when the operation instruction is a braking instruction, and judging the phase change state of the motor according to the encoded three-phase Hall values;
the controller is further used for conducting and switching off a preset power switch tube in the switch selection circuit according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with the power supply to feed back energy generated during motor braking to the power supply.
It should be noted that, in the control system of this embodiment, the controller obtains information of each circuit in the system, and controls the operation of the circuit in the system based on the current status of the circuit, and the controller may be a computer or a circuit controller, or may be other electronic devices capable of implementing the same or similar functions, which is not limited in this embodiment.
It can be understood that the three-phase motor circuit is a short term of a brushless direct current motor and a three-phase inverter circuit, and the three-phase inverter circuit converts direct current provided by a power supply into three-phase alternating current for the brushless direct current motor to operate.
It is understood that the operating command refers to a command in an operating state of the motor, for example, an electric command and a braking command for the controller in an electric state of the motor and in a braking state of the motor, respectively.
The Hall state is a commutation state of the motor, the Hall element is realized based on the Hall element of the motor, the Hall element is a magnetic field sensor, and the Hall element is used for detecting the position of a magnetic pole and can play a role in controlling the speed of the brushless motor. The braking command is a command collected by a deceleration braking mode adopted by the motor in the normal running process.
It should be understood that a commutation state is a state in which the motor changes the phase sequence or phase of the connection during operation of the motor, for balancing a three-phase load or changing the direction of rotation of the motor, including both a commutation state and a non-commutation state.
It can be understood that the preset power switching tube is a plurality of preset power switching tubes in the switch selection circuit, and the switch selection circuit can realize the integral fusion and function switching of functions of power supply, bus voltage lifting, energy feedback, torque pulsation suppression, motor speed regulation and the like of the annual control system based on the preset power switching tube.
The embodiment provides a brushless DC motor energy feedback control system, which comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit; the controller is used for acquiring operation instructions and Hall states of the motor in the three-phase motor circuit in advance, then coding three-phase Hall values in the acquired Hall states when the operation instructions are received as braking instructions, and judging a phase-change state of the motor according to the coded three-phase Hall values; and finally, the controller judges whether a preset power switch tube in the switch selection circuit is turned on or off according to the commutation state of the motor, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with a power supply to feed back energy generated during motor braking to the power supply, thereby realizing energy feedback braking of the motor. Compared with the traditional conversion circuit, the invention enables the switch selection circuit to be switched on and off under different conditions by judging the running instruction and the Hall state of the motor, realizes the control of energy feedback braking while realizing the regulation of bus voltage by the front-end buck-boost conversion circuit to inhibit the commutation torque, and improves the cruising ability of the power supply.
Based on the above embodiments, a second embodiment of the brushless dc motor energy feedback control system of the present invention is proposed. In this embodiment, the switch selection circuit includes ninth to eleventh power switching tubes, where a source of the ninth power switching tube is connected to the first end of the power supply, a drain of the ninth power switching tube is connected to a source of the tenth power switching tube, a source of the tenth power switching tube is connected to the first end of the three-phase motor circuit, a drain of the tenth power switching tube is connected to the third end of the front-end buck-boost conversion circuit, a source of the eleventh power switching tube is connected to a drain of the ninth power switching tube, and a drain of the eleventh power switching tube is connected to a source of the ninth power switching tube;
the controller is further configured to turn off the tenth power switching tube according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit;
the controller is further configured to turn off the eleventh power switch tube and turn on the ninth power switch tube, so that the three-phase motor circuit is connected with the power circuit, and feedback energy generated when the motor is braked to the power circuit.
It should be noted that, the power switch tube may be a MOS tube or a transistor, and is selected according to practical situations, which is not limited in this embodiment.
It should be understood that the switch selection circuit can realize the integral fusion and function switching of the functions of power supply, bus voltage rise and fall, energy feedback, torque ripple suppression, motor speed regulation and the like of the system.
When the brushless DC motor works in a braking state, the three-phase inverter circuit adopts an OFF_PWM modulation mode, and in a feedback braking process, the motor can pass through an energy storage state and an energy feedback state, and in the energy storage state, the mechanical energy of the motor can be converted into electric energy and stored in a stator winding of the motor, and in the energy feedback state, the energy feedback can be carried out on the power supply.
In a specific implementation, referring to fig. 2, at this time, T9 is turned on and T10 and T11 are turned off, so that the front-end buck-boost conversion circuit is disconnected from the three-phase inverter circuit, so that the three-phase inverter circuit is connected with the power supply and energy generated during braking of the motor is fed back to the power supply circuit, at this time, the current conduction direction of the circuit is that the three-phase inverter circuit is turned on to the power supply in a unidirectional manner, reverse charging of the power supply can be achieved, and the cruising ability of the power supply is improved.
Further, considering that in a non-braking state, namely an electric state, during commutation, the commutation torque ripple can be restrained by regulating the bus voltage of the three-phase inverter circuit through the front-end step-up and step-down circuit of the brushless DC motor energy feedback control system, and the motor torque ripple control function during commutation is conveniently realized. The controller is further used for encoding three-phase Hall values in the Hall state when the operation instruction is an electric instruction, and judging the phase change state of the motor according to the encoded three-phase Hall values; the controller is further configured to turn off the ninth power switching tube and the eleventh power switching tube when the commutation state is commutation, so that the power supply is disconnected from the three-phase motor circuit; and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
During the phase change, the front-end step-up/step-down circuit adjusts the bus voltage of the three-phase inverter circuit to inhibit the phase change torque ripple, and controls the PWM duty ratio of the front-end step-up/step-down circuit.
In a specific implementation, the controller judges the running interval of the motor rotor according to the real-time rotor position information provided by the Hall position sensor, so as to obtain the commutation moment. During the phase change in the electric state, the bus voltage of the three-phase inverter circuit is regulated through the front-end buck-boost circuit to inhibit the phase change torque ripple, the PWM duty ratio of the front-end buck-boost circuit is controlled, at the moment, T10 is turned on, T9 and T11 are turned off, so that the power supply is disconnected from the three-phase motor circuit, the front-end buck-boost circuit is connected with the three-phase motor circuit, and the torque ripple generated during the phase change of the motor is inhibited; the controller can rapidly adjust the bus voltage of the three-phase inverter circuit, and the commutation torque ripple suppression is realized. The voltage regulation time of the buck-boost conversion circuit used in the embodiment is longer, but the phase change time interval of the brushless direct current motor is very short and even smaller than the voltage regulation time of the conversion circuit, so as to ensure the rapid response of the bus voltage during the phase change of the motor, the switch selection circuit adopted in the embodiment can be used for rapidly switching during the phase change of the motor. And the busbar voltage regulation is realized during the commutation period of the motor, so that the rising rate of the on-phase current and the falling rate of the off-phase current are ensured to be the same during the commutation, and the commutation torque pulsation problem of the brushless direct current motor is solved.
Further, considering the rotation speed control of the motor in the phase change period under the electric state, the motor speed regulation can be conveniently realized through a control system. The controller is further configured to obtain current rotation speed data of the motor when the commutation state is non-commutation; the controller is further configured to turn off the ninth power switching tube and the tenth power switching tube, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit; and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
The preset threshold is a threshold of a rotation speed range of the motor in a working state, and the motor can work normally.
In a specific implementation, when the brushless direct current motor works in a normal electric running state, the controller only needs to control the three-phase inverter circuit to adopt a modulation mode of H_ONL_ON, so that the inverter function is realized, alternating current is output, and complex voltage regulation control is not needed. At this time, during the non-commutation period, the T9 and the T10 are turned off, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit, the T11 is subjected to PWM modulation, the speed regulation of the motor is realized by adjusting the duty ratio of the PWM to the T11, and the circuit conduction direction is the unidirectional conduction from the power supply to the three-phase inversion circuit.
In the embodiment, during the non-commutation period when the motor is in an electric state, the controller only carries out PWM modulation on T11 in the switch selection circuit, and the three-phase inverter circuit only carries out commutation but not PWM modulation on bus voltage, so that during the non-commutation period, the diodes in the circuit do not carry out freewheeling any more, the freewheeling loss and the switching loss can be reduced, the service life of the system is prolonged, and meanwhile, torque pulsation caused by freewheeling of the non-conductive phase diodes during the non-commutation period is restrained. Further, during the phase conversion of the motor in an electric state, the controller regulates the bus voltage through the front-end buck-boost converter, so that torque pulsation of the brushless direct-current motor during the phase conversion is restrained, and during the phase conversion, the T10 in the switch selection circuit is used for directly controlling the on or off of the front-end buck-boost converter, so that the response speed of the bus voltage regulation of the three-phase inverter circuit is accelerated. Further, when the motor is in a braking state, the controller directly connects the power supply with the three-phase inverter circuit through T9 in the switch selection circuit, so that the front-end buck-boost converter can regulate the bus voltage to inhibit the commutation torque, and meanwhile, the energy feedback braking control is realized, and the cruising ability of the power supply is improved.
Other embodiments or specific implementations of the brushless dc motor energy feedback control system of the present invention may refer to the above-mentioned method embodiments, and will not be described herein.
It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or system that comprises the element.
The foregoing embodiment numbers of the present invention are merely for the purpose of description, and do not represent the advantages or disadvantages of the embodiments.
From the above description of the embodiments, it will be clear to those skilled in the art that the above-described embodiment method may be implemented by means of software plus a necessary general hardware platform, but of course may also be implemented by means of hardware, but in many cases the former is a preferred embodiment. Based on such understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art in the form of a software product stored in a storage medium (e.g. read-only memory/random-access memory, magnetic disk, optical disk), comprising instructions for causing a terminal device (which may be a mobile phone, a computer, a server, or a network device, etc.) to perform the method according to the embodiments of the present invention.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, but rather is intended to cover any equivalents of the structures or equivalent processes disclosed herein or in the alternative, which may be employed directly or indirectly in other related arts.

Claims (10)

1. The brushless DC motor energy feedback control method is characterized in that the brushless DC motor energy feedback control method is applied to a control system, and the system comprises a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit; the method comprises the following steps:
acquiring an operation instruction and a Hall state of a motor in the three-phase motor circuit;
when the operation instruction is a braking instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values;
and switching on and switching off a preset power switch tube in the switch selection circuit according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit, and enabling the three-phase motor circuit to be connected with the power supply so as to feed back energy generated during motor braking to the power supply.
2. The brushless dc motor power feedback control method of claim 1, wherein a first end of the power supply is connected to a first end of the front-end buck-boost converter circuit, a second end of the power supply is connected to a second end of the front-end buck-boost converter circuit, a first end of the switch selection circuit is connected to the first end of the power supply, a second end of the switch selection circuit is connected to a third end of the front-end buck converter circuit, a third end of the switch selection circuit is connected to the first end of the three-phase motor circuit, and a second end of the three-phase motor circuit is connected to a fourth end of the front-end buck-boost converter circuit.
3. The brushless dc motor energy feedback control method according to claim 2, wherein the switch selection circuit includes ninth to eleventh power switching transistors;
the source electrode of the ninth power switch tube is connected with the first end of the power supply, the drain electrode of the ninth power switch tube is connected with the source electrode of the tenth power switch tube, the source electrode of the tenth power switch tube is connected with the first end of the three-phase motor circuit, the drain electrode of the tenth power switch tube is connected with the third end of the front-end buck-boost conversion circuit, the source electrode of the eleventh power switch tube is connected with the drain electrode of the ninth power switch tube, and the drain electrode of the eleventh power switch tube is connected with the source electrode of the ninth power switch tube.
4. The brushless dc motor power feedback control method as claimed in claim 3, wherein the step of turning on and off a preset power switching tube in the switching selection circuit according to the commutation state to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit and to feedback energy generated when the motor is braked to the power supply by connecting the three-phase motor circuit to the power supply comprises:
turning off the tenth power switching tube according to the commutation state so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit;
and turning off the eleventh power switching tube and turning on the ninth power switching tube so as to enable the three-phase motor circuit to be connected with the power circuit and feed back energy generated during motor braking to the power circuit.
5. The brushless dc motor power feedback control method as claimed in claim 3, wherein the step of acquiring the operation command and the hall state of the motor in the three-phase motor circuit further comprises:
when the operation instruction is an electric instruction, encoding three-phase Hall values in the Hall state, and judging the phase change state of the motor according to the encoded three-phase Hall values;
When the commutation state is commutation, the ninth power switching tube and the eleventh power switching tube are turned off, so that the power supply is disconnected with the three-phase motor circuit;
and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
6. The brushless dc motor energy feedback control method according to claim 5, wherein the step of encoding three-phase hall values in the hall state when the operation command is an electric command, and determining the commutation state of the motor according to the encoded three-phase hall values further comprises:
when the commutation state is non-commutation, current rotation speed data of the motor are obtained;
turning off the ninth power switching tube and the tenth power switching tube so as to disconnect the front-end buck-boost conversion circuit from the three-phase motor circuit;
and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
7. The brushless DC motor energy feedback control system is characterized by comprising a controller, a power supply, a front-end buck-boost conversion circuit, a switch selection circuit and a three-phase motor circuit;
the controller is used for acquiring the operation instruction and the Hall state of the motor in the three-phase motor circuit;
the controller is further used for encoding three-phase Hall values in the Hall state when the operation instruction is a braking instruction, and judging the phase change state of the motor according to the encoded three-phase Hall values;
the controller is further used for conducting and switching off a preset power switch tube in the switch selection circuit according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected with the three-phase motor circuit, and the three-phase motor circuit is connected with the power supply to feed back energy generated during motor braking to the power supply.
8. The brushless dc motor energy feedback control system according to claim 7, wherein the switch selection circuit includes ninth to eleventh power switching transistors, wherein a source of the ninth power switching transistor is connected to the first terminal of the power supply, a drain of the ninth power switching transistor is connected to a source of the tenth power switching transistor, a source of the tenth power switching transistor is connected to the first terminal of the three-phase motor circuit, a drain of the tenth power switching transistor is connected to the third terminal of the front-end buck-boost conversion circuit, a source of the eleventh power switching transistor is connected to a drain of the ninth power switching transistor, and a drain of the eleventh power switching transistor is connected to a source of the ninth power switching transistor;
The controller is further configured to turn off the tenth power switching tube according to the commutation state, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit;
the controller is further configured to turn off the eleventh power switch tube and turn on the ninth power switch tube, so that the three-phase motor circuit is connected with the power circuit, and feedback energy generated when the motor is braked to the power circuit.
9. The brushless dc motor energy feedback control system of claim 8 wherein the controller is further configured to encode three-phase hall values in the hall state when the operation command is an electric command, and determine a commutation state of the motor based on the encoded three-phase hall values;
the controller is further configured to turn off the ninth power switching tube and the eleventh power switching tube when the commutation state is commutation, so that the power supply is disconnected from the three-phase motor circuit; and conducting the tenth power switching tube so as to enable the front-end buck-boost conversion circuit to be connected with the three-phase motor circuit and inhibit torque pulsation generated during motor commutation.
10. The brushless dc motor energy feedback control system of claim 9 wherein the controller is further configured to obtain current rotational speed data of the motor when the commutation state is non-commutation;
the controller is further configured to turn off the ninth power switching tube and the tenth power switching tube, so that the front-end buck-boost conversion circuit is disconnected from the three-phase motor circuit; and controlling the conduction of the eleventh power switch tube by utilizing a pulse modulation technology according to the current rotating speed data so that the running speed of the motor does not exceed a preset threshold value.
CN202310210037.6A 2023-03-03 2023-03-03 Brushless DC motor energy feedback control method and system Pending CN116317731A (en)

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Application Number Priority Date Filing Date Title
CN202310210037.6A CN116317731A (en) 2023-03-03 2023-03-03 Brushless DC motor energy feedback control method and system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310210037.6A CN116317731A (en) 2023-03-03 2023-03-03 Brushless DC motor energy feedback control method and system

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CN116317731A true CN116317731A (en) 2023-06-23

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