CN215934689U - Direct current brushless motor, motor control system and rail train - Google Patents

Abstract

The utility model relates to a direct-current brushless motor which comprises two permanent magnet cylinders which are coaxially arranged and connected at the ends, wherein a plurality of groups of three-phase armature windings which are arranged along the circumference in a staggered manner are arranged in the permanent magnet cylinders, each permanent magnet cylinder comprises a plurality of N poles and a plurality of S poles which are arranged along the circumference in a staggered manner, the two permanent magnet cylinders are identical in structure, and each magnetic pole in one permanent magnet cylinder and the corresponding magnetic pole with the same polarity in the other permanent magnet cylinder are staggered by a first preset angle. By staggering two permanent magnet cylinders at a preset angle, the tangential force at the junction of the two poles is dispersed, the torque fluctuation is reduced, and the running stability is improved. The utility model also discloses a motor control system comprising the direct current brushless motor and a rail train comprising the motor control system.

Description

Direct current brushless motor, motor control system and rail train

Technical Field

The utility model relates to the field of rail transit, in particular to a direct-current brushless motor, a motor control system and a rail train.

Background

The brushless DC motor is one kind of synchronous motor, and is widely used in various fields. Unlike common DC motor, which has no commutator, the phase change of the motor is realized by applying three-phase AC with adjustable frequency to the armature winding of the stator via inverter frequency converting technology to generate rotating magnetic field and thus to drive the rotor to rotate. However, in the dc brushless motor, the permanent magnets are usually arranged in parallel, and the N pole and the S pole are arranged in a staggered manner, so that the tangential force applied to the boundary between the N pole and the S pole is the largest and tends to decrease gradually toward both sides, and therefore, the motor may generate torque fluctuation, which causes adverse conditions such as motor resonance.

In addition, when the brushless dc motor is used as an essential device of a rail train auxiliary system, it is usually connected to a heat sink. The traditional direct current brushless motor generally adopts a single chip control strategy, integrates control, signal processing and monitoring protection functions in a chip, and can meet the use requirement in a common static environment. For rail transit vehicles, the service environment is severe, so that the requirements on the stability and the reliability of the motor are high. Traditional single-chip brushless DC motor probably leads to the chip to damage because outside various factors, such as vehicle vibration, voltage and current fluctuation, external disturbance etc. are using the in-process to arouse motor trouble, and then influence vehicle normal operating.

Therefore, how to provide a dc brushless motor and a motor control system that overcome the above problems is a technical problem to be solved by those skilled in the art.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a brushless direct current motor and a motor control system. Another object of the present invention is to provide a rail train comprising the above system.

In order to solve the technical problem, the utility model provides a brushless direct-current motor which comprises two permanent magnet cylinders which are coaxially arranged and the ends of which are connected, wherein a plurality of groups of three-phase armature windings which are circumferentially staggered are arranged in the permanent magnet cylinders, each permanent magnet cylinder comprises a plurality of N poles and a plurality of S poles which are circumferentially staggered, the two permanent magnet cylinders have the same structure, and each magnetic pole in one permanent magnet cylinder is staggered with the corresponding magnetic pole with the same polarity in the other permanent magnet cylinder by a first preset angle.

Preferably, the first preset angle is one sixth of the mechanical angle occupied by a single magnetic pole in the permanent magnet cylinder.

Preferably, each permanent magnet cylinder includes three N poles and three S poles, a single magnetic pole occupies 60 degrees of mechanical angle, and the first preset angle is 10 degrees and includes three sets of three-phase armature windings.

Preferably, three hall sensors are sequentially installed on the three-phase armature winding along the circumference, a mechanical angle is formed between every two adjacent hall sensors at a distance of 20 degrees, a second preset angle is formed at the junction of the hall sensor and the armature winding, which is located on the outer side, and the second preset angle is formed by subtracting one half of the first preset angle from 20 degrees.

The utility model also provides a motor control system, which comprises a main chip, a safety protection chip, a signal processing chip, a switching power supply, a driver, an inverter and the direct current brushless motor, wherein the main chip is connected with all the parts and used for controlling the direct current brushless motor to operate and monitoring the state of the direct current brushless motor, the safety protection chip is connected with the driver and the direct current brushless motor and used for turning off the driver or resetting the main chip in an abnormal state, and the signal processing chip is used for inputting and outputting signals and communicating with the main chip.

Preferably, the signal processing chip and the main chip are isolated through an optical coupling isolator in a communication mode, and the switching power supply comprises an isolation side power supply connected with the signal processing chip and a non-isolation side power supply connected with the main chip.

The utility model also provides a rail train, which comprises a heat dissipation device and a motor control system connected with the heat dissipation device, wherein the motor control system is specifically any one of the motor control systems.

The utility model provides a direct-current brushless motor which comprises two permanent magnet cylinders which are coaxially arranged and connected at the ends, wherein a plurality of groups of three-phase armature windings which are arranged along the circumference in a staggered manner are arranged in the permanent magnet cylinders, each permanent magnet cylinder comprises a plurality of N poles and a plurality of S poles which are arranged along the circumference in a staggered manner, the two permanent magnet cylinders are identical in structure, and each magnetic pole in one permanent magnet cylinder and the corresponding magnetic pole with the same polarity in the other permanent magnet cylinder are staggered by a first preset angle.

By staggering two permanent magnet cylinders at a preset angle, the tangential force at the junction of the two poles is dispersed, the torque fluctuation is reduced, and the running stability is improved.

Furthermore, a three-chip control scheme is adopted, the three chips respectively undertake independent work, do not interfere with each other, and are physically and electrically isolated, so that the stability and reliability of a motor control system can be enhanced, and the service life of the motor is prolonged.

Furthermore, by adopting the control method and the optimal electrifying mode, each armature winding can be positioned at a better stress point, so that the torque of the motor is increased, and the efficiency of the motor is improved.

The utility model also provides a motor control system comprising the direct current brushless motor and a rail train comprising the system.

Drawings

Fig. 1 is a schematic top view of a dc brushless motor according to an embodiment of the present invention;

fig. 2 is a schematic front view of a dc brushless motor according to an embodiment of the present invention;

FIG. 3 is a block diagram of an embodiment of a motor control system provided by the present invention;

FIG. 4 is a schematic diagram of an inverter circuit in one embodiment of a motor control system according to the present invention;

fig. 5 is a timing diagram of bridge arm control signals of an inverter circuit in an embodiment of a motor control system provided in the present invention.

Detailed Description

The core of the utility model is to provide a DC brushless motor and a motor control system, which disperse tangential force at the junction of two poles by staggering two permanent magnet cylinders at a preset angle, reduce torque fluctuation and improve operation stability. Another core of the present invention is to provide a rail train comprising the above system.

In order that those skilled in the art will better understand the disclosure, the utility model will be described in further detail with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1 and fig. 2, fig. 1 is a schematic top view illustrating a dc brushless motor according to an embodiment of the present invention; fig. 2 is a schematic front view of a dc brushless motor according to an embodiment of the present invention.

The utility model provides a brushless direct-current motor which comprises a rotor and a stator arranged in the rotor, wherein the stator is a plurality of groups of three-phase armature windings 2 which are arranged in a staggered mode along the circumference, namely the stator comprises a plurality of groups of U-phase armature windings, V-phase armature windings and W-phase armature windings. The rotor comprises two permanent magnet cylinders 1, the two permanent magnet cylinders 1 are coaxially arranged and connected at the ends to form a complete sleeve structure, a plurality of groups of three-phase armature windings 2 are arranged in the sleeve structure as a stator, each permanent magnet cylinder 1 comprises a plurality of N poles and a plurality of S poles, the N poles and the S poles are arranged in a staggered mode along the circumference, namely, the arc-shaped plate-shaped N poles and the S poles are arranged in a staggered mode to form a cylinder structure, the N poles and the S poles have the same size, and the magnetic poles are uniformly arranged, further, the two permanent magnet cylinders 1 have the same structure, namely, the arc lengths of the magnetic poles are the same, the two permanent magnet cylinders 1 are arranged in a staggered mode, namely, the complete cylinder structure is still formed in the shape, but the magnetic poles are staggered, the N poles are not opposite to the S poles, and one magnetic pole is staggered due to the same arc length of each magnetic pole, other magnetic poles are also staggered, each magnetic pole in one permanent magnet cylinder 1 is staggered with a corresponding magnetic pole with the same polarity in the other permanent magnet cylinder 1 by a first preset angle, as can be seen from fig. 2, the N pole of the upper permanent magnet cylinder 1 simultaneously contacts the N pole and the S pole of the lower permanent magnet cylinder 1, the S pole of the lower permanent magnet cylinder 1 also simultaneously contacts the N pole and the S pole of the lower permanent magnet cylinder 1, in fig. 1, the outer circle solid line represents the upper permanent magnet cylinder 1, and the dotted line represents the lower permanent magnet cylinder 1.

By staggering two permanent magnet cylinders 1 at a preset angle, the tangential force at the junction of the two poles is dispersed, the torque fluctuation is reduced, and the running stability is improved.

Further, the staggered angle between the upper permanent magnet cylinder 1 and the lower permanent magnet cylinder 1 is not suitable to be too large, because the transverse magnetic field generated between the same layers is the magnetic field actually worked by the motor, and the longitudinal magnetic field generated between the upper layer and the lower layer cannot work on the armature. As the stagger angle increases, the longitudinal magnetic field increases, resulting in a decrease in motor torque. According to experience, the staggered preset angle α is preferably 1/6 degrees of the mechanical angle occupied by a single magnetic pole, and taking a three-pole logarithmic motor as an example, each permanent magnet cylinder 1 comprises three N poles and three S poles, the mechanical angle occupied by the single magnetic pole is 60 degrees, the first preset angle is 10 degrees, and the three-phase permanent magnet cylinder further comprises three groups of three-phase armature windings 2. The larger the offset angle is, the smaller the torque fluctuation is, but the larger the torque loss is, and correspondingly, the smaller the offset angle is, the larger the torque fluctuation is, but the smaller the torque loss is.

On the basis of the dc brushless motor provided in each of the above embodiments, the tangential forces applied to the armature winding at different positions are different, and in order to obtain a larger torque, the accurate position of the armature winding needs to be known, so three hall sensors 3 are sequentially installed on the three-phase armature winding 2 along the circumference, the distance between two adjacent hall sensors 3 is 20 degrees, the distance between the hall sensor 3 located at the outer side and the boundary of the armature winding is a second preset angle β, and the second preset angle β is 20 degrees minus one half of the first preset angle α, that is, β is 20- α/2. Through above-mentioned arrangement, can reduce the moment loss, reach bigger output torque to and higher efficiency.

Referring to fig. 3, fig. 3 is a block diagram of a motor control system according to an embodiment of the present invention.

The utility model further provides a motor control system, which comprises a main chip, a safety protection chip, a signal processing chip, a switching power supply, a driver, an inverter, three-phase EMI, a bridge rectifier circuit and the DC brushless motor provided in the above embodiment, wherein the main chip is connected with each component and used for controlling the operation of the DC brushless motor and monitoring the state of the DC brushless motor, the safety protection chip is connected with the driver and the DC brushless motor and used for turning off the driver or resetting the main chip in an abnormal state, and the signal processing chip is used for signal input and output and is communicated with the main chip. Further, the signal processing chip and the main chip are isolated through the optical coupling isolator in a communication mode, and the switching power supply comprises an isolation side power supply connected with the signal processing chip and a non-isolation side power supply connected with the main chip.

Specifically, the three-phase EMI is arranged at the input end of a three-phase power supply of the motor, the three-phase 380V/50Hz alternating current is provided by a vehicle auxiliary system and is connected with a bridge rectifier circuit, the purpose of inhibiting the electromagnetic interference of the three-phase input power supply is achieved, and the power utilization quality is improved. The bridge rectifier circuit full-wave rectifies the three-phase alternating current subjected to the three-phase EMI treatment into intermediate direct current voltage for supplying to a switching power supply and an inverter. An inverter circuit in the inverter inverts the intermediate dc voltage to an ac square wave voltage, which is supplied to a three-phase armature winding 2 of the motor. The Hall sensor 3 adopts a magnetic-sensing position sensor, converts the collected rotor position signals into electric signals and transmits the electric signals to the control circuit, and the control circuit and the control algorithm determine the conduction sequence and the on-off time of the armature windings of each phase so as to control the power module.

The signal processing chip is responsible for collecting input digital/analog signals including but not limited to 485 bus signals, 4-20mA current signals and 0-10V voltage signals and controlling output digital/analog signals including but not limited to fault reporting signals and running state signals. The signal processing chip and related peripheral circuits are isolated from the main circuit through an isolator, and the communication with the main chip is also isolated through an optical coupler isolator by using an independent isolation power supply and an isolation ground. All input and output signals are processed by the signal processing chip, then are transmitted to the main chip through the dual-computer communication after being isolated by the isolator, so that the interference of external input/output to the main chip can be effectively prevented, and the system stability is improved. The main chip is responsible for the control work of the direct current brushless motor, provides a driving signal, monitors the running state of the motor in real time and ensures the normal running of the motor. The safety protection chip is responsible for monitoring the running state of the motor, and once the abnormality is found, the driver can be switched off or the main chip can be reset, so that the abnormal running of the motor caused by the fault of the main chip can be prevented. Furthermore, the driver performs PWM driving according to 6 paths of PWM signals output by the main chip to enhance the on-off of two power tubes on the same bridge arm in the driving inverter circuit, and meanwhile, an overcurrent detection and protection module is integrated in the driver, so that once the system has an overcurrent fault, the output of the driver stops the motor, and the function of protecting the circuit is achieved. The intermediate direct current loop of the switching power supply gets electricity and is converted into two low-voltage power supplies through a high-frequency transformer, wherein one low-voltage power supply is an isolated side power supply and supplies power for the signal input module, and the other low-voltage power supply is a non-isolated side power supply and supplies power for the motor control circuit.

In the working process, the signal processing chip is responsible for input and output control, firstly collects externally input rotating speed and torque signals, converts the externally input rotating speed and torque signals into digital signals, sends the digital signals to the main chip through the isolator, then receives feedback signals returned by the main chip, and outputs the feedback signals through the output circuit. The main chip is responsible for driving and managing the motor, firstly receives rotating speed and torque signals from the signal processing chip through the isolator, and then collects state information of the motor, including voltage, current, temperature, Hall and the like. Under the condition that the motor is in a normal state, namely no overcurrent, overvoltage or overtemperature occurs, the controller sets the output duty ratio value according to the rotating speed and sets the output phase sequence according to the position of the Hall sensor 3. Once an abnormality occurs, the drive is turned off until normal.

By adopting the three-chip control scheme, the three chips respectively undertake independent work, do not interfere with each other, are physically and electrically isolated, can enhance the stability and reliability of the motor control system, and prolong the service life of the motor.

Referring to fig. 4 and 5, fig. 4 is a schematic diagram of an inverter circuit in an embodiment of a motor control system provided in the present invention; fig. 5 is a timing diagram of bridge arm control signals of an inverter circuit in an embodiment of a motor control system provided in the present invention.

The specific embodiment of the present invention further provides a method for controlling a dc brushless motor, which is used to control the dc brushless motor provided in the above specific embodiment, and includes the steps of:

according to the position of the three-phase armature winding 2 obtained by the Hall sensor 3, judging that the three armature windings are an optimal stressed armature winding, a sub-optimal stressed armature winding and a difference stressed armature winding;

the optimal stressed armature winding is electrified in the forward direction and fully electrified, the next optimal stressed armature winding is electrified in the reverse direction and fully electrified, and the differential stressed armature winding is electrified with 0 voltage;

in the same Hall state rotating process, the best stressed armature winding keeps being electrified in a forward direction to full power, the next best stressed armature winding is electrified and reduced from reverse full power to 0 voltage, and the difference stressed armature winding is electrified and increased from 0 voltage to reverse full power;

rotating to enter a next Hall state, wherein the former best stressed armature winding is changed into a second best stressed armature winding, the former second best stressed armature winding is changed into a difference armature winding, and the former difference armature winding is changed into a best stressed armature winding;

in the rotating process in the Hall state, the optimal stressed armature winding keeps being electrified reversely to full power, the power on of the sub-optimal stressed armature winding is reduced from the positive full power to 0 voltage, and the power on of the sub-optimal stressed armature winding is increased from the 0 voltage to the positive full power;

and rotating to enter a Hall state and then moving downwards, and repeating the winding change and the electrifying process.

Specifically, six hall states are included, each occupying 40 degrees of mechanical angle. Further, the duty ratios of the three-phase armature winding 2 are sin (ang × 90/40) duty _ x, and cos (ang × 90/40) duty _ x, respectively, where ang is the motor rotation angle, and duty _ x is the current duty ratio of the motor.

As can be seen from fig. 4, the inverter circuit has three arms, each of which is composed of an upper part and a lower part, i.e., H1, L1, H2, L2, H3, and L3, and controls the on-off of the upper and lower arms to control the voltage of the corresponding armature winding, and the motor windings are generally star-connected. The existing control method cannot exert the maximum torque of the motor, and in addition, the motor efficiency is damaged because the motor is not always selected to be electrified by an optimal armature.

The control method provided by the specific embodiment of the utility model firstly obtains the position of each phase of armature winding according to the Hall sensor 3, thereby calculating the three armature windings as the optimal stressed armature winding, the sub-optimal stressed armature winding and the difference stressed armature winding. The inverter can control the armature windings to be in three states, namely positive electricity, negative electricity and suspension, so that the best stressed armature winding is fully electrified, can be fully electrified in a positive direction or fully electrified in a negative direction, the other two armature windings are electrified in a reverse direction, namely the best stressed armature winding is electrified in the positive direction, the other two armature windings are electrified in the negative direction, the best stressed armature winding is electrified in the negative direction, and the other two armature windings are electrified in the positive direction. And in the case of full power supply relative to the current motor state, for example, if the current duty ratio is 50%, 50% of the full power supply is considered as the full power supply state, and the other two windings are distributed with corresponding duty ratios according to the current stress trend. And combining the distance of the following table, wherein the following table is a Hall state and phase sequence relation logic table. Positive represents that the upper bridge arm is conducted and positive electricity is conducted; negative represents that the lower bridge arm is conducted and is electrified negatively; ") activate, increasing from 0 to a set duty cycle; "↓" represents a trend decrease from the set duty cycle down to 0. The following table shows the hall states and the positive and negative voltages applied to the windings, which are related to the hall placement positions and the winding direction of the windings. This example only illustrates the control algorithm and does not list all combinations.

When the Hall state is 000, the V phase is the optimal stressed armature winding and is electrified with positive full voltage, the W phase is the sub-optimal stressed armature winding and is electrified with negative full voltage, the U phase is the differential stressed armature winding and is electrified with 0 voltage, the V phase is kept electrified with positive full voltage, the W phase is electrified to be reduced from the reverse full voltage to the 0 voltage, and the U phase is electrified to be increased from the 0 voltage to the reverse full voltage in the rotating process in the 000 state.

At the moment, a Hall state of moving downwards is entered, a 100 state is entered, a U phase is changed into an optimal stressed armature winding, a V phase is changed into a second optimal stressed armature winding, a W phase is changed into a poor stressed armature winding, actually, when the 000 state rotates over half, a U phase voltage starts to be equal to a W phase voltage, the U phase is upgraded into the second optimal stressed armature winding, the W phase voltage is changed into the poor stressed armature winding until the voltage change is completed, a 100 state is entered, the U phase is changed into the optimal stressed armature winding, and the V phase is changed into the second optimal stressed armature winding.

In the rotating process in the 100 state, the U phase is kept to be electrified and negatively charged, the V phase is electrified and reduced to 0 voltage from the positive full power, the W phase is electrified and increased to the positive full power from 0 voltage, therefore, after the state of 110, the W phase is changed into the best stressed armature winding, the U phase is changed into the second best stressed armature winding, the V phase is changed into the poor stressed armature winding, and the optimal electrification is realized according to the above steps of the above-mentioned cycle. By the control method, the armature windings can be positioned at a better stress point by adopting an optimal electrifying mode, so that the torque of the motor is increased, and the efficiency of the motor is improved.

The variation of the suboptimal stressed armature winding and the difference stressed armature winding follows a sine relationship. And according to the current rotating speed and the current time, the current rotating angle can be obtained. The mechanical angle (0-40 degrees) of each state is firstly linearized to (0-90 degrees), then sine/cosine is taken, and then the current duty ratio is multiplied, so that the final duty ratio can be obtained. Assume that in the 000 state, the motor has rotated ang °, and the duty cycle of the current motor is duty _ x. The control signal duty ratios of the legs (upper V leg, lower U, W leg) corresponding to the U/V/W armature winding are sin (ang x 90/40) duty _ x, and cos (ang x 90/40) duty _ x, respectively.

In addition to the motor control system, a rail train including the motor control system is provided in the embodiments of the present invention, and the structure of other parts of the rail train refers to the prior art and is not described herein again.

The dc brushless motor, the motor control system and the rail train provided by the present invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims (7)

1. The utility model provides a brushless DC motor, its characterized in that, includes two permanent magnet drums (1) that coaxial setting and tip link to each other, be provided with along circumference staggered arrangement 'S multiunit three-phase armature winding (2) in permanent magnet drum (1), every permanent magnet drum (1) all includes along circumference staggered arrangement' S a plurality of N utmost point and a plurality of S utmost point, two the structure of permanent magnet drum (1) is the same, and one each magnetic pole in permanent magnet drum (1) all with another the same polarity magnetic pole that corresponds in permanent magnet drum (1) staggers first preset angle.

2. The direct current brushless electric machine according to claim 1, characterized in that the first preset angle is one sixth of the mechanical angle occupied by a single pole inside the permanent magnet cylinder (1).

3. Brushless dc motor according to claim 2, characterized in that each permanent magnet cylinder (1) comprises three said N poles and three said S poles, a single said pole occupying 60 degrees of mechanical angle, said first preset angle being 10 degrees, comprising three sets of said three-phase armature windings (2).

4. The brushless direct-current motor according to any one of claims 1 to 3, wherein three Hall sensors (3) are sequentially mounted on the three-phase armature winding (2) along the circumference, two adjacent Hall sensors (3) are separated by a mechanical angle of 20 degrees, the Hall sensor (3) located at the outer side is separated by a second preset angle from the interface of the armature winding, and the second preset angle is 20 degrees minus one half of the first preset angle.

5. A motor control system is characterized by comprising a main chip, a safety protection chip, a signal processing chip, a switching power supply, a driver, an inverter and the direct current brushless motor according to any one of claims 1 to 4, wherein the main chip is connected with all parts and used for controlling the direct current brushless motor to operate and monitoring the state of the direct current brushless motor, the safety protection chip is connected with the driver and the direct current brushless motor and used for turning off the driver or resetting the main chip in an abnormal state, and the signal processing chip is used for signal input and output and is communicated with the main chip.

6. The motor control system of claim 5, wherein the signal processing chip and the main chip are communicatively isolated by an optocoupler isolator, and the switching power supply comprises an isolated side power supply connected to the signal processing chip and a non-isolated side power supply connected to the main chip.

7. A rail train comprising a heat sink and a motor control system connected to the heat sink, wherein the motor control system is specifically the motor control system of any one of claims 5 or 6.

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