Permanent magnet segmented synchronous linear motor and vector control method based on switch Hall sensor

Abstract

The present invention relates to a permanent magnet segmented synchronous linear motor and vector control method based on a switch Hall sensor, and belongs to the field of motor control. Two groups of switch Hall position sensors are used, and a signal acquisition scheme that is mutually standby is designed, which solves the problem of Hall signal failure caused by the segmented interval of the permanent magnet; secondly, the square wave control technology of the brushless DC motor (BLDC) is used for reference, and the three-phase six-state 120° control method is applied to the startup phase of the sinusoidal permanent magnet synchronous linear motor, which solves the problem of startup jitter or even failure to start caused by the position estimation error in the startup phase to the vector control; for different modes (constant speed state or non-constant speed state) of given speed, the present invention respectively uses the average speed method and the average acceleration method to estimate the mover speed and electrical angle, thereby performing vector closed-loop control, enhancing the speed control performance of the system, and taking into account the simplicity and reliability of the algorithm.

Description

Technical Field

[0001] The invention belongs to the technical field of motor drive control, and in particular relates to a permanent magnet segmented synchronous linear motor vector control method based on a switch Hall sensor. Background Art

[0002] The permanent magnet synchronous linear motor has a simple structure, a high speed limit, and excellent speed regulation capability, which can meet the increasing speed requirements of the logistics sorting system. The primary of the linear motor is fixed, and the secondary is segmented and fixed to the bottom of the mobile device, which can form the basic power unit for logistics sorting; according to the logistics sorting stroke, the number of permanent magnet segments can be flexibly adjusted.

[0003] However, due to the secondary segmentation and long-stroke characteristics of logistics sorting, the traditional encoder position feedback solution has problems such as difficult installation, increased cost and reduced reliability, while the low-speed speed control performance and anti-interference ability of the position sensorless control technology need to be improved.

[0004] The position feedback solution based on the switch Hall position sensor has low cost, simple structure and high reliability. Combined with the position sensorless control technology, it can realize the vector control of the permanent magnet synchronous motor, thereby giving full play to the superior speed regulation performance of the permanent magnet synchronous linear motor.

[0005] The technical solution in the invention patent with patent number 201010166572.9 requires the use of a large number of switch Hall sensors to feedback the position of the mover, which not only increases the production cost, but also increases the probability of damage and the difficulty of maintenance due to the complex structure. Patent application CN201910377391.1 uses three switch Hall elements equidistantly distributed in three consecutive coils to estimate the mover speed and position based on the average speed method. Since the abnormal Hall signal caused by the secondary segment interval is not considered, it cannot be applied to the permanent magnet segmented linear motor system. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a permanent magnet segmented synchronous linear motor and a vector control method based on a switch Hall sensor, so as to reduce the cost of the permanent magnet segmented synchronous linear motor used in a logistics sorting system and improve the linear motion speed control performance.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is: a permanent magnet segmented synchronous linear motor based on a switch Hall sensor, comprising a primary component, a secondary component and a Hall element; the primary component is composed of a primary iron core and an armature winding, and the secondary component is composed of a plurality of segmented secondary permanent magnets; the Hall element adopts 6 switch Hall elements, which are divided into two groups, and the Hall elements in the group are equidistantly distributed with a distance of 2τ / 3, where τ is the pole pitch, and the corresponding positions of the two groups of Hall elements are 2kτ apart, and k is a preset integer greater than 1; the Hall element is placed on the outside of the winding, and the center axis of the Hall element close to the end of the primary component is Nτ / 6 away from the center axis of the end slot of the primary component, and N is a preset integer.

[0008] Furthermore, the installation position of the Hall element is relatively fixed to the position of the primary component.

[0009] Furthermore, the sequence of the armature winding coils is CYAZBX.

[0010] The present invention also provides a vector control method for a permanent magnet segmented synchronous linear motor based on a switch Hall sensor, comprising the following steps:

[0011] (1) Detect 6 Hall signals, judge and select a group of normal Hall signals as the main signal, and estimate the speed and position of the mover;

[0012] (2) When the Hall signal jumps for the third time or more, the vector control mode is entered; before the mover speed reaches the rated value, the mover is accelerated to the rated speed at a preset acceleration; in the uniform acceleration stage, the average acceleration method is used to estimate the mover speed and position, and in the uniform speed stage, the average speed method is used to estimate the mover speed and position;

[0013] (3) The speed of the mover is fed back to the PI controller, which outputs the given value of the quadrature-axis current. The three-phase current is transformed according to the position estimation result of the mover to obtain the feedback value of the quadrature-axis and direct-axis current. The PI controller is used to output the given voltage value of the quadrature-axis and direct-axis. After the coordinate transformation, the given voltage in the two-phase stationary coordinate system is obtained and output to the SVPWM to modulate into a 6-way switch tube drive signal, driving the inverter to apply a specific voltage vector to the motor, thereby completing the speed and current dual closed-loop vector control of the permanent magnet linear motor.

[0014] Furthermore, the specific steps of the vector control mode in step (2) are:

[0015] Step 1: Every time the Hall signal changes, you need to record the holding time Δt of the first two Hall signal intervals. p2 and Δt p1 , and update the initial electrical angle θ of the Hall interval r0 ;

[0016] Step 2: Based on the average velocity method, get the average angular velocity ω of the first two Hall signal intervals p2 and ω p1 , the formula is as follows:

[0017]

[0018] Step 3: Determine whether the speed setting state is acceleration state or constant speed state:

[0019] When the mover is in the accelerating state, the average angular acceleration a1 of the first two Hall intervals is calculated using the following formula:

[0020]

[0021] Calculation of the rotor electrical angle θ in the rotor acceleration state based on the average acceleration method r and the rotor speed v, the formula is as follows:

[0022] Where Δt c Hold time for the current Hall interval;

[0023] When the mover is in a uniform speed state, the electrical angle θ of the mover is calculated based on the average velocity method. r and the rotor speed v, the formula is as follows:

[0024] Where Δt c Hold time for the current Hall interval.

[0025] Furthermore, before the third jump of the Hall signal occurs, a PI current controller is used to control the bus current value. According to the state of the Hall signal, the conduction winding is selected, and three-phase six-state 120° commutation control is adopted. The modulation method adopts the on-pwm method. For the switch tube that is turned on for 120°, the first 60° interval remains in the on state, and the second 60° interval uses PWM chopping to control the on and off of the corresponding switch tube of the inverter.

[0026] Furthermore, in the step (1), 20 ns is used as a fault detection cycle to detect whether the main signal is faulty. When a main signal fault is detected, the backup Hall signal is set as the main signal, and the previous main signal is set as the backup signal, and the mover speed and position are estimated based on the main signal.

[0027] Furthermore, during the fault detection cycle, it is detected whether the combination of the three Hall signals of the main signal is one of the basic Hall signal combination states. If not, it is determined to be a fault.

[0028] The advantages of the present invention are specifically as follows:

[0029] (1) The present invention adopts a switch Hall position sensor to perform closed-loop vector control on a permanent magnet segmented linear motor, thereby simplifying the structure of the motion system and improving reliability. In view of the segmented characteristics of the permanent magnet, a solution for installing and processing two sets of Hall elements is proposed, thereby solving the problem of position signal errors caused by the segmented gap of the permanent magnet.

[0030] (2) In the first Hall interval, the BLDC control method is adopted to control the DC current of the corresponding winding according to the Hall interval state to ensure the smooth starting of the permanent magnet synchronous motor; in different motion states of the mover, different position estimation algorithms are used to improve the accuracy of speed and position estimation, and ultimately improve the vector control performance of the permanent magnet synchronous linear motor based on the Hall switch sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the permanent magnet segmented synchronous linear motor described in the present invention.

[0032] Figure 2 This is a schematic diagram of the Hall element installation solution of the present invention.

[0033] Figure 3 It is a schematic diagram of the Hall signal and the start-up period PWM modulation method of the present invention.

[0034] Figure 4 It is the vector control flow chart of the present invention.

[0035] Description of the accompanying drawings: 1-primary iron core; 2-armature winding; 3-secondary permanent magnet. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation modes of the present invention are further described below in conjunction with specific drawings.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] Embodiment 1:

[0039] like Figure 1As shown, the permanent magnet segmented synchronous linear motor based on the switch Hall sensor described in this embodiment adopts a 30-slot 10-pole structure, including a primary component, a secondary component and a Hall element; the primary component is composed of a primary iron core 1 and an armature winding 2, and the coil sequence of the armature winding 2 is CYAZBX; the secondary component is composed of a plurality of segmented secondary permanent magnets 3, the pole pitch τ is 50 mm, and the segment interval d of the secondary permanent magnet 3 is 100 mm.

[0040] The installation position of the Hall element is relatively fixed to the position of the primary component. The Hall element is placed outside the winding. The installation method is as follows Figure 2 As shown. The Hall elements are divided into two groups of Hall elements, namely the first group of Hall elements and the second group of Hall elements, and the two groups of Hall elements are in standby relationship with each other; the first group of Hall elements includes 3 Hall elements, namely the A-phase Hall element HallA1, the B-phase Hall element HallB1 and the C-phase Hall element HallC1; the second group of Hall elements includes 3 Hall elements, namely the A-phase Hall element HallA2, the B-phase Hall element HallB2 and the C-phase Hall element HallC2; a total of 6 Hall elements. The spacing between the Hall elements in each group is 2τ / 3 (33.3mm in this embodiment).

[0041] In order to ensure that at any time, at least one of the signals of the two groups of Hall elements can contain the correct position information of the mover, the spacing between the two groups of Hall elements is set to d (set to 100mm in this embodiment), that is, the spacing between the A-phase Hall element HallA1 of the first group and the A-phase Hall element HallA2 of the second group is 2d (200mm in this embodiment), and similarly, the spacing between the B-phase Hall element HallB1 of the first group and the B-phase Hall element HallB2 of the second group is also 2d, and the spacing between the C-phase Hall element HallC1 of the first group and the C-phase Hall element HallC2 of the second group is also 2d. In order to achieve three-phase six-state 120° control in the first Hall element interval, the installation position of the A-phase Hall element HallA1 of the first group needs to make the output signal of the A-phase Hall element HallA1 of the first group or the A-phase Hall element HallA2 of the second group jump when the rotor flux electrical angle is 30°. Since the end winding coil of the primary component is X-phase, it is necessary to ensure during installation that the distance between the axis of the first group of A-phase Hall element HallA1 and the axis of the end slot of the primary component is 7τ / 6 (58.3mm in this embodiment), which is equivalent to an electrical angle of 210°.

[0042] Embodiment 2:

[0043] like Figure 4 As shown, the vector control method of the permanent magnet segmented synchronous linear motor based on the switch Hall sensor described in this embodiment includes the following steps:

[0044] (1) Detect 6 Hall signals, judge and select a group of normal Hall signals as the main signal, estimate the speed and position of the mover, use 20ns as the fault detection cycle, detect whether the main signal is faulty, and when the main signal fault is detected, set the backup Hall signal as the main signal, and the previous main signal as the backup signal, and estimate the speed and position of the mover based on the main signal; Specifically: The switch Hall installation method of Example 1 ensures that at least one of the two groups of Hall signals contains the correct mover position information. Within the fault detection cycle, detect whether the combination of the three Hall signals of the main signal is one of the basic Hall signal combination states. If not, it is judged as a fault.

[0045] (2) Before the Hall signal jumps for the third time, the bus current value is controlled by a PI current controller. According to the Hall signal state, the conduction winding is selected, and three-phase six-state 120° commutation control is adopted. The modulation mode adopts the on-pwm mode. For the switch tube that is turned on for 120°, the first 60° interval remains in the on state, and the latter 60° interval adopts PWM chopping to control the on and off of the corresponding switch tube of the inverter. It can start smoothly without the premise of precise position feedback. Specifically:

[0046] If the Hall element outputs a high level signal when it is close to the N pole of the secondary permanent magnet, the Hall signal combination and the A phase no-load back electromotive force e a The electrical angle correspondence is as follows Figure 3 As shown in Part 1. In order to ensure that the mover starts smoothly in the first Hall signal interval, the BLDC three-phase six-state 120° control method is adopted to control the inverter bus current through the PI controller;

[0047] The start-up state conduction winding corresponding to the motor electrical angle range is as follows Figure 3 As shown in Part 2 of the PWM modulation method, the on-pwm method is adopted, such as Figure 3 As shown in the third part, that is, in the 120° interval when the A-phase winding, the B-phase winding or the C-phase winding is turned on, the DC current is passed through the first 60° interval, and the PWM chopping current is passed through the second 60° interval, where T1 and T4 represent the upper bridge arm switch tube and the lower bridge arm switch tube of the inverter A phase, respectively, T3 and T6 represent the upper and lower tubes of the B phase, and T5 and T2 represent the upper and lower tubes of the C phase;

[0048] Taking the first Hall signal interval combination of HallA=0, HallB=1, HallC=0 as an example, that is, the electrical angle range of the mover is (30°, 90°), then T1 and T6 are turned on, and the remaining switches are disconnected. The T1 switch tube remains on before the Hall signal jumps, and the inverter bus current is fed back through the current sensor. The difference between the current set value is input into the PI current control, thereby controlling the duty cycle of the PWM chopping signal of the T6 switch tube.

[0049] (3) When the Hall signal jumps for the third time or more, an interrupt is triggered. In order to reduce the output thrust fluctuation, the control mode is switched from the BLDC startup mode to the sinusoidal permanent magnet motor vector control mode; before the mover speed reaches the rated value, the speed setting value is a ramp signal, so that the mover accelerates to the rated speed with a preset acceleration; in the uniform acceleration stage, the average acceleration method is used to estimate the mover speed and position, and in the uniform speed stage, the average speed method is used to estimate the mover speed and position; the vector control mode based on the switch Hall sensor specifically includes the following steps:

[0050] Step 1: Every time the Hall signal changes, you need to record the holding time Δt of the first two Hall signal intervals. p2 and Δt p1 , and update the initial electrical angle θ of the Hall interval r0 ;

[0051] Step 2: Based on the average velocity method, get the average angular velocity ω of the first two Hall signal intervals p2 and ω p1 , the formula is as follows:

[0052]

[0053] Step 3: Determine whether the speed setting state is acceleration state or constant speed state:

[0054] When the mover is in the accelerating state, the average angular acceleration a1 of the first two Hall intervals is calculated using the following formula:

[0055]

[0056] Calculation of the rotor electrical angle θ in the rotor acceleration state based on the average acceleration method r and the rotor speed v, the formula is as follows:

[0057] Where Δt c Hold time for the current Hall interval;

[0058] When the mover is in a uniform speed state, the electrical angle θ of the mover is calculated based on the average velocity method. r and the rotor speed v, the formula is as follows:

[0059] Where Δt c Hold time for the current Hall interval;

[0060] (4) The rotor speed v is fed back to the speed PI controller, and the quadrature-axis current set value is output. The direct-axis current set value is set to 0. According to the electrical angle of the rotor, the three-phase current is transformed to obtain the quadrature-axis and direct-axis current feedback values. The quadrature-axis and direct-axis current PI controllers are used to output the quadrature-axis and direct-axis set voltage values. Through Clark inverse transformation, the given voltage in the two-phase stationary coordinate system is obtained. Through SVPWM modulation, it is converted into 6-way switch tube drive signals to drive the inverter to apply a specific voltage vector to the motor, thereby completing the speed and current dual closed-loop vector control of the permanent magnet linear motor.

[0061] The above is a detailed introduction to a permanent magnet segmented synchronous linear motor and vector control method based on a switch Hall sensor provided by the present application. This article uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for general technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A permanent magnet segmented synchronous linear motor based on a switch Hall sensor, characterized in that: The invention comprises a primary component, a secondary component and a Hall element; the primary component comprises a primary iron core (1) and an armature winding (2); the secondary component comprises a plurality of segmented secondary permanent magnets (3); the Hall element adopts 6 switch Hall elements, which are divided into two groups; the Hall elements in each group are evenly distributed, with a distance of 2τ / 3, wherein τ is the pole pitch; the corresponding positions of the two groups of Hall elements are 2kτ apart, and k is a preset integer greater than 1; the Hall element is placed outside the winding, and the center axis of the Hall element at the end close to the primary component is Nτ / 6 apart from the center axis of the end slot of the primary component, where N is a preset integer.

2. The permanent magnet segmented synchronous linear motor based on switch Hall sensor according to claim 1, characterized in that: The installation position of the Hall element is relatively fixed to the position of the primary component.

3. The permanent magnet segmented synchronous linear motor based on switch Hall sensor according to claim 1, characterized in that: The coil sequence of the armature winding (2) is CYAZBX.

4. A vector control method for a permanent magnet segmented synchronous linear motor based on a switch Hall sensor as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Detect 6 Hall signals, judge and select a group of normal Hall signals as the main signal, and estimate the speed and position of the mover; (2) When the Hall signal jumps for the third time or more, the vector control mode is entered; before the mover speed reaches the rated value, the mover is accelerated to the rated speed at a preset acceleration; in the uniform acceleration stage, the average acceleration method is used to estimate the mover speed and position, and in the uniform speed stage, the average speed method is used to estimate the mover speed and position; (3) The speed of the mover is fed back to the PI controller, which outputs the given value of the quadrature-axis current. The three-phase current is transformed according to the position estimation result of the mover to obtain the feedback value of the quadrature-axis and direct-axis current. The PI controller is used to output the given voltage value of the quadrature-axis and direct-axis. After the coordinate transformation, the given voltage in the two-phase stationary coordinate system is obtained and output to the SVPWM to modulate into a 6-way switch tube drive signal, driving the inverter to apply a specific voltage vector to the motor, thereby completing the speed and current dual closed-loop vector control of the permanent magnet linear motor.

5. The vector control method of the permanent magnet segmented synchronous linear motor based on the switch Hall sensor according to claim 4, characterized in that: The specific steps of the vector control mode in step (2) are: Step 1: Every time the Hall signal changes, you need to record the holding time Δt of the first two Hall signal intervals. p2 and Δt p1 , and update the initial electrical angle θ of the Hall interval r0 ; Step 2: Based on the average velocity method, get the average angular velocity ω of the first two Hall signal intervals p2 and ω p1 , the formula is as follows: Step 3: Determine whether the speed setting state is acceleration state or constant speed state: When the mover is in the accelerating state, the average angular acceleration a1 of the first two Hall intervals is calculated using the following formula: Calculation of the rotor electrical angle θ in the rotor acceleration state based on the average acceleration method r and the rotor speed v, the formula is as follows: Where Δt c Hold time for the current Hall interval; When the mover is in a uniform speed state, the electrical angle θ of the mover is calculated based on the average velocity method. r and the rotor speed v, the formula is as follows: Where Δt c Hold time for the current Hall interval.

6. The vector control method of the permanent magnet segmented synchronous linear motor based on the switch Hall sensor according to claim 4, characterized in that: Before the third jump of the Hall signal, the bus current value is controlled by a PI current controller. According to the state of the Hall signal, the conduction winding is selected, and three-phase six-state 120° commutation control is adopted. The modulation method adopts the on-pwm method. For the switch tube that is turned on for 120°, the first 60° interval remains in the on state, and the second 60° interval uses PWM chopping to control the on and off of the corresponding switch tube of the inverter.

7. The vector control method of the permanent magnet segmented synchronous linear motor based on the switch Hall sensor according to claim 4, characterized in that: In the step (1), 20 ns is used as a fault detection cycle to detect whether the main signal is faulty. When a main signal fault is detected, the backup Hall signal is set as the main signal, and the previous main signal is set as the backup signal. The mover speed and position are estimated based on the main signal.

8. The vector control method of the permanent magnet segmented synchronous linear motor based on the switch Hall sensor according to claim 7, characterized in that: During the fault detection cycle, the three-way Hall signal combination of the main signal is detected to see if it is one of the basic Hall signal combination states. If not, it is determined to be a fault.

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