A permanent magnet linear synchronous motor magnetic pole detection system

Abstract

The invention relates to a permanent magnet linear synchronous motor magnetic pole detection system, comprising at least one detection unit installed between fixed linear motor primary windings and used to detect the magnetic field signal of the moving linear motor secondary permanent magnet, and a signal processing unit connected to the detection unit; the detection unit comprises a plurality of Hall sensors, each of which generates a series of switch signals when the linear motor secondary permanent magnet passes by, and the signal processing unit processes these switch signals to generate three signals (ABP), the ABP signal is similar to an incremental encoder signal, and by analyzing the continuous ABP signals, the movement direction, movement speed and magnetic pole polarity information of the linear motor secondary permanent magnet can be determined, the design is ingenious, the signal quality is high, and the system performance is stable.

Description

[Technical field]

[0001] The invention relates to the technical field of linear motors, in particular to a permanent magnet linear synchronous motor magnetic pole detection system. [Background technology]

[0002] The permanent magnet linear synchronous motor consists of a primary (coil winding) and a secondary (permanent magnet). According to the structure, it is divided into two types: long primary, short secondary and short primary, long secondary. When three-phase alternating current is applied to the three-phase winding of the primary, a traveling wave magnetic field is generated in the air gap. The traveling wave magnetic field interacts with the permanent magnet of the secondary to generate electromagnetic thrust. If the primary is fixed, the secondary will move in a straight line along the direction of the traveling wave; conversely, if the secondary is fixed, the primary will move in the opposite direction of the traveling wave magnetic field under the action of the electromagnetic thrust.

[0003] Long primary and short secondary motors generally use the moving magnet installation method: the primary winding is fixedly arranged along the running direction, and the permanent magnet is fixed on the moving mechanism. The main advantage of this method is the simple structure: it is convenient for wiring and installation, and the movement method is also simple; the disadvantage is that the motor efficiency is low due to the long winding. This type of motor is mainly used in situations where short-distance high-speed movement is required.

[0004] Short primary and long secondary motors generally use the moving coil (winding) installation method: the permanent magnets are fixedly arranged along the running direction, and the windings are fixed on the moving mechanism. The main advantages of this method are high motor efficiency and flexible operation; the disadvantages are that since the windings are moving, the problem of running with wires (electricity) needs to be solved, and the environmental requirements for the equipment are high (magnetic field influence). This type of motor is mainly used in vertical lifting systems, production conveyor lines, and high-precision machine tools.

[0005] However, in some equipment occasions, due to application and structural limitations such as not allowing the laying of a large number of magnetic tracks, not allowing the moving body to be charged, or inconvenient for the moving body to obtain power, and at the same time, it is necessary to improve energy efficiency, the above-mentioned long primary, short secondary and short primary, long secondary structures are optimized: segmented long primary, short secondary structure.

[0006] The so-called segmented long primary and short secondary structure combines the advantages of the above two structures: multiple windings are arranged along the running track, and the secondary permanent magnets are installed on the moving parts. This installation method has a simple structure, and the moving parts are not charged, which greatly increases the safety of the equipment. Each winding segment and secondary permanent magnet can independently form a short primary and long secondary structure, and the motor efficiency is high.

[0007] The detection of the magnetic pole position of the secondary permanent magnet is the basis of synchronous motor control. Only by effectively identifying the position information of the motor's secondary magnetic pole can the motor winding power supply be controlled, and then the running direction and speed of the motor's secondary can be controlled. Traditional linear motor magnetic pole detection mainly uses the motor's built-in Hall sensor method: a Hall sensor is built into the winding to output UVW phase and AB direction signals, and the control driver controls the motor direction and speed through the signal. This method is widely used in low-power motors or short primary and long secondary linear motors, but for some high-power linear motors with relatively large heat generation, the built-in detection method is not feasible due to the influence of temperature on the sensor. Some also use external wire encoders or QR code sensors for position measurement, but they all have problems such as wired operation or limited detection space. [Summary of the invention]

[0008] To solve the above problems, the present invention provides a permanent magnet linear synchronous motor magnetic pole detection system, which adopts an external detection method, is not affected by motor heating, operates without belt lines, is not restricted by space or distance, has a clever design, and has stable system performance.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] A permanent magnet linear synchronous motor magnetic pole detection system comprises at least one detection unit installed between fixed linear motor primary windings and used to detect the magnetic field signal of the moving linear motor secondary permanent magnet, and a signal processing unit connected to the detection unit; the detection unit comprises a plurality of Hall sensors evenly arranged along the moving direction of the linear motor secondary permanent magnet, each of the Hall sensors generates a series of switch signals when the linear motor secondary permanent magnet passes by, and the signal processing unit processes these switch signals to generate three signals ABP that can be used to analyze the running direction, running speed and magnetic pole of the linear motor secondary permanent magnet.

[0011] As a preferred implementation, it is further defined as: the detection unit comprises at least four Hall sensors, and the Hall sensors are evenly arranged on the mounting base along the moving direction of the secondary permanent magnet of the linear motor.

[0012] As a preferred embodiment, it is further defined as: the secondary permanent magnet of the linear motor includes a plurality of groups of evenly arranged permanent magnetic pole pairs, and the Hall sensor should satisfy the following relationship between the installation width D1 of the detection unit and the pole pitch D2 of the permanent magnetic pole pair: D1≤D2.

[0013] As a preferred implementation, it is further defined as: the Hall sensors on the same detection unit are the same unipolar switch Hall sensors.

[0014] As a preferred implementation, it is further defined as: one of the detection units is electrically connected to one of the signal processing units.

[0015] As a preferred embodiment, it is further defined as: the signal processing unit includes an ABP signal generating chip, a signal processing chip, a power supply loop circuit, an isolation circuit, an input port, an output port and a signal port; the input end of the ABP signal generating chip is electrically connected to the output end of the isolation circuit, the input end of the isolation circuit is electrically connected to the detection port of the detection unit through the input port, the input port and the output end of the ABP signal generating chip are respectively electrically connected to the input end of the signal processing chip, and the output end of the signal processing chip is electrically connected to the output port; one end of the power supply loop circuit is electrically connected to the ABP signal generating chip, and the other end is electrically connected to the output port.

[0016] As a preferred implementation, it is further defined as: when there are multiple detection units, each detection unit corresponds to one signal processing unit, the output port of each signal processing unit is electrically connected to the input port of the next signal processing unit, and the output port of the last signal processing unit is electrically connected to the host computer or the driver.

[0017] As a preferred implementation, it is further defined as: when there are multiple detection units, the installation spacing D3 between two adjacent detection units and the length D4 of the secondary permanent magnet of the linear motor should satisfy the following relationship: D3<D4.

[0018] The beneficial effect of the invention is that a detection unit for detecting the magnetic field signal of the secondary permanent magnet of the linear motor is arranged between the primary windings of the linear motor, and an ABP signal is generated by a signal processing unit electrically connected to the detection unit. The ABP signal is similar to an incremental encoder signal, and by analyzing the continuous ABP signal, the movement direction, movement speed and magnetic pole polarity information of the secondary permanent magnet of the linear motor can be determined. The design is ingenious, the signal quality is high, and the system performance is stable.

[0019] In addition, the external detection unit is not restricted by the structure of the primary winding of the linear motor, nor is it affected by the heating of the motor, and the signal quality is high.

Brief Description of the Drawings

[0020] Figure 1 It is a structural schematic diagram of the invention;

[0021] Figure 2 yes Figure 1 The enlarged schematic diagram at A in the middle;

[0022] Figure 3 It is a schematic diagram of the structure of the detection unit using four Hall sensors;

[0023] Figure 4 It is the circuit schematic diagram of the signal processing unit;

[0024] Figure 5 yes Figure 4 The circuit schematic diagram of the isolation circuit;

[0025] Figure 6 yes Figure 4 Circuit diagram of the power supply loop circuit;

[0026] Figure 7 It is a waveform diagram of the input signal and output signal of the ABP signal generation chip when four Hall sensors are used as detection units. [Specific implementation method]

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0028] As attached Figure 1 To Attachment Figure 3 As shown, a permanent magnet linear synchronous motor magnetic pole detection system is suitable for a permanent magnet linear synchronous motor with a segmented long primary and short secondary structure, including at least one detection unit 1 installed between fixed linear motor primary windings 4 and used to detect the magnetic field signal of the moving linear motor secondary permanent magnet 5, and a signal processing unit 2 connected to the detection unit 1; the detection unit 1 includes a plurality of Hall sensors 12 evenly arranged along the moving direction of the linear motor secondary permanent magnet 5, each of the Hall sensors 12 will generate a series of switch signals when the linear motor secondary permanent magnet 5 passes, and the signal processing unit 2 processes these switch signals to generate three signals ABP that can be used to analyze the running direction, running speed and magnetic pole of the linear motor secondary permanent magnet 5, and the ABP signal has a similar function to the incremental encoder signal. By analyzing the continuous ABP signal, the moving direction, moving speed and magnetic pole polarity information of the linear motor secondary permanent magnet can be determined, and the design is ingenious, the signal quality is high, and the system performance is stable.

[0029] In this embodiment, the number of detection units 1 is not limited, and each detection unit 1 is connected to a signal processing unit 2. By electrically connecting all signal processing units 2 in sequence, a complete detection system is formed, and the ABP signal generated by the detection system can be fed back to the host computer or driver 3. The detection unit 1 includes at least four Hall sensors 12, and the Hall sensors 12 are evenly arranged on the mounting base plate 11 along the moving direction of the secondary permanent magnet 5 of the linear motor. When the secondary permanent magnet 5 of the linear motor passes by, each sensor 12 can generate a continuous square wave signal individually and is connected to the signal processing unit 2 through the detection port 13.

[0030] In this embodiment, the secondary permanent magnet 5 of the linear motor includes a plurality of groups of evenly arranged permanent magnetic pole pairs 6, and the Hall sensor 12 should satisfy the following relationship between the installation width D1 of the detection unit 1 and the pole pitch D2 of the permanent magnetic pole pair 6: D1≤D2, so that the four Hall sensors can detect the same permanent magnetic pole pair 6 within a certain period of time to ensure the accuracy of the detection. The Hall sensors 12 on the same detection unit 1 are the same unipolar switch Hall sensors 12.

[0031] As attached Figure 4 To Attachment Figure 6 As shown, the signal processing unit 2 includes an ABP signal generating chip 21, a signal processing chip, a power supply loop circuit, an isolation circuit, an input port, an output port and a signal port; the input end of the ABP signal generating chip 21 is electrically connected to the output end of the isolation circuit, the input end of the isolation circuit is electrically connected to the detection port 13 of the detection unit 1 through the input port, the input port and the output end of the ABP signal generating chip 21 are electrically connected to the input end of the signal processing chip respectively, and the output end of the signal processing chip is electrically connected to the output port; the input port INPUT includes VCC, GND, A, B and P terminals, the output port OUTPUT includes VCC, GND, A, B and P terminals, and the signal port SENSOR includes VCC, GND, S1, S2, S3, S4 and other terminals. The isolation circuit is a photoelectric isolation circuit, which performs voltage isolation on the input detection unit signal to ensure the stability of the chip input signal voltage. In order to meet the chip voltage requirement, one end of the power loop circuit is electrically connected to the ABP signal generating chip 21, and the other end is electrically connected to the output port, and the power loop circuit plays a role in power supply voltage stabilization and voltage regulation.

[0032] In this embodiment, there may be multiple detection units, and multiple detection units 1 are arranged between the fixed primary windings of the linear motor. The number of the signal processing units 2 corresponds to the detection units 1 one by one. Starting from the first signal processing unit, the output port of each signal processing unit 2 is electrically connected to the input port of the next signal processing unit 2, and the output port of the last signal processing unit 2 can be electrically connected to the host computer or the driver 3. The signal output by the detection unit 1 is connected to the isolation circuit through the signal port of the signal processing unit 2, and is electrically connected to the ABP signal generation chip 21 after passing through the isolation circuit. The ABP signal generation chip 21 generates a corresponding ABP signal through algorithm processing, and the ABP signal is transmitted to the signal processing chip. The signal processing chip integrates the ABP signal output by the front-end signal processing unit with the ABP signal generated by the current signal processing unit, and generates a new ABP signal, which is transmitted to the next signal processing unit or the driver through the output port.

[0033] like Figure 7The figure shows the waveform relationship between the input and output signals of the signal generation chip in the signal processing unit in the detection system taking four Hall sensors as an example. When the linear motor pole permanent magnet passes through the detection unit, the four Hall sensors 12 on the detection unit 1 generate square wave signals S1, S2, S3 and S4. Since the four Hall sensors 12 are evenly distributed along the moving direction of the secondary permanent magnet 5 of the linear motor, there is the same phase difference between the four square wave signals. When there are multiple detection units 1, the installation spacing D3 between two adjacent detection units 1 and the length D4 of the secondary permanent magnet 5 of the linear motor should satisfy the following relationship: D3<D4, so as to ensure that the ABP signal fed back to the host computer or driver 3 is a continuous square wave signal.

[0034] In this embodiment, the host computer or driver 3 controls the power-on state of the primary winding 4 of the linear motor. After the primary winding 4 of the linear motor is powered on, the secondary permanent magnet 5 of the linear motor can move relative to the primary winding 4 of the linear motor. The four Hall sensors 12 on the detection unit 1 detect and sense the permanent magnetic pole pair 6. When the linear motor magnetic pole permanent magnet passes through the detection unit 1, the four Hall sensors 12 on the detection unit 1 will generate continuous square wave signals S1, S2, S3 and S4. Since there is the same phase difference between the four square wave signals, the signal processing unit 2 processes the detection signal of the detection unit 1 to form an ABP signal, and finally transmits the ABP signal to the host computer or driver 3. The host computer or driver 3 compares and calculates the preset given speed and the detected ABP signal and outputs a three-phase current. The speed control of the secondary permanent magnet 5 of the linear motor is achieved by controlling the three-phase current of the primary winding 4 of the linear motor, forming a closed-loop control. The design is ingenious and precise control of the secondary permanent magnet 5 of the linear motor is achieved.

Claims

1. A permanent magnet linear synchronous motor magnetic pole detection system, characterized in that It comprises at least one detection unit (1) installed between fixed primary windings (4) of a linear motor and used to detect magnetic field signals of a moving secondary permanent magnet (5) of the linear motor, and a signal processing unit (2) connected to the detection unit (1); the detection unit (1) comprises a plurality of Hall sensors (12) evenly arranged along the moving direction of the secondary permanent magnet (5) of the linear motor, each of the Hall sensors (12) generating a series of switch signals when the secondary permanent magnet (5) of the linear motor passes by, the signal processing unit (2) processing the switch signals to generate three ABP signals that can be used to analyze the running direction, running speed and magnetic pole of the secondary permanent magnet (5) of the linear motor, and each sensor (12) can generate a continuous square wave signal individually when the secondary permanent magnet (5) of the linear motor passes by, and is connected to the signal processing unit (2) through a detection port (13); The linear motor secondary permanent magnet (5) comprises a plurality of groups of evenly arranged permanent magnetic pole pairs (6), and the installation width D1 of the Hall sensor (12) on the detection unit (1) and the pole pitch D2 of the permanent magnetic pole pair (6) satisfy the following relationship: D1≤D2, so that the four Hall sensors can detect the same permanent magnetic pole pair (6) within a certain period of time; The signal processing unit (2) comprises an ABP signal generating chip (21), a signal processing chip, a power supply loop circuit, an isolation circuit, an input port, an output port and a signal port; the input end of the ABP signal generating chip (21) is electrically connected to the output end of the isolation circuit, the input end of the isolation circuit is electrically connected to the detection port (13) of the detection unit (1) via the input port, the input port and the output end of the ABP signal generating chip (21) are electrically connected to the input end of the signal processing chip respectively, and the output end of the signal processing chip is electrically connected to the output port; one end of the power supply loop circuit is electrically connected to the ABP signal generating chip (21), and the other end is electrically connected to the output port; When there are multiple detection units (1), the installation spacing D3 between two adjacent detection units (1) and the length D4 of the secondary permanent magnet (5) of the linear motor should satisfy the following relationship: D3<D4, so as to ensure that the ABP signal fed back to the host computer or the driver (3) is a continuous square wave signal; The detection unit (1) comprises at least four Hall sensors (12), and the Hall sensors (12) are evenly arranged on a mounting base plate (11) along a moving direction of the secondary permanent magnet (5) of the linear motor.

2. The permanent magnet linear synchronous motor magnetic pole detection system according to claim 1 is characterized in that The Hall sensors (12) on the same detection unit (1) are identical unipolar switch Hall sensors (12).

3. The permanent magnet linear synchronous motor magnetic pole detection system according to claim 1 is characterized in that One of the detection units (1) is electrically connected to one of the signal processing units (2).

4. The permanent magnet linear synchronous motor magnetic pole detection system according to any one of claims 1 to 3, characterized in that When there are multiple detection units (1), each detection unit (1) corresponds to one signal processing unit (2), the output port of each signal processing unit (2) is electrically connected to the input port of the next signal processing unit (2), and the output port of the last signal processing unit (2) is electrically connected to a host computer or a driver (3).

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