Zero angle test circuit structure of magnetic encoder

Abstract

A zero angle test circuit structure of a magnetic encoder comprises a first voltage stabilization module, a second voltage stabilization module and a comparator module. One end of the first voltage stabilization module is electrically connected to a first phase voltage of the permanent magnet synchronous motor, the first voltage stabilization module is connected in series with the comparator module, and the comparator module can measure a voltage value of the first voltage stabilization module; one end of the second voltage stabilization module is electrically connected to a second phase voltage of the permanent magnet synchronous motor, the second voltage stabilization module is connected in series with the comparator module, and the comparator module can measure a voltage value of the second voltage stabilization module; the comparator module is used for comparing the voltage value of the first voltage stabilizing module with the voltage value of the second voltage stabilizing module to control the electric angle of the motor so as to obtain the zero angle of a motor rotor; through the arrangement, the problem that a certain deviation exists between the position of the rotor and the real zero position at the moment due to interference of motor friction and cogging torque is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of magnetic encoders, in particular to a zero angle test circuit structure of a magnetic encoder. Background Art

[0002] Synchronous motors are widely used in many fields due to their stable performance, high power / torque density, and simple and compact structure. Accurately measuring the rotor position is essential for achieving the high performance and reliability of synchronous motors. Magnetic encoders, a common rotor position sensor for synchronous motors, are widely used in automobiles due to their high accuracy and reliability. However, due to manufacturing and tolerance variations between synchronous motors and magnetic encoders, the zero angle of the magnetic encoder often deviates from the zero angle of the synchronous motor, and the magnitude of this deviation cannot be guaranteed.

[0003] A common method involves applying current to the U phase, allowing the rotor to rotate to the motor's zero position, and then recording the angle value from the magnetic encoder. This method uses the interaction of magnetic fields to attract the motor's rotor position to near zero. However, due to interference from motor friction and cogging torque, the rotor position at this point deviates slightly from the true zero position. Utility Model Content

[0004] In view of this, the present application provides a zero angle test circuit structure of a magnetic encoder to solve the interference of motor friction and cogging torque, which causes a certain deviation between the rotor position and the true zero position.

[0005] According to one aspect of the present application, a zero angle test circuit structure of a magnetic encoder is provided, comprising a first voltage stabilizing module, a second voltage stabilizing module and a comparator module; one end of the first voltage stabilizing module is electrically connected to a first phase voltage of a permanent magnet synchronous motor, and the first voltage stabilizing module and the comparator module are connected in series; one end of the second voltage stabilizing module is electrically connected to a second phase voltage of the permanent magnet synchronous motor, and the second voltage stabilizing module and the comparator module are connected in series; the comparator module controls the motor electrical angle of the motor by comparing the voltage value of the first voltage stabilizing module with the voltage value of the second voltage stabilizing module, thereby obtaining the zero angle of the motor rotor.

[0006] In one possible implementation, the voltage stabilizing module includes a first resistor, a third resistor, a first voltage stabilizing diode and a first capacitor; the first resistor and the third resistor are connected in series, the third resistor, the first voltage stabilizing diode and the first capacitor are connected in parallel, and one end is grounded.

[0007] In a possible implementation, the second voltage stabilizing module includes a second resistor, a fourth resistor, a second voltage stabilizing diode and a second capacitor, the second resistor and the fourth resistor are connected in series, the fourth resistor, the second voltage stabilizing diode and the second capacitor are connected in parallel, and one end is grounded.

[0008] In one possible implementation, the output end of the first voltage stabilizing module is connected to the IN1- pin of the comparator module, the output end of the second voltage stabilizing module is connected to the IN1+ pin of the comparator module, and the input end of the MCU module is connected to the OUT1 pin of the comparator module.

[0009] In one possible implementation, a third capacitor is provided between the IN1- pin of the comparator module and the output end of the first voltage stabilizing module; a fourth capacitor is provided between the OUT2 pin of the comparator module and the MCU module; and a fifth resistor is provided between the OUT1 pin of the comparator module and the MCU module.

[0010] In a possible implementation, the IN2- pin of the comparator module and the OUT2 pin of the comparator module are both grounded.

[0011] In a possible implementation, a first power supply voltage is further included, and the first power supply voltage is connected to the third capacitor.

[0012] In a possible implementation, the comparator module is LM2903YPT.

[0013] In a possible implementation, the fifth resistor is a pull-up resistor, and the fourth capacitor is a decoupling capacitor.

[0014] In one possible implementation, the UVW three-phase phase voltage formula is as follows: e is the motor electrical angle:

[0015]

[0016] Read the encoder angle θ t , magnetic encoder angle A:

[0017] θ e =mod(N*θ t -A+150,360)=mod(N*θ) t +θ0,360)

[0018] The beneficial effects of the present invention are as follows: when the U-phase voltage is higher than the V-phase voltage, a high level is output. The dual comparator module consists of two independent low-power voltage comparator modules, which are specially designed to operate within a wide voltage range. It can operate from a single power supply voltage, and its input common-mode voltage range includes the negative rail, which is a unique feature. When the output terminal (OUT) of the comparator module is working, when the voltage of the non-inverting input terminal (IN-) is greater than the voltage of the inverting input terminal (IN+), a high level is output; otherwise, a low level is output. This setting makes the motor zero position measurement more accurate and can eliminate the interference of the motor friction torque and the motor cogging torque on the motor zero position. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram showing the overall circuit structure of a zero angle test circuit of a magnetic encoder according to an embodiment of the present application;

[0020] Figure 2 A voltage comparison circuit diagram showing a first embodiment of a zero angle test circuit structure of a magnetic encoder according to an embodiment of the present application;

[0021] Figure 3 A diagram showing a voltage comparison between the V phase and the U phase of Example 2 of the zero angle test circuit structure of the magnetic encoder according to an embodiment of the present application;

[0022] Figure 4 A diagram showing a voltage comparison between the U phase and the W phase of Example 3 of the zero angle test circuit structure of the magnetic encoder according to an embodiment of the present application;

[0023] Figure 5 A diagram showing a voltage comparison between the U phase and the W phase of Example 4 of the zero angle test circuit structure of the magnetic encoder according to an embodiment of the present application;

[0024] Figure 6 A diagram showing a voltage comparison between the V phase and the W phase of Example 5 of the zero angle test circuit structure of the magnetic encoder according to an embodiment of the present application;

[0025] Figure 7 A voltage comparison diagram of the V phase and the W phase of Example 6 of the zero angle test circuit structure of the magnetic encoder of the embodiment of the present application is shown. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0028] In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, "plurality" means two or more, unless otherwise specifically defined.

[0030] In this utility model, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," "fixed," "joined," and "hinge" should be understood in a broad sense. For example, they may refer to fixed or detachable connections, or integration; they may refer to mechanical or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; they may refer to internal communication between two components or the interaction between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0031] like Figure 1 As shown, the zero angle test circuit structure of the magnetic encoder includes a first voltage stabilizing module, a second voltage stabilizing module and a comparator module U1102; one end of the first voltage stabilizing module is electrically connected to the first phase voltage of the permanent magnet synchronous motor, and the first voltage stabilizing module and the comparator module U1102 are connected in series; one end of the second voltage stabilizing module is electrically connected to the second phase voltage of the permanent magnet synchronous motor, and the second voltage stabilizing module and the comparator module U1102 are connected in series; the comparator module U1102 controls the motor electrical angle of the motor by comparing the voltage value of the first voltage stabilizing module with the voltage value of the second voltage stabilizing module to obtain the zero angle of the motor rotor.

[0032] Specifically, this embodiment is illustrated with V-phase voltage and U-phase voltage. The first voltage stabilizing module receives the V-phase voltage, and the second voltage stabilizing module receives the U-phase voltage. The two voltage stabilizing modules transmit the voltage to the comparator module U1102 for comparison, output a high level or a low level, and finally transmit it to the MCU module.

[0033] In one possible implementation, the first voltage stabilizing module includes a first resistor R1121, a second resistor R1122, a first voltage stabilizing diode D1101 and a first capacitor C1121; the input end of the first resistor R1121 is connected to the V-phase voltage, and the output end of the first resistor R1121 is connected to the input end of the second resistor R1122; the output end of the second resistor R1122 is respectively connected to the input end of the first voltage stabilizing diode D1101 and the input end of the first capacitor C1121; the output end of the first capacitor C1121 is grounded.

[0034] Specifically, such as Figure 1 As shown, the first resistor R1121 is connected in series with the second resistor R1122 to reduce the voltage, and the second resistor R1122, the first voltage stabilizing diode D1101 and the first capacitor C1121 are arranged in parallel to form a voltage stabilizing circuit to stabilize the output voltage.

[0035] In one possible implementation, the second voltage stabilizing module includes a third resistor R1123, a fourth resistor R1124, a second voltage stabilizing diode D1102 and a second capacitor C1122; the input end of the third resistor R1123 is connected to the U-phase voltage, and the output end of the third resistor R1123 is connected to the input end of the fourth resistor R1124; the output end of the fourth resistor R1124 is respectively connected to the input end of the second voltage stabilizing diode D1102 and the input end of the second capacitor C1122; the output end of the second capacitor C1122 is grounded.

[0036] Specifically, such as Figure 1 As shown, the third resistor R1123 and the fourth resistor R1124 are connected in series to reduce the voltage, and the fourth resistor R1124, the second voltage stabilizing diode D1102 and the second capacitor C1122 are arranged in parallel to form a voltage stabilizing circuit to stabilize the output voltage.

[0037] In one possible implementation, the output end of the first voltage regulator module is connected to the IN1- pin of the comparator module U1102, the output end of the second voltage regulator module is connected to the IN1+ pin of the comparator module U1102; the input end of the MCU is connected to the OUT1 pin of the comparator module U1102.

[0038] Specifically, such as Figure 1As shown, the first voltage stabilizing module transmits the voltage to the IN1- pin of the comparator module U1102, and the second voltage stabilizing module transmits the voltage to the IN1+ pin of the comparator module U1102, and then outputs it through the OUT1 of the comparator module U1102.

[0039] In one possible implementation, a third capacitor C1123 is provided between the IN1- pin of the comparator module and the output end of the first voltage regulator module; a fourth capacitor C1124 is provided between the OUT2 pin of the comparator module and the MCU module; and a fifth resistor R1125 is provided between the OUT1 pin of the comparator module and the MCU module.

[0040] Specifically, such as Figure 1 As shown, the fifth resistor R1125 and the fourth capacitor C1124 are set for signal stabilization and noise reduction. The fifth resistor R1125 is set as a pull-up resistor because the pull-up resistor is connected to the signal line to pull the signal line to a high level. When there is no other signal driving, it ensures that the signal is kept at a high level first to prevent the signal line from being suspended, thereby avoiding false triggering; the fourth capacitor C1124 is a decoupling capacitor. The fourth capacitor C1124 is connected between the signal line and the ground, and is used to filter high-frequency noise on the power line. The decoupling capacitor can absorb and release charges, smooth voltage fluctuations, reduce the impact of high-frequency noise on the circuit, and provide a more stable power supply voltage.

[0041] In a possible implementation, the IN2- pin of the comparator module and the OUT2 pin of the comparator module are both grounded, and further include a first power supply voltage VCC1, which is connected to the third capacitor C1123.

[0042] In a possible implementation, the comparator module is LM2903YPT.

[0043] Example 1

[0044] According to the magnetic encoder's zero-angle test circuit structure, the motor zero-angle test condition is: rotation in the positive direction to a specified speed, such as 4000 rpm. Hybrid-excitation synchronous motors also require a certain rotor excitation current, while permanent-magnet synchronous motors do not. The number of motor pole pairs is N.

[0045] The UVW three-phase voltage formula is as follows:

[0046]

[0047] U0 is the phase voltage amplitude, θ e is the motor electrical angle.

[0048] MCU reads the encoder angle θ in real time tWhen the U-phase voltage is higher than the V-phase voltage, the voltage comparison module outputs a high level. When the MCU captures this rising edge, it records the magnetic encoder angle A at this time. At this time, the motor rotor electrical angle is 150°. Therefore, the motor rotor angle can be obtained as:

[0049] θ e =mod(N*θ t -A+150,360)=mod(N*θ) t +θ0,360)

[0050] The zero position of the motor rotor θ0: θ0 = mod (150° - A)

[0051] Example 2

[0052] When comparing the voltage between phase V and phase U: When the voltage of phase V is higher than that of phase U, the voltage comparison module outputs a high level. When the MCU captures this rising edge, the electrical angle of the motor rotor is 330°. The zero position of the motor rotor is θ0: θ0 = mod(330°-A).

[0053] Example 3

[0054] When comparing the voltage between phase U and phase W: When the voltage of phase U is higher than that of phase W, the voltage comparison module outputs a high level. When the MCU captures this rising edge, the electrical angle of the motor rotor is 210°. The zero position of the motor rotor is θ0: θ0-mod(210°-Λ)

[0055] Example 4

[0056] When using W phase and U phase voltage comparison: When the W phase voltage is higher than the U phase, the voltage comparison module outputs a high level. When the MCU captures this rising edge, the motor rotor electrical angle is 30°. The zero position of the motor rotor is θ0: θ0 = mod(30°-A)

[0057] Example 5

[0058] When comparing the voltages of phase V and phase W: When the voltage of phase V is higher than that of phase W, the voltage comparison module outputs a high level. When the MCU captures this rising edge, the electrical angle of the motor rotor is 270°. The zero position of the motor rotor is θ0: θ0 = mod(270°-A).

[0059] Example 6

[0060] When using W phase and V phase voltage comparison: When the W phase voltage is higher than the V phase voltage, the voltage comparison module outputs a high level. When the MCU captures this rising edge, the motor rotor electrical angle is 90°. The zero position of the motor rotor is θ0: θ0 = mod(90°-A)

[0061] This application comprises a first voltage regulator module, a second voltage regulator module, and a comparator module U1102. The first voltage regulator module receives the V-phase voltage, and the second voltage regulator module receives the U-phase voltage. The voltage received by the first voltage regulator module is then transmitted to the first detection point P1106, and the voltage received by the second voltage regulator module is then transmitted to the second detection point P1107. The first detection point P1106 and the second detection point P1107 transmit the voltage to the comparator module U1102 for comparison, and outputs a high or low level, which is ultimately transmitted to the MCU module. When the U-phase voltage is higher than the V-phase voltage, the comparator module U1102 outputs a high level. The comparator module U1102 consists of two independent low-power voltage comparator modules, specifically designed to operate over a wide voltage range. It can operate from a single power supply voltage, and its input common-mode voltage range includes the negative rail, which is a unique feature. During operation, the output terminal OUT of the comparator module U1102 outputs a high level when the voltage at the non-inverting input terminal IN- is greater than the voltage at the inverting input terminal IN+; otherwise, it outputs a low level. This setting makes the motor zero position measurement more accurate and can eliminate the interference of motor friction torque and motor cogging torque on the motor zero position.

[0062] The above description is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and concept of the present invention, should be covered by the protection scope of the present invention.

Claims

1. A zero angle test circuit structure of a magnetic encoder, characterized in that: It includes a first voltage stabilizing module, a second voltage stabilizing module and a comparator module; One end of the first voltage stabilizing module is electrically connected to the first phase voltage of the permanent magnet synchronous motor, the first voltage stabilizing module is connected in series with the comparator module, and the comparator module is capable of measuring the voltage value of the first voltage stabilizing module; One end of the second voltage stabilizing module is electrically connected to the second phase voltage of the permanent magnet synchronous motor, the second voltage stabilizing module is connected in series with the comparator module, and the comparator module is capable of measuring the voltage value of the second voltage stabilizing module; The comparator module controls the motor electrical angle of the motor and obtains the zero angle of the motor rotor by comparing the voltage value of the first voltage stabilizing module with the voltage value of the second voltage stabilizing module.

2. The zero angle test circuit structure of the magnetic encoder according to claim 1, characterized in that: The voltage stabilizing module includes a first resistor, a third resistor, a first voltage stabilizing diode and a first capacitor; the first resistor and the third resistor are connected in series, the third resistor, the first voltage stabilizing diode and the first capacitor are connected in parallel, and one end is grounded.

3. The zero angle test circuit structure of the magnetic encoder according to claim 1, characterized in that: The second voltage stabilizing module includes a second resistor, a fourth resistor, a second voltage stabilizing diode and a second capacitor. The second resistor and the fourth resistor are connected in series. The fourth resistor, the second voltage stabilizing diode and the second capacitor are connected in parallel, and one end is grounded.

4. The zero angle test circuit structure of the magnetic encoder according to claim 1, characterized in that: It also includes an MCU module, the output end of the first voltage stabilizing module is connected to the IN1- pin of the comparator module, the output end of the second voltage stabilizing module is connected to the IN1+ pin of the comparator module, and the input end of the MCU module is connected to the OUT1 pin of the comparator module.

5. The zero angle test circuit structure of the magnetic encoder according to claim 4, characterized in that: A third capacitor is provided between the IN1- pin of the comparator module and the output end of the first voltage stabilizing module; A fourth capacitor is provided between the OUT2 pin of the comparator module and the MCU module, and a fifth resistor is provided between the OUT1 pin of the comparator module and the MCU module.

6. The zero angle test circuit structure of the magnetic encoder according to claim 4, characterized in that: The IN2- pin of the comparator module and the OUT2 pin of the comparator module are both grounded.

7. The zero angle test circuit structure of the magnetic encoder according to claim 5, characterized in that: It also includes a first power supply voltage, which is connected to the third capacitor.

8. The zero angle test circuit structure of the magnetic encoder according to claim 1, characterized in that: The model of the comparator module is LM2903YPT.

9. The zero angle test circuit structure of the magnetic encoder according to claim 5, characterized in that: The fifth resistor is a pull-up resistor, and the fourth capacitor is a decoupling capacitor.

10. The zero angle test circuit structure of the magnetic encoder according to claim 1, characterized in that: The three-phase voltage formula of UVW is as follows: U0 is the phase voltage amplitude, θ e is the motor electrical angle: Read the encoder angle θ t , magnetic encoder angle A: i e =mod(N*θ t -A+150,360))=mod(N*θ) t +θ0.360).

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