Voltage signal amplification circuit of permanent magnet synchronous motor

Abstract

The invention discloses a voltage signal amplification circuit of a permanent magnet synchronous motor, and relates to the field of zero-cross detection of the voltage of the permanent magnet synchronous motor, and the circuit is characterized in that the positive electrode of a voltage signal of the permanent magnet synchronous motor is connected with the first end of a primary winding of a transformer U1 through a blocking circuit, and the second end of the primary winding is connected with the negative electrode of the voltage signal; a first end and a second end of a secondary winding of the transformer U1 are respectively connected with one end of a bias resistor R2 and one end of a bias resistor R3, and the other end of the bias resistor R2 is connected with a first input end of the clamping circuit; a second input end of the clamping circuit is connected with the other end of the bias resistor R3; when the amplitude of the voltage signal is larger than a preset voltage value, the output end of the clamping circuit outputs a preset voltage signal, and when the amplitude of the voltage signal is smaller than or equal to the preset voltage value, the output end of the clamping circuit outputs a voltage signal with the original size. The noise of the voltage near the zero crossing point can be reduced, and the characteristics of the voltage near the zero crossing point are improved.

Description

Technical Field

[0001] This application relates to the field of zero-crossing detection of voltage in permanent magnet synchronous motors, and in particular to a voltage signal amplification circuit for permanent magnet synchronous motors. Background Technology

[0002] In permanent magnet synchronous motor (PMSM) drive systems, high-precision zero-crossing detection of voltage signals is crucial for accurate rotor position estimation and closed-loop speed control. The motor terminal voltage typically exists as a sinusoidal wave with an amplitude of tens of volts. Its weak amplitude near the zero-crossing point is easily masked by noise, interference from switching devices, and cable coupling signals, leading to increased errors when directly determining the zero-crossing point and consequently reducing the drive system's response speed and stability. Summary of the Invention

[0003] The purpose of this application is to provide a voltage signal amplification circuit for a permanent magnet synchronous motor, which can clamp the voltage signal of the permanent magnet synchronous motor near the zero crossing point within a preset voltage range, reduce the noise of the voltage near the zero crossing point, and improve the characteristics of the voltage near the zero crossing point.

[0004] To achieve the above objectives, this application provides the following solution:

[0005] This application provides a voltage signal amplification circuit for a permanent magnet synchronous motor, including:

[0006] DC blocking circuit, transformer U1, bias resistor R2, bias resistor R3, and clamping circuit;

[0007] One end of the DC blocking circuit is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, and the other end of the DC blocking circuit is connected to the first end of the primary winding of transformer U1; the first end of the secondary winding of transformer U1 is connected to one end of the bias resistor R2, and the other end of the bias resistor R2 is connected to the first input terminal of the clamping circuit.

[0008] The second input terminal of the clamping circuit is connected to the other end of the bias resistor R3, and one end of the bias resistor R3 is connected to the second end of the secondary winding of transformer U1; the second end of the primary winding of transformer U1 is connected to the negative terminal of the voltage signal of the permanent magnet synchronous motor.

[0009] When the amplitude of the voltage signal is greater than the preset voltage value, the output terminal of the clamping circuit outputs the preset voltage signal; when the amplitude of the voltage signal is less than or equal to the preset voltage value, the output terminal of the clamping circuit outputs the original voltage signal.

[0010] Furthermore, the DC blocking circuit includes a capacitor C1 and a resistor R1;

[0011] One end of the capacitor C1 is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, the other end of the capacitor C1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the first end of the primary winding of the transformer U1.

[0012] Furthermore, the clamping circuit includes diode D1 and diode D2;

[0013] The cathode of the diode D1 is connected to the other end of the bias resistor R2 and the anode of the diode D2, respectively.

[0014] The anode of diode D1 is connected to the other end of the bias resistor R3 and the cathode of diode D2, respectively.

[0015] The anode and cathode of diode D2 serve as the output terminals of the clamping circuit.

[0016] Furthermore, the capacitance of capacitor C1 is 10uF.

[0017] Furthermore, the resistance of resistor R1 is 100kΩ.

[0018] Furthermore, the bias resistors R2 and R3 have the same resistance value.

[0019] Furthermore, the resistance values ​​of the bias resistors R2 and R3 are 5kΩ.

[0020] Furthermore, the turns ratio of the primary winding to the secondary winding of transformer U1 is 1:1.

[0021] Furthermore, the preset voltage value is 1.2V.

[0022] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0023] This application provides a voltage signal amplification circuit for a permanent magnet synchronous motor (PMSM). One end of the DC blocking circuit in this amplification circuit is connected to the positive terminal of the PMSM voltage signal, and the other end is connected to the first end of the primary winding of transformer U1. The DC blocking circuit blocks the DC bias in the voltage signal, improving its clarity. Then, the transformer couples and initially isolates the voltage signal, filtering out high-frequency common-mode interference. Finally, a clamping circuit in the subsequent stage clamps and limits the voltage signal. When the voltage signal amplitude is greater than a preset voltage value, the clamping circuit outputs the preset voltage signal; when the voltage signal amplitude is less than or equal to the preset voltage value, the clamping circuit outputs the original voltage signal, ensuring that the voltage signal near the zero-crossing point has sufficient amplitude and clear zero-crossing characteristics, providing a reliable hardware guarantee for a high-performance PMSM drive system. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a circuit diagram of a voltage signal amplification circuit for a permanent magnet synchronous motor according to one embodiment of this application. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] To make the objectives, features, and advantages of this application more apparent and understandable, the following detailed description of this application is provided in conjunction with the accompanying drawings and specific embodiments.

[0028] This application provides a voltage signal amplification circuit for a permanent magnet synchronous motor, such as... Figure 1 As shown, it includes a DC blocking circuit A1, a transformer U1, a bias resistor R2, a bias resistor R3, and a clamping circuit B1.

[0029] One end of the DC blocking circuit A1 is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, and the other end of the DC blocking circuit A1 is connected to the first terminal 1 of the primary winding of transformer U1; the first terminal 4 of the secondary winding of transformer U1 is connected to one end of the bias resistor R2, and the other end of the bias resistor R2 is connected to the first input terminal of the clamping circuit B1. Transformer U1 is used for electrical isolation, blocking DC and common-mode interference from the high-voltage end of the motor; the turns ratio of the primary winding and the secondary winding of transformer U1 is 1:1, coupling the AC voltage signal to the secondary winding at a turns ratio of 1:1.

[0030] The second input terminal of the clamping circuit B1 is connected to the other end of the bias resistor R3, and one end of the bias resistor R3 is connected to the second terminal 3 of the secondary winding of the transformer U1; the second terminal 2 of the primary winding of the transformer U1 is connected to the negative terminal of the voltage signal of the permanent magnet synchronous motor.

[0031] When the amplitude of the voltage signal is greater than a preset voltage value, the output terminal of the clamping circuit outputs the preset voltage signal; when the amplitude of the voltage signal is less than or equal to the preset voltage value, the output terminal of the clamping circuit outputs a voltage signal of the original value. In this embodiment, the preset voltage value is 1.2V.

[0032] In an exemplary embodiment, the DC blocking circuit A1 includes a capacitor C1 and a resistor R1. One end of the capacitor C1 is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, and the other end of the capacitor C1 is connected to one end of the resistor R1. The other end of the resistor R1 is connected to the first terminal I of the primary winding of the transformer U1. The capacitor C1 only allows the AC component to pass through, removing any DC bias that may exist in the original voltage signal and improving the sampling cleanliness. In this embodiment, the capacitance of the capacitor C1 is 10uF, and the resistance of the resistor R1 is 100kΩ.

[0033] Capacitors R1 and C1 together form a high-pass filter, which on the one hand limits the input current and reduces the load on the motor signal source; on the other hand, it suppresses low-frequency interference and sudden changes in capacitor charging and discharging.

[0034] In an exemplary embodiment, the clamping circuit B1 includes diodes D1 and D2. The cathode of diode D1 is connected to the other end of the bias resistor R2 and the anode of diode D2, respectively; the anode of diode D1 is connected to the other end of the bias resistor R3 and the cathode of diode D2, respectively; the anode and cathode of diode D2 serve as the output terminals of the clamping circuit.

[0035] Bias resistors R2 and R3 are symmetrically connected across the secondary winding of transformer U1 to pull the coupled sinusoidal signal to a midpoint level (e.g., 0V), thus biasing the subsequent bidirectional limiting. In this embodiment, the resistance values ​​of bias resistors R2 and R3 are the same, both being 5kΩ.

[0036] Specifically, diodes D1 and D2 limit the positive and negative half-cycles of the secondary output, allowing the voltage across them to be within approximately ±1.2V, and maintaining linearity in the region near zero (diode off state). When the voltage signal amplitude exceeds ±1.2V, diode D1 or D2 conducts, clamping the output to ±1.2V, thereby amplifying the zero-point region. Small changes in the signal near zero are not clamped and are output at their original value. The portion exceeding the diode threshold is clamped to prevent overvoltage in the subsequent stage, while also making the controller pay more attention to subtle changes near zero.

[0037] During the diode cutoff range (i.e., when the output voltage amplitude |V|<≈1.2V), the voltage signal output between OUT+ and OUT– maintains a linear correspondence with the small changes of the original voltage signal near the zero crossing point, exhibiting "high sensitivity"; when the original voltage signal leaves the zero point and the amplitude increases to the diode conduction level, the output is clamped and no longer increases.

[0038] This application utilizes a segmented amplification design based on capacitor isolation, transformer coupling, and diode clamping, which significantly improves zero-crossing detection accuracy, enhances anti-interference capabilities, and provides a faster dynamic response, outperforming traditional zero-crossing detection circuits. This provides a more reliable hardware foundation for the precision drive control of high-performance permanent magnet synchronous motors.

[0039] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A voltage signal amplification circuit for a permanent magnet synchronous motor, characterized in that, include: DC blocking circuit, transformer U1, bias resistor R2, bias resistor R3, and clamping circuit; One end of the DC blocking circuit is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, and the other end of the DC blocking circuit is connected to the first end of the primary winding of transformer U1; the first end of the secondary winding of transformer U1 is connected to one end of the bias resistor R2, and the other end of the bias resistor R2 is connected to the first input terminal of the clamping circuit. The second input terminal of the clamping circuit is connected to the other end of the bias resistor R3, and one end of the bias resistor R3 is connected to the second end of the secondary winding of transformer U1; the second end of the primary winding of transformer U1 is connected to the negative terminal of the voltage signal of the permanent magnet synchronous motor. When the amplitude of the voltage signal is greater than the preset voltage value, the output terminal of the clamping circuit outputs the preset voltage signal; when the amplitude of the voltage signal is less than or equal to the preset voltage value, the output terminal of the clamping circuit outputs the original voltage signal.

2. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The DC blocking circuit includes a capacitor C1 and a resistor R1; One end of the capacitor C1 is connected to the positive terminal of the voltage signal of the permanent magnet synchronous motor, the other end of the capacitor C1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the first end of the primary winding of the transformer U1.

3. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The clamping circuit includes diode D1 and diode D2; The cathode of the diode D1 is connected to the other end of the bias resistor R2 and the anode of the diode D2, respectively. The anode of diode D1 is connected to the other end of the bias resistor R3 and the cathode of diode D2, respectively. The anode and cathode of diode D2 serve as the output terminals of the clamping circuit.

4. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The capacitance of capacitor C1 is 10uF.

5. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The resistance of resistor R1 is 100kΩ.

6. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The bias resistor R2 and the bias resistor R3 have the same resistance value.

7. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The resistance values ​​of the bias resistors R2 and R3 are 5kΩ.

8. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The turns ratio of the primary winding to the secondary winding of transformer U1 is 1:

1.

9. The voltage signal amplification circuit for a permanent magnet synchronous motor according to claim 1, characterized in that, The preset voltage value is 1.2V.

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