A ground current sampling circuit for stepper motor vector control

Abstract

The utility model relates to a ground current sampling circuit for vector control of a stepper motor. The utility model includes a DC power supply VDC, a first H-bridge circuit, a second H-bridge circuit and a two-phase four-wire stepper motor; the two-phase four-wire stepper motor includes a motor rotor and an A-phase stator winding and a B-phase stator winding distributed around the motor rotor; the first H-bridge circuit is connected to the A-phase stator winding for controlling the current direction of the A-phase stator winding, and the second H-bridge circuit is connected to the B-phase stator winding for controlling the current direction of the B-phase stator winding; the positive pole of the DC power supply VDC is respectively connected to the input end of the first H-bridge circuit and the second H-bridge circuit, and the output end of the first H-bridge circuit and the second H-bridge circuit is respectively connected to the negative pole of the DC power supply VDC through a ground current sensing resistor. High detection accuracy and system stability are achieved while reducing hardware costs.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit current sampling, in particular to a ground current sampling circuit for vector control of a stepping motor. Background Art

[0002] A stepper motor is a motor that converts electrical pulse signals into angular displacement and is widely used in various mechanical devices that require precise control. In order to achieve precise control of stepper motors, current sampling circuits are usually used. The current sampling circuit calculates the vector position of the motor by real-time detection of the motor's current and voltage signals, thereby generating a corresponding drive signal to achieve precise control of the motor. In the driving process of a two-phase four-wire stepper motor, the current sampling circuit plays an important role in current detection.

[0003] In the existing phase current detection scheme, since the motor phase voltage is the same as the bus voltage, the common-mode voltage requirement of the operational amplifier (op amp) is relatively high. In order to meet this requirement, an op amp with a higher common-mode voltage tolerance must be used, and the price of such an op amp is usually more than twice that of an ordinary op amp, resulting in a significant increase in hardware costs. In addition, an op amp with a high common-mode voltage may also have certain limitations in performance, affecting the accuracy of current detection and the overall stability of the system. Summary of the invention

[0004] To this end, the utility model provides a ground current sampling circuit for a stepping motor vector control to achieve high detection accuracy and system stability while reducing hardware costs.

[0005] In order to solve the above technical problems, the utility model provides a stepper motor vector control ground current sampling circuit, including a DC power supply VDC, a first H-bridge circuit, a second H-bridge circuit and a two-phase four-wire stepper motor;

[0006] Wherein, the two-phase four-wire stepping motor comprises a motor rotor and an A-phase stator winding and a B-phase stator winding distributed around the motor rotor;

[0007] The first H-bridge circuit is connected to the A-phase stator winding for controlling the current direction of the A-phase stator winding, and the second H-bridge circuit is connected to the B-phase stator winding for controlling the current direction of the B-phase stator winding;

[0008] The positive electrode of the DC power supply VDC is connected to the input end of the first H-bridge circuit and the second H-bridge circuit respectively, and the output end of the first H-bridge circuit and the second H-bridge circuit is connected to the negative electrode of the DC power supply VDC through the ground current sensing resistor respectively.

[0009] In one embodiment of the present utility model, the first H-bridge circuit includes four transistors S1-S4, and the A-phase stator winding includes an A+ pole and an A- pole;

[0010] The collectors of transistor S1 and transistor S2 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S1 is connected to the A+ electrode, and the emitter of transistor S2 is connected to the A- electrode;

[0011] The collector of transistor S3 is connected to the emitter of transistor S1, and the emitter of transistor S3 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R1;

[0012] The collector of the transistor S4 is connected to the emitter of the transistor S2, and the emitter of the transistor S4 is connected to the negative electrode of the DC power supply VDC through the ground current detection resistor R1.

[0013] In one embodiment of the present invention, a diode D1 is connected between the collector and emitter of each of the transistors S1 - S4 and is connected to the cathode and anode of the diode D1 , respectively.

[0014] In one embodiment of the present utility model, the first H-bridge circuit includes four transistors S5-S8, and the B-phase stator winding includes a B+ pole and a B- pole;

[0015] The collectors of transistor S5 and transistor S6 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S5 is connected to the B+ electrode, and the emitter of transistor S6 is connected to the B- electrode;

[0016] The collector of transistor S7 is connected to the emitter of transistor S5, and the emitter of transistor S7 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R2;

[0017] The collector of transistor S8 is connected to the emitter of transistor S6, and the emitter of transistor S8 is connected to the negative electrode of DC power supply VDC through ground current detection resistor R2.

[0018] In one embodiment of the present invention, a diode D2 is connected between the collector and emitter of each of the transistors S5 - S8 and is connected to the cathode and anode of the diode D2 , respectively.

[0019] The above technical solution of the utility model has the following advantages compared with the prior art:

[0020] The utility model discloses a stepper motor vector control ground current sampling circuit, which adopts a ground current detection scheme to reduce hardware cost and simplifies PCB wiring while reducing hardware cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to make the content of the utility model more clearly understood, the utility model is further described in detail below based on specific embodiments of the utility model in combination with the accompanying drawings.

[0022] Figure 1 It is a structural diagram of a ground current sampling circuit for vector control of a stepping motor of the utility model.

[0023] Figure 2 It is the control waveform and vector diagram of different sectors of the utility model.

[0024] Figure 3 It is a directional diagram of the current detected to the ground when the utility model is working. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0026] In the present invention, if directions (up, down, left, right, front and back) are described, it is only for the convenience of describing the technical solution of the present invention, and does not indicate or imply that the technical features referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0027] In the present utility model, "several" means one or more, "multiple" means more than two, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself. In the description of the present utility model, if there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0028] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected or electrically connected or able to communicate with each other; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0029] Reference Figure 1 As shown, a ground current sampling circuit for a stepper motor vector control of the utility model includes a DC power supply VDC, a first H-bridge circuit, a second H-bridge circuit and a two-phase four-wire stepper motor;

[0030] Wherein, the two-phase four-wire stepping motor comprises a motor rotor and an A-phase stator winding and a B-phase stator winding distributed around the motor rotor;

[0031] The first H-bridge circuit is connected to the A-phase stator winding for controlling the current direction of the A-phase stator winding, and the second H-bridge circuit is connected to the B-phase stator winding for controlling the current direction of the B-phase stator winding;

[0032] The positive electrode of the DC power supply VDC is connected to the input end of the first H-bridge circuit and the second H-bridge circuit respectively, and the output end of the first H-bridge circuit and the second H-bridge circuit is connected to the negative electrode of the DC power supply VDC through the ground current sensing resistor respectively.

[0033] Specifically, the first H-bridge circuit includes four transistors S1-S4, and the A-phase stator winding includes an A+ pole and an A- pole;

[0034] The collectors of transistor S1 and transistor S2 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S1 is connected to the A+ electrode, and the emitter of transistor S2 is connected to the A- electrode;

[0035] The collector of transistor S3 is connected to the emitter of transistor S1, and the emitter of transistor S3 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R1;

[0036] The collector of the transistor S4 is connected to the emitter of the transistor S2, and the emitter of the transistor S4 is connected to the negative electrode of the DC power supply VDC through the ground current detection resistor R1.

[0037] In one embodiment of the present invention, a diode D1 is connected between the collector and emitter of each of the transistors S1 - S4 and is connected to the cathode and anode of the diode D1 , respectively.

[0038] Specifically, the first H-bridge circuit includes four transistors S5-S8, and the B-phase stator winding includes a B+ pole and a B- pole;

[0039] The collectors of transistor S5 and transistor S6 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S5 is connected to the B+ electrode, and the emitter of transistor S6 is connected to the B- electrode;

[0040] The collector of transistor S7 is connected to the emitter of transistor S5, and the emitter of transistor S7 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R2;

[0041] The collector of transistor S8 is connected to the emitter of transistor S6, and the emitter of transistor S8 is connected to the negative electrode of DC power supply VDC through ground current detection resistor R2.

[0042] Specifically, a diode D2 is connected between the collector and emitter of each of the transistors S5 - S8 and are respectively connected to the cathode and anode of the diode D2 .

[0043] Two H-bridge circuits are used to control a dual-winding motor. By controlling the on and off of transistors S1-S8, the current direction in the motor winding is controlled to drive the motor to rotate.

[0044] Working principle: Figure 2 In the control waveforms and vector diagrams of different sectors, the sector is judged according to the position of the voltage vector in space (Uα and Uβ), and then the wave type is selected according to the sector to obtain the synthetic vector of the corresponding sector. Figure 3 It is the direction diagram of the detection current to ground.

[0045] When the target synthetic vector is in the first sector U0 (1011), the currents of phase A and phase B detected by the ground current sensing resistor are consistent with the actual currents of phase A and phase B of the motor coil in magnitude and direction;

[0046] When the target synthetic vector is in the second sector U90 (0010), the A-phase current detected by the ground current-sense resistor is consistent with the actual A-phase current in the coil in magnitude and opposite in direction, and the B-phase current detected by the ground current-sense resistor is consistent with the actual B-phase current in the coil in magnitude and direction;

[0047] When the target synthetic vector is in the third sector U180 (0111), the current detected by the ground current-sense resistor for phase A is the same in magnitude but opposite in direction to the actual current of phase A in the coil, and the current detected by the ground current-sense resistor for phase B is the same in magnitude but opposite in direction to the actual current of phase B in the coil;

[0048] When the target synthetic vector is in the fourth sector U270 (0001), the current detected by the ground current sensing resistor is consistent with the actual current of phase A in the coil in magnitude and direction, and the current detected by the ground current sensing resistor is consistent with the actual current of phase B in the coil in magnitude and opposite in direction.

[0049] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to examples, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A stepper motor vector control ground current sampling circuit, characterized in that: It includes a DC power supply VDC, a first H-bridge circuit, a second H-bridge circuit and a two-phase four-wire stepping motor; Wherein, the two-phase four-wire stepping motor comprises a motor rotor and an A-phase stator winding and a B-phase stator winding distributed around the motor rotor; The first H-bridge circuit is connected to the A-phase stator winding for controlling the current direction of the A-phase stator winding, and the second H-bridge circuit is connected to the B-phase stator winding for controlling the current direction of the B-phase stator winding; The positive electrode of the DC power supply VDC is connected to the input end of the first H-bridge circuit and the second H-bridge circuit respectively, and the output end of the first H-bridge circuit and the second H-bridge circuit is connected to the negative electrode of the DC power supply VDC through the ground current sensing resistor respectively.

2. The ground current sampling circuit for stepper motor vector control according to claim 1, characterized in that: The first H-bridge circuit includes four transistors S1-S4, and the A-phase stator winding includes an A+ pole and an A- pole; The collectors of transistor S1 and transistor S2 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S1 is connected to the A+ electrode, and the emitter of transistor S2 is connected to the A- electrode; The collector of transistor S3 is connected to the emitter of transistor S1, and the emitter of transistor S3 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R1; The collector of the transistor S4 is connected to the emitter of the transistor S2, and the emitter of the transistor S4 is connected to the negative electrode of the DC power supply VDC through the ground current detection resistor R1.

3. The ground current sampling circuit for stepper motor vector control according to claim 2, characterized in that: A diode D1 is connected between the collector and emitter of each of the transistors S1 - S4 and is connected to the cathode and anode of the diode D1 , respectively.

4. The ground current sampling circuit for stepper motor vector control according to claim 1, characterized in that: The first H-bridge circuit includes four transistors S5-S8, and the B-phase stator winding includes a B+ pole and a B- pole; The collectors of transistor S5 and transistor S6 are connected to the positive electrode of the DC power supply VDC, the emitter of transistor S5 is connected to the B+ electrode, and the emitter of transistor S6 is connected to the B- electrode; The collector of transistor S7 is connected to the emitter of transistor S5, and the emitter of transistor S7 is connected to the negative electrode of DC power supply VDC through the ground current detection resistor R2; The collector of transistor S8 is connected to the emitter of transistor S6, and the emitter of transistor S8 is connected to the negative electrode of DC power supply VDC through ground current detection resistor R2.

5. The ground current sampling circuit for stepping motor vector control according to claim 4, characterized in that: A diode D2 is connected between the collector and emitter of each of the transistors S5 - S8 and is connected to the cathode and anode of the diode D2 , respectively.

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