Drive circuit of stepping motor
By dividing each phase of the stepper motor into small windings and adopting a driving circuit structure with parallel output, combining common mode inductance and current sensor, the problem of excessive power loss and heat generation of the stepper motor driving circuit is solved, and the positioning accuracy is improved and output power.
Patent Information
- Application Number
- CN202420351737.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-26
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2034-02-26
AI Technical Summary
In high-precision applications, stepper motor drive circuits have problems with excessive power loss and heat generation, which leads to increased circuit volume and difficulty in meeting the accuracy requirements.
Each phase of the stepper motor is divided into independent small windings, and is driven by a full-bridge or half-bridge circuit. Combined with a common mode inductor and current sensor, the parallel output and precise control of the drive circuit are realized, and the positioning accuracy and output of the stepper motor are improved. power.
It effectively reduces the power loss and heat generation of the driving circuit, reduces the circuit volume, and improves the positioning accuracy and output power of the stepper motor.
Smart Images
Figure CN222192173U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of stepping motors. Background Art
[0002] Stepper motors are generally used with matching drivers. Some usage scenarios that require high precision of stepper motors are also equipped with encoders for closed-loop control. Encoders have evolved from the initial 2000-line encoder to the current encoders with a precision of more than 24 bits (equivalent to 16 million lines). The encoders are highly accurate, and the density of encoder orthogonal signals reaches the nanosecond level, but signal transmission becomes a problem.
[0003] For example, the patent publication number is CN103404020A, the publication date is November 20, 2013, and the patent name is "Drive circuit of stepper motor, its integrated circuit and electronic device including the integrated circuit and control method of drive circuit of stepper motor". The disclosed drive circuit of stepper motor includes: D / A converter); current control unit including comparison unit; and abnormality detection unit. DAC generates a target voltage indicating a target value of the excitation current determined based on a reference voltage indicating an upper limit value of the excitation current flowing through the stepper motor. The current control unit controls the excitation current based on the target voltage. The comparison unit compares the voltage corresponding to the excitation current with the target voltage. The abnormality detection unit detects abnormality of the wiring between the drive circuit and the stepper motor based on the output signal from the comparison unit and the control signal indicating the polarity of the excitation current.
[0004] In terms of stepper motor drive circuits, MOS circuit technology is also changing with each passing day. Similar low-power stepper motor drive circuits have very small internal resistance, little power loss, and very little circuit heat. However, drive circuits with several times greater power will have internal resistance that is more than ten or even dozens of times higher, and the size of high-power drive circuits also grows exponentially.
[0005] To resolve these contradictions, miniaturization and integration of stepper motors and their drivers and encoders are required, which puts forward requirements on the circuit volume, power loss, heat generation, etc. of the stepper motor drive circuit. Utility Model Content
[0006] The technical problem to be solved by the utility model is to realize a stepper motor output line structure, which can improve the positioning accuracy of the stepper motor through the design of the output line structure and reduce the power loss and heat generation of the drive circuit.
[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a driving circuit of a stepper motor, each phase of the stepper motor is provided with a winding, each phase winding of the stepper motor is composed of n independent small windings, each small winding is respectively provided with a P end and a Q end, and the winding unit is provided with n small windings in each phase winding, which are respectively composed of n small windings in combination.
[0008] The stepper motor is a three-phase motor, which includes winding A, winding B, and winding C. The small windings obtained by dividing winding A into n equal parts are named A1, A2, ..., An respectively; the small windings obtained by dividing winding B into n equal parts are named B1, B2, ..., Bn respectively; the small windings obtained by dividing winding C into n equal parts are named C1, A2, ..., Cn respectively;
[0009] The P end of the winding A1 is named AP1, and the Q end is named AQ1; the P end of the winding A2 is named AP2, and the Q end is named AQ2, and so on;
[0010] Connect the three terminals AQ1, BQ1, and CQ1 together and name it Q1. Connect the three terminals AQ2, BQ2, and CQ2 together and name it Q2. And so on.
[0011] The stepper motor is a two-phase motor, which includes winding A and winding B. The small windings obtained by dividing winding A into n equal parts are named A1, A2, ..., An, and the small windings obtained by dividing winding B into n equal parts are named B1, B2, ..., Bn.
[0012] The P end of winding A1 is named AP1, and the Q end is named AQ1. The P end of winding A2 is named AP2, and the Q end is named AQ2, and so on.
[0013] Connect the three terminals AQ1, BQ1, and CQ1 together and name it Q1. Connect the three terminals AQ2, BQ2, and CQ2 together and name it Q2. And so on.
[0014] The three-phase motor has two winding units;
[0015] In the first winding unit, the three terminals AQ1, BQ1, and CQ1 of the small winding are connected together and named as the Q1 terminal;
[0016] In the second winding unit, the three terminals of the small winding, AP2, BP2, and CP2, are connected together and named as the P2 terminal;
[0017] The stepper motor is provided with a driving circuit, which is composed of a plurality of full-bridge circuits, wherein the output OUT of the first full-bridge circuit is connected to AP1, Connect to AQ2, and the output of the second full-bridge circuit OUT is connected to BP1. Connect to BQ2, and the OUT of the third full-bridge circuit output is connected to CP1. Connect with CQ2.
[0018] The driving circuit of the stepper motor is an H-bridge circuit, or is composed of a plurality of half-bridge circuits.
[0019] Each two half-bridge circuits in the driving circuit are equipped with a common-mode inductor, the input signals of the two half-bridge circuits are the same, and the two half-bridge circuits are not in the same full-bridge circuit, and the output ends of the multiple common-mode inductors are connected to the stepper motor.
[0020] The driving circuit is provided with a current sensor, the input end of the current sensor is connected to the power input, and the output end of the current sensor is connected to each full-bridge circuit or half-bridge circuit of the driving motor to obtain the current signal of the driving motor and transmit the obtained signal to the processor.
[0021] The processor is connected to an encoder, and a plurality of PWM signals of the processor are respectively connected to the input end of each full-bridge circuit or half-bridge circuit.
[0022] The driving circuit of the stepping motor of the utility model can increase the torque and output power of the stepping motor, improve the positioning accuracy of the stepping motor, reduce the volume of the driving circuit, and can effectively reduce the power loss of the driving circuit while reducing heat generation. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The following is a brief description of the contents of each figure in the utility model specification:
[0024] Figure 1 This is a schematic diagram of the output structure of a three-phase stepper motor;
[0025] Figure 2 It is a schematic diagram of the output structure of a two-phase stepper motor;
[0026] Figure 3 It is a schematic diagram of a three-phase stepper motor drive circuit;
[0027] Figure 4 It is a schematic diagram of a two-phase stepper motor drive circuit;
[0028] Figure 5 This is an example diagram of a three-phase stepper motor drive circuit;
[0029] Figure 6 It is a schematic diagram of an independent driving circuit. DETAILED DESCRIPTION
[0030] The following is a further detailed description of the specific implementation methods of the present invention, such as the shapes and structures of the components involved, the relative positions and connection relationships between the components, the functions and working principles of the components, the manufacturing process and the operation and use methods, etc., through the description of the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.
[0031] The utility model relates to a driving circuit of a stepping motor and a driving circuit of a stepping motor with an outlet structure, which includes two parts: a driving circuit of a stepping motor and a stepping motor driving circuit. In terms of product performance, the driving circuit of the stepping motor belongs to the production and manufacturing of the stepping motor, and the stepping motor driving circuit belongs to the production and manufacturing of the motor driver. The following is a detailed description of the two parts as follows;
[0032] Stepper motors include three-phase motors and two-phase motors. Each phase of the stepper motor is provided with a winding, that is, the output method of the stepper motor is to divide each winding of the original stepper motor into n equal small windings, and divide each phase winding of the stepper motor into n independent small windings. The number of small windings on each phase is the same, and the number of windings of each small winding is also the same. Each small winding is respectively provided with a P terminal and a Q terminal, and a winding unit is provided with n small windings in each phase winding, which are respectively composed of a combination of one of the small windings in each phase winding, that is, a winding unit contains a small winding on each phase of the motor.
[0033] like Figure 1 As shown, the three-phase stepper motor has three windings, namely winding A, winding B, and winding C. Each winding has two terminals, namely P and Q. The small windings after dividing winding A into n equal parts are named A1, A2, ..., An respectively. The P end of winding A1 is named AP1, and the Q end is named AQ1. The P end of winding A2 is named AP2, and the Q end is named AQ2. By analogy, AP1, AP2, ..., APn are terminals with the same name, and AQ1, AQ2, ..., AQn are terminals with the same name. The three terminals AQ1, BQ1, and CQ1 are connected together and named Q1. The three terminals AQ2, BQ2, and CQ2 are connected together and named Q2. By analogy, Q1, Q2, ..., Qn are terminals with the same level and can be connected together or not. The obtained stepper motor output line can be equivalent to having n groups of independent three-phase stepper motor windings in the stepper motor.
[0034] like Figure 2As shown, the two-phase stepper motor has two windings, namely winding A and winding B. Each winding has two terminals, namely P and Q. The small windings after dividing winding A into n equal parts are named A1, A2, ..., An respectively. The P end of winding A1 is named AP1, and the Q end is named AQ1. The P end of winding A2 is named AP2, and the Q end is named AQ2. By analogy, AP1, AP2, ..., APn are terminals with the same name, and AQ1, AQ2, ..., AQn are terminals with the same name. The obtained stepper motor output line can be equivalent to n groups of independent two-phase stepper motor windings in the stepper motor.
[0035] like Figure 3 , Figure 4 As shown, the driving circuit of the stepper motor is to equip n groups of independent stepper motor windings in the stepper motor with the same driving circuit to drive them synchronously with the same signal.
[0036] like Figure 5 As shown, some drive circuits work in a full-bridge mode, and the full bridge cannot be split into two half-bridges for use. In order to fully utilize this drive circuit, we divide a three-phase stepper motor into two groups of independent three-phase stepper motor windings, connect the three terminals AQ1, BQ1, and CQ1 of the first group together, named Q1, and connect the three terminals AP2, BP2, and CP2 of the second group together, named P2. The Q1 terminal and the P2 terminal are not at the same level and cannot be connected together, so the two groups of independent winding outputs are AP1, BP1, CP1 and AQ2, BQ2, CQ2; correspondingly, connect the first full-bridge drive output OUT and AP1 and AQ2 respectively, and the second full-bridge driver output OUT and BP1 and BQ2 respectively, and the third full-bridge driver outputs OUT and CP1 and CQ2 respectively.
[0037] After determining the number of independent windings of the stepper motor, if we want a higher driving power, we need to parallel output the driving circuit. We know that the driving circuit of the stepper motor is generally an H-bridge circuit or multiple half-bridge circuits. The output state change of this half-bridge circuit has a dead time, and the dead time of each half-bridge circuit is different. Therefore, even if the half-bridge circuit uses the same input control signal, the output cannot be directly connected. However, we found that if the input control signal is the same, the output state of the half-bridge circuit is the same most of the time, and there is only a very short time in the dead time when the output state is opposite. Here we use common-mode inductors to realize the parallel output of the driving circuit, such as Figure 6As shown, when the outputs of the two half-bridge circuits to be connected in parallel are opposite, the common-mode inductor is equivalent to connecting an inductor at the two output ends. When the outputs of the two half-bridge circuits to be connected in parallel are the same, because the currents in the two sets of coils of the common-mode inductor are in opposite directions and cancel each other out, the common-mode inductor has no inductive effect on the output of the half-bridge circuit.
[0038] The utility model is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the utility model is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the utility model, or the concept and technical solution of the utility model are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.
Claims
1. The driving circuit of the stepper motor, each phase of the stepper motor is provided with a winding, characterized in that: Each phase winding of the stepper motor is composed of n independent small windings, each small winding is respectively provided with a P end and a Q end, and a winding unit is provided with n small windings in each phase winding respectively.
2. The stepper motor driving circuit according to claim 1, characterized in that: The stepper motor is a three-phase motor, which includes winding A, winding B, and winding C. The small windings obtained by dividing winding A into n equal parts are named A1, A2, ..., An respectively; the small windings obtained by dividing winding B into n equal parts are named B1, B2, ..., Bn respectively; the small windings obtained by dividing winding C into n equal parts are named C1, A2, ..., Cn respectively; The P end of the winding A1 is named AP1, and the Q end is named AQ1; the P end of the winding A2 is named AP2, and the Q end is named AQ2, and so on; Connect the three terminals AQ1, BQ1, and CQ1 together and name it Q1. Connect the three terminals AQ2, BQ2, and CQ2 together and name it Q2. And so on.
3. The stepper motor driving circuit according to claim 1, characterized in that: The stepper motor is a two-phase motor, which includes winding A and winding B. The small windings obtained by dividing winding A into n equal parts are named A1, A2, ..., An, and the small windings obtained by dividing winding B into n equal parts are named B1, B2, ..., Bn. The P end of winding A1 is named AP1, and the Q end is named AQ1. The P end of winding A2 is named AP2, and the Q end is named AQ2, and so on. Connect the three terminals AQ1, BQ1, and CQ1 together and name it Q1. Connect the three terminals AQ2, BQ2, and CQ2 together and name it Q2. And so on.
4. The stepping motor driving circuit according to claim 2, characterized in that: The three-phase motor has two winding units; In the first winding unit, the three terminals AQ1, BQ1, and CQ1 of the small winding are connected together and named as the Q1 terminal; In the second winding unit, the three terminals of the small winding, AP2, BP2, and CP2, are connected together and named as the P2 terminal; The stepper motor is provided with a driving circuit, which is composed of a plurality of full-bridge circuits, wherein the output OUT of the first full-bridge circuit is connected to AP1, Connect to AQ2, and the output of the second full-bridge circuit OUT is connected to BP1. Connect to BQ2, and the OUT of the third full-bridge circuit output is connected to CP1. Connect with CQ2.
5. The stepping motor driving circuit according to claim 1, 2 or 3, characterized in that: The driving circuit of the stepper motor is an H-bridge circuit, or is composed of a plurality of half-bridge circuits.
6. The stepping motor driving circuit according to claim 5, characterized in that: Each two half-bridge circuits in the driving circuit are equipped with a common-mode inductor, the input signals of the two half-bridge circuits are the same, and the two half-bridge circuits are not in the same full-bridge circuit, and the output ends of the multiple common-mode inductors are connected to the stepper motor.
7. The stepping motor driving circuit according to claim 4 or 6, characterized in that: The driving circuit is provided with a current sensor, the input end of the current sensor is connected to the power input, and the output end of the current sensor is connected to each full-bridge circuit or half-bridge circuit of the driving motor to obtain the current signal of the driving motor and transmit the obtained signal to the processor.
8. The stepper motor driving circuit according to claim 7, characterized in that: The processor is connected to an encoder, and a plurality of PWM signals of the processor are respectively connected to the input end of each full-bridge circuit or half-bridge circuit.