PWM (Pulse Width Modulation) speed regulation circuit for direct current brushless motor driver
By introducing a PWM speed control circuit with components such as a drive transformer and a Zener diode into the brushless DC motor driver, the problem of erroneous operation of the motor at 100% duty cycle was solved, and the motor was able to stop stably during the initialization process.
Patent Information
- Application Number
- CN202423274296.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-30
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing brushless DC motor drivers may cause the motor to malfunction and operate when the PWM speed control duty cycle is 100% constant high level, affecting the system's operating status.
Design a PWM speed control circuit that includes a drive transformer, a signal input terminal, a signal output terminal, a clamping diode, a current limiting resistor, and a Zener diode. By utilizing the AC-DC blocking characteristic of the drive transformer, the signal output terminal is kept at a low level at 100% duty cycle to prevent the motor from running.
This circuit ensures that the motor remains stopped when the PWM speed control duty cycle is 100% constant high level, thus preventing the motor from running erroneously and solving the problem of erroneous operation during the initialization process of motor drive control.
Smart Images
Figure CN223744607U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to motor control technical field, especially related to a PWM speed regulation circuit for direct current brushless motor driver. BACKGROUND
[0002] Brushless motor driver is a kind of equipment for controlling brushless motor operation.In the existing motor drive circuit, the PWM speed regulation duty cycle is usually 0~100%.In the initialization process of the front-stage control circuit, the PWM speed regulation may be 100% duty cycle constant high level, at this time, the motor may be mis-triggered to run, which affects the running state of the system.
[0003] How to design a PWM speed regulation circuit for direct current brushless motor driver, use low-cost simple circuit to solve the above technical problems, long plagued the technical personnel in this field. INVENTION CONTENTS
[0004] For the above technical problems, the utility model provides a PWM speed regulation circuit for direct current brushless motor driver, which is suitable for brushless direct current motor driver, and the driver will not drive the motor to run when the PWM speed regulation duty cycle is 100% constant high level.
[0005] The utility model solves the above problems by the following technical means:
[0006] A PWM speed regulation circuit for direct current brushless motor driver, characterized by comprising drive transformer, signal input end, signal output end, wherein: the signal input end is connected with the primary same name end of drive transformer through the third capacitor, the primary different name end of drive transformer is connected with digital ground through the eighth resistance, there is the first clamping diode between signal input end and digital ground, and the primary two ends of drive transformer are connected with primary load resistance;The same name end of the secondary of the drive transformer is divided into three ways, wherein: the first way of the same name end of the secondary is connected with the anode of the stabilizing diode through the second current-limiting resistance and the third current-limiting resistance, the second way of the same name end of the secondary is connected with the different name end of the secondary through the secondary load, and the third way of the same name end of the secondary is connected with the different name end of the secondary through the parallel circuit of the second capacitor, the second clamping diode and the fourth capacitor in turn;The cathode of the stabilizing diode is connected with reference ground, and the signal output end is connected with the anode of the stabilizing diode.
[0007] Preferably, the anode of the second clamping diode is connected between the second current-limiting resistance and the third current-limiting resistance through a lead, and the cathode of the second clamping diode is connected with reference ground.
[0008] Preferably, it further includes gate drive circuit, the input end of gate drive circuit is connected with signal output end, and the output end of gate drive circuit inputs the square wave signal of signal output end after reversing to the rear-stage logic circuit.
[0009] Preferably, the inverter is further connected to the signal output end, and the output end of the inverter inputs the square wave signal of the signal output end after being reversed to the subsequent logic circuit.
[0010] Preferably, the buffer is further connected between the signal output end and the subsequent logic circuit.
[0011] The PWM speed regulation circuit for the direct-current brushless motor driver has the following beneficial effects:
[0012] The circuit is applicable to a brushless direct-current motor driver, and when the PWM speed regulation duty ratio is 100% constant high level, the driver will not drive the motor to run, compared with the prior art, the circuit solves the technical problem of motor misoperation in the initialization process of motor drive control by using a simple drive transformer. Through the use of the circuit, the control system keeps the motor in a stopped state during the initialization process, which can prevent the motor from running incorrectly. BRIEF DESCRIPTION OF DRAWINGS
[0013] In order to more clearly illustrate the technical scheme of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.
[0014] Figure 1 It is the overall circuit schematic diagram of the present application. DETAILED DESCRIPTION
[0015] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation of the present application. The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included one or more features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0016] The present application will be described in detail below with reference to the drawings.
[0017] AsFigure 1 As shown, the PWM speed regulation circuit includes a driving transformer T1, a signal input end PWM, and a signal output end SR. In the figure: the signal input end PWM is connected to the primary same-named end of the driving transformer T1 through a third capacitor C3, the primary different-named end of the driving transformer T1 is connected to a digital ground DGND through an eighth resistor R8, a first clamping diode D1 is connected between the signal input end PWM and the digital ground DGND, and a primary load resistor R6 is connected to the two ends of the primary of the driving transformer T1; the secondary same-named end of the driving transformer T1 is divided into three paths, in which: the first path of the secondary same-named end is connected to the anode of a voltage stabilizing diode VD1 through a second current-limiting resistor R2 and a third current-limiting resistor R3, the second path of the secondary same-named end is connected to the secondary different-named end through a secondary load R7, and the third path of the secondary same-named end is connected to the secondary different-named end through a parallel circuit composed of a second capacitor C2, a second clamping diode D2, and a fourth capacitor C4 in sequence; the cathode of the voltage stabilizing diode VD1 is connected to a reference ground GND, and the signal output end SR is connected to the anode of the voltage stabilizing diode VD1. Specifically, the anode of the second clamping diode D2 is connected to the second current-limiting resistor R2 and the third current-limiting resistor R3 through a lead, and the cathode of the second clamping diode D2 is connected to the reference ground GND.
[0018] In actual application, when the brushless DC motor driver is powered on, the PWM chopping signal passes through the driving transformer, and a square wave signal is generated at the signal output end SR. After being reversed by the gate drive circuit or the inverter, the logic circuit in the rear stage is input, so that the motor operates normally. When the PWM duty cycle is 100%, the SR is always low due to the AC-DC isolation characteristic of the driving transformer, and the motor stops operating.
[0019] It should be noted that the input end of the gate drive circuit is connected to the signal output end SR, and the output end of the gate drive circuit inputs the square wave signal of the signal output end SR after being reversed to the logic circuit in the rear stage. The input end of the inverter is connected to the signal output end SR, and the output end of the inverter inputs the square wave signal of the signal output end SR after being reversed to the logic circuit in the rear stage.
[0020] The specific working principle is as follows:
[0021] The primary and secondary turns ratio of the drive transformer can be set as n according to actual conditions, the PWM signal is a high-frequency chopping signal, the secondary of the drive transformer will induce a PWM high-frequency square signal with an amplitude of about n times, and then the signal is stabilized by the stabilizing two-stage tube VD1, the SR signal input into the gate drive circuit or the inverter is a high-frequency square signal with a relatively stable amplitude, and the PWMOUT is a high-frequency square signal with a relatively stable amplitude and opposite to the SR signal. R7 is the load of the secondary of the drive transformer, which can make the voltage waveform of the secondary relatively stable. D2 can make the negative voltage amplitude of the square signal clamped in a certain range. R2 and R3 are the current limiting resistors of the stabilizing tube VD1. The VD1 stabilizing tube can stabilize the SR signal to a certain range. The circuit is suitable for brushless DC motor driver, when the PWM speed regulation duty cycle is 100% constant high level, the driver will not drive the motor to run, and the circuit solves the technical problem of motor misoperation in the initialization process of motor drive control by using a simple drive transformer. Through the use of the circuit, the motor always keeps the state of stopping in the initialization process of the control system, which can prevent the motor from running incorrectly.
[0022] It should be further pointed out that a buffer can be arranged between the signal output end SR and the later-stage logic circuit or they can be directly connected.
[0023] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the utility model, but not to limit them; although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the utility model.
Claims
1. A PWM speed control circuit for a direct current brushless motor drive, characterized by, Including drive transformer (T1), signal input end (PWM), signal output end (SR), wherein: The signal input end (PWM) is connected to the primary same end of the drive transformer (T1) through the third capacitor (C3), the primary opposite end of the drive transformer (T1) is connected to the digital ground (DGND) through the eighth resistor (R8), the first clamping diode (D1) is connected between the signal input end (PWM) and the digital ground (DGND), and the primary end of the drive transformer (T1) is connected with the primary load resistor (R6); The secondary same end of the drive transformer (T1) is divided into three paths, wherein: the first path of the secondary same end is connected to the anode of the voltage stabilizing diode (VD1) through the second current limiting resistor (R2) and the third current limiting resistor (R3), the second path of the secondary same end is connected to the secondary opposite end through the secondary load (R7), and the third path of the secondary same end is connected to the secondary opposite end through the parallel circuit composed of the second capacitor (C2), the second clamping diode (D2) and the fourth capacitor (C4) in sequence. The cathode of the voltage stabilizing diode (VD1) is connected to the reference ground (GND), and the signal output end (SR) is connected to the anode of the voltage stabilizing diode (VD1).
2. The PWM speed control circuit for a direct current brushless motor driver according to claim 1, wherein, The anode of the second clamping diode (D2) is connected between the second current limiting resistor (R2) and the third current limiting resistor (R3) through a lead, and the cathode of the second clamping diode (D2) is connected to the reference ground (GND).
3. The PWM speed control circuit for a DC brushless motor drive of claim 1, wherein, It also includes a gate drive circuit, the input end of the gate drive circuit is connected to the signal output end (SR), and the output end of the gate drive circuit inputs the square wave signal of the signal output end (SR) after being reversed to the subsequent logic circuit.
4. The PWM speed control circuit for a DC brushless motor drive of claim 1, wherein, It also includes an inverter, the input end of the inverter is connected to the signal output end (SR), and the output end of the inverter inputs the square wave signal of the signal output end (SR) after being reversed to the subsequent logic circuit.
5. The PWM speed control circuit for a DC brushless motor drive of claim 1, wherein, It also includes a buffer connected between the signal output end (SR) and the subsequent logic circuit.