Low-cost PWM speed regulation circuit and motor controller using the same

Abstract

The utility model discloses a low -cost PWM speed regulation circuit and the motor controller of applying it, including PWM signal generating circuit, it still includes triode Q1, PWM signal frequency and duty ratio adjusting circuit and PWM signal amplitude selection circuit, PWM signal amplitude selection circuit connects the collector of triode Q1, and the output of PWM signal frequency and duty ratio adjusting circuit is connected the input of PWM signal generating circuit, and the output PWM_1 of PWM signal generating circuit is connected to the base of triode Q1, and the emitter of triode Q1 is grounded GND, and the collector of triode Q1 is formed PWM signal's output terminal PWM_OUT and is led out, it realizes the function that PWM signal frequency, duty ratio and amplitude are all adjustable, and the function is more perfect, and the adjustment is more flexible and convenient, and the manufacturing cost is low.

Description

Technical Field

[0001] This utility model relates to a low-cost PWM speed control circuit and a motor controller using the same. Background Technology

[0002] Currently, PWM speed control circuits are widely used in industry (e.g., in motor controllers). The vast majority of solutions use high-precision dedicated PWM chips, which are costly and incompatible in terms of frequency and output voltage. Major manufacturers are seeking lower-cost solutions that meet accuracy requirements and offer strong substitutability. The following are some examples. Figure 1 A PWM speed control circuit designed with a chip is described, characterized in that the potentiometer-to-PWM speed control circuit includes a PWM controller and a potentiometer; at least one pin of the PWM controller is connected to the potentiometer, and the PWM controller is used to obtain the input voltage of the potentiometer to output a PWM signal with a duty cycle corresponding to the input voltage; the PWM controller is also connected to peripheral circuitry. This PWM speed control circuit has the following disadvantages: it uses a dedicated speed control chip, which is relatively expensive; secondly, the voltage amplitude, duty cycle, and frequency of the output PWM signal are fixed, and adjusting them requires modifying the hardware circuitry, which is very troublesome and inflexible. Summary of the Invention

[0003] This invention provides a low-cost PWM speed control circuit and a motor controller using it, to solve the technical problems of existing PWM speed control circuits that use dedicated speed control chips, which are relatively expensive, and whose output PWM signal voltage amplitude, duty cycle and frequency are fixed, requiring hardware circuit modifications for adjustment, which is very troublesome and inflexible.

[0004] The technical solution of this utility model is implemented as follows:

[0005] A low-cost PWM speed control circuit includes a PWM signal generation circuit, characterized in that it further includes a transistor Q1, a PWM signal frequency and duty cycle adjustment circuit, and a PWM signal amplitude selection circuit. The PWM signal amplitude selection circuit is connected to the collector of the transistor Q1. The output terminal of the PWM signal frequency and duty cycle adjustment circuit is connected to the input terminal of the PWM signal generation circuit. The output terminal PWM_1 of the PWM signal generation circuit is connected to the base of the transistor Q1. The emitter of the transistor Q1 is grounded to GND. The collector of the transistor Q1 is led out to form the output terminal PWM_OUT of the PWM signal.

[0006] Preferably, the PWM signal generation circuit uses a single-chip microcomputer (MCU).

[0007] Preferably, the PWM signal frequency and duty cycle adjustment circuit is a key input selection circuit.

[0008] Preferably, the key input selection circuit includes several keys, a capacitor C64, resistors R95, R98, R100, R103, R106, and R123. Resistor R95 and capacitor C64 are connected in series, with one end connected to a DC power supply and the other end grounded (GND). Resistor R98 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R100 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R103 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R106 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R123 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. A signal output terminal is led out between resistors R95 and capacitor C64 and connected to a signal input terminal of the microcontroller (MCU).

[0009] Preferably, the PWM signal amplitude selection circuit includes resistors R91, R92, R93, and R96, and a selection switch S1-3. The 24V DC power supply is connected to resistor R96 and then to pin 1 of the selection switch S1-3. Resistors R91, R92, and R93 are connected in series, and their two ends are connected to the 24V DC power supply and ground (GND) respectively. A lead is made between resistors R91 and R92 and connected to pin 3 of the selection switch S1-3. A lead is made between resistors R92 and R93 and connected to pin 4 of the selection switch S1-3. Pin 2 of the selection switch S1-3 is connected to the collector of transistor Q1.

[0010] Preferably, a resistor R101 is connected between the output terminal PWM_1 of the PWM signal generation circuit and the base of the transistor Q1, one end of the capacitor C70 is connected between the resistor R101 and the base of the transistor Q1, and the other end of the capacitor C70 is grounded to GND.

[0011] Preferably, a resistor R99 is connected between the collector of transistor Q1 and the output terminal PWM_OUT of the PWM signal, one end of capacitor C69 is connected between resistor R99 and the output terminal PWM_OUT of the PWM signal, and the other end of capacitor C69 is grounded to GND.

[0012] A motor controller includes a microprocessor, an inverter circuit, and a PWM speed control circuit. The output terminal of the PWM speed control circuit is connected to the input terminal of the microprocessor, and the microprocessor controls the operation of the inverter circuit. The characteristic of the controller is that the PWM speed control circuit adopts the low-cost PWM speed control circuit described above.

[0013] Compared with the prior art, this utility model has the following advantages:

[0014] 1. By pressing the independent button to adjust the frequency and duty cycle of the PWM signal, and by toggling the single-pole triple-throw switch to change the amplitude of the PWM signal, the function of adjusting the frequency, duty cycle and amplitude of the PWM signal can be realized, making the function more complete and the adjustment more flexible and convenient.

[0015] 2. A PWM signal output circuit with adjustable frequency, duty cycle, and amplitude is constructed using a transistor (i.e., a triode), a single-pole three-throw switch (i.e., selector switches S1-3), five independent buttons, and some resistors and capacitors. It offers strong substitutability and low cost.

[0016] 3. Other advantages of this utility model are described in detail in the embodiments section. Attached Figure Description

[0017] Figure 1 This is a circuit block diagram of Embodiment 1 of the present invention;

[0018] Figure 2 for Figure 1 The corresponding part of the circuit diagram;

[0019] Figure 3 for Figure 1 The corresponding other part of the circuit diagram;

[0020] Figure 4 This is the circuit block diagram corresponding to Embodiment 2 of this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] Example 1:

[0023] like Figures 1 to 3 As shown, this embodiment provides a low-cost PWM speed control circuit, including a PWM signal generation circuit. Its features include: a transistor Q1, a PWM signal frequency and duty cycle adjustment circuit, and a PWM signal amplitude selection circuit. The PWM signal amplitude selection circuit is connected to the collector of transistor Q1. The output terminal of the PWM signal frequency and duty cycle adjustment circuit is connected to the input terminal of the PWM signal generation circuit. The output terminal PWM_1 of the PWM signal generation circuit is connected to the base of transistor Q1. The emitter of transistor Q1 is grounded to GND. The collector of transistor Q1 is led out to form the PWM signal output terminal PWM_OUT.

[0024] Preferably, the PWM signal generation circuit uses a single-chip microcomputer (MCU), which is low in cost.

[0025] Preferably, the PWM signal frequency and duty cycle adjustment circuit is a key input selection circuit.

[0026] Preferably, the key input selection circuit includes several keys, capacitor C64, resistors R95, R98, R100, R103, R106, and R123. Resistor R95 and capacitor C64 are connected in series, with one end connected to a DC power supply and the other end grounded (GND). Resistor R98 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R100 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R103 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R106 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. Resistor R123 is connected in series with a key, and its two ends are connected in parallel across capacitor C64. A signal output terminal is led out between resistors R95 and capacitor C64 and connected to a signal input terminal of the microcontroller (MCU). The circuit structure is simple and allows for convenient and flexible adjustment of the PWM signal frequency and duty cycle.

[0027] Preferably, the PWM signal amplitude selection circuit includes resistors R91, R92, R93, and R96, and a selection switch S1-3. The 24V DC power supply is connected to resistor R96 and then to pin 1 of the selection switch S1-3. Resistors R91, R92, and R93 are connected in series, and their two ends are connected to the 24V DC power supply and ground (GND) respectively. A lead is made between resistors R91 and R92 and connected to pin 3 of the selection switch S1-3. A lead is made between resistors R92 and R93 and connected to pin 4 of the selection switch S1-3. Pin 2 of the selection switch S1-3 is connected to the collector of transistor Q1, which facilitates flexible adjustment of the PWM signal voltage amplitude.

[0028] This invention offers the following technical advantages: By pressing independent buttons to adjust the frequency and duty cycle of the PWM signal, and toggling a single-pole triple-throw switch to change the amplitude of the PWM signal, the function of adjusting the PWM signal frequency, duty cycle, and amplitude is achieved, resulting in more complete functionality and more flexible and convenient adjustment. A PWM signal output circuit with adjustable frequency, duty cycle, and amplitude is constructed using one transistor (Q1), one single-pole triple-throw switch (S1-3), five independent buttons, and some resistors and capacitors. It offers strong substitutability and low cost.

[0029] Preferably, a resistor R101 is connected between the output terminal PWM_1 of the PWM signal generation circuit and the base of transistor Q1. One end of capacitor C70 is connected between resistor R101 and the base of transistor Q1, and the other end of capacitor C70 is grounded to GND. Resistor R101 and capacitor C70 form a filter circuit to improve anti-interference capability.

[0030] Preferably, a resistor R99 is connected between the collector of transistor Q1 and the output terminal PWM_OUT of the PWM signal. One end of capacitor C69 is connected between resistor R99 and the output terminal PWM_OUT of the PWM signal, and the other end of capacitor C69 is grounded to GND. Resistor R99 and capacitor C69 form a filter circuit to improve anti-interference capability.

[0031] The working principle of this invention is as follows: the output PWM signals have amplitudes of V1, V2, and V3. The values ​​of V1, V2, and V3 can be determined by changing the resistance values ​​of R91, R92, and R93. When the single-pole triple-throw switch (i.e., selector switch S1-3) is in pin 1, it outputs a PWM signal with an amplitude of V1; when the single-pole triple-throw switch is in pin 3, it outputs a PWM signal with an amplitude of V2; and when the single-pole triple-throw switch is in pin 4, it outputs a PWM signal with an amplitude of V3.

[0032] The PWM_1 signal is output from a pin of the microcontroller (MCU). The key input selection circuit has five buttons, S1-S5. When S1 is pressed, the frequency of the PWM_1 signal output by the MCU increases, thus increasing the frequency of the PWM_OUT output. Similarly, pressing S2 decreases the frequency of the PWM_1 signal output by the MCU, thus decreasing the frequency of the PWM_OUT output. Pressing S3 increases the duty cycle of the PWM_1 signal output by the MCU, thus increasing the duty cycle of the PWM_OUT output. Similarly, pressing S4 decreases the duty cycle of the PWM_OUT output. Pressing S5 switches the MCU output mode. The PWM_OUT output signal is adjusted by controlling the PWM_1 signal output by the MCU.

[0033] Example 2:

[0034] like Figure 4 As shown, a motor controller includes a microprocessor, an inverter circuit, and a PWM speed control circuit. The output terminal of the PWM speed control circuit is connected to the input terminal of the microprocessor, and the microprocessor controls the operation of the inverter circuit. The characteristic of the controller is that the PWM speed control circuit adopts a low-cost PWM speed control circuit as described in Embodiment 1.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A low cost PWM speed control circuit comprising a PWM signal generating circuit, characterized by: It also includes a transistor Q1, a PWM signal frequency and duty cycle adjustment circuit, and a PWM signal amplitude selection circuit. The PWM signal amplitude selection circuit is connected to the collector of transistor Q1. The output terminal of the PWM signal frequency and duty cycle adjustment circuit is connected to the input terminal of the PWM signal generation circuit. The output terminal PWM_1 of the PWM signal generation circuit is connected to the base of transistor Q1. The emitter of transistor Q1 is grounded to GND. The collector of transistor Q1 is led out to form the output terminal PWM_OUT of the PWM signal.

2. A low cost PWM speed control circuit as claimed in claim 1, wherein: The PWM signal generation circuit uses a single-chip microcomputer (MCU).

3. The low-cost PWM speed control circuit according to claim 2, characterized in that: The PWM signal frequency and duty cycle adjustment circuit is a key input selection circuit.

4. The low-cost PWM speed control circuit according to claim 3, characterized in that: The button input selection circuit includes several buttons, capacitor C64, resistors R95, R98, R100, R103, R106, and R123. Resistor R95 and capacitor C64 are connected in series, with one end connected to a DC power supply and the other end grounded (GND). Resistor R98 is connected in series with one button, and its two ends are connected in parallel across capacitor C64. Resistor R100 is connected in series with one button, and its two ends are connected in parallel across capacitor C64. Resistor R103 is connected in series with one button, and its two ends are connected in parallel across capacitor C64. Resistor R106 is connected in series with one button, and its two ends are connected in parallel across capacitor C64. Resistor R123 is connected in series with one button, and its two ends are connected in parallel across capacitor C64. A signal output terminal is led out from resistor R95 and capacitor C64 and connected to a signal input terminal of the microcontroller (MCU).

5. A low-cost PWM speed control circuit according to any one of claims 1 to 4, characterized in that: The PWM signal amplitude selection circuit includes resistors R91, R92, R93, and R96, and a selection switch S1-3. The 24V DC power supply is connected to resistor R96 and then to pin 1 of the selection switch S1-3. Resistors R91, R92, and R93 are connected in series, and their two ends are connected to the 24V DC power supply and ground (GND) respectively. A lead is made between resistors R91 and R92 and connected to pin 3 of the selection switch S1-3. A lead is made between resistors R92 and R93 and connected to pin 4 of the selection switch S1-3. Pin 2 of the selection switch S1-3 is connected to the collector of transistor Q1.

6. The low-cost PWM speed control circuit according to claim 5, characterized in that: A resistor R101 is connected between the output terminal PWM_1 of the PWM signal generation circuit and the base of transistor Q1. One end of capacitor C70 is connected between resistor R101 and the base of transistor Q1, and the other end of capacitor C70 is grounded to GND.

7. A low-cost PWM speed control circuit according to claim 5, characterized in that: A resistor R99 is connected between the collector of transistor Q1 and the output terminal PWM_OUT of the PWM signal. One end of capacitor C69 is connected between resistor R99 and the output terminal PWM_OUT of the PWM signal, and the other end of capacitor C69 is grounded to GND.

8. A motor controller, comprising a microprocessor, an inverter circuit, and a PWM speed control circuit, wherein the output terminal of the PWM speed control circuit is connected to the input terminal of the microprocessor, and the microprocessor controls the operation of the inverter circuit, characterized in that: The PWM speed control circuit described herein employs a low-cost PWM speed control circuit as described in any one of claims 1 to 7.

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