Magnetic control resistance control circuit

The voltage and current are detected by push-pull circuit and in-phase proportional amplifier, and combined with the PID algorithm to regulate the PWM signal, the accuracy and stability problems of the magnetron resistance system of the fitness equipment are solved, and high-precision resistance adjustment and stability control are achieved.

CN223260078UActive Publication Date: 2025-08-22POKANG TECH CO LTD
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Patent Information

Application Number
CN202422856029.1
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-11-21
Publication Date
2025-08-22
Estimated Expiration
2034-11-21

AI Technical Summary

Technical Problem

The magnetron resistance system of existing fitness equipment has shortcomings in resistance adjustment accuracy, stability and voltage and current detection, and cannot meet the needs of high accuracy and stability, especially when the EMI magnetron wheel is heated, which affects the accuracy of resistance control.

Method used

The push-pull circuit composed of transistors and MOS tubes is used to drive the MOS tubes, combine the in-phase proportional amplifier formed by resistors and capacitors to detect voltage and current, and the PWM signal is controlled in real time through the PID algorithm to ensure the accuracy and stability of resistance adjustment.

Benefits of technology

It realizes high-precision resistance adjustment and stability control, and can automatically compensate current and voltage when the EMI magnetron heats up, ensuring constant resistance and improving user experience and training effects.

✦ Generated by Eureka AI based on patent content.

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Abstract

The utility model relates to a magnetic control resistance control circuit which comprises a triode Q8, a base electrode of which is connected with a PWM control signal and an emitter electrode of which is grounded, and which is used for reversing the PWM control signal and inputting the PWM control signal to a push-pull circuit; the input end of the push-pull circuit is connected with the collector electrode of the triode Q8, and the output end of the push-pull circuit is connected with the MOS tube Q1 and used for driving the MOS tube Q1; the MOS tube Q1 is connected with a VDD voltage end and a port JP2; and the port JP2 is used for connecting an EMI magnetic control wheel. According to the circuit, high-precision magnetic control resistance adjustment can be realized through software regulation and control and temperature compensation.
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Description

Technical Field

[0001] The utility model relates to the technical field of circuits, in particular to a magnetically controlled resistance control circuit. Background Art

[0002] Magnetic resistance systems are widely used in fitness equipment, spinning bikes, and other equipment to provide varying degrees of exercise resistance. Traditional resistance adjustment methods have many shortcomings and are unable to meet the demand for high-precision resistance control.

[0003] For example, some simple mechanical adjustment methods cannot achieve continuous and precise resistance adjustment and are prone to wear during use, resulting in unstable resistance adjustment performance. Earlier electromagnetic control methods, due to the lack of effective feedback and precise control methods, often cannot accurately maintain the set resistance value.

[0004] As people's expectations for fitness equipment continue to rise, especially in terms of exercise intensity, training results, and user experience, the control accuracy and stability of magnetic resistance systems are becoming increasingly challenging. Existing control circuits are unable to effectively compensate for resistance changes caused by heating of the EMI magnetic control wheel, thereby affecting the stability and accuracy of the resistance. Furthermore, traditional circuits can suffer from issues such as low accuracy and limited detection range in voltage and current detection, further hindering the performance of magnetic resistance systems.

[0005] In order to overcome the above-mentioned defects, the present invention provides an improved magnetically controlled resistance control circuit, which can achieve high-precision resistance adjustment and effectively solve the problems existing in the prior art. Utility Model Content

[0006] The purpose of the utility model is to provide a magnetic control resistance control circuit to solve the above problems in the prior art.

[0007] In order to achieve the above application objectives, the present invention adopts the following technical solutions: a magnetic control resistance control circuit includes:

[0008] Transistor Q8, with its base connected to the PWM control signal and its emitter grounded, is used to invert the PWM control signal and input it into the push-pull circuit;

[0009] A push-pull circuit, with its input end connected to the collector of transistor Q8 and its output end connected to MOS transistor Q1, is used to drive MOS transistor Q1;

[0010] MOS tube Q1 is connected to the VDD voltage terminal and port JP2;

[0011] Port JP2 is used to connect the EMI magnetic control wheel.

[0012] Furthermore, the push-pull circuit includes transistors Q2 and Q7 and resistor R12. The bases of transistors Q2 and Q7 are connected to the collector of transistor Q8. One end of resistor R2 is connected to the emitters of transistors Q2 and Q7, and the other end is connected to MOS transistor Q1.

[0013] Furthermore, it includes resistors RD1, RD2 and capacitor CD1. One end of resistor RD1 is connected to pin 1 of port JP2, and the other end is connected to resistor RD2. The end of resistor RD2 away from resistor RD1 is grounded. Capacitor CD1 is connected in parallel with resistor RD2.

[0014] Furthermore, a network label VOLTAGE is provided on one end of the capacitor CD1, and the network label VOLTAGE is used to connect to the AD detection port of the single chip microcomputer to realize voltage detection of the EMI magnetic control wheel.

[0015] Furthermore, it also includes a current sampling resistor RD3, one end of which is connected to pin 2 of port JP2, and the other end is connected to a resistor RD4, which is respectively connected to a capacitor CD2 and an operational amplifier UD1A to form a first-level in-phase proportional amplifier for amplifying the voltage signal of the current sampling resistor RD3.

[0016] Furthermore, it includes a resistor RD5 and a resistor RD6. One end of the resistor RD5 is grounded, and the other end is connected to the resistor RD6 and the cathode of the operational amplifier UD1A respectively. The resistor RD6 is also connected to the output end of the operational amplifier UD1A. The resistance values ​​of the resistors RD5 and RD6 determine the primary amplification factor of the voltage signal of the current sampling resistor RD3.

[0017] Furthermore, it also includes a secondary in-phase proportional amplifier located at the output end of the primary in-phase proportional amplifier. The output end of the secondary in-phase proportional amplifier is connected to the AD detection port of the microcontroller through the resistor RD10 to realize current sampling of the EMI magnetic control wheel.

[0018] Furthermore, the secondary in-phase proportional amplifier includes a resistor RD7, a capacitor CD3, an op amp UD1B, a resistor RD8, and a resistor RD9. One end of the resistor RD7 is connected to the output end of the op amp UD1A, and the other end is connected to the capacitor CD3 and the op amp UD1B respectively. One end of the resistor RD8 is grounded, and the other end is connected to the cathode of the resistor RD9 and the op amp UD1B respectively. The resistor RD9 is also connected to the output end of the op amp UD1B. The secondary amplification factor of the voltage signal of the current sampling resistor RD3 is determined by the resistance values ​​of the resistors RD8 and RD9. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a circuit diagram of the utility model;

[0020] Figure 2 yes Figure 1 An enlarged view of the push-pull circuit section;

[0021] Figure 3 yes Figure 1 A magnified view of the two middle op amp stages. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of the present invention.

[0023] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms cannot be understood as limiting the present invention.

[0024] like Figure 1-3 As shown, the magnetic control resistance control circuit includes:

[0025] Transistor Q8, with its base connected to the PWM control signal and its emitter grounded, is used to invert the PWM control signal and input it into the push-pull circuit;

[0026] A push-pull circuit has an input end connected to the collector of transistor Q8 and an output end connected to MOS transistor Q1, and is used to drive MOS transistor Q1. The push-pull circuit includes transistor Q2, transistor Q7, and resistor R12. The bases of transistors Q2 and Q7 are both connected to the collector of transistor Q8. One end of resistor R2 is connected to the emitters of transistor Q2 and transistor Q7, and the other end is connected to MOS transistor Q1.

[0027] MOS tube Q1 is connected to the VDD voltage terminal and port JP2;

[0028] Port JP2 is used to connect the EMI magnetic control wheel.

[0029] Resistors RD1 and RD2, and capacitor CD1. One end of resistor RD1 is connected to pin 1 of port JP2, and the other end is connected to resistor RD2. The end of resistor RD2, away from resistor RD1, is grounded. Capacitors CD1 and RD2 are connected in parallel. One end of capacitor CD1 is labeled VOLTAGE, which is connected to the AD detection port of the microcontroller to detect the voltage of the EMI magnetic control wheel.

[0030] The current sampling resistor RD3 has one end connected to pin 2 of the port JP2, and the other end connected to the resistor RD4. The resistor RD4 is respectively connected to the capacitor CD2 and the operational amplifier UD1A to form a first-stage non-inverting proportional amplifier for amplifying the voltage signal of the current sampling resistor RD3.

[0031] Resistors RD5 and RD6, one end of resistor RD5 is grounded, and the other end is connected to resistor RD6 and the cathode of op amp UD1A respectively. Resistor RD6 is also connected to the output end of op amp UD1A. The resistance values ​​of resistors RD5 and RD6 determine the primary amplification factor of the voltage signal of the current sampling resistor RD3.

[0032] A secondary non-inverting proportional amplifier is located at the output of the primary non-inverting proportional amplifier. The output of this secondary non-inverting proportional amplifier is connected to the AD detection port of the microcontroller via resistor RD10 to enable current sampling of the EMI magnetron wheel. The secondary non-inverting proportional amplifier includes resistor RD7, capacitor CD3, op amp UD1B, resistor RD8, and resistor RD9. One end of resistor RD7 is connected to the output of op amp UD1A, and the other end is connected to capacitor CD3 and op amp UD1B, respectively. Resistor RD8 has one end connected to ground, and the other end is connected to resistor RD9 and the cathode of op amp UD1B, respectively. Resistor RD9 is also connected to the output of op amp UD1B. The resistance values ​​of resistors RD8 and RD9 determine the secondary amplification factor of the voltage signal from current sampling resistor RD3.

[0033] In this embodiment, POWER_PWM is the PWM control signal output by the microcontroller. After being inverted by transistor Q8, the PWM signal passes through a push-pull circuit consisting of transistors Q2 and Q7, ultimately driving MOSFET Q1. This controls the voltage applied by VDD to the EMI magnetron. JP2 is connected to the EMI magnetron. Because MOSFET Q1 is a voltage-driven transistor, a push-pull circuit consisting of Q2 and Q7 is required to drive it. Otherwise, the MOSFET's IO port drive capability alone would be insufficient.

[0034] The PWM signal is generated by the microcontroller software and output to the control circuit through the POWER_PWM pin. When the PWM output is high, the R10 resistor output is high, the Q8 transistor is turned on, and the bases of the transistors Q2 and Q7 are low. At this time, Q2 is turned off and Q7 is turned on, causing the voltage at the R12 terminal to be low, which causes the MOS transistor Q1 to turn on. The VDD voltage is passed from pin 3 of the MOS transistor Q1 to pin 2, thereby applying the VDD voltage to one end of the EMI magnetic control wheel coil, causing the EMI magnetic control wheel to power up and operate. When the PWM output is low, the R10 resistor output is low, the Q3 transistor is turned off, and the bases of the transistors Q2 and Q7 are high. At this time, Q2 is turned on and Q7 is turned off, causing the voltage at the R12 terminal to be high, causing the MOS transistor Q1 to turn off. The VDD voltage cannot pass from pin 3 of the MOS transistor Q1 to pin 2, and the VDD voltage cannot be applied to the one end of the EMI magnetic control wheel coil, causing the EMI magnetic control wheel to power up and operate.

[0035] In this embodiment, RD1 and RD2 are used to detect the input voltage of the EMI magnetic control wheel. Finally, the network label VOLTAGE is connected to the AD detection port of the microcontroller to complete the detection of the EMI magnetic control wheel voltage.

[0036] In this embodiment, since the MCU interface is generally powered by 3.3V or 5V, the voltage of the AD detection port of the MCU cannot exceed this value. The VDD voltage value passing through the MOS tube Q1 generally exceeds 12V. Therefore, in order to detect this voltage value, RD1 and RD2 need to be used for voltage division. After the divided voltage value is detected through the MCU AD interface, the VDD voltage value can be calculated.

[0037] In this embodiment, RD3 is a current sampling resistor. When the magnetic wheel is powered through JP2, the current is ultimately connected to the negative power supply via sampling resistor RD3. Op amp UD1A forms a non-inverting proportional amplifier, which amplifies the voltage signal at RD3. The specific amplification factor is determined by RD5 and RD6. After this initial amplification, the voltage signal is amplified again by op amp UD1B, which forms a non-inverting proportional amplifier. The specific amplification factor is determined by RD8 and RD9. The amplified signal is finally connected to the AD detection pin (current) of the microcontroller network via RD10. This completes current sampling for the EMI magnetic wheel.

[0038] In this embodiment, the software uses the detected voltage and current values ​​of the magnetic control wheel in combination with the PID algorithm to adjust the PWM signal in real time to ensure that the current value on the corresponding gear current loop remains unchanged, thereby ensuring that the resistance of the magnetic control remains unchanged. In this way, the current is controlled and adjusted to ensure high-precision resistance adjustment.

[0039] Since the resistance of the EMI magnetic control wheel will increase after heating, if the output PWM is fixed at this time, that is, the voltage value loaded on the EMI magnetic control wheel remains unchanged, according to the formula I=U / R, it can be seen that the increase in resistance R will cause the current I to decrease, and the magnetic field strength generated by the coil and the current are in direct proportion. Therefore, in order to ensure that the power remains unchanged, the current must be kept unchanged. At this time, the only way to compensate is to increase the U value accordingly, that is, to increase the PWM pulse width to ensure that the current value remains unchanged.

[0040] The parts not described in detail in this utility model are prior art, so this utility model does not describe them in detail.

[0041] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0042] Although this article uses a lot of professional terms, it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

[0043] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, any product with the same or similar technical solutions as the present invention falls within the scope of protection of the present invention.

Claims

1. A magnetic control resistance control circuit, characterized in that: include: Transistor Q8, with a base connected to the PWM control signal and an emitter grounded, for inverting the PWM control signal and inputting it into the push-pull circuit; A push-pull circuit, with its input end connected to the collector of transistor Q8 and its output end connected to MOS transistor Q1, is used to drive MOS transistor Q1; MOS tube Q1 is connected to the VDD voltage terminal and port JP2; Port JP2 is used to connect the EMI magnetic control wheel.

2. The magnetic control resistance control circuit according to claim 1, characterized in that: The push-pull circuit includes a transistor Q2, a transistor Q7 and a resistor R12. The bases of the transistors Q2 and Q7 are connected to the collector of the transistor Q8. One end of the resistor R2 is connected to the emitters of the transistors Q2 and Q7, and the other end is connected to the MOS transistor Q1.

3. The magnetic control resistance control circuit according to claim 1, characterized in that: It also includes a resistor RD1, a resistor RD2, and a capacitor CD1. One end of the resistor RD1 is connected to pin 1 of the port JP2, and the other end is connected to the resistor RD2. The end of the resistor RD2 away from the resistor RD1 is grounded. The capacitor CD1 is connected in parallel with the resistor RD2.

4. The magnetic control resistance control circuit according to claim 3, characterized in that: One end of the capacitor CD1 is provided with a network label VOLTAGE, and the network label VOLTAGE is used to connect to the AD detection port of the single chip microcomputer to realize voltage detection of the EMI magnetic control wheel.

5. The magnetic control resistance control circuit according to claim 1, characterized in that: It also includes a current sampling resistor RD3, one end of which is connected to pin 2 of port JP2, and the other end is connected to a resistor RD4, which is respectively connected to a capacitor CD2 and an operational amplifier UD1A to form a first-level in-phase proportional amplifier for amplifying the voltage signal of the current sampling resistor RD3.

6. The magnetic control resistance control circuit according to claim 5, characterized in that: It also includes a resistor RD5 and a resistor RD6. One end of the resistor RD5 is grounded, and the other end is connected to the resistor RD6 and the cathode of the operational amplifier UD1A respectively. The resistor RD6 is also connected to the output end of the operational amplifier UD1A. The resistance values ​​of the resistors RD5 and RD6 determine the primary amplification factor of the voltage signal of the current sampling resistor RD3.

7. The magnetic control resistance control circuit according to claim 5, characterized in that: It also includes a secondary in-phase proportional amplifier located at the output end of the primary in-phase proportional amplifier. The output end of the secondary in-phase proportional amplifier is connected to the AD detection port of the microcontroller through the resistor RD10 to achieve current sampling of the EMI magnetic control wheel.

8. The magnetic control resistance control circuit according to claim 7, characterized in that: The secondary in-phase proportional amplifier includes a resistor RD7, a capacitor CD3, an op amp UD1B, a resistor RD8, and a resistor RD9. One end of the resistor RD7 is connected to the output end of the op amp UD1A, and the other end is connected to the capacitor CD3 and the op amp UD1B respectively. One end of the resistor RD8 is grounded, and the other end is connected to the resistor RD9 and the cathode of the op amp UD1B respectively. The resistor RD9 is also connected to the output end of the op amp UD1B. The secondary amplification factor of the voltage signal of the current sampling resistor RD3 is determined by the resistance values ​​of the resistors RD8 and RD9.