Self-adaptive ignition control circuit with presettable ignition frequency

Abstract

The invention relates to an electronic ignition circuit, in particular to a self-adaptive ignition control circuit with a presettable ignition frequency. A self-adaptive ignition control circuit with a presettable ignition frequency comprises an MCU (Microprogrammed Control Unit) which is configured to output a PWM (Pulse Width Modulation) driving signal and is connected with a frequency feedback circuit to receive a feedback voltage signal; and the MCU control unit is further programmed to execute the following operations: comparing a preset target frequency range with the actual ignition frequency detected by the frequency feedback circuit, and dynamically adjusting the duty ratio of the PWM driving signal, so that the actual ignition frequency is stabilized in the target frequency range. The method has the advantages that digital presetting of the ignition frequency is achieved, environment and component changes are automatically compensated through closed-loop feedback, quick starting is achieved by recording optimal control parameters, and the method is suitable for scenes such as gas stoves and industrial combustors where the ignition frequency needs to be accurately controlled.

Description

Technical Field

[0001] This invention relates to electronic ignition circuits, and more particularly to an adaptive ignition control circuit with a preset ignition frequency. Background Technology

[0002] Traditional ignition circuits have the following drawbacks: 1. Uncontrollable frequency: After production, the igniter frequency can only be screened to fall within a certain range and cannot be precisely controlled; 2. Low precision: Open-loop control is easily affected by component aging, voltage fluctuations, etc., causing frequency drift; 3. No adaptive capability: The product needs to manually adjust parameters to maintain the target frequency within a certain range. If it exceeds the range, it cannot be automatically adjusted. Currently, the use of dedicated frequency control chips is costly and lacks parameter learning function. Summary of the Invention

[0003] To address the aforementioned technical problem of lacking parameter learning capabilities due to reliance on dedicated frequency control chips, this invention provides an adaptive ignition control circuit with a preset ignition frequency.

[0004] The technical solution of the present invention is as follows: An adaptive ignition control circuit with a preset ignition frequency includes an MCU control unit configured to output a PWM drive signal and connected to a frequency feedback circuit to receive a feedback voltage signal; the MCU control unit is also programmed to perform the following operations:

[0005] The duty cycle of the PWM drive signal is dynamically adjusted by comparing the preset target frequency range with the actual ignition frequency detected by the frequency feedback circuit, so that the actual ignition frequency is stabilized within the target frequency range. The PWM output terminal of the MCU control unit is connected to the rectifier energy storage circuit through a first-stage boost circuit, and the output terminal of the rectifier energy storage circuit is connected to a high-voltage generating circuit. The frequency feedback circuit is connected to the rectifier energy storage circuit and is used to detect its voltage and input it to the ADC pin of the MCU control unit.

[0006] The first-stage boost circuit includes a switching transistor and a transformer; the PWM output terminal of the MCU control unit is connected to the control electrode of the switching transistor through a current-limiting resistor, and the current path of the switching transistor is connected in series between the primary winding of the transformer and ground; the secondary winding of the transformer is connected to the rectifier energy storage circuit.

[0007] The rectifier energy storage circuit includes a rectifier diode and an energy storage capacitor; the anode of the rectifier diode is connected to the secondary winding of the transformer, and the cathode is connected to the positive terminal of the energy storage capacitor; the negative terminal of the energy storage capacitor is grounded.

[0008] The high-voltage generating circuit includes a discharge tube and an ignition transformer; the positive terminal of the energy storage capacitor is connected to one end of the discharge tube, and the other end of the discharge tube is connected to the primary winding of the ignition transformer; the secondary winding of the ignition transformer is used to output high voltage.

[0009] The frequency feedback circuit includes a voltage divider network consisting of a first voltage divider resistor and a second voltage divider resistor. The input terminal of the voltage divider network is connected to the positive terminal of the energy storage capacitor, and the output terminal is connected to the ADC input pin of the MCU control unit through a filter resistor.

[0010] The MCU control unit is also programmed to store the current optimal PWM duty cycle parameter in a non-volatile memory after the actual ignition frequency has been stable within the target range for a preset time, so that it can be directly called upon the next startup.

[0011] The technical solution of this invention has a novel structure and a clever and simple design, which realizes the digital preset of ignition frequency. It automatically compensates for changes in the environment and components through closed-loop feedback, records the optimal control parameters to achieve rapid start-up, simplifies the circuit structure and reduces costs. It is suitable for scenarios such as gas stoves and industrial burners that require precise control of ignition frequency. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the circuit structure of the present invention; Figure 2 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example

[0014] like Figure 1 , 2 An adaptive ignition control circuit with a preset ignition frequency is shown, comprising an MCU control unit configured to output a PWM drive signal and connected to a frequency feedback circuit to receive a feedback voltage signal. The MCU control unit is further programmed to perform the following operations: dynamically adjusting the duty cycle of the PWM drive signal based on a preset target frequency range compared with the actual ignition frequency detected by the frequency feedback circuit, so that the actual ignition frequency is stabilized within the target frequency range. The PWM output terminal of the MCU control unit is connected to a rectifier energy storage circuit via a boost circuit, and the output terminal of the rectifier energy storage circuit is connected to a high-voltage generator circuit. The frequency feedback circuit is connected to the rectifier energy storage circuit and is used to detect its voltage and input it to the ADC pin of the MCU control unit.

[0015] The first-stage boost circuit includes a switching transistor Q1 and a transformer T1; the PWM output terminal of the MCU control unit is connected to the control electrode of the switching transistor Q1 through a current-limiting resistor R1, and the current path of the switching transistor Q1 is connected in series between the primary winding of the transformer T1 and ground; the secondary winding of the transformer T1 is connected to the rectifier energy storage circuit.

[0016] The rectifier energy storage circuit includes a rectifier diode D1 and an energy storage capacitor C1; the anode of the rectifier diode D1 is connected to the secondary winding of the transformer T1, and the cathode is connected to the positive terminal of the energy storage capacitor C1; the negative terminal of the energy storage capacitor C1 is grounded.

[0017] The high-voltage generating circuit includes a discharge tube K1 and an ignition transformer HV1; the positive terminal of the energy storage capacitor C1 is connected to one end of the discharge tube K1, and the other end of the discharge tube K1 is connected to the primary winding of the ignition transformer HV1; the secondary winding of the ignition transformer HV1 is used to output high voltage.

[0018] The frequency feedback circuit includes a voltage divider network consisting of a first voltage divider resistor R2 and a first voltage divider resistor R4. The input terminal of the voltage divider network is connected to the positive terminal of the energy storage capacitor C1, and the output terminal is connected to the ADC input pin of the MCU control unit through a filter resistor R3.

[0019] The MCU control unit is also programmed to store the current optimal PWM duty cycle parameter in a non-volatile memory after the actual ignition frequency has been stable within the target range for a preset time, so that it can be directly called upon the next startup.

[0020] Circuit Connection: An adaptive ignition control circuit with a preset ignition frequency includes an MCU control unit. The MCU control unit outputs a PWM signal (20kHz, duty cycle 30-80%). The MCU control unit is connected to a first-stage boost circuit and a frequency feedback circuit. The first-stage boost circuit has one end of a current-limiting resistor R1 connected to the PWM output terminal of the MCU, and the other end connected to the base of a switching transistor Q1. The emitter of the switching transistor Q1 is grounded, and its collector is connected to the primary winding (pin 1) of transformer T1. Pin 3 of the primary winding of transformer T1 is connected to a +5V power supply. The turns ratio of the secondary winding (between pins 4 and 6) is 1:15. The frequency feedback circuit consists of a first voltage divider resistor R2 and a second voltage divider resistor R4 forming a 100:1 voltage divider network. The voltage division point is between the first voltage divider resistor R2 and the second voltage divider resistor R4. The connection point of resistor R4 is connected to the ADC input pin of the MCU control unit via a filter resistor R3. The first-stage boost circuit and frequency feedback circuit are connected to the rectifier energy storage circuit. In the rectifier energy storage circuit, the positive terminal of diode D1 is connected to the secondary winding (pin 4) of transformer T1, and the negative terminal is connected to the energy storage capacitor C1, the discharge tube K1 and the voltage divider resistor R2. The other end of the energy storage capacitor C1 is grounded. The rectifier energy storage circuit is connected to the high-voltage generating circuit. In the high-voltage generating circuit, the energy storage capacitor C1 is connected to one end of the discharge tube K1, and the other end of the discharge tube K1 is connected to the primary coil (pin 1) of the ignition transformer HV1. Pin 2 of the primary winding of the ignition transformer HV1 is grounded. The turns ratio of the primary winding (between pins 1 and 2) to the secondary winding (between pins 3 and 4) of the ignition transformer HV1 is 1:100 (pin 3 is grounded, and pin 4 outputs high voltage).

[0021] The steps of an adaptive ignition control circuit with a preset ignition frequency are as follows: The MCU outputs an initial PWM signal to drive the switching transistor Q1, generating an alternating current in the primary winding of transformer T1. This induces an AC current with a peak voltage of approximately 100-200V in the secondary winding. Diode D1 rectifies the current to charge the energy storage capacitor C1. When the voltage of the energy storage capacitor C1 reaches or exceeds the breakdown voltage of the discharge transistor K1 (e.g., 150V), the discharge transistor K1 breaks down, triggering the ignition transformer HV1 to discharge. The MCU monitors the voltage waveform (Vdetect) on the voltage divider network composed of the first voltage divider resistor R2 and the second voltage divider resistor R4 via an ADC (and uses edge detection and timer counting to measure the frequency). If the target frequency is reached, the MCU compares it with the current PWM parameters, stores the current PWM parameters, and if the frequency value is too high, decreases the PWM duty cycle; if the frequency value is too low, increases the PWM duty cycle.

[0022] 1. Initial parameter settings: PWM frequency = 20kHz, duty cycle = 60% Target range: 9-11Hz 2. Startup process: MCU outputs PWM → Q1 conducts → T1 secondary outputs approximately 150V peak AC power → D1 rectifies and C1 charges to 150V → K1 breaks down. HV1 primary current flow → secondary generation of 15kV high voltage discharge 3. Frequency adjustment: Actual frequency detected: 12Hz (higher than target) → Duty cycle reduced to 58% Secondary detection frequency 10.5Hz → maintain duty cycle Stabilize at 10.2Hz for 3 seconds → Store D=58% in EEPROM 4. Restart: Directly call the D=58% parameter, and the ignition frequency stabilizes at 10.3Hz.

[0023] Adaptive Algorithm: 1. Define the target frequency range [f_min, f_max] (e.g., 9-11Hz). 2. Initialize the PWM duty cycle D = 60%. 3. Real-time detection of actual frequency f_actual 4. Dynamic adjustment: ○When f_actual > f_max: D = D - ΔD (ΔD=1%) ○When f_actual < f_min: D = D + ΔD 5. When f_actual∈[f_min,f_max] lasts for 3 seconds, store the value of D to non-volatile memory (such as EEPROM). The technical effects of using this method are shown in the table below: index Traditional solution This invention Frequency control accuracy ±3Hz ±0.5Hz Response time >5 seconds <2 seconds Component temperature drift Frequency offset 20% Offset <2% Startup Consistency Random fluctuations Standard deviation < 0.1 Hz Applied to the field of high-voltage ignition control technology, it is an electronic ignition circuit that achieves adaptive adjustment of ignition frequency through closed-loop feedback.

Claims

1. An adaptive ignition control circuit with a preset ignition frequency, comprising an MCU control unit, characterized in that: The MCU control unit is configured to output a PWM drive signal and is connected to a frequency feedback circuit to receive a feedback voltage signal; the MCU control unit is also programmed to perform the following operations: The duty cycle of the PWM drive signal is dynamically adjusted by comparing the preset target frequency range with the actual ignition frequency detected by the frequency feedback circuit, so that the actual ignition frequency is stabilized within the target frequency range. The PWM output terminal of the MCU control unit is connected to the rectifier energy storage circuit through a first-stage boost circuit, and the output terminal of the rectifier energy storage circuit is connected to a high-voltage generating circuit; the frequency feedback circuit is connected to the rectifier energy storage circuit and is used to detect its voltage and input it to the ADC pin of the MCU control unit.

2. The adaptive ignition control circuit with a preset ignition frequency according to claim 1, characterized in that: The first-stage boost circuit includes a switching transistor (Q1) and a transformer (T1); the PWM output terminal of the MCU control unit is connected to the control electrode of the switching transistor (Q1) through a current-limiting resistor (R1), and the current path of the switching transistor (Q1) is connected in series between the primary winding of the transformer (T1) and ground; the secondary winding of the transformer (T1) is connected to the rectifier energy storage circuit.

3. The adaptive ignition control circuit with a preset ignition frequency according to claim 2, characterized in that: The rectifier energy storage circuit includes a rectifier diode (D1) and an energy storage capacitor (C1); the anode of the rectifier diode (D1) is connected to the secondary winding of the transformer (T1), and the cathode is connected to the positive terminal of the energy storage capacitor (C1); the negative terminal of the energy storage capacitor (C1) is grounded.

4. The adaptive ignition control circuit with a preset ignition frequency according to claim 3, characterized in that: The high-voltage generating circuit includes a discharge tube (K1) and an ignition transformer (HV1); the positive terminal of the energy storage capacitor (C1) is connected to one end of the discharge tube (K1), and the other end of the discharge tube (K1) is connected to the primary winding of the ignition transformer (HV1); the secondary winding of the ignition transformer (HV1) is used to output high voltage.

5. The adaptive ignition control circuit with a preset ignition frequency according to claim 1, characterized in that: The frequency feedback circuit includes a voltage divider network consisting of a first voltage divider resistor (R2) and a first voltage divider resistor (R4). The input terminal of the voltage divider network is connected to the positive terminal of the energy storage capacitor (C1), and the output terminal is connected to the ADC input pin of the MCU control unit through a filter resistor (R3).

6. The adaptive ignition control circuit with a preset ignition frequency according to any one of claims 1-5, characterized in that: The MCU control unit is also programmed to store the current optimal PWM duty cycle parameter in a non-volatile memory after the actual ignition frequency has been stable within the target range for a preset time, so that it can be directly called upon the next startup.

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