An ignition drive circuit for controlling high-voltage pulses via relay and a gas wall-hung boiler

Abstract

This application provides an ignition drive circuit for controlling high-voltage pulses via a relay, relating to gas-fired wall-hung boilers and other gas equipment. The circuit includes: a main control microcontroller, a Darlington transistor, a mains power processing circuit, a relay, a pulse drive circuit, a transformer, and an ignition needle. The main control microcontroller controls the Darlington transistor to drive the relay, which in turn controls the switching of the mains power supply. Current passes through the pulse drive circuit to generate a sinusoidal pulse, which is input to the transformer. The high voltage output from the transformer passes through the ignition needle for tip discharge, generating energy to ignite and burn combustible gas. The main control microcontroller controls the Darlington transistor via its pins, thereby controlling the opening and closing of the relay and achieving remote automated control. Using the mains power supply as the primary pulse generator and employing a single transformer to generate high voltage for tip discharge results in a simple circuit structure, reduced equipment cost, and improved power utilization.

Description

Technical Field

[0001] This application relates to the field of gas-fired wall-hung boilers and other gas equipment, and in particular to an ignition drive circuit for controlling high-voltage pulses via a relay. Background Technology

[0002] During the startup phase of the gas combustion equipment, a momentary high-voltage electric spark is generated by the discharge of the tip of the ignition needle to ignite the premixed gas. An ionization flame detection device is typically used to determine whether the gas has ignited. If it has, ignition stops; if not, the ignition process repeats. The ignition process must continue until the gas is stably burning in the boiler's combustion chamber, typically lasting about 3-5 seconds. The entire ignition process can be integrated with a controller to achieve fully automated combustion control, and alarms and abnormality alerts can be provided for any ignition anomalies.

[0003] Currently, gas wall-hung boilers typically use two main types of ignition circuits: one integrates the ignition circuit onto the control board. This circuit converts low voltage to 100-200V via a drive circuit transformer, and then to tens of kilovolts for point discharge ignition via another drive transformer. This circuit is relatively complex, requires multiple transformers, has a high cost, and causes significant interference to the internal control circuit. The other type uses a separate ignition module, which encapsulates the electronic ignition circuit and components into an independent module. This module is then connected to the controller to control ignition. This ignition method is more expensive.

[0004] Patent CN219199259U discloses a digital pulse ignition circuit, which includes a power supply control circuit, an ignition control circuit, a self-excited oscillation boost circuit, a high-voltage transformer primary circuit, a control module, a trigger circuit, and a voltage acquisition circuit. It uses a low-voltage power supply, then a transistor resistor to generate an oscillation waveform using PWM, which is then converted to a voltage of over 100V by a transformer. This voltage is then further converted to a high voltage of tens of kilovolts by diodes, capacitors, a trigger module, and another transformer, and connected to the ignition needle for ignition. Its disadvantages are: 1. It requires a low-voltage power supply and a control module to provide the pulse waveform, consuming main control chip resources; 2. It requires two transformers for conversion, resulting in high cost; 3. The entire circuit's single-function implementation is complex, wasting space and cost; 4. Furthermore, the lack of effective isolation between the primary and subsequent stages of the low-voltage control transformer leads to interference problems during operation.

[0005] Patent number CN115614774A discloses an integrated stove pulse igniter, which is used in an integrated stove scenario that is different from the application scenario of this utility model. Moreover, its overall circuit is more complex, which increases the cost.

[0006] The existing gas wall-hung boiler ignition circuit is susceptible to the following: 1. Humid weather or poor grounding can cause the high voltage generated by ignition to cause pulse interference to the subsequent low-voltage circuit, which can lead to abnormal operation in severe cases; 2. The existing low-voltage ignition module is relatively expensive; 3. The need to consider the real-time installation of the whole unit requires customers to specify the manufacturer to purchase separately, resulting in a single supply chain. Summary of the Invention

[0007] To solve the above problems, this application provides an ignition drive circuit for relay-controlled high-voltage pulses, including: a main control microcontroller, a Darlington transistor, a mains power processing circuit, a relay, a pulse drive circuit, a transformer T2, and an ignition needle;

[0008] The main control microcontroller is connected to the Darlington transistor; the Darlington transistor is connected to the relay; the relay is connected to the pulse drive circuit; the pulse drive circuit is connected to the transformer T2; the transformer T2 is connected to the ignition needle; the mains power processing circuit is connected to the relay and the pulse drive circuit.

[0009] The mains power processing circuit is used to process the input 220V mains current and then connect the processed current to the relay.

[0010] The main control microcontroller controls the Darlington transistor to drive the relay, which in turn controls the switching of the mains power supply. The current passes through the pulse drive circuit to generate a sine pulse, which is input to the transformer T2. The high voltage output from the transformer T2 is discharged through the ignition needle to generate energy and ignite the combustible gas.

[0011] Optionally, the Darlington tube is model ULN2003A.

[0012] Optionally, the relay model is A1-V-1-12HA2F.

[0013] Optionally, the pulse driving circuit includes: a charging circuit, a rectifier, a high-voltage bidirectional trigger diode, a resistor Rx5, a resistor Rx6, and a capacitor C73;

[0014] The charging circuit includes: capacitor C72, resistor Rx3 and resistor Rx4;

[0015] The first output terminal of the relay is connected to one end of the capacitor C72 and one end of the resistor Rx3; the other end of the resistor Rx3 is connected to one end of the resistor Rx4; the other end of the resistor Rx4 is connected to the other end of the capacitor C72 and the fourth port of the rectifier;

[0016] One end of the high-voltage bidirectional trigger diode is connected to the first port of the rectifier, one end of the resistor Rx5, and one end of the capacitor C73; the other end of the high-voltage bidirectional trigger diode is connected to the second port of the rectifier and the second input port of the transformer T2.

[0017] The other end of resistor Rx5 is connected to one end of resistor Rx6; the other end of resistor Rx6 is connected to the other end of capacitor C73 and the first input port of transformer T2.

[0018] Optionally, the mains power processing circuit includes: AC-L mains power live wire, AC-L mains power neutral wire, and safety circuit;

[0019] The safety circuit includes: fuse resistor F1, resistor TR1, adjustable resistor VR2, and capacitor CX2;

[0020] One end of the fuse resistor F1 is connected to the AC-L mains power supply live wire, and the other end is connected to one end of resistor TR1 and one end of adjustable resistor VR2.

[0021] The other end of the adjustable resistor VR2 is connected to the neutral line of the AC-L mains power supply, one end of the capacitor CX2, and the third port of the rectifier.

[0022] The other end of the resistor TR1 is connected to the other end of the capacitor CX2 and the first input terminal of the relay.

[0023] Optionally, the main control microcontroller is connected to the Darlington transistor via resistor Rx10.

[0024] Optionally, one end of the resistor Rx10 is connected to the main control microcontroller, and the other end is connected to pin 2 of the Darlington transistor; pin 9 of the Darlington transistor is connected to the second input terminal of the relay, and pin 15 of the Darlington transistor is connected to the second output terminal of the relay.

[0025] A gas-fired wall-hung boiler includes the ignition drive circuit described above, which uses a relay to control a high-voltage pulse.

[0026] The beneficial effects of the technical solution provided in this application are:

[0027] 1. By controlling the Darlington transistor through the pins of the main control microcontroller, the opening and closing of the relay is controlled, realizing remote automated control. This effectively saves space, and the relay can effectively isolate the circuit, reducing interference to other circuits and improving safety. The mains power supply is used as the primary pulse generator. An interactive pulse signal is generated through a pulse drive circuit, then high voltage is generated through transformer T2, and finally, the ignition needle discharges through the tip. The improved circuit structure is simpler, reducing equipment costs and improving power utilization compared to the conventional method using two step-up transformers T2 and an external ignition module.

[0028] 2. The high-voltage pulse drive circuit uses a rectifier in conjunction with resistors, capacitors, and high-voltage trigger diodes to form a simple oscillating pulse signal, which flows through transformer T2. The number of components in the entire circuit is reduced, and the cost is greatly reduced, solving the problem of high cost caused by the traditional use of two transformers T2 or separate ignition modules.

[0029] 3. A safety circuit is installed after the AC mains power supply to provide safety protection for the subsequent circuits. This is highly efficient and reliable, and solves the electromagnetic compatibility problem of the preceding AC mains power supply. Attached Figure Description

[0030] The present application will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0031] Figure 1 This is a circuit diagram of the relay-controlled high-voltage pulse ignition drive circuit in the embodiments of this application;

[0032] Figure 2 This is a diagram of the high-voltage pulse signal generated by the mains power in the relay-controlled high-voltage pulse ignition drive circuit of this application embodiment. Detailed Implementation

[0033] To provide a clearer understanding of the technical features, objectives, and effects of this application, the specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0034] Embodiments of this application provide an ignition drive circuit for controlling high-voltage pulses via a relay.

[0035] Please refer to Figure 1 , Figure 1 This is a circuit diagram of an ignition drive circuit for controlling high-voltage pulses via a relay, as described in an embodiment of this application. The circuit includes: a main control microcontroller, a Darlington transistor, a mains power processing circuit, a relay, a pulse drive circuit, a transformer T2, and an ignition needle.

[0036] The main control microcontroller is connected to the Darlington transistor; the Darlington transistor is connected to the relay; the relay is connected to the pulse drive circuit; the pulse drive circuit is connected to the transformer T2; the transformer T2 is connected to the ignition needle; the mains power processing circuit is connected to the relay and the pulse drive circuit.

[0037] The mains power processing circuit is used to process the input 220V mains current and then connect the processed current to the relay.

[0038] The main control microcontroller controls the Darlington transistor to drive the relay, which in turn controls the switching of the mains power supply. The current passes through the pulse drive circuit to generate a sine pulse, which is input to the transformer T2. The high voltage output from the transformer T2 is discharged through the ignition needle to generate energy and ignite the combustible gas.

[0039] Specifically, when the wall-hung boiler reaches the ignition and combustion stage, the microcontroller's I / O pins control a Darlington transistor via resistor Rx10, which in turn drives a relay to control the switching of the mains power supply. This method is safe, reliable, and provides good isolation, minimizing interference to downstream processes and enabling fully automated ignition control. By switching the power supply to mains power, power utilization is improved, components and space are saved, and the power loss problem associated with traditional low-voltage power supply solutions is resolved.

[0040] Specifically, the microcontroller controls the opening and closing of the relay through the Darlington transistor to remotely control the high-voltage pulse ignition. It works with the ignition detection device to determine whether ignition has occurred, achieving fully automated control. It has the advantages of high and low voltage isolation, strong anti-interference, and safety and reliability.

[0041] The Darlington tube is model ULN2003A.

[0042] The relay model is A1-V-1-12HA2F.

[0043] The pulse drive circuit includes: a charging circuit, a rectifier, a high-voltage bidirectional trigger diode, a resistor Rx5, a resistor Rx6, and a capacitor C73.

[0044] The charging circuit includes: capacitor C72, resistor Rx3 and resistor Rx4;

[0045] The first output terminal of the relay is connected to one end of the capacitor C72 and one end of the resistor Rx3; the other end of the resistor Rx3 is connected to one end of the resistor Rx4; the other end of the resistor Rx4 is connected to the other end of the capacitor C72 and the fourth port of the rectifier;

[0046] One end of the high-voltage bidirectional trigger diode is connected to the first port of the rectifier, one end of the resistor Rx5, and one end of the capacitor C73; the other end of the high-voltage bidirectional trigger diode is connected to the second port of the rectifier and the second input port of the transformer T2.

[0047] The other end of resistor Rx5 is connected to one end of resistor Rx6; the other end of resistor Rx6 is connected to the other end of capacitor C73 and the first input port of transformer T2.

[0048] Specifically, a pulse drive signal is generated using a rectifier, a high-voltage bidirectional trigger diode, a capacitor, and a transformer T2. The circuit is simple and low in cost.

[0049] Specifically, the mains power pulse passes through the pulse drive circuit. The high-voltage bidirectional trigger diode only conducts under high voltage and is connected in series with capacitor C72. When power is applied, capacitor C72 charges slowly. When the trigger voltage of the high-voltage bidirectional trigger diode is reached, the high-voltage bidirectional trigger diode conducts instantaneously. After capacitor C72 discharges, if the voltage is insufficient to turn on the high-voltage bidirectional trigger diode, it returns to a high-impedance state. The cycle repeats until capacitor C72 charges to the set value.

[0050] The high-voltage bidirectional trigger diode inputs the processed waveform to capacitor C73 to form a brief switching drive pulse. The energy is then stored in the primary coil of transformer T2 and passed through the secondary coil of transformer T2 to form an instantaneous voltage of tens of kilovolts. The voltage is then discharged through the ignition needle. The entire hardware solution is an onboard layout, which effectively reduces the cost required for separate modules and also reduces the interference to subsequent circuits during discharge.

[0051] The mains power processing circuit includes: AC-L mains power live wire, AC-L mains power neutral wire, and safety circuit;

[0052] The safety circuit includes: fuse resistor F1, resistor TR1, adjustable resistor VR2, and capacitor CX2;

[0053] One end of the fuse resistor F1 is connected to the AC-L mains power supply live wire, and the other end is connected to one end of resistor TR1 and one end of adjustable resistor VR2.

[0054] The other end of the adjustable resistor VR2 is connected to the neutral line of the AC-L mains power supply, one end of the capacitor CX2, and the third port of the rectifier.

[0055] The other end of the resistor TR1 is connected to the other end of the capacitor CX2 and the first input terminal of the relay.

[0056] Specifically, AC mains power is filtered by a safety circuit and then connected to the relay pins to send current into the subsequent circuits, thereby improving power utilization. Adding EMC devices after the mains power supply can effectively suppress electromagnetic compatibility (EMC) damage to subsequent components.

[0057] The main control microcontroller is connected to the Darlington transistor via resistor Rx10.

[0058] One end of the resistor Rx10 is connected to the main control microcontroller, and the other end is connected to pin 2 of the Darlington transistor; pin 9 of the Darlington transistor is connected to the second input terminal of the relay, and pin 15 of the Darlington transistor is connected to the second output terminal of the relay.

[0059] Specifically, the mains power is used to generate a high-voltage pulse signal through a pulse drive circuit, such as... Figure 2 As shown.

[0060] A gas-fired wall-hung boiler includes the ignition drive circuit described above, which uses a relay to control a high-voltage pulse.

[0061] The relay-controlled high-voltage pulse ignition drive circuit of this application can be applied to other devices that require ignition, such as gas stoves.

[0062] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Other embodiments of this disclosure will readily conceive of those skilled in the art upon consideration of the specification and the disclosure of practical truths.

[0063] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. An ignition drive circuit for controlling high-voltage pulses via a relay, characterized in that, include: The main control microcontroller, Darlington transistor, mains power processing circuit, relay, pulse drive circuit, transformer, and ignition needle; The main control microcontroller is connected to the Darlington transistor; The Darlington transistor is connected to the relay; The relay is connected to the pulse drive circuit; The pulse drive circuit is connected to the transformer; The transformer is connected to the ignition needle; The mains power processing circuit is connected to the relay and the pulse drive circuit; The pulse drive circuit includes: a charging circuit, a rectifier, a high-voltage bidirectional trigger diode, a resistor Rx5, a resistor Rx6, and a capacitor C73. The charging circuit includes: capacitor C72, resistor Rx3 and resistor Rx4; The first output terminal of the relay is connected to one end of the capacitor C72 and one end of the resistor Rx3; the other end of the resistor Rx3 is connected to one end of the resistor Rx4; the other end of the resistor Rx4 is connected to the other end of the capacitor C72 and the fourth port of the rectifier; One end of the high-voltage bidirectional trigger diode is connected to the first port of the rectifier, one end of the resistor Rx5, and one end of the capacitor C73; the other end of the high-voltage bidirectional trigger diode is connected to the second port of the rectifier and the second input port of the transformer. The other end of resistor Rx5 is connected to one end of resistor Rx6; the other end of resistor Rx6 is connected to the other end of capacitor C73 and the first input port of transformer; The mains power processing circuit is used to process the input 220V mains current and then connect the processed current to the relay. The mains power processing circuit includes: AC-L mains power live wire, AC-L mains power neutral wire, and safety circuit; The safety circuit includes: fuse resistor F1, resistor TR1, adjustable resistor VR2, and capacitor CX2; One end of the fuse resistor F1 is connected to the AC-L mains power supply live wire, and the other end is connected to one end of resistor TR1 and one end of adjustable resistor VR2. The other end of the adjustable resistor VR2 is connected to the neutral line of the AC-L mains power supply, one end of the capacitor CX2, and the third port of the rectifier. The other end of the resistor TR1 is connected to the other end of the capacitor CX2 and the first input terminal of the relay; The main control microcontroller controls the Darlington transistor to drive the relay, which in turn controls the switching of the mains power supply. The current passes through the pulse drive circuit to generate a sine pulse, which is input to the transformer. The high voltage output from the transformer is discharged through the ignition needle, generating energy to ignite and burn the combustible gas.

2. The ignition drive circuit for relay-controlled high-voltage pulses as described in claim 1, characterized in that, The Darlington tube is model ULN2003A.

3. The ignition drive circuit for relay-controlled high-voltage pulses as described in claim 1, characterized in that, The relay model is A1-V-1-12HA2F.

4. The ignition drive circuit for relay-controlled high-voltage pulses as described in claim 2, characterized in that, The main control microcontroller is connected to the Darlington transistor via resistor Rx10.

5. The ignition drive circuit for relay-controlled high-voltage pulses as described in claim 4, characterized in that, One end of the resistor Rx10 is connected to the main control microcontroller, and the other end is connected to pin 2 of the Darlington transistor; pin 9 of the Darlington transistor is connected to the second input terminal of the relay, and pin 15 of the Darlington transistor is connected to the second output terminal of the relay.

6. A gas-fired wall-hung boiler, characterized in that, This includes an ignition drive circuit for controlling high-voltage pulses via a relay, as described in any one of claims 1-5.

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