PFC circuit starting control system and method based on condensation risk

Abstract

The invention discloses a condensation risk-based PFC circuit start control system and method. The system comprises a main chip, an environment temperature and humidity sensor, a radiator, a radiator temperature and humidity sensor, a pull-up resistor, a switch tube, a rectifier bridge and a BOOST-PFC module. Wherein the main chip comprises an IC interface, an ADC interface and a PWM interface; the IC interface is connected with the environment temperature and humidity sensor through the pull-up resistor; the ADC interface is connected with the radiator temperature and humidity sensor; the PWM interface is connected with the switch tube; the switch tube is respectively connected with the rectifier bridge and the BOOST-PFC module; the radiator temperature and humidity sensor is arranged on the surface of the radiator; the main chip is used for judging whether a condensation risk exists or not. On the basis of PFC starting reliability, a condensation risk judgment link is added, and the control logic of'safety first and then starting 'is achieved. The circuit can be seamlessly integrated with an existing PFC starting control circuit, and is suitable for driving main control boards of various variable frequency air conditioners.

Description

A PFC circuit start-up control system and method based on condensation risk Technical Field

[0001] This invention belongs to the field of circuit control technology, and in particular relates to a PFC circuit start-up control system and method based on condensation risk. Background Technology

[0002] In the main control drive board of an air conditioner, the PFC circuit, as the front-end power module, needs to start reliably under various power supply conditions to ensure the normal operation of the system. To improve startup reliability, existing technologies have proposed various control circuit schemes. For example, existing technologies disclose a startup control circuit that, by setting a first switching transistor and a startup module, controls the switching transistor to conduct when the power supply module outputs a pulsating DC signal, enabling the PFC circuit to establish an operating voltage and start normally, effectively solving the problem of PFC startup failure under low voltage or unstable power supply conditions.

[0003] However, the above solutions primarily focus on electrical startup reliability, neglecting the impact of environmental factors on the physical safety of the PFC circuit. In high-temperature and high-humidity environments, moisture easily accumulates inside the air conditioner chassis after shutdown. When the PFC circuit restarts, the surface temperature of its power device heatsink may still be below the air dew point temperature, causing water vapor to condense into water droplets. Water droplets falling onto the PCB board can cause serious malfunctions such as short circuits, arcing, or component breakdown, threatening the safe operation of the equipment. Existing refrigerant flow technologies suffer from fundamental drawbacks such as slow response, low accuracy, high energy consumption, and susceptibility to system risks. In contrast, by using the high-frequency switching transistors of the PFC circuit to generate heat, a fast, accurate, low-energy-consumption, and safe active anti-condensation mechanism is achieved.

[0004] Prior art 1 discloses a temperature control method applied to a frequency converter with a power factor correction circuit. The circuit includes an IGBT power switch with a heat sink at the IGBT power switch. The method includes: acquiring the temperature of the IGBT power switch and the ambient humidity around the heat sink; adjusting the refrigerant flow rate in the refrigerant pipe within the heat sink based on the IGBT power switch temperature and the ambient humidity, thereby adjusting the surface temperature of the heat sink. However, the shortcoming of prior art 1 is that it only switches the sampling resistor based on known temperature conditions to improve sampling accuracy. This design cannot solve the problem of unknown temperature and unknown sampling circuit conditions, whether in hardware or software.

[0005] Prior art 2 discloses an air conditioning system and its anti-condensation control method, device, storage medium, and processor, including: in the anti-condensation mode of the air conditioning system, acquiring the temperature of an electronic control element and the ambient temperature of the air conditioning system; determining the temperature difference between the ambient temperature of the air conditioning system and the temperature of the electronic control element, and adjusting the temperature of the electronic control element first based on the temperature difference; and / or determining the rate of change of the temperature difference between the ambient temperature of the air conditioning system and the temperature of the electronic control element within a set time period, and adjusting the temperature of the electronic control element second based on the rate of change of the temperature difference. However, the deficiency of this prior art is that: prior art 2 does not involve the processing of different hardware circuits, but only analyzes and improves the NTC single temperature sampling circuit to improve its sampling accuracy, and does not involve any switching of temperature sampling methods and logic.

[0006] Therefore, there is an urgent need to provide a PFC circuit startup control method based on condensation risk. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a PFC (Power Factor Correction) circuit startup control method based on condensation risk. It addresses the following technical problems: 1. PFC radiators are prone to condensation in high humidity environments, leading to serious electrical faults; 2. The startup enable condition is singular.

[0008] The present invention adopts the following technical solution.

[0009] The first aspect of this invention provides a PFC circuit startup control system based on condensation risk, comprising: a main chip, an ambient temperature and humidity sensor, a heat sink, a heat sink temperature and humidity sensor, a pull-up resistor, a switching transistor, a rectifier bridge, and a BOOST-PFC module; wherein the main chip includes an I²C interface, an ADC interface, and a PWM interface; the I²C interface is connected to the ambient temperature and humidity sensor through the pull-up resistor; the ADC interface is connected to the heat sink temperature and humidity sensor; the PWM interface is connected to the switching transistor; the switching transistor is connected to the rectifier bridge and the BOOST-PFC module respectively; the heat sink temperature and humidity sensor is disposed on the surface of the heat sink; the main chip is used to determine whether there is a condensation risk.

[0010] Preferably, the radiator temperature and humidity sensor is an NTC resistor.

[0011] Preferably, the radiator temperature and humidity sensor is a temperature and humidity sensor chip.

[0012] A second aspect of the present invention provides a PFC circuit: including the above-described PFC circuit start-up control system based on condensation risk.

[0013] The third aspect of the present invention provides a main control and drive board, which includes the above-mentioned PFC circuit.

[0014] The fourth aspect of the present invention provides an air conditioner, which includes the above-mentioned main control and drive board.

[0015] The fifth aspect of the present invention provides a method for starting and controlling a PFC circuit. Based on the above-mentioned PFC circuit starting control system based on condensation risk, it includes: Step 1, collect the real-time temperature T1 of the radiator and the ambient humidity, and calculate the dew point temperature T2 of the current environment; Step 2, based on the real-time temperature T1 of the radiator and the dew point temperature T2 of the current environment collected in Step 1, calculate the temperature difference value ΔT; Step 3, based on the temperature difference value ΔT, determine the triggering condition of the condensation risk. If there is a condensation risk, execute the active protection mechanism and return to Step 1.

[0016] Preferably, the temperature difference value is: ΔT = T1 - T2.

[0017] [[ID=**12**]]Preferably, the triggering condition of the condensation risk is: if ΔT > T0, it is in a safe state and the PFC works normally; if ΔT ≤ T0, it is determined that there is a condensation risk and the active protection mechanism is triggered; T0 is a set safety threshold.

[0018] Preferably, the active protection mechanism includes a frequency modulation strategy, a burst mode strategy, and a fail-safe mode strategy; among them, the frequency modulation strategy is that the main chip adjusts the frequency or working mode of the PWM drive signal output to the switching tube, and the heat is conducted to the radiator through the switching tube until ΔT > T0, where T0 is a set safety threshold; the burst mode strategy is to operate intermittently to maintain the temperature; the fail-safe mode strategy is to record the fault code and cooperate for protection.

[0019] Preferably, the frequency modulation strategy is to calculate the safety threshold T0' after reserving a safety margin according to the safety threshold T0; if ΔT < T0', enter the frequency modulation strategy, and the PWM frequency linearly increases from the base value.

[0020] The sixth aspect of the present invention provides a terminal, which includes a processor and a storage medium; the storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the above method.

[0021] The seventh aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above method are implemented.

[0022] The beneficial effects of this invention are as follows, compared with the prior art: 1. Based on the reliability of PFC startup, this invention adds a condensation risk judgment link to realize the control logic of "safety first, then startup"; 2. Reduces the failure rate of air conditioner outdoor units in the plum rain season and high humidity areas, and improves the overall reliability of the unit; 3. Can be seamlessly integrated with existing PFC startup control circuits and is suitable for various variable frequency air conditioner drive main control boards. Attached Figure Description

[0023] Figure 1 shows the circuit for temperature and humidity sampling and dew point calculation; Figure 2 shows the control logic diagram of this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. The embodiments described in this application are merely some embodiments of this invention, and not all embodiments. Based on the spirit of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this invention.

[0025] As shown in Figure 1, Embodiment 1 of the present invention provides a PFC circuit start-up control system based on condensation risk, including: a main chip, an ambient temperature and humidity sensor, a heat sink, an NTC resistor (Negative Temperature Coefficient thermistor), a pull-up resistor, a switching transistor Q1, a rectifier bridge, and a BOOST-PFC module.

[0026] The main chip includes an I²C interface, an ADC (Analog-to-Digital Converter) interface, and a PWM (Pulse-width modulation) interface. The I²C interface of the main chip is connected to the ambient temperature and humidity sensor through a pull-up resistor, the ADC interface is connected to an NTC resistor, and the PWM interface is connected to the switching transistor Q1. The switching transistor Q1 is connected to the rectifier bridge and the BOOST-PFC module, respectively. The NTC resistor is placed on the surface of the heat sink.

[0027] An ambient temperature and humidity sensor is used to collect ambient temperature and humidity data, laying the groundwork for subsequent calculation of the current ambient dew point temperature.

[0028] NTC resistors are used to obtain the surface temperature of the heat sink in real time, enabling condensation detection.

[0029] The main chip is used to determine whether there is a risk of condensation, and thus whether to trigger the active protection mechanism; at the same time, it adjusts the frequency or operating mode of the PWM drive signal output to the PFC switch Q1.

[0030] As shown in Figure 2, Embodiment 2 of the present invention provides a PFC circuit start-up control method based on condensation risk. The ambient dew point temperature and the surface temperature of the radiator are collected by an ambient temperature and humidity sensor and a thermistor on the surface of the PFC radiator, respectively. The main chip calculates the temperature difference (ΔT) between the two to determine the condensation risk. When ΔT is too small, the PFC start-up is prohibited or adjusted to avoid electrical faults caused by condensation on the radiator in high humidity environments. This realizes the intelligent control logic of "safety first, then start-up" and supports dynamic switching to anti-condensation mode during operation, forming a closed-loop protection, which greatly improves the reliability and safety of the air conditioner outdoor unit in humid environments.

[0031] The system detects condensation using a temperature and humidity sensor (I²C interface) and an NTC resistor on the heatsink surface (ADC acquisition): the temperature and humidity sensor is connected to the main control chip's I²C bus via a pull-up resistor to acquire ambient temperature and humidity in real time and calculate the dew point temperature; the NTC resistor and the pull-up resistor form a voltage divider circuit, converting the heatsink surface temperature into an analog voltage signal that is sent to the main control ADC. The main control chip compares the measured temperature of the heatsink surface with the dew point temperature. If the surface temperature is lower than or equal to the dew point temperature, it determines that there is a risk of condensation and outputs an adjustable PWM signal to control the switching frequency of the switching transistor Q1, dynamically adjusting the PFC operating mode to ensure efficient operation of the system in a safe environment. A new heatsink and ambient temperature detection module is added: used to monitor the heatsink temperature and ambient temperature and humidity of the PFC switching transistor Q1 in real time to calculate the dew point.

[0032] Heatsink temperature sensing: An NTC resistor (thermistor) is used in conjunction with an ADC. It is physically mounted on the heatsink, as close as possible to the heat source, to sense its true temperature. The signal output is connected to the ADC pin of the main chip.

[0033] Step 1: Collect the real-time temperature T1 of the radiator and the ambient humidity, and calculate the current dew point temperature T2 of the environment: sense the real-time temperature T1 of the radiator.

[0034] The temperature value is converted into a digital signal (or analog voltage) and sent out through the Data line.

[0035] Signal processing and risk assessment: Step 2, based on the real-time radiator temperature T1 and the current ambient dew point temperature T2 collected in Step 1, calculate the temperature difference ΔT; the main chip simultaneously receives the signal from the humidity sensor, obtains the ambient humidity, and calculates the current ambient dew point temperature T2.

[0036] The main chip performs the following judgment: ΔT = T1 - T2, where ΔT is the temperature difference, T1 is the real-time temperature of the heat sink, and T2 is the dew point temperature of the current environment.

[0037] Step 3: Based on the temperature difference value ΔT calculated in Step 2, determine the triggering conditions for condensation risk. If there is a condensation risk, execute the active protection mechanism; if ΔT > T0, the system is in a safe state and the PFC works normally; if ΔT ≤ T0, the system determines that there is a condensation risk and triggers the active protection mechanism.

[0038] T0 is the set safety threshold. Refer to industry standards. If there is no industry standard, consider factors such as the accuracy of the temperature and humidity sensor and the heat conduction of the radiator to retain the dew point temperature margin to determine the value of T0.

[0039] The active protection mechanism executes intelligent thermal management strategies: The intelligent thermal management strategies include frequency modulation strategy, burst mode strategy, and fail-safe mode strategy; among them, the frequency modulation strategy is to increase the switching tube frequency to increase loss heat generation. Once the condensation risk is triggered, the main chip will immediately adjust the frequency or working mode of the PWM drive signal it outputs to the PFC switching tube Q1.

[0040] This operation will controllably increase the switching loss of the switching tube Q1, and these additional losses will be converted into heat.

[0041] The heat is conducted to the radiator through the case of the switching tube Q1, causing the real-time temperature T1 of the radiator to rise precisely and quickly.

[0042] After the real-time temperature of the radiator increases, ΔT > T0 becomes greater than the safety threshold again, and the condensation risk is eliminated, forming an intelligent closed-loop control for the system.

[0043] The burst mode strategy is to run intermittently to maintain the temperature.

[0044] The fail-safe mode strategy is to record the fault code and cooperate for protection.

[0045] State machine design (working mode switching): (1) State 0 (Initialization): The system starts and completes sensor calibration.

[0046] (2) State 1 (Monitoring mode): The PFC operates with optimal efficiency. Read sensor data every 100 ms and calculate ΔT = T1 - T2.

[0047] (3) State 2 (Frequency modulation mode): A proper safety margin is reserved for the calculated safety threshold T0 to obtain the safety threshold T0' after reserving the safety margin. Enter when ΔT < T0'. The PWM frequency linearly increases from the base value (such as 65 kHz) to the maximum (such as 100 kHz). The frequency increase slope is PID-regulated according to the magnitude of ΔT to achieve smooth heating.

[0048] (4) State 3 (burst mode): Enter when ΔT < T0 or the frequency modulation effect is insufficient. In a preferred but non-limiting embodiment of the present invention, the PFC is set to work for 200 ms and then turned off for 100 ms, repeating this cycle until the risk is eliminated.

[0049] (5) State 4 (fail-safe mode): If the condensation risk continues to intensify, the system will record a fault code and can carry out collaborative protection through system-level operations such as reducing the compressor load or increasing the fan speed.

[0050] In Embodiment 3, the NTC resistor on the radiator surface can be replaced with a temperature and humidity sensor chip, which has higher accuracy and stronger anti-interference ability, but slightly higher cost. The temperature and humidity sensor chip is closely attached to the metal surface of the radiator using thermal grease or thermal adhesive. It communicates with the main chip through the I2C protocol.

[0051] Embodiment 4 The present invention provides a PFC circuit in Embodiment 4, including the PFC circuit startup control system based on condensation risk in Embodiment 1 or 3.

[0052] Embodiment 5 The present invention provides a main control and drive board in Embodiment 5, including the PFC circuit in Embodiment 4.

[0053] Embodiment 6 The present invention provides an air conditioner in Embodiment 6, including the main control and drive board in Embodiment 5.

[0054] 1. The present invention provides a brand-new PFC startup debugging and risk judgment logic based on the operating conditions of the air conditioner; 2. A new type of self-adaptive condensation risk identification and startup enabling control mechanism; This disclosure can be a system, method, and / or computer program product. The computer program product may include a computer-readable storage medium having thereon computer-readable program instructions for causing a processor to implement various aspects of this disclosure.

[0055] Computer-readable storage media can be tangible devices capable of holding and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0056] The computer-readable program instructions described herein can be downloaded from computer-readable storage media to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage media in the respective computing / processing device.

[0057] Computer program instructions used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, status setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing the status information of the computer-readable program instructions to implement various aspects of this disclosure.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A PFC circuit start-up control system based on condensation risk, characterized in that, Comprising: A main chip, an environmental temperature and humidity sensor, a radiator, a radiator temperature and humidity sensor, a pull-up resistor, a switching tube, a rectifier bridge, and a BOOST-PFC module; Wherein the main chip includes an I²C interface, an ADC interface, and a PWM interface; the I²C interface is connected to the environmental temperature and humidity sensor through the pull-up resistor; the ADC interface is connected to the radiator temperature and humidity sensor; the PWM interface is connected to the switching tube; the switching tube is respectively connected to the rectifier bridge and the BOOST-PFC module; the radiator temperature and humidity sensor is arranged on the surface of the radiator; The main chip is used to judge whether there is a risk of condensation.

2. The PFC circuit start-up control system based on condensation risk according to claim 1, characterized in that: The radiator temperature and humidity sensor is an NTC resistor.

3. The PFC circuit start-up control system based on condensation risk according to claim 1, characterized in that: The radiator temperature and humidity sensor is a temperature and humidity sensor chip.

4. A PFC circuit, characterized in that: Comprising the PFC circuit startup control system based on the condensation risk according to any one of claims 1-3.

5. A main control driver board, characterized in that: Comprising the PFC circuit according to claim 4.

6. An air conditioner, characterized in that: Comprising the main control driving board according to claim 5.

7. A PFC circuit startup control method, based on the PFC circuit startup control system based on condensation risk as described in any one of claims 1-3, characterized in that, Comprising: Step 1, collect the real-time temperature T1 of the radiator and the environmental humidity, and calculate the dew point temperature T2 of the current environment; Step 2, based on the real-time temperature T1 of the radiator and the dew point temperature T2 of the current environment collected in Step 1, calculate the temperature difference value ΔT; Step 3, based on the temperature difference value ΔT, judge the triggering condition of the condensation risk. If there is a condensation risk, execute the active protection mechanism and return to Step 1.

8. The PFC circuit start-up control method based on condensation risk according to claim 7, characterized in that: The temperature difference value is: ΔT = T1 - T2.

9. The PFC circuit start-up control method based on condensation risk according to claim 7, characterized in that: The triggering condition of the condensation risk is: if ΔT > T0, it is in a safe state and the PFC works normally; if ΔT ≤ T0, it is judged that there is a condensation risk and the active protection mechanism is triggered; T0 is a set safety threshold.

10. The PFC circuit start-up control method based on condensation risk according to claim 7, characterized in that: The active protection mechanism includes a frequency modulation strategy, a burst mode strategy, and a fail-safe mode strategy; wherein, the frequency modulation strategy is that the main chip adjusts the frequency or working mode of the PWM drive signal output to the switching tube, and the heat is conducted to the radiator through the switching tube until ΔT > T0, and T0 is a set safety threshold; the burst mode strategy is to run intermittently to maintain the temperature; the fail-safe mode strategy is to record the fault code and cooperate for protection.

11. The PFC circuit start-up control method based on condensation risk according to claim 10, characterized in that: The frequency modulation strategy is to calculate the safety threshold T0' after reserving a safety margin according to the safety threshold T0; if ΔT < T0', enter the frequency modulation strategy, and the PWM frequency linearly increases from the base value.

12. A terminal, comprising a processor and a storage medium; characterized in that: The storage medium is used to store instructions; the processor is used to operate according to the instructions to execute the steps of the method according to any one of claims 7-11.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, the steps of the method according to any one of claims 7-11 are implemented.

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