A low-impact power supply system and method for a vehicle-mounted refrigerator based on Type-C PD power supply

Abstract

The application provides a low-impact power supply system and method for a vehicle-mounted refrigerator based on Type-C PD power supply, which comprises the following steps: performing protocol handshake analysis based on a level state and a preset voltage request sequence to obtain a target direct-current voltage; performing voltage drop compensation analysis based on the target direct-current voltage and a conduction resistance to obtain a driving opening signal; performing soft start timing analysis based on the driving opening signal and a winding inductance characteristic of a compressor motor to obtain a staged current-limiting pulse width modulation signal; performing slow-rising conduction analysis based on the staged current-limiting pulse width modulation signal and a gate charge characteristic to obtain a motor driving current; performing overload retention analysis based on the motor driving current and a preset steady-state current threshold to obtain a power switch tube control signal; and performing closed-loop voltage stabilization analysis based on the power switch tube control signal in a full conduction state and a back electromotive force of the compressor motor to obtain a compressor operation power supply voltage. The application improves power supply reliability and a compressor start success rate.

Description

Technical Field

[0001] This invention relates to the field of vehicle electrical power supply control technology, and in particular to a low-impact power supply system and method for a vehicle refrigerator based on Type-C PD power supply. Background Technology

[0002] With the increasing popularity of car refrigerators, Type-C PD (Power Delivery) power supply, due to its advantages of universal interface and convenient charging, is gradually replacing traditional car cigarette lighter power supply and becoming the mainstream power supply method for car refrigerators. Existing Type-C PD power supply solutions for car refrigerators typically include a PD protocol handshake circuit, a reverse connection protection circuit, and an overcurrent protection circuit. The PD protocol handshake circuit negotiates the output voltage with the external adapter; the reverse connection protection circuit often uses a series diode or MOSFET structure to prevent reverse polarity; and the overcurrent protection circuit cuts off abnormal current by detecting the current magnitude.

[0003] However, in existing solutions, the various functional modules (PD decoy, reverse connection protection, and overcurrent protection) often operate independently, lacking coordinated timing control. Especially during compressor startup, the vehicle refrigerator generates a momentary peak current of up to 15A / 200ms, while the rated current of the Type-C PD adapter and wiring is typically only 3-5A. Due to the lack of differentiated timing control targeting the difference between startup peak and steady-state current, existing fixed-threshold overcurrent protection is prone to false triggering during compressor startup, leading to power interruption and preventing the compressor from starting normally; or, if a large load is applied before the PD handshake is stable, it can cause a voltage drop, triggering the PD adapter to enter protection mode or restart. Furthermore, this disordered loading method results in poor PD handshake stability, abnormal voltage output, and a tendency for PD handshake failure or unstable voltage lockout.

[0004] Therefore, due to the lack of timing coordination control for compressor startup characteristics, the Type-C PD power supply system is prone to overcurrent protection false triggering or voltage instability at the moment of compressor startup in the vehicle refrigerator, which reduces the reliability of the power supply system and the success rate of compressor startup. Summary of the Invention

[0005] This invention provides a low-impact power supply system and method for vehicle-mounted refrigerators based on Type-C PD power supply, aiming to solve the technical problem that the Type-C PD power supply system is prone to overcurrent protection false triggering or voltage instability at the moment of compressor start-up in vehicle-mounted refrigerators, and to improve the power supply reliability and compressor start-up success rate of the Type-C PD power supply system in vehicle-mounted refrigerator applications.

[0006] In a first aspect, the present invention provides a low-impact power supply method for an on-board refrigerator based on Type-C PD power supply, comprising:

[0007] Based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence, PD protocol handshake analysis is performed to obtain the target DC voltage. Based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch, voltage drop compensation analysis is performed to obtain the drive start signal of the reverse connection protection switch.

[0008] Based on the drive start signal and the winding inductance characteristics of the compressor motor, a soft start timing analysis is performed to obtain a graded current limiting pulse width modulation signal.

[0009] Based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch, a gradual turn-on analysis is performed to obtain the motor drive current. Based on the motor drive current and the preset steady-state current threshold, an overload holding analysis is performed to obtain the power switch control signal in the fully on state.

[0010] Closed-loop voltage regulation analysis is performed based on the power switch control signal in the fully on state and the back electromotive force of the compressor motor to obtain the compressor operating power supply voltage.

[0011] In a second aspect, the present invention provides a low-impact power supply system for an in-vehicle refrigerator based on Type-C PD power supply, for implementing the low-impact power supply method for an in-vehicle refrigerator based on Type-C PD power supply as described in the first aspect; the low-impact power supply system for an in-vehicle refrigerator based on Type-C PD power supply includes:

[0012] The reverse connection protection drive unit is used to perform PD protocol handshake analysis based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence to obtain the target DC voltage, and to perform voltage drop compensation analysis based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch to obtain the drive start signal of the reverse connection protection switch.

[0013] A soft-start timing generation unit is used to perform soft-start timing analysis based on the drive start signal and the winding inductance characteristics of the compressor motor to obtain a graded current-limiting pulse width modulation signal.

[0014] The steady-state switching holding unit is used to perform a gradual turn-on analysis based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch to obtain the motor drive current, and to perform an overload holding analysis based on the motor drive current and a preset steady-state current threshold to obtain the power switch control signal in the fully on state.

[0015] The closed-loop voltage regulation unit is used to perform closed-loop voltage regulation analysis based on the power switch control signal in the fully on state and the back electromotive force of the compressor motor to obtain the compressor operating power supply voltage.

[0016] Thirdly, the present invention provides an electronic device, comprising: a memory for storing a computer program; and a processor for reading and executing the computer program, thereby realizing the low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply as described above.

[0017] Fourthly, the present invention provides a non-transitory computer-readable storage medium storing a computer program, which, when executed by a processor, implements the low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply as described above.

[0018] The low-impact power supply method for vehicle-mounted refrigerators based on Type-C PD power supply provided in this invention ensures that the voltage level of the power supply head meets the rated requirements of the vehicle-mounted refrigerator compressor based on the target DC voltage, avoiding start-up failure due to voltage mismatch. A drive-on signal for the reverse-connection protection switch is obtained based on the target DC voltage, establishing a low-impedance, low-power current transmission path and reducing heat loss and voltage drop caused by traditional diode reverse-connection protection. A graded current-limiting pulse width modulation signal is obtained based on the drive-on signal, utilizing the inductive characteristics of the compressor motor to shape the starting current in the time domain, suppressing the generation of instantaneous peak current at the source. A linearly rising motor drive current is obtained based on the graded current-limiting pulse width modulation signal, transforming the originally steep starting peak into a gently rising current curve, ensuring that its peak value is always below the overcurrent protection threshold of the Type-C PD adapter, thereby preventing the adapter from cutting off power supply due to misjudgment of a short circuit. A fully conducting power switch control signal is obtained based on the linearly rising motor drive current, achieving seamless switching from limited start-up mode to full-power operation mode, ensuring that the compressor immediately receives sufficient driving force after successful start-up. A constant compressor operating voltage is obtained based on the power switch control signal in the fully on state, eliminating the impact of voltage fluctuations during startup on subsequent steady-state operation. This solves the problem that the Type-C PD power supply system is prone to overcurrent protection false triggering or voltage instability at the moment of compressor startup due to the lack of timing coordination control for compressor startup characteristics. This improves the power supply reliability and compressor startup success rate of the Type-C PD power supply system in vehicle refrigerator applications. Attached Figure Description

[0019] Figure 1 This is a schematic flowchart of a low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply provided in an embodiment of the present invention;

[0020] Figure 2 This is one of the structural schematic diagrams of a low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided in an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided in an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the Type-C input protection module circuit provided in an embodiment of the present invention;

[0023] Figure 5 This is a schematic diagram of the PD deception module circuit provided in an embodiment of the present invention;

[0024] Figure 6 This is a schematic diagram of the P-MOS reverse connection protection module circuit provided in an embodiment of the present invention;

[0025] Figure 7 This is a schematic diagram of the overcurrent protection module circuit provided in an embodiment of the present invention;

[0026] Figure 8 This is a schematic diagram of the output energy storage module circuit provided in an embodiment of the present invention;

[0027] Figure 9 This is the second schematic diagram of the low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided in this embodiment of the invention;

[0028] Figure 10 An embodiment diagram of the electronic device provided in this invention;

[0029] Figure 11 An embodiment diagram of a computer-readable storage medium provided in accordance with the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In the description of this invention, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this invention is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.

[0033] Reference Figures 1 to 3 , Figure 1 This is a schematic flowchart of the low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply provided by the present invention. Figure 2 This is one of the structural schematic diagrams of a low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided in an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the principle of a low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply, provided in an embodiment of the present invention. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply is applied to a low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply includes:

[0034] Step 10: Perform PD protocol handshake analysis based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence to obtain the target DC voltage. Then, perform voltage drop compensation analysis based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch to obtain the drive start signal of the reverse connection protection switch.

[0035] Optionally, embodiments of the present invention rely on a Type-C input protection module (including a Type-C female connector J1, an ESD protection chip U2, a TVS surge suppressor D1, and an input filter capacitor C1) and a PD decoy module (using a CH224K chip U1).

[0036] When the Type-C PD charger is connected to the Type-C female connector J1, VBUS initially outputs a default 5V voltage. The CH224K chip U1 draws power from VBUS through a 1kΩ current-limiting resistor R1, and begins operation after internal LDO regulation. The chip detects the voltage level through the CC1 and CC2 pins (corresponding to pins A5 and B5) and communicates with the PD charger via the BMC protocol (i.e., PD protocol handshake analysis). By reading the grounding configuration of the CH224K chip's CFG1, CFG2, and CFG3 pins (a preset voltage request sequence, where CFG1 and CFG2 are connected to 24kΩ resistors R2 and R3, and CFG3 is directly grounded), the chip sends a fixed 12V voltage request to the charger. After confirmation, the charger raises the VBUS voltage to 12V (i.e., the target DC voltage).

[0037] When the CH224K chip detects that VBUS is stable at 12V, the PG pin (pin 7) outputs a high-level EN_PWR enable signal. This signal serves as the drive signal for the reverse connection protection switch (using an AOD403 P-channel MOSFET Q1). Because the AOD403 MOSFET has extremely low on-resistance (Rds(on)), its theoretical voltage drop is minimal under a target DC voltage of 12V. The high-level EN_PWR signal makes the gate voltage (G) of the MOSFET close to the source voltage (S) (VGS≈0), causing the MOSFET to fully conduct. The VBUS voltage outputs a PVCC signal through the drain (D) of the MOSFET, achieving low-loss voltage drop compensation and reverse connection protection drive activation. If the power supply is reversed, VBUS becomes negative, and the MOSFET is reverse-biased and cut off, achieving hardware reverse connection protection.

[0038] Step 20: Perform soft-start timing analysis based on the drive start signal and the winding inductance characteristics of the compressor motor to obtain the graded current limiting pulse width modulation signal.

[0039] Optionally, embodiments of the present invention rely on an overcurrent protection module (using an SGM2538 eFuse chip U3) and an output energy storage module (including low ESR electrolytic capacitors C5~C9 and a supercapacitor module C10).

[0040] When the EN_PWR enable signal (drive start signal) reaches the EN pin of the SGM2538 chip, the chip is enabled and conducts. Based on the inductive characteristics of the motor windings of the vehicle refrigerator compressor (which generates a momentary spike current of 15A / 200ms during startup), soft-start timing analysis is performed. The SGM2538 chip uses an external 2kΩ current-limiting resistor R5 connected to the ILIM pin to set the steady-state current limit threshold to 5A (covering the 2A steady-state operating current). At the moment of compressor startup, instead of relying on the PD adapter to provide the spike current, the chip uses the pre-stored energy in the output energy storage module for "soft-start" buffering. Five 100μF / 25V low-ESR electrolytic capacitors and one 1F / 16V supercapacitor module C10 in the output energy storage module are connected in parallel at the VOUT output terminal, adjacent to the load terminal, forming a low-impedance energy storage discharge circuit. This hardware configuration is equivalent to generating a physical-level "graded current-limiting pulse width modulation signal". In the initial startup phase (first 200ms), the energy storage capacitor bears most of the current surge, limiting the current slope drawn from the PD adapter.

[0041] Step 30: Perform a gradual turn-on analysis based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch to obtain the motor drive current. Then, perform an overload holding analysis based on the motor drive current and the preset steady-state current threshold to obtain the power switch control signal in the fully on state.

[0042] Optionally, the embodiments of the present invention rely on the power switching transistor (eFuse built-in MOSFET) inside the SGM2538 chip and its gate charge characteristics, as well as the charging and discharging characteristics of the output energy storage module.

[0043] When the SGM2538 chip's internal power switch is enabled by EN_PWR, its gate charge characteristics determine the soft-start process of conduction, resulting in a gradual increase in the output voltage VOUT and thus a linearly increasing motor drive current. During the first 200ms of compressor startup, the 15A peak current is primarily supplied by the discharge of the supercapacitor module C10 and the low-ESR electrolytic capacitors C5-C9 (motor drive current), while the SGM2538 chip only withstands approximately 2A of steady-state current.

[0044] Overload holding analysis is performed by monitoring the output current in real time and comparing it with a preset steady-state current threshold (5A current limiting threshold). Since the peak current is independently handled by the energy storage module, the current detected by the SGM2538 chip is always below the 5A threshold and will not trigger current limiting protection. After the 200ms startup peak, the compressor current drops back to the 2A steady state, the system confirms that the startup is complete, and the power switch inside the SGM2538 chip remains fully on (duty cycle 100%), outputting a fully on power switch control signal.

[0045] Step 40: Perform closed-loop voltage regulation analysis based on the power switch control signal in full conduction state and the back electromotive force of the compressor motor to obtain the compressor operating power supply voltage.

[0046] Optionally, this embodiment of the invention relies on the steady-state operation of the entire power supply circuit and the voltage regulation and filtering characteristics of the output energy storage module. After the compressor enters steady-state operation, the SGM2538 chip remains fully conductive. The back electromotive force generated by the compressor motor and load fluctuations will cause slight voltage fluctuations. At this time, the 0.1μF filter capacitor C4 in the output energy storage module is used to filter out high-frequency noise at the VOUT output terminal. The 100μF electrolytic capacitor and the 1F supercapacitor module act as a huge "energy reservoir," rapidly discharging to compensate when the current demand increases instantaneously due to changes in load torque (changes in back electromotive force); and absorbing excess energy when the current demand decreases. The PD charger continuously provides a steady-state current of 2A to replenish the energy storage capacitor. This dynamic energy throughput at the hardware level is equivalent to closed-loop voltage regulation analysis, effectively offsetting the effects of line voltage drop and load fluctuations, and finally obtaining a constant and smooth 12V compressor operating power supply voltage at the power supply terminal (J2) of the vehicle refrigerator.

[0047] The embodiments of the present invention eliminate the impact of voltage fluctuations during the startup process on subsequent steady-state operation, and solve the problem that the Type-C PD power supply system is prone to overcurrent protection false triggering or voltage instability at the moment of compressor startup due to the lack of timing coordination control for compressor startup characteristics. This improves the power supply reliability and compressor startup success rate of the Type-C PD power supply system in vehicle refrigerator applications.

[0048] Optionally, the processes of steps 101 to 103 include:

[0049] Step 101: Perform impedance matching analysis based on the pull-down resistor value and pull-up voltage level of the Type-C PD protocol communication pin to obtain the connection confirmation signal of the CC pin.

[0050] Step 102: Based on the connection confirmation signal and the voltage level encoding table of the USB PD standard protocol, perform protocol negotiation analysis to obtain an initial voltage request command containing 12V voltage levels.

[0051] Step 103: Perform voltage regulation verification analysis based on the initial voltage request command and the voltage feedback waveform of the VBUS pin to obtain the target DC voltage whose voltage fluctuation range meets the preset threshold.

[0052] Optionally, after the Type-C female connector J1 is connected to the PD charger, the pull-up resistor on the CC pin inside the charger and the pull-down resistors on the CC1 and CC2 pins of the CH224K chip U1 form an impedance matching voltage divider. The CH224K chip detects the voltage level change on the CC pin to confirm that the physical connection has been established, thereby generating a connection confirmation signal on the CC pin and waking up the PD protocol state machine inside the chip.

[0053] After confirming the connection, the CH224K chip communicates with the PD charger via BMC (Biphase Mark Coding) encoding to read the PDO (Power Data Object) capability list broadcast by the charger. Combining the hardware configuration of the chip's external CFG1, CFG2, and CFG3 pins (CFG1 connected to 24kΩ, CFG2 connected to 24kΩ, CFG3 grounded, corresponding to the fixed 12V voltage level code in the USB PD standard protocol), the chip internally generates an initial voltage request message containing the 12V voltage level and sends it to the charger via the CC line. Upon receiving the 12V request message, the PD charger adjusts its internal power conversion circuit to switch the VBUS voltage from 5V to 12V.

[0054] The internal voltage detection circuit of the CH224K chip monitors the voltage feedback waveform of the VBUS pin in real time. When the VBUS voltage is detected to be stable at 12V and the voltage fluctuation range meets the chip's internal preset accuracy threshold (e.g., ±5%), the chip determines that the voltage regulation verification is successful, locks the 12V voltage as the target DC voltage, and controls the PG pin (pin 7) to output a high-level EN_PWR enable signal. If the voltage fluctuation exceeds the threshold or the handshake fails, the PG pin remains low to prevent subsequent circuits from starting under abnormal voltage conditions.

[0055] This invention utilizes impedance matching analysis of the Type-C PD protocol communication pins to obtain connection confirmation signals and combines this with the voltage level encoding table of the USB PD standard protocol for protocol negotiation analysis. This allows for precise requesting of a 12V target DC voltage from the charger that matches the rated operating voltage of the vehicle refrigerator compressor. By performing voltage regulation verification analysis on the voltage feedback waveform of the VBUS pin, it ensures that the fluctuation range of the target DC voltage meets the preset threshold, thereby providing a stable and compliant input power supply for subsequent circuits. This effectively avoids device damage or abnormal startup caused by voltage instability or handshake failure, improving the reliability and safety of the Type-C PD power supply system in vehicle refrigerator applications.

[0056] Optionally, steps 104 to 106 include:

[0057] Step 104: Based on the target DC voltage value and the maximum on-resistance parameter of the reverse connection protection switch, perform limit voltage drop calculation and analysis to obtain the theoretical voltage drop value under the maximum allowable operating current.

[0058] Step 105: Based on the theoretical voltage drop value and the preset safety margin coefficient, perform a drive capability evaluation and analysis to obtain the gate drive voltage threshold that meets the full conduction condition.

[0059] Step 106: Based on the gate drive voltage threshold and the charge pump output voltage inside the controller, perform level shift analysis to obtain the drive turn-on signal of the reverse connection protection switch that is higher than the source potential and has a constant amplitude.

[0060] Optionally, the reverse connection protection switching transistor is an AOD403 P-channel MOSFET (Q1), with a rated current of up to 80A, fully covering the 15A peak current requirement of the vehicle refrigerator. At a target DC voltage of 12V, assuming a maximum allowable operating current of 15A (startup peak), the maximum on-resistance Rds(on) in the AOD403 datasheet is only in the milliohm range at VGS=-10V. Through limiting voltage drop calculation (V_drop = I_max * Rds(on)), the theoretical voltage drop at the 15A peak current is extremely small (typically less than 0.1V), far lower than traditional diode solutions (approximately 0.5V-0.7V), thus ensuring sufficient supply voltage for subsequent circuits.

[0061] It should be noted that, to ensure the AOD403 MOSFET remains in the deep linear region (fully on) under various operating conditions, an evaluation was conducted using both theoretical voltage drop values ​​and a preset safety margin factor. Specifically, for a P-channel MOSFET, for it to be fully on, the gate-source voltage VGS must be sufficiently negative (i.e., the gate voltage must be significantly lower than the source voltage). The evaluation analysis showed that when the source (S) is connected to 12V VBUS, the gate (G) needs to be pulled low to near ground potential (0V), causing VGS to reach -12V. This value is much higher than the AOD403's turn-on threshold voltage (typically -2V to -4V), thus determining that the gate drive voltage threshold required to satisfy the full on condition is a low level (close to 0V).

[0062] In this embodiment of the invention, the EN_PWR signal output from the PG pin of the CH224K chip serves as the drive enable signal. When the PG pin outputs a high level, its voltage is close to VBUS (12V). At this time, the gate voltage (G) of the AOD403 (12V) is close to the source voltage (S) (12V), VGS≈0, and the MOSFET is reliably turned off (this is the safe state when the handshake is not complete). When the PG pin outputs a low level (0V), the gate G is reliably grounded through the 10kΩ pull-down resistor R4. At this time, VGS = 0V - 12V = -12V, and the MOSFET is fully turned on. This method of directly controlling the gate potential through the PG pin level achieves a constant amplitude and reliable drive enable signal without the need for an additional charge pump circuit.

[0063] It should be noted that if an N-channel MOSFET is used to prevent reverse connection, a charge pump is required to generate a drive voltage higher than that of the source. Here, a P-MOS is used as an example for equivalent explanation.

[0064] This invention, through extreme voltage drop calculation and analysis of the target DC voltage and the maximum on-resistance parameter of the reverse connection protection switch, combined with a preset safety margin coefficient for drive capability evaluation and analysis, can accurately determine the gate drive voltage threshold that meets the full conduction condition. Then, through level shift analysis, a reliable drive turn-on signal with constant amplitude is generated, which makes the on-resistance voltage drop of the reverse connection protection switch extremely small during normal operation, reducing power loss and heat generation. At the same time, it can reliably cut off when the power supply is reversed, realizing low-loss, high-efficiency reverse connection protection and improving the overall energy efficiency of the vehicle refrigerator power supply system.

[0065] Optionally, steps 201 to 203 include:

[0066] Step 201: Based on the rising edge time of the drive start signal and the measured inductance of the compressor motor winding, the time constant is calculated and analyzed to obtain the minimum delay period required for current establishment.

[0067] Step 202: Perform duty cycle step planning analysis based on the minimum delay period and the preset maximum start-up current limit to obtain a duty cycle increment sequence consisting of multiple fixed duty cycle stages.

[0068] Step 203: Based on the duty cycle increment sequence and the timer interrupt frequency of the controller, signal generation analysis is performed to obtain a graded current-limiting pulse width modulation signal with a linear growth trend.

[0069] Optionally, when the EN_PWR enable signal triggers the subsequent power-on, the current in the compressor motor winding (inductive load) cannot change abruptly. Based on the measured inductance L of the motor winding and the equivalent circuit resistance R, the electrical time constant τ = L / R is calculated. Combining the starting characteristics of the vehicle refrigerator compressor (15A / 200ms), the analysis shows that the time required for the current to build up and reach its peak is approximately 200ms, which is the minimum delay period for soft start and peak suppression.

[0070] To avoid overcurrent protection caused by directly drawing 15A current from the PD adapter within 200ms, a "duty cycle laddering" is implemented through the output energy storage module. During the initial startup phase (0-200ms), the PD adapter only provides 2A steady-state current (equivalent to a low duty cycle input), and the remaining 13A peak current is instantly compensated by the output energy storage module (1F supercapacitor C10 and five 100μF electrolytic capacitors C5~C9).

[0071] As the compressor speed increases, the back electromotive force is established, the current demand gradually decreases, and the discharge current of the energy storage capacitor also decreases accordingly. This energy supply process, which is composed of the discharge curve of the energy storage capacitor and the constant current output of the PD adapter, is physically equivalent to a duty cycle increasing sequence (i.e., the proportion of energy drawn by the load from the power supply gradually increases, and the proportion drawn from the energy storage module gradually decreases).

[0072] The SGM2538 chip's internal Soft-Start function, combined with the discharge characteristics of the external energy storage capacitor, generates a current waveform with a linear growth trend, which is the graded current-limiting pulse width modulation signal. The SGM2538's internal control circuit adjusts the conduction state of the internal power transistor at an extremely high frequency (timer interrupt frequency), causing the output voltage VOUT to rise smoothly and limiting inrush current. Combined with the low ESR characteristics of the energy storage capacitor, a smooth starting current curve is ultimately formed at the motor end, effectively suppressing di / dt (rate of change of current) and achieving the physical effect of graded current limiting.

[0073] This invention utilizes time constant calculation and analysis based on the rising edge of the drive start signal and the measured inductance of the compressor motor windings to accurately determine the minimum delay period required for current establishment. Combined with a preset maximum starting current limit, a duty cycle step planning analysis is performed to generate a duty cycle increment sequence consisting of multiple fixed duty cycle stages. This ultimately yields a graded current-limiting pulse width modulation signal with a linear growth trend, effectively suppressing current surges (such as a 15A / 200ms spike) during compressor startup. This keeps the rate of change of starting current within a safe range, preventing PD adapter overcurrent protection triggering or voltage drops due to sudden current changes, thus ensuring smooth system startup.

[0074] Optionally, the processes of steps 301 to 303 include:

[0075] Step 301: Based on the frequency of the graded current-limiting pulse width modulation signal and the input capacitance parameters of the power switch, perform charge and discharge rate analysis to obtain the slope limit value of the gate voltage change.

[0076] Step 302: Based on the slope limit value and the transconductance characteristic curve of the power switch, perform linear region mapping analysis to obtain the linear correspondence between drain source current and gate voltage.

[0077] Step 303: Based on the linear correspondence and the duty cycle change rate of the graded current limiting pulse width modulation signal, current slope control analysis is performed to obtain a motor drive current with a constant change rate and no overshoot.

[0078] Optionally, the power MOSFETs within the SGM2538 chip have a specific input capacitance (Ciss). The chip's internal gate driver charges and discharges Ciss with a controlled current, thereby limiting the slope of the gate voltage change. This hardware-level slope limitation prevents current overshoot and ringing caused by excessively fast power transistor turn-on, ensuring a smooth build-up of the motor drive current.

[0079] During the soft-start phase of the SGM2538 chip, the internal power transistors operate in the linear region (ohmic region). According to the transconductance characteristic curve of the MOSFET, the drain-source current Ids and the gate-source voltage Vgs are linearly related. Since the gate voltage increases linearly due to the slope limitation, the drain-source current (i.e., the current output to the subsequent stage) also increases linearly, avoiding instantaneous large current surges.

[0080] By combining the linear soft-start capability of the SGM2538 with the peak-shaving and valley-filling function of the output energy storage module, when the compressor requires a 15A peak during startup, the energy storage capacitor responds instantaneously (its discharge current changes extremely rapidly), while the SGM2538 limits the rate of change of current drawn from the input. The combined effect results in a smooth, controlled-rate-of-change upward curve for the total drive current supplied to the compressor motor, perfectly matching the compressor's mechanical starting characteristics and avoiding mechanical shocks and electromagnetic interference caused by sudden current changes.

[0081] This invention analyzes the charge / discharge rate based on the frequency of the graded current-limiting pulse width modulation signal and the input capacitance parameters of the power switch to obtain the slope limit value of the gate voltage change. Combined with the transconductance characteristic curve of the power switch, linear region mapping analysis is performed to accurately control the linear correspondence between the drain-source current and the gate voltage. Furthermore, through current slope control analysis, a linearly rising motor drive current with a constant rate of change and no overshoot is obtained. This can accurately match the mechanical starting characteristics of the compressor motor, avoid mechanical shock and electromagnetic interference caused by current overshoot, and extend the service life of the compressor.

[0082] Optionally, the processes of steps 304 to 306 include:

[0083] Step 304: Based on the real-time sampled value of the linearly increasing motor drive current and the preset steady-state current threshold, a hysteresis analysis is performed to obtain the judgment flag that the current has stably reached the steady-state range.

[0084] Step 305: Perform duration verification analysis based on the judgment flag and the preset de-jitter timer to obtain a state lock signal confirming normal startup completion.

[0085] Step 306: Based on the state lock signal and the drive logic level of the power switch, perform a pass-through mode switching analysis to obtain the power switch control signal in the fully on state with a duty cycle of 100%.

[0086] Optionally, the SGM2538 chip integrates a high-precision current sensing amplifier to sample the current flowing through the power transistor in real time. The preset steady-state current threshold is 5A (configured by an external 2kΩ resistor R5 connected to the ILIM pin). During the first 200ms of compressor startup, although the total motor current demand reaches 15A, the input current sampled by the SGM2538 is consistently limited to around 2A (the spike is provided by the energy storage capacitor). After startup is complete, the motor current drops back to a steady-state of 2A, and the sampled value stabilizes below the 5A threshold, generating a current stability indicator.

[0087] To prevent transient fluctuations during compressor operation (such as minor current fluctuations caused by refrigerant pressure changes) from being misinterpreted as start-up failures or overcurrent, the SGM2538 chip incorporates a deglitch timer. Only when the sampled current remains consistently within a safe threshold for more than the deglitch time does the chip confirm a successful start-up, generating a status lock signal to prevent accidental shutdown.

[0088] After startup is confirmed, the drive logic inside the SGM2538 chip pulls the gate voltage of the power MOSFET to its maximum, putting it into a fully on state (Rds(on) minimized). At this time, the equivalent duty cycle of the power switch is 100%, and there is an extremely low on-state voltage drop between VIN and VOUT, entering an efficient steady-state power supply mode, and obtaining the power switch control signal in a fully on state.

[0089] This invention, through hysteresis analysis comparing the real-time sampled value of the linearly increasing motor drive current with a preset steady-state current threshold, can accurately determine whether the current has stably reached the steady-state range. Combined with a preset de-jitter timer for duration verification analysis, it effectively prevents instantaneous fluctuations during compressor operation, such as minor current jumps caused by refrigerant pressure changes, from being misjudged as start-up failures or overcurrent faults. Finally, through direct-mode switching analysis, it obtains the power switch control signal with a 100% duty cycle in a fully conductive state, enabling the system to enter a highly efficient steady-state power supply mode. This reduces conduction losses during steady-state operation and improves the energy utilization efficiency of the vehicle refrigerator.

[0090] Optionally, the processes of steps 401 to 403 include:

[0091] Step 401: Based on the control signal of the power switch tube in the fully conducting state and the speed feedback of the compressor motor, back electromotive force estimation analysis is performed to obtain the internal voltage reference value reflecting the change of load torque.

[0092] Step 402: Based on the internal voltage reference value and the equivalent series resistance of the Type-C PD power supply line, perform line loss compensation analysis to obtain the target terminal voltage increment that needs to be supplemented.

[0093] Step 403: Based on the target voltage increment and the minimum voltage adjustment step size of the PD protocol, perform fine-tuning instruction generation and analysis to obtain a constant compressor operating power supply voltage that can offset the effect of line voltage drop.

[0094] Optionally, during steady-state operation, the compressor motor speed remains stable, generating a stable back electromotive force. When the refrigerator's cooling load changes (such as changes in the internal temperature causing a change in the compressor load), the motor current will change slightly. The supercapacitor module C10 and electrolytic capacitors C5~C9 in the output energy storage module have extremely low equivalent series resistance (ESR), enabling them to sensitively detect minute voltage drops or rises caused by changes in load torque, serving as a compensation source for the internal voltage reference.

[0095] There is an equivalent series resistance between the Type-C cable and the PCB traces. Under a steady-state current of 2A, the line loss voltage drop is relatively constant. The 12V voltage requested by the PD decoy module already takes into account the voltage drop of the preceding circuitry. Simultaneously, the output energy storage module is placed close to the vehicle refrigerator's power supply terminal J2, shortening the trace distance from the energy storage capacitor to the load and minimizing the equivalent series resistance of the subsequent circuitry, thereby reducing the required voltage increment at the target terminal.

[0096] In this embodiment of the invention, the CH224K chip requests a fixed 12V voltage. To compensate for the line voltage drop, "hardware-level fine-tuning" is achieved through physical means such as selecting low-ESR capacitors, thickening the power supply traces, and shortening the physical distance between the energy storage module and the load terminal (placing it adjacent to J2). When the load terminal voltage shows a slight downward trend due to line loss, the adjacent supercapacitor module C10 instantly discharges to compensate, ensuring that the voltage at the power supply terminal J2 remains constant, effectively offsetting the effect of the line voltage drop and obtaining a constant 12V compressor operating power supply voltage.

[0097] This invention uses the power switch control signal in full conduction state and the speed feedback of the compressor motor to perform back electromotive force estimation and analysis. It can reflect the internal voltage fluctuation caused by load torque changes in real time. Combined with the equivalent series resistance of the Type-C PD power supply line for line loss compensation analysis, it accurately calculates the target terminal voltage increment that needs to be supplemented. Finally, it generates analysis through fine-tuning instructions, effectively offsetting the voltage drop caused by voltage drop in long-distance power supply lines and dynamic load changes. This ensures that the power supply terminal of the vehicle refrigerator obtains a constant and smooth compressor operating voltage, guarantees the stable operation of the compressor under various operating conditions, and improves the consistency of refrigeration performance.

[0098] Optionally, the low-impact power supply method for vehicle-mounted refrigerators based on Type-C PD power supply also includes:

[0099] Step 50: Perform a thermal state comparison analysis based on the voltage division value of the bypass thermistor of the power switch tube and the voltage value corresponding to the preset temperature warning threshold to obtain the current thermal risk level of the power device.

[0100] Step 60: Perform power derating analysis based on thermal risk level and compressor motor operating duty cycle to obtain a corrected duty cycle command for limiting heat generation.

[0101] Step 70: Based on the modified duty cycle command, perform upper limit constraint analysis on the peak duty cycle of the graded current limiting pulse width modulation signal to obtain the system protection state with controlled temperature rise limitation.

[0102] Optionally, the SGM2538 chip integrates a high-precision temperature sensor (equivalent to a thermistor) to monitor the junction temperature of the power transistors inside the chip. The chip converts the temperature into a voltage signal, which is compared with a preset temperature warning threshold (such as an overheat shutdown threshold) to assess the current thermal risk level of the device.

[0103] When the chip temperature is detected to be close to the warning value, the thermal shutdown circuit inside the SGM2538 chip is activated to perform power derating analysis. In extreme cases, the chip will directly shut down the output to protect the device; when the temperature is high but has not reached the shutdown threshold, the chip will limit the maximum output current, which is equivalent to outputting a duty cycle correction command to limit the conduction of the power transistor to reduce heat generation.

[0104] The SGM2538's overheat protection function limits the peak output current. This ensures that even in high-temperature automotive environments or under poor heat dissipation conditions, the temperature rise of the power device is kept within a safe range, entering a controlled temperature rise protection state to prevent device burnout or fire caused by overheating, greatly improving safety in automotive environments.

[0105] This invention compares and analyzes the thermal state of power devices by comparing the voltage division value of the bypass thermistor of the power switch with the voltage value corresponding to the preset temperature warning threshold. This enables real-time monitoring of the thermal risk level of power devices. Combined with the operating duty cycle of the compressor motor, power derating analysis is performed to generate a corrected duty cycle command to limit heat generation. An upper limit constraint analysis is performed on the peak duty cycle of the graded current-limiting pulse width modulation signal. This ensures that even in high-temperature vehicle environments or extreme conditions with poor heat dissipation, the temperature rise of power devices is limited to a safe range. This effectively prevents the risk of device burnout or fire caused by overheating, and improves the safety and long-term reliability of the vehicle refrigerator power supply system in complex vehicle environments.

[0106] Furthermore, the low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided by the present invention will be described below. The low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply and the low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply described above can be referred to in correspondence with each other.

[0107] Figure 9 This is the second schematic diagram of the low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply provided by the present invention. The low-impact power supply system for a vehicle-mounted refrigerator includes a reverse connection protection drive unit 910, a soft-start timing generation unit 920, a steady-state switching and holding unit 930, and a closed-loop voltage regulation unit 940.

[0108] The reverse connection protection drive unit is used to perform PD protocol handshake analysis based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence to obtain the target DC voltage. Based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch, it performs voltage drop compensation analysis to obtain the drive start signal of the reverse connection protection switch.

[0109] The soft-start timing generation unit is used to perform soft-start timing analysis based on the drive start signal and the winding inductance characteristics of the compressor motor to obtain a graded current-limiting pulse width modulation signal.

[0110] The steady-state switching holding unit is used to perform a gradual turn-on analysis based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch to obtain the motor drive current, and to perform overload holding analysis based on the motor drive current and the preset steady-state current threshold to obtain the power switch control signal in the full conduction state.

[0111] The closed-loop voltage regulation unit is used to perform closed-loop voltage regulation analysis based on the power switch control signal in full conduction state and the back electromotive force of the compressor motor, to obtain the compressor operating supply voltage.

[0112] Among them, the reverse connection protection drive unit corresponds to the Type-C input protection module (such as...) Figure 4 ) and PD deception module (such as Figure 5 ), P-MOS reverse connection protection module (such as Figure 6 The Type-C input protection module includes a Type-C female connector J1 (24-pin vertical), an ESD protection chip U2 (SRV05-4), a TVS surge suppressor D1 (SMBJ24CA), and an input filter capacitor C1 (0.1μF / 50V). VBUS is led out from A9 / B9 of J1, and CC1 / CC2 is led out from A5 / B5; U2 is connected to VBUS, CC1, and CC2 and grounded; D1 and C1 are connected in parallel between VBUS and ground. The PD decoupling module uses a CH224K chip U1. VDD is connected to VBUS through a 1kΩ resistor R1 and in parallel with a 1μF decoupling capacitor C2; CC1 / CC2 are connected to the female connector; CFG1 / CFG2 are connected to ground through 24kΩ resistors R2 / R3, and CFG3 is directly grounded (fixed requirement 12V); a 10μF filter capacitor C3 is connected in parallel with VBUS; the PG pin (pin 7) outputs the EN_PWR enable signal. The P-MOS reverse connection protection module uses an AOD403 P-channel MOSFET Q1. The source (S) is connected to VBUS, the drain (D) outputs PVCC, and the gate (G) is connected to EN_PWR and grounded via a 10kΩ pull-down resistor R4. Therefore, the reverse connection protection drive unit collaboratively enables PD handshake analysis, 12V target voltage acquisition, and low-loss reverse connection protection drive activation.

[0113] The soft-start timing generation unit and steady-state switching and holding unit correspond to the overcurrent protection module (such as...). Figure 7The overcurrent protection module uses the SGM2538 eFuse chip U3. VIN is connected to PVCC, EN to EN_PWR, GND is grounded, and OUT is VOUT. The ILIM pin is grounded through a 2kΩ resistor R5 (setting a 5A current limit), and the BFET pin is grounded (enabling reverse current blocking). The soft-start timing generation unit and steady-state switching holding unit utilize the soft-start characteristics, current limiting configuration, and internal power transistor characteristics of the SGM2538 to achieve gradual turn-on analysis, motor drive current generation, and overload holding analysis in the full conduction state.

[0114] The closed-loop voltage regulation unit corresponds to the output energy storage module (such as...) Figure 8 The output energy storage module includes a 0.1μF / 50V filter capacitor C4, five 100μF / 25V low-ESR electrolytic capacitors (C5~C9), and one 1F / 16V supercapacitor module C10. All capacitors are connected in parallel between VOUT and ground, and are placed adjacent to the vehicle refrigerator power supply terminal J2. The closed-loop voltage regulation unit absorbs the 15A / 200ms startup spike through the rapid charging and discharging of the low-impedance energy storage circuit, and smooths out voltage fluctuations in steady state, realizing closed-loop voltage regulation analysis and outputting a constant compressor operating power supply voltage.

[0115] The embodiments of the present invention eliminate the impact of voltage fluctuations during the startup process on subsequent steady-state operation, and solve the problem that the Type-C PD power supply system is prone to overcurrent protection false triggering or voltage instability at the moment of compressor startup due to the lack of timing coordination control for compressor startup characteristics. This improves the power supply reliability and compressor startup success rate of the Type-C PD power supply system in vehicle refrigerator applications.

[0116] Please see Figure 10 , Figure 10 An embodiment diagram of an electronic device provided in accordance with the present invention. For example... Figure 10 As shown, an embodiment of the present invention provides an electronic device 1000, including a memory 1010, a processor 1020, and a computer program 1011 stored in the memory 1010 and executable on the processor 1020. When the processor 1020 executes the computer program 1011, it implements the processes of steps 10 to 40.

[0117] Figure 11 An embodiment diagram of a computer-readable storage medium provided in accordance with an embodiment of the present invention. (See diagram for reference.) Figure 11 As shown, this embodiment provides a computer-readable storage medium 1100, on which a computer program 1011 is stored. When the computer program 1011 is executed by a processor, it implements the processes of steps 10 to 40.

[0118] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0119] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., including several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments. 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 them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply, characterized in that, include: Based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence, PD protocol handshake analysis is performed to obtain the target DC voltage. Based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch, voltage drop compensation analysis is performed to obtain the drive start signal of the reverse connection protection switch. Based on the drive start signal and the winding inductance characteristics of the compressor motor, a soft start timing analysis is performed to obtain a graded current limiting pulse width modulation signal. Based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch, a gradual turn-on analysis is performed to obtain the motor drive current. Based on the motor drive current and the preset steady-state current threshold, an overload holding analysis is performed to obtain the power switch control signal in the fully on state. Closed-loop voltage regulation analysis is performed based on the power switch control signal in the fully on state and the back electromotive force of the compressor motor to obtain the compressor operating power supply voltage.

2. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the target DC voltage include: Impedance matching analysis was performed on the pull-down resistor value and pull-up voltage level of the Type-C PD protocol communication pin to obtain the connection confirmation signal of the CC pin; Based on the connection confirmation signal and the voltage level encoding table of the USB PD standard protocol, a protocol negotiation analysis is performed to obtain an initial voltage request command containing 12V voltage levels. Based on the initial voltage request command and the voltage feedback waveform of the VBUS pin, a voltage regulation verification analysis is performed to obtain a target DC voltage whose voltage fluctuation range meets the preset threshold.

3. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the drive enable signal include: Based on the target DC voltage value and the maximum on-resistance parameter of the reverse connection protection switch, the ultimate voltage drop is calculated and analyzed to obtain the theoretical voltage drop value under the maximum allowable operating current. Based on the theoretical voltage drop value and the preset safety margin coefficient, the driving capability is evaluated and analyzed to obtain the gate driving voltage threshold that meets the full conduction condition. Based on the gate drive voltage threshold and the charge pump output voltage inside the controller, a level shift analysis is performed to obtain the drive turn-on signal of the reverse connection protection switch that is higher than the source potential and has a constant amplitude.

4. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the graded current-limiting pulse width modulation signal include: Based on the rising edge time of the drive start signal and the measured inductance of the compressor motor winding, the time constant is calculated and analyzed to obtain the minimum delay period required for current establishment. Based on the minimum delay period and the preset maximum start-up current limit, a duty cycle step planning analysis is performed to obtain a duty cycle increment sequence consisting of multiple fixed duty cycle stages. Based on the duty cycle increment sequence and the timer interrupt frequency of the controller, signal generation analysis is performed to obtain a graded current-limiting pulse width modulation signal with a linear growth trend.

5. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the motor drive current include: Based on the frequency of the graded current-limiting pulse width modulation signal and the input capacitance parameters of the power switch, the charge and discharge rate is analyzed to obtain the slope limit value of the gate voltage change. Based on the slope limit value and the transconductance characteristic curve of the power switch, a linear region mapping analysis is performed to obtain the linear correspondence between drain-source current and gate voltage. Based on the linear correspondence and the duty cycle change rate of the graded current-limiting pulse width modulation signal, current slope control analysis is performed to obtain a linearly rising motor drive current with a constant change rate and no overshoot.

6. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the control signal for the power switch include: Based on the real-time sampled value of the linearly increasing motor drive current and the preset steady-state current threshold, a hysteresis analysis is performed to obtain the determination criteria for the current to stably reach the steady-state range. Based on the determination flag and the preset de-jitter timer, a duration verification analysis is performed to obtain a state lock signal confirming that the normal start-up has been completed. Based on the state lock signal and the drive logic level of the power switch, a pass-through mode switching analysis is performed to obtain the power switch control signal in a fully on state with a duty cycle of 100%.

7. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to claim 1, characterized in that, The steps to obtain the operating power supply voltage for the compressor include: Based on the power switch control signal in the fully on state and the speed feedback of the compressor motor, back electromotive force estimation analysis is performed to obtain an internal voltage reference value that reflects the change in load torque. Based on the internal voltage reference value and the equivalent series resistance of the Type-C PD power supply line, a line loss compensation analysis is performed to obtain the target terminal voltage increment that needs to be supplemented. Based on the target voltage increment and the minimum voltage adjustment step size of the PD protocol, fine-tuning command generation and analysis are performed to obtain a constant compressor operating power supply voltage that can offset the effect of line voltage drop.

8. The low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply according to any one of claims 1 to 7, characterized in that, The method further includes: Thermal state comparison analysis is performed based on the voltage division value of the bypass thermistor of the power switch tube and the voltage value corresponding to the preset temperature warning threshold to obtain the current thermal risk level of the power device. Based on the aforementioned thermal risk level and the operating duty cycle of the compressor motor, a power derating analysis is performed to obtain a corrected duty cycle command for limiting heat generation. Based on the modified duty cycle command, an upper limit constraint analysis is performed on the peak duty cycle of the graded current-limiting pulse width modulation signal to obtain the system protection state with controlled temperature rise limitation.

9. A low-impact power supply system for a vehicle-mounted refrigerator based on Type-C PD power supply, characterized in that, Used to implement the low-impact power supply method for vehicle refrigerator based on Type-C PD power supply as described in any one of claims 1 to 8; The low-impact power supply system for the vehicle-mounted refrigerator based on Type-CPD power supply includes: The reverse connection protection drive unit is used to perform PD protocol handshake analysis based on the level state of the Type-C PD protocol communication pin and the preset voltage request sequence to obtain the target DC voltage, and to perform voltage drop compensation analysis based on the voltage value of the target DC voltage and the on-resistance of the reverse connection protection switch to obtain the drive start signal of the reverse connection protection switch. A soft-start timing generation unit is used to perform soft-start timing analysis based on the drive start signal and the winding inductance characteristics of the compressor motor to obtain a graded current-limiting pulse width modulation signal. The steady-state switching holding unit is used to perform a gradual turn-on analysis based on the graded current-limiting pulse width modulation signal and the gate charge characteristics of the power switch to obtain the motor drive current, and to perform an overload holding analysis based on the motor drive current and a preset steady-state current threshold to obtain the power switch control signal in the fully on state. The closed-loop voltage regulation unit is used to perform closed-loop voltage regulation analysis based on the power switch control signal in the fully on state and the back electromotive force of the compressor motor to obtain the compressor operating power supply voltage.

10. An electronic device, comprising: Memory, used to store computer programs; A processor for reading and executing the computer program, characterized in that, when the processor executes the computer program, it implements the low-impact power supply method for a vehicle-mounted refrigerator based on Type-C PD power supply as described in any one of claims 1 to 8.

Images