Power supply control circuit for power grid power distribution cabinet

Abstract

The invention relates to the field of power supply systems, and provides a power supply control circuit for a power grid power distribution cabinet, which comprises a main control module and an alternating current power supply module connected with the main control module, and the alternating current power supply module is used for supplying power to a vehicle-mounted alternating current electric appliance. The low-voltage direct-current power supply is converted into high-frequency high-voltage alternating-current power supply to be output in a multi-path high-frequency voltage transformation interconnection mode; the input end of the rectifying and filtering module is connected with the output end of the high-frequency switch boosting module, and the rectifying and filtering module is used for converting the high-voltage alternating-current output into a direct-current high-voltage power supply; the controlled end of the high-voltage inversion module is connected with the main control module, the input end of the high-voltage inversion module is connected with the output end of the rectifying and filtering circuit, the output end of the high-voltage inversion module is connected with an alternating-current output port, and the high-voltage inversion module is used for performing inversion conversion on the direct-current high-voltage power supply and outputting a low-frequency 220V alternating-current power supply to the alternating-current output port; the device is small in size and convenient to use on a vehicle.

Description

Technical Field

[0001] This invention relates to the field of power supply systems, and more specifically, to a power control circuit for a power distribution cabinet in a power grid. Background Technology

[0002] Nowadays, users have an increasing demand for charging electrical devices. In cars, users may need to charge various mobile devices, and cars also carry multiple electrical appliances such as refrigerators and fans. All of these require power from the car battery. Cars and trucks require 12 volts of voltage from their own battery to start the engine. When the car battery fails, the car cannot start. To reduce battery wear, provide power to onboard electrical appliances, and also serve as a backup power source for starting the 12-volt starting system of cars and trucks in case the car battery freezes or malfunctions, users often install a backup power source in their cars and trucks to power onboard appliances such as refrigerators and fans, and to serve as a starting power source for the car. Emergency power supplies are available, but when providing backup power, the low-voltage DC power stored inside needs to be inverted into high-voltage AC power. This conversion requires a transformer. To keep the transformer compact, a high frequency is needed. While the transformer outputs AC power, the frequency is too high, typically reaching tens of kHz. Although a higher voltage AC power is available, many electronic components cannot operate at such a high frequency and are easily damaged. Most electronic components in vehicle electrical systems use AC mains voltage and cannot operate on high-frequency AC power. Using a low frequency of 50Hz for direct inversion would require a large transformer, making it inconvenient for vehicle use. Summary of the Invention

[0003] The problem solved by this invention is how to provide a small, easy-to-use vehicle-mounted backup power supply.

[0004] To address the above problems, this invention provides a power control circuit for a power distribution cabinet, a main control module, and an AC power supply module connected to the main control module. The AC power supply module is used to supply power to vehicle-mounted AC electrical appliances, and includes:

[0005] The high-frequency switching boost module connects to a low-voltage DC power supply at its input and uses a multi-channel high-frequency transformer interconnection method to convert the low-voltage DC power supply into a high-frequency high-voltage AC output.

[0006] The rectifier and filter module has its input terminal connected to the output terminal of the high-frequency switching boost module, and is used to convert the high-voltage AC output into a DC high-voltage power supply.

[0007] The high-voltage inverter module has its controlled end connected to the main control module, its input end connected to the output end of the rectifier and filter circuit, and its output end connected to the AC output port. It is used to invert and convert the DC high-voltage power supply to output a low-frequency 220V AC power supply to the AC output port.

[0008] Furthermore, it also includes an emergency power supply module, a USB power supply module, and a solar power generation module connected to the main control module.

[0009] Furthermore, the high-frequency switching boost module includes a PWM controller circuit, a push-pull circuit, and a voltage conversion circuit. The input terminal of the push-pull circuit is connected to the output terminal of the PWM controller circuit, and the output terminal is connected to the controlled terminal of the voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the low-voltage DC power supply input, and the output terminal is connected to the rectifier and filter module.

[0010] Furthermore, the push-pull circuit includes two transistors Q1 and Q2 and two diodes D4 and D5. The bases of transistors Q1 and Q2 are respectively connected to one output port of the PWM controller circuit, and their collectors are grounded. The anode of diode D4 is connected to the base of transistor Q1, and the cathode is connected to the emitter of transistor Q1. The anode of diode D5 is connected to the base of transistor Q2, and the cathode is connected to the emitter of transistor Q2.

[0011] Furthermore, the voltage conversion circuit includes four high-frequency transformers T1-T4 and eight MOSFETs Q3-Q10. The first end of the output winding of transformer T1 is connected to the first input terminal of the rectifier and filter module, and the second end is connected in series with the output windings of transformers T2-T4. The second end of the output winding of transformer T4 is connected to the second input terminal of the rectifier and filter module. The center taps of the input windings of transformers T1-T4 are respectively connected to the low-voltage DC power supply, and the MOSFETs Q3, Q10, Q20, Q30, Q40, Q1 ...20, Q30, Q40, Q30, Q40, Q10, Q20, Q30, Q40, Q30, Q40, Q10, Q20, Q30, Q40, Q30, Q40, Q10, Q20, Q30, Q40, Q30, Q40, Q30, Q40, Q30, Q40, Q30, Q40, Q30, Q40, Q30, Q40, Q30, Q40, Q40, Q30, Q40, Q40, Q30, Q40, Q40, Q30, 5. The gates of Q7 and Q9 are connected to the emitter of transistor Q2, their sources are grounded, and their drains are connected to the first end of the input winding of transformers T1-T4, respectively. The gates of MOSFETs Q4, Q6, Q8, and Q10 are connected to the emitter of transistor Q1, their sources are grounded, and their drains are connected to the second end of the input winding of transformers T1-T4, respectively. The drains of MOSFETs Q3, Q5, Q7, and Q9 are connected to the second end of the input winding of transformers T1-T4 through an RC snubber circuit, respectively.

[0012] Furthermore, the high-voltage inverter module includes an inverter circuit, a current detection circuit, a switching control circuit, a voltage source selection output circuit, and a photovoltaic power selection output circuit. The input terminal of the inverter circuit is connected to the output terminal of the rectifier and filter module, the input terminal of the current detection circuit is connected to the output terminal of the inverter circuit, and the output terminal is connected to the main control module. The controlled terminal of the switching control circuit is connected to the main control module and is used to switch the connection between the voltage source selection output circuit and the photovoltaic power selection output circuit and the output terminal of the inverter circuit according to the power supply of the low-voltage DC power supply.

[0013] Furthermore, the current detection circuit includes a current sensor circuit and a detection amplification circuit. The detection terminal of the current sensor circuit is connected to the output terminal of the inverter circuit, and the output terminal is connected to the main control module via the detection amplification circuit.

[0014] Furthermore, the inverter circuit includes four transistors Q19-Q22 and three inductors L31, L30, and L33. The bases of the four transistors are connected to the main control module. The collectors of transistors Q20 and Q19 are connected to the positive terminal of the DC high-voltage power supply. The emitters of transistors Q21 and Q22 are connected to the negative terminal of the DC high-voltage power supply. The emitter of transistor Q20 and the collector of transistor Q21 are connected to the first terminal of inductor L31. The second terminal of inductor L31 is connected to the first terminal of inductor L30 via the current sensor circuit. The emitter of transistor Q19 and the collector of transistor Q22 are connected to the first terminal of inductor L33.

[0015] Furthermore, the switching control circuit includes one MOSFET Q23 and two relays RY1 and RY2. The gate of the MOSFET Q23 is connected to the main control module, and its source is grounded. The coils of the relays RY1 and RY2 are energized by the drain output of the MOSFET Q23. The stationary contact of the relay RY1 is connected to the second terminal of the inductor L30, and its two moving contacts are connected to the positive input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit, respectively. The stationary contact of the relay RY2 is connected to the second terminal of the inductor L33, and its two moving contacts are connected to the negative input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit, respectively.

[0016] Furthermore, the voltage source selection output circuit includes two capacitors, C258 and C266. Capacitors C258 and C266 are respectively connected to the first moving contacts of relays RY1 and RY2, so that when the stationary contacts of relays RY1 and RY2 are connected to the first moving contacts, capacitor C258 and inductor L30, and capacitor C266 and inductor L33 respectively form LC filter circuits. The photovoltaic power source selection output circuit includes a common-mode inductor L32, capacitor C264, and varistor RV1. The two input terminals of the common-mode inductor L32 are respectively connected to the second moving contacts of relays RY1 and RY2, and the two output terminals are respectively connected to the positive and negative terminals of the AC output port.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] The high-frequency switching boost module employs a multi-channel high-frequency transformer interconnection method. It first converts low-voltage DC power into high-frequency high-voltage AC output. Due to the high-frequency transformation method, the required transformer size is significantly reduced compared to direct inversion to low-frequency AC voltage. Simultaneously, the interconnection of multiple high-frequency transformers improves load-carrying capacity, while the smaller size of individual transformers facilitates circuit packaging and wiring, allowing for easier placement of transformers and components in the backup power supply, further reducing its size. The high-frequency high-voltage AC output is then converted to DC high-voltage power by a rectifier and filter module. This DC high-voltage power is then inverted by a high-voltage inverter module to generate approximately 220V / 50Hz AC current, which is output to the AC output port. This allows convenient power supply for 220V appliances such as refrigerators and fans in vehicles. Through this method, the backup power supply of this invention meets the power requirements of 220V appliances in vehicles while significantly reducing the size of the required transformer, resulting in an overall advantage of small size and ease of use. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall principle structure of an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the principle structure of the high-frequency switching boost module according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the principle structure of the high-voltage inverter module according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of the principle structure of the current detection circuit in an embodiment of the present invention.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-Main control module; 2-AC power supply module; 21-High frequency switching boost module; 22-Rectifier and filter module; 23-High voltage inverter module; 3-Emergency power supply module; 4-USB power supply module; 5-Solar power generation module. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In the description of this specification, references to terms such as "embodiment," "one embodiment," and "one implementation" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or implementation is included in at least one embodiment or illustrative implementation of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or implementation. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.

[0028] like Figure 1 As shown, the present invention provides a power control circuit for a power distribution cabinet, a main control module 1, and an AC power supply module 2 connected to the main control module 1. The AC power supply module 2 is used to supply power to vehicle-mounted AC electrical appliances, and includes:

[0029] The high-frequency switching boost module 21 is connected to a low-voltage DC power supply at its input terminal and uses a multi-channel high-frequency transformer interconnection method to convert the low-voltage DC power supply into a high-frequency high-voltage AC output.

[0030] The rectifier and filter module 22 has its input terminal connected to the output terminal of the high-frequency switching boost module 21, and is used to convert the high-voltage AC output into a DC high-voltage power supply.

[0031] The high-voltage inverter module 23 has its controlled end connected to the main control module 1, its input end connected to the output end of the rectifier and filter circuit, and its output end connected to the AC output port. It is used to invert and convert the DC high-voltage power supply to output a low-frequency 220V AC power supply to the AC output port.

[0032] It should be noted that the intelligent vehicle backup power control circuit in this embodiment also includes an emergency power module 3, a USB power supply module 4, and a solar power generation module 5 connected to the main control module 1. The backup power supply uses a battery for energy storage. The emergency power module 3 is used to provide a 12-volt starting voltage for cars, trucks, etc. in the event that the vehicle battery is frozen or malfunctions. The USB power supply module 4 is used to convert the battery voltage to a 5V DC voltage and charge the mobile terminal device through the USB port. In this way, the 220V AC, 12V DC, and 5V DC USB power supply meet all the user's needs for using backup power.

[0033] The low-voltage DC power input to the high-frequency switching boost module 21 can come from the battery inside the backup power supply or from the photovoltaic power output of the solar power generation module 5. The source of the low-voltage DC power supply can be switched by the main control module 1 according to the actual situation. In use, the high-frequency switching boost module 21 adopts a multi-channel high-frequency transformer interconnection method to first convert the low-voltage DC power supply into a high-frequency high-voltage AC output. Due to the high-frequency transformer method, the size of the transformer is greatly reduced. At the same time, the use of multi-channel high-frequency transformer interconnection and multiple high-frequency transformer interconnection improves the load capacity. At the same time, the size of a single transformer is smaller, which facilitates the packaging and wiring of the circuit. It makes it easier to arrange the transformer and the position of each component in the backup power supply, further reducing the size. The high-frequency high-voltage AC output is then converted into a DC high-voltage power supply by the rectifier and filter module 22. The DC high-voltage power supply generated in this invention is 300V. The 300V DC high-voltage power supply is inverted by the high-voltage inverter module 23 to generate an AC current of about 220V / 50hz, which is output to the AC output port, which can be conveniently used for 220V appliances such as refrigerators and fans in vehicles.

[0034] The photovoltaic power output of the solar power generation module 5 is controlled by a relay switching switch controlled by the main control module 1. Its output port can charge the battery inside the backup power supply, or it can be directly connected to the high-frequency switching boost module 21 when needed, as a low-voltage DC power input, and then converted into AC output for use by vehicle electrical appliances. The solar power generation module 5 adopts an MPPT solar controller. The MPPT charging control has an efficiency of 96% in a 12V system and has the functions of battery reverse polarity protection, overcharge protection and over-discharge protection. It can detect the DC voltage and output current of the main circuit, calculate the output power of the solar cell array, and realize maximum power point tracking.

[0035] In one embodiment of the present invention, the high-frequency switching boost module 21 includes a PWM controller circuit, a push-pull circuit, and a voltage conversion circuit. The input terminal of the push-pull circuit is connected to the output terminal of the PWM controller circuit, and the output terminal is connected to the controlled terminal of the voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the low-voltage DC power supply input, and the output terminal is connected to the rectifier and filter module 22. The rectifier and filter module 22 includes a rectifier circuit and a filter circuit.

[0036] It should be noted that the PWM controller circuit is used to issue PWM drive pulse signals according to the control of the main control module 1. After being amplified by the push-pull circuit, the MOSFET in the voltage conversion circuit is driven to operate, thereby adjusting the output of the voltage conversion circuit. The rectifier and filter module 22 is used to rectify and filter the AC output of the voltage conversion circuit.

[0037] like Figure 2 As shown, the PWM controller circuit includes a PWM controller U1, which can be a TL494. The rectifier circuit uses eight diodes to form a rectifier bridge, and capacitors C20 and C21 are parallel filter capacitors, forming a filter circuit.

[0038] In one embodiment of the present invention, the push-pull circuit includes two transistors Q1 and Q2 and two diodes D4 and D5. The bases of transistors Q1 and Q2 are respectively connected to an output port of the PWM controller circuit, and their collectors are grounded. The anode of diode D4 is connected to the base of transistor Q1, and the cathode is connected to the emitter of transistor Q1. The anode of diode D5 is connected to the base of transistor Q2, and the cathode is connected to the emitter of transistor Q2.

[0039] It should be noted that, as Figure 2 As shown, transistors Q1 and Q2 and diodes D4 and D5 form two push-pull amplifiers, which can amplify the two PWM signals output by the PWM controller circuit to stably drive the MOSFETs. The two push-pull amplifiers are used to control the MOSFETs on both sides of the high-frequency transformer.

[0040] In one embodiment of the present invention, the voltage conversion circuit includes four high-frequency transformers T1-T4 and eight MOSFETs Q3-Q10. The first end of the output winding of transformer T1 is connected to the first input terminal of the rectifier-filter module 22, and the second end is connected in series with the output windings of transformers T2-T4. The second end of the output winding of transformer T4 is connected to the second input terminal of the rectifier-filter module 22. The center taps of the input windings of transformers T1-T4 are respectively connected to the low-voltage DC power supply. The gates of transistors Q3, Q5, Q7, and Q9 are connected to the emitter of transistor Q2, their sources are grounded, and their drains are connected to the first end of the input windings of transformers T1-T4, respectively. The gates of MOSFETs Q4, Q6, Q8, and Q10 are connected to the emitter of transistor Q1, their sources are grounded, and their drains are connected to the second end of the input windings of transformers T1-T4, respectively. The drains of MOSFETs Q3, Q5, Q7, and Q9 are connected to the second end of the input windings of transformers T1-T4 through an RC snubber circuit, respectively.

[0041] It should be noted that, as Figure 2 As shown, MOSFETs Q3-Q10 form four pairs of MOSFET half-bridge switches to control four series-connected high-frequency transformers T1-T4. The interconnection of multiple high-frequency transformers improves the load-carrying capacity, while the individual transformers are smaller, making it easier to arrange the transformers and components in the backup power supply, further reducing the overall size. Taking the first group as an example, by adjusting the switches of MOSFETs Q3 and Q4, the charging and energy storage time of the inductor coil inside the high-frequency transformer T1 can be changed to boost the voltage. In this way, the output voltage can be controlled by the duty cycle of the PWM signal. The RC snubber circuit also has four channels. Taking the first channel as an example, it includes capacitor C3 and resistor R32, which can effectively absorb the voltage generated during switching and protect the MOSFETs.

[0042] In one embodiment of the present invention, the high-voltage inverter module 23 includes an inverter circuit, a current detection circuit, a switching control circuit, a voltage source selection output circuit, and a photovoltaic power source selection output circuit. The input terminal of the inverter circuit is connected to the output terminal of the rectifier filter module 22, the input terminal of the current detection circuit is connected to the output terminal of the inverter circuit, and the output terminal is connected to the main control module 1. The controlled terminal of the switching control circuit is connected to the main control module 1 and is used to switch the connection between the voltage source selection output circuit and the photovoltaic power source selection output circuit and the output terminal of the inverter circuit according to the power supply of the low-voltage DC power supply.

[0043] It should be noted that, as Figure 3As shown, the inverter circuit inverts the 300V DC high voltage output from the high-frequency switching boost module 21 to generate approximately 220V / 50Hz AC power for use by vehicle electrical appliances. The current detection circuit is used for current monitoring and overcurrent protection. Since this backup power supply is powered by solar energy, the inverter section supports two operating modes. The first mode is for uninterruptible power supply, i.e., the stable output of the internal battery. The second mode is for photovoltaic power supply, which requires better filtering and lightning protection. The switching control circuit is controlled by the main control module 1 and can automatically switch according to actual needs, selecting either the voltage source selection output circuit or the photovoltaic power selection output circuit to achieve energy saving and environmental protection while ensuring stable power supply. This invention supports both voltage source and photovoltaic grid-connected modes through switching; peak efficiency is 98%; total harmonic distortion (THD) is low: less than 1% for linear loads and less than 3% for typical nonlinear loads.

[0044] In one embodiment of the present invention, the current detection circuit includes a current sensor circuit and a detection amplification circuit. The detection terminal of the current sensor circuit is connected to the output terminal of the inverter circuit, and the output terminal is connected to the main control module 1 via the detection amplification circuit.

[0045] It should be noted that the current sensor circuit is located at the output of the inverter circuit to detect the magnitude of the current under load. The detected current signal is amplified by the detection amplifier circuit and then transmitted to the main control module 1. The main control module 1 can then perform overcurrent protection based on this signal, stopping the inverter circuit when the current is too high. The current sensor circuit can be found in [reference needed]. Figure 3 U66 is a Hall effect current transformer, forming a current sensor circuit. The detection and amplification circuit is as follows: Figure 4 As shown, an operational amplifier is used to amplify the current signal to improve detection accuracy.

[0046] In one embodiment of the present invention, the inverter circuit includes four transistors Q19-Q22 and three inductors L31, L30, and L33. The bases of the four transistors are respectively connected to the main control module 1. The collectors of transistors Q20 and Q19 are connected to the positive terminal of the DC high-voltage power supply. The emitters of transistors Q21 and Q22 are connected to the negative terminal of the DC high-voltage power supply. The emitter of transistor Q20 and the collector of transistor Q21 are connected to the first terminal of inductor L31. The second terminal of inductor L31 is connected to the first terminal of inductor L30 via the current sensor circuit. The emitter of transistor Q19 and the collector of transistor Q22 are connected to the first terminal of inductor L33.

[0047] It should be noted that, as Figure 3As shown, inductor L31 is an energy storage inductor, and four transistors Q19-Q22 form a bridge inverter circuit. The main control module 1 sends a PWM signal to control two sets of corresponding transistor switches among the four transistors Q19-Q22, thereby storing energy in inductor L31, controlling inductor L31 to charge and discharge, realizing inversion, and outputting AC power. The main control module 1 can adjust the voltage of the output AC power by changing the duty cycle of the PWM signal, and can adjust the frequency of the AC power by changing the frequency of the PWM signal, thus realizing the output of 220V / 50Hz AC power.

[0048] In one embodiment of the present invention, the switching control circuit includes one MOSFET Q23 and two relays RY1 and RY2. The gate of the MOSFET Q23 is connected to the main control module 1, and the source is grounded. The coils of the relays RY1 and RY2 are respectively powered on by the drain output of the MOSFET Q23. The stationary contact of the relay RY1 is connected to the second terminal of the inductor L30, and the two moving contacts are respectively connected to the positive input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit. The stationary contact of the relay RY2 is connected to the second terminal of the inductor L33, and the two moving contacts are respectively connected to the negative input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit.

[0049] It should be noted that, as Figure 3 As shown, the first terminals of the coils of relays RY1 and RY2 are connected to a 15V voltage, and the second terminals are grounded. Both are controlled by the drain output of MOSFET Q23. The gate of MOSFET Q23 is controlled by the main control module 1. When MOSFET Q23 is turned on, the RYCOM signal is grounded through its drain-source, which provides a grounding signal to the second terminals of the coils of relays RY1 and RY2, causing relays RY1 and RY2 to engage. This enables the main control module 1 to control the connection between the stationary contacts of relays RY1 and RY2 and the first or second moving contacts. When powered by the internal battery, the stationary contacts of relays RY1 and RY2 are connected to the first moving contact, and the front-end inverter circuit is connected to the voltage source selection output circuit. When directly powered by the solar power generation module 5, the stationary contacts of relays RY1 and RY2 are connected to the second moving contact, and the front-end inverter circuit is connected to the photovoltaic power selection output circuit.

[0050] In one embodiment of the present invention, the voltage source selection output circuit includes two capacitors C258 and C266. The capacitors C258 and C266 are respectively connected to the first moving contacts of the relays RY1 and RY2, so that when the stationary contacts of the relays RY1 and RY2 are connected to the first moving contacts, the capacitors C258 and L30, and the capacitors C266 and L33 respectively form LC filter circuits. The photovoltaic power source selection output circuit includes a common-mode inductor L32, a capacitor C264, and a varistor RV1. The two input terminals of the common-mode inductor L32 are respectively connected to the second moving contacts of the relays RY1 and RY2, and the two output terminals are respectively connected to the positive and negative terminals of the AC output port.

[0051] It should be noted that when powered by the internal battery, the pre-amplifier circuit selects and connects to the voltage source selection output circuit. At this time, capacitor C258 and inductor L30, and capacitor C266 and inductor L33 are connected respectively to form an LC filter circuit. The two poles of the AC power supply are filtered by the LC filter circuit and then output. The positive terminal passes through resistors R321, R320, and R319 in sequence to reach the positive terminal of the AC output port, and the negative terminal passes through resistors R341, R342, and R343 in sequence to reach the negative terminal of the AC output port. When directly powered by the solar power generation module 5, the pre-amplifier circuit selects and connects to the photovoltaic power selection output circuit. At this time, the AC power supply passes through common-mode inductor L32, filter capacitor C10, and protection devices in sequence before being output. Among them, the varistor RV1 is a surge protector that can effectively reduce interference and strengthen protection when powered by solar power, so that the output can be stable even when powered by photovoltaic power.

[0052] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A power control circuit for a power distribution cabinet in a power grid, characterized in that, The system includes a main control module (1) and an AC power supply module (2) connected to the main control module (1). The AC power supply module (2) is used to supply power to the vehicle's AC electrical appliances and includes: The high-frequency switching boost module (21) is connected to a low-voltage DC power supply at its input terminal. It adopts a multi-channel high-frequency transformer interconnection method to convert the low-voltage DC power supply into a high-frequency high-voltage AC output. The rectifier and filter module (22) has its input end connected to the output end of the high-frequency switch boost module (21) and is used to convert the high-voltage AC output into a DC high-voltage power supply. The high-voltage inverter module (23) is connected to the main control module (1) at the controlled end, and to the output end of the rectifier filter circuit at the input end. The output end is connected to the AC output port. It is used to invert and convert the DC high-voltage power supply and output a low-frequency 220V AC power supply to the AC output port.

2. The intelligent vehicle backup power control circuit according to claim 1, characterized in that, It also includes an emergency power supply module (3), a USB power supply module (4), and a solar power generation module (5) connected to the main control module (1).

3. The intelligent vehicle backup power control circuit according to claim 2, characterized in that, The high-frequency switching boost module (21) includes a PWM controller circuit, a push-pull circuit and a voltage conversion circuit. The input terminal of the push-pull circuit is connected to the output terminal of the PWM controller circuit, and the output terminal is connected to the controlled terminal of the voltage conversion circuit. The input terminal of the voltage conversion circuit is connected to the low-voltage DC power supply input, and the output terminal is connected to the rectifier and filter module (22).

4. The intelligent vehicle backup power control circuit according to claim 3, characterized in that, The push-pull circuit includes two transistors (Q1, Q2) and two diodes (D4, D5). The bases of transistors (Q1) and (Q2) are respectively connected to one output port of the PWM controller circuit, and their collectors are grounded. The anode of diode (D4) is connected to the base of transistor (Q1), and the cathode is connected to the emitter of transistor (Q1). The anode of diode (D5) is connected to the base of transistor (Q2), and the cathode is connected to the emitter of transistor (Q2).

5. The intelligent vehicle backup power control circuit according to claim 4, characterized in that, The voltage conversion circuit includes four high-frequency transformers (T1-T4) and eight MOSFETs (Q3-Q10). The first end of the output winding of transformer (T1) is connected to the first input terminal of the rectifier-filter module (22), and the second end is connected in series with the output windings of transformers (T2-T4). The second end of the output winding of transformer (T4) is connected to the second input terminal of the rectifier-filter module (22). The center taps of the input windings of transformers (T1-T4) are respectively connected to the low-voltage DC power supply. The MOSFETs (Q3, Q10, Q20, Q30, Q40) are connected to the output windings of transformers (T1-T4). The gates of MOSFETs (Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q9) are connected to the emitter of transistor (Q2), the source is grounded, and the drains are connected to the first end of the input winding of transformer (T1-T4). The gates of MOSFETs (Q4, Q6, Q8, Q10) are connected to the emitter of transistor (Q1), the source is grounded, and the drains are connected to the second end of the input winding of transformer (T1-T4). The drains of MOSFETs (Q3, Q5, Q7, Q9) are connected to the second end of the input winding of transformer (T1-T4) through an RC snubber circuit.

6. The intelligent vehicle backup power control circuit according to claim 2, characterized in that, The high-voltage inverter module (23) includes an inverter circuit, a current detection circuit, a switching control circuit, a voltage source selection output circuit, and a photovoltaic power source selection output circuit. The input terminal of the inverter circuit is connected to the output terminal of the rectifier filter module (22). The input terminal of the current detection circuit is connected to the output terminal of the inverter circuit, and the output terminal is connected to the main control module (1). The controlled terminal of the switching control circuit is connected to the main control module (1) and is used to switch the connection between the voltage source selection output circuit and the photovoltaic power source selection output circuit and the output terminal of the inverter circuit according to the power supply of the low-voltage DC power supply.

7. The intelligent vehicle backup power control circuit according to claim 6, characterized in that, The current detection circuit includes a current sensor circuit and a detection amplification circuit. The detection end of the current sensor circuit is connected to the output end of the inverter circuit, and the output end is connected to the main control module (1) via the detection amplification circuit.

8. The intelligent vehicle backup power control circuit according to claim 7, characterized in that, The inverter circuit includes four transistors (Q19-Q22) and three inductors (L31, L30, L33). The bases of the four transistors are connected to the main control module (1). The collectors of transistors (Q20) and (Q19) are connected to the positive terminal of the DC high-voltage power supply. The emitters of transistors (Q21) and (Q22) are connected to the negative terminal of the DC high-voltage power supply. The emitter of transistor (Q20) and the collector of transistor (Q21) are connected to the first terminal of inductor (L31). The second terminal of inductor (L31) is connected to the first terminal of inductor (L30) via the current sensor circuit. The emitter of transistor (Q19) and the collector of transistor (Q22) are connected to the first terminal of inductor (L33).

9. The intelligent vehicle backup power control circuit according to claim 8, characterized in that, The switching control circuit includes one MOSFET (Q23) and two relays (RY1, RY2). The gate of the MOSFET (Q23) is connected to the main control module (1), and the source is grounded. The coils of the relays (RY1) and (RY2) are powered on by the drain output of the MOSFET (Q23). The stationary contact of the relay (RY1) is connected to the second end of the inductor (L30), and the two moving contacts are connected to the positive input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit, respectively. The stationary contact of the relay (RY2) is connected to the second end of the inductor (L33), and the two moving contacts are connected to the negative input terminals of the voltage source selection output circuit and the photovoltaic power selection output circuit, respectively.

10. The intelligent vehicle backup power control circuit according to claim 9, characterized in that, The voltage source selection output circuit includes two capacitors (C258 and C266). The capacitors (C258) and (C266) are respectively connected to the first moving contacts of the relays (RY1) and (RY2). When the stationary contacts of the relays (RY1) and (RY2) are connected to the first moving contacts, the capacitors (C258) and (L30) and (C266) and (L33) respectively form LC filter circuits. The photovoltaic power source selection output circuit includes a common-mode inductor (L32), a capacitor (C264), and a varistor (RV1). The two input terminals of the common-mode inductor (L32) are respectively connected to the second moving contacts of the relays (RY1) and (RY2), and the two output terminals are respectively connected to the positive and negative terminals of the AC output port.

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