A vehicle-mounted inverter

Abstract

The application discloses a vehicle-mounted inverter, which comprises a power supply module, a mainboard circuit, a PWM control circuit and an SPWM driving circuit connected in sequence, wherein the mainboard circuit comprises a DC voltage boosting module and a voltage conversion module; the power supply module is connected with the DC voltage boosting module and the PWM control circuit respectively; the PWM control circuit is further connected with the DC voltage boosting module; the SPWM driving circuit is connected with the PWM control circuit and the voltage conversion module respectively; the PWM control circuit comprises a first chip and a second chip; the second chip is used for collecting various signals in the mainboard circuit and judging whether the collected various signals are normal; and the first chip is used for driving the DC voltage boosting module to start working if the various signals collected by the second chip are normal. When the vehicle-mounted inverter fails, the current failure of the inverter can be fed back, and the reliability and safety of the vehicle-mounted inverter are improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive low-voltage power supply systems, and specifically relates to an on-board inverter. Background Technology

[0002] Currently, the use of household appliances in vehicles during daily driving is increasing. In traditional gasoline vehicles, the low-voltage power supply system powers all electrical loads. For hybrid, range-extended, and pure electric vehicles, the system powers all low-voltage loads except for the high-voltage motor and high-voltage air conditioning system. However, customers are not satisfied with just the appliances provided by the vehicle itself. Although most cars provide 220V AC outlets, solving the problem of using most household appliances while driving, customer demand for in-vehicle household appliances is increasing in different scenarios, and the power requirements of different household appliances vary greatly. Therefore, with the development of vehicle electrification and intelligence, the need for vehicles to provide power for more household appliances in daily driving scenarios is becoming increasingly apparent and a pressing technical problem that needs to be solved. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide an on-board inverter, comprising a power supply module, a main board circuit, a PWM control circuit, and an SPWM drive circuit connected in sequence. The main board circuit includes a DC-DC boost module and a voltage conversion module. The power supply module is connected to both the DC-DC boost module and the PWM control circuit. The PWM control circuit is also connected to the DC-DC boost module. The SPWM drive circuit is connected to both the PWM control circuit and the voltage conversion module.

[0004] The power supply module is used to provide power input;

[0005] The PWM control circuit includes a first chip and a second chip. The second chip is used to collect various signals from the motherboard circuit and determine whether the collected signals are normal. The first chip is used to drive the DC boost module to start working if the signals collected by the second chip are normal.

[0006] The motherboard circuit is used to collect its own output voltage, output current and MOSFET temperature signals, and send them to the SPWM drive circuit.

[0007] The SPWM drive circuit is used to determine whether there is a short circuit, overload, and / or excessive machine temperature in the motherboard circuit based on the output voltage, output current, and / or MOSFET temperature signal. If so, the drive voltage conversion module stops working, and the AC fault abnormality feedback signal is fed back to the PWM control circuit, causing the second chip to control the first chip to stop working, and finally causing the DC boost module to stop working.

[0008] Furthermore, the power supply module is connected to the PWM control circuit via an ACC switch. The power supply module includes a battery, a transistor Q6, and a MOSFET Q4. When the ACC signal is turned on, the transistor Q6 is turned on, which in turn turns on the MOSFET Q4. The positive terminal of the battery can supply 14.9V power to the vehicle inverter through the MOSFET Q4.

[0009] The battery is a DC 12V low-voltage battery for a low-voltage power system, which includes flooded lead-acid batteries, enhanced flooded lead-acid batteries, glass fiber valve-regulated batteries, lithium iron phosphate batteries, ternary lithium batteries, lithium manganese oxide batteries, and sodium-ion batteries.

[0010] Furthermore, the motherboard circuit also includes a voltage feedback circuit, which is connected to the rectifier and filter circuit. The voltage feedback circuit is also connected to the first chip of the PWM control circuit via a closed-loop voltage regulator circuit; wherein...

[0011] The voltage feedback circuit is used to collect the voltage signal after the DC boost module boosts the voltage and determine whether it is normal. If there is overvoltage or undervoltage, it means that the battery voltage is too high or too low. Then, the PU-1 signal is output through the closed-loop voltage regulation circuit and fed back to the first chip of the PWM control circuit.

[0012] Furthermore, the PWM control circuit also includes MOSFETs Q1, Q2, Q3, Q5, and Q7. MOSFET Q1 is connected to both the closed-loop voltage regulator circuit and the first chip. The gates of MOSFETs Q5 and Q7 are connected together and then connected to the first chip. The gates of MOSFETs Q2 and Q3 are also connected together and then connected to the first chip, forming two sets of totem-pole circuits.

[0013] The PWM control circuit is also used to amplify the drive signal through two sets of totem-pole circuits using MOSFETs Q2, Q3, Q5, and Q7, thereby driving the DC boost module in the mainboard circuit; and,

[0014] When the PU-1 signal is received, the drive control MOSFET Q1 stops conducting, the first chip stops working, and the DC boost module stops working.

[0015] Furthermore, the SPWM drive circuit includes a third chip, a first signal drive amplifier chip, a second signal drive amplifier chip, and an amplifier circuit. The third chip is connected to both the first and second signal drive amplifier chips. The first and second signal drive amplifier chips are also connected to the amplifier circuit.

[0016] The third chip generates a first drive signal and a second drive signal. The first drive signal is amplified by the first signal drive amplifier chip and the amplifier circuit, respectively. The second drive signal is amplified by the second signal drive amplifier chip and the amplifier circuit, respectively. The amplified first drive signal and the second drive signal drive the voltage conversion module in the motherboard circuit to work.

[0017] Furthermore, the motherboard circuit also includes an auxiliary power supply circuit, an AC fault indication circuit, a leakage protection circuit, a fault indicator circuit, and a current feedback circuit, wherein...

[0018] The auxiliary power supply circuit is connected to transformer T1 and the third chip respectively, and is used to output 15V and 5V auxiliary power to the third chip respectively;

[0019] The AC fault indication circuit is connected to the second chip and the third chip respectively. The AC fault indication circuit includes a second optocoupler. When the enable signal of the third chip in the SPWM drive circuit is received, the second optocoupler triggers the AC fault abnormality feedback signal and sends it to the second chip.

[0020] The fault indicator circuit is connected to the second chip in the PWM control circuit. It is used to control the fault indicator light to turn on when the second chip receives the AC fault abnormality feedback signal and the leakage protection signal.

[0021] The leakage current protection circuit is used to cut off the power supply to protect the main board circuit when a leakage current protection signal is received.

[0022] The current feedback circuit is connected to the negative terminal of the voltage conversion module output and the third chip respectively, and is used to collect the output current of the motherboard circuit and send it to the third chip.

[0023] Furthermore, the motherboard circuit includes a first EMC snubber circuit and a second EMC snubber circuit, wherein,

[0024] The input of the first EMC absorption circuit is connected to the power supply module via a fuse, and the output is connected to the DC boost module and the ACC switch respectively, which are used to filter the input power supply to remove noise.

[0025] The input of the second EMC absorption circuit is connected to the voltage conversion module, and the output is connected to the socket. It is used to filter out the electromagnetic radiation of the output voltage of the voltage conversion module.

[0026] Furthermore, it also includes an input connector and input cable N1, a waterproof ring for the output hole and a lower shell N2, an insulating sheet N3, a waterproof ring N4, a PCB board N5, PCB board screws N6, an upper shell N7, upper and lower shell screws N8, and an output cable and output connector N9; among which,

[0027] During assembly, install the insulating sheet N3 at the bottom of the lower housing in the outlet hole waterproof ring and lower housing N2. Install the waterproof ring N4 on the four mounting edges of the lower housing in the outlet hole waterproof ring and lower housing N2. Solder the components on the PCB board N5. Solder the input wires and output wires in the input connector and input line N1 and the output wires in the output connector N9 to the PCB board N5. Then, assemble the soldered PCB board N5 onto the lower housing in the outlet hole waterproof ring and lower housing N2, and tighten the PCB board N5 with the PCB board screw N6. Then, assemble the upper housing N7. When assembling the upper housing N7, the input wires and output wires in the input connector and input line N1 and the output wires in the output connector N9 should be placed on the outlet hole of the lower housing in the outlet hole waterproof ring and lower housing N2. Then, tighten the upper housing N7 and the lower housing in the outlet hole waterproof ring and lower housing N2 with the upper and lower housing screws N8.

[0028] Furthermore, it also includes a power socket, which comprises a cover C1, a connecting rod C2, a panel and upper shell C3, an LED light C4, a PCB board C5, a lower shell C6, and connecting screws between the upper and lower shells C7; wherein,

[0029] During assembly, the cover C1 is assembled onto the upper shell via the connecting rod C2. The cover C1 is rotated and opened and closed via the connecting rod C2 as an axis. The terminal is soldered onto the PCB board C5, and the LED light C4 is fixed onto the PCB board C5. Then, the PCB board C5 is assembled into the front panel and the upper shell C3. Next, the lower shell C6 is assembled, and the upper shell C3 and the lower shell C6 are fastened together and secured with the connecting screw C7 between the upper and lower shells.

[0030] Furthermore, LED C4 is connected to the fault indicator circuit of the main board circuit to display the working status of the vehicle inverter, and to display different indication statuses based on different fault states when there are abnormal signals in the various signals collected by the second chip.

[0031] The vehicle-mounted inverter of the present invention can meet the daily use of household appliances in vehicles, and can provide feedback on the current fault of the inverter when it fails, thereby improving the applicability and reliability of the inverter and further enhancing the user experience.

[0032] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims, and drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of the structure of an on-board inverter according to an embodiment of the present invention is shown;

[0035] Figure 2 A schematic diagram of another vehicle-mounted inverter in an embodiment of the present invention is shown;

[0036] Figure 3 A circuit diagram of a power supply module according to an embodiment of the present invention is shown;

[0037] Figure 4 A circuit diagram of a motherboard circuit according to an embodiment of the present invention is shown;

[0038] Figure 4a This shows a circuit diagram of the portion to the left of the dashed line in a motherboard circuit according to an embodiment of the present invention;

[0039] Figure 4b This shows a circuit diagram of the portion to the right of the dashed line in a motherboard circuit according to an embodiment of the present invention;

[0040] Figure 5 A circuit diagram of a PWM control circuit according to an embodiment of the present invention is shown;

[0041] Figure 6 A flowchart of a vehicle-mounted inverter fault control method is shown in an embodiment of the present invention.

[0042] Figure 7 A circuit diagram of an SPWM drive circuit according to an embodiment of the present invention is shown;

[0043] Figure 8 An exploded view of an on-board inverter according to an embodiment of the present invention is shown;

[0044] Figure 9 An exploded view of a power socket for a vehicle-mounted inverter according to an embodiment of the present invention is shown. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0046] like Figure 1 As shown in the illustration, this invention provides an on-board inverter. The on-board inverter includes a power supply module, a mainboard circuit, a PWM control circuit, and an SPWM drive circuit connected in sequence. The mainboard circuit includes a DC-DC boost module and a voltage conversion module. The power supply module is connected to both the DC-DC boost module and the PWM control circuit. The PWM control circuit is also connected to the DC-DC boost module. The SPWM drive circuit is connected to both the PWM control circuit and the voltage conversion module. The power supply module provides power input. The PWM control circuit includes a first chip and a second chip. The second chip is used to determine whether the acquired signals are normal and to determine the acquired signals... The first chip is used to drive the DC-DC boost module to start working if the signals collected by the second chip are normal. The mainboard circuit is used to collect its own output voltage, output current, and MOSFET temperature signals, and send them to the SPWM drive circuit. The SPWM drive circuit is used to determine whether there is a short circuit, overload, and / or excessive machine temperature in the mainboard circuit based on the output voltage, output current, and / or MOSFET temperature signals. If so, it drives the voltage conversion module to stop working and feeds back the AC fault abnormality feedback signal to the PWM control circuit, causing the second chip to control the first chip to stop working, and finally causing the DC-DC boost module to stop working. In this embodiment of the invention, when the inverter fails, the current fault of the inverter can be fed back, which improves the reliability and safety of the vehicle inverter.

[0047] Specifically, such as Figure 2 As shown, the power supply module is connected to the PWM control circuit via an ACC switch. Figure 3 As shown, the power supply module includes a battery, transistor Q6, and MOSFET Q4. When the ACC signal is activated, transistor Q6 conducts, causing MOSFET Q4 to conduct as well. The positive terminal of the battery can then supply 14.9V power to the vehicle inverter through MOSFET Q4. The battery is a 12V DC low-voltage battery for a low-voltage power system. This 12V DC low-voltage battery can be one of the following: flooded lead-acid battery, enhanced flooded lead-acid battery, glass fiber valve-regulated battery, lithium iron phosphate battery, ternary lithium battery, lithium manganese oxide battery, or sodium-ion battery. However, it is not limited to these types of batteries; other batteries are also suitable for this invention.

[0048] like Figure 2 , 4 As shown in Figures 4a and 4b, the circuit diagram of the mainboard circuit includes two main parts: a DC-DC boost module and a voltage conversion module. The DC-DC boost module is the DC-DC (DC to DC) converter, and the voltage conversion module is the DC-AC (DC to AC) converter. Further, the DC-DC converter includes a PWM drive switch circuit, a transformer T1, and a rectifier and filter circuit connected in sequence. The PWM drive switch circuit includes MOSFETs Q1 and Q5, and the rectifier and filter circuit includes a rectifier bridge formed by diodes D1, D2, D4, and D5 and a capacitor C1. Under the control of the PWM control circuit, MOSFETs Q1 and Q5 boost the 12V DC input voltage (BT+ and BT-) through transformer T1. The voltage is then rectified by diodes D1, D2, D4, and D5 and filtered by capacitor C1, resulting in an output 380V DC voltage. The DC-AC (Direct Current to Alternating Current) conversion section includes a T2 common-mode inductor and an SPWM drive switch circuit. The SPWM drive switch circuit is connected to both the SPWM drive circuit and the T2 common-mode inductor. The SPWM drive switch circuit includes MOSFETs Q2, Q3, Q6, and Q7 that form an H-bridge circuit. MOSFETs Q2 and Q3 form the upper arm of the H-bridge, and MOSFETs Q6 and Q7 form the lower arm. The DC-AC conversion section uses 380V DC voltage, which is modulated and controlled by the third chip U1 in the SPWM drive circuit through the four MOSFETs Q2, Q3, Q6, and Q7. The common-mode inductor T2 filters out high-frequency noise signals in the output signal, converting the 380V DC voltage into a 220V AC output.

[0049] In addition, the motherboard circuit also collects the voltage, current, and MOSFET temperature signals of the output 220V AC power and transmits these signals to the third chip U1 in the SPWM drive circuit. If a short circuit, overload, or excessively high machine temperature occurs, the SPWM drive circuit stops driving the four MOSFETs Q2, Q3, Q6, and Q7, causing the DC-AC conversion section to stop working. It also feeds back an AC fault feedback signal to the PWM control circuit, causing the second chip U2 in the PWM control circuit to control the first chip U1 to stop working, thus stopping the DC-DC conversion section. Specifically, the AC voltage is the VFB (AC-VFB) signal, such as... Figure 4 , 4bIn the circuit, the AC voltage acquisition circuit includes resistors R1, R2, R3, R55, and capacitor C2. The current is the IFB signal, and the current acquisition circuit, i.e., the current feedback circuit, includes resistors R41 and R2. The MOSFET temperature signal is the TFB (NTC) signal. The NTC (Negative Temperature Coefficient) thermistor is attached near the MOSFET (not shown in the diagram). If the MOSFET temperature exceeds a certain threshold, the machine temperature is considered too high. When the VFB, IFB, or TFB signals are abnormal, they are fed back to the third chip U1. The third chip U1 outputs the PU-2 signal, controlling the transistor Q4 on the main board circuit to operate, causing the closed-loop voltage regulator circuit on the main board circuit to output the PU-1 signal, thus stopping the front-end drive PWM control circuit. Furthermore, the enable EN pin of the third chip U1 (pin 40) can also feed back the AC fault feedback signal from the main board circuit to the first chip. Furthermore, for short-circuit faults, the drive will also be stopped directly through the SPWM drive circuit.

[0050] Figure 4 , 4a In section 4b, the mainboard circuit also includes an auxiliary power supply circuit, a closed-loop voltage regulator circuit, an AC fault indicator circuit, a leakage protection circuit, a fault indicator circuit, and a current feedback circuit. The auxiliary power supply circuit is connected to both transformer T1 and the third chip. It includes a rectifier and filter circuit composed of diodes D8 and D9 and an RC converter. The output voltage of transformer T1 is processed by the rectifier and filter circuit to output 15V and 5V auxiliary power supplies to the third chip, respectively, for powering the third chip. However, it is not limited to powering only the third chip U3; it also powers other circuits in the vehicle inverter.

[0051] The closed-loop voltage regulator circuit includes an optocoupler PC1 connected to the voltage feedback circuit and the first chip U1 respectively. When the transistor Q4 in the voltage feedback circuit is activated, it triggers the optocoupler PC1 to output the PU-1 signal, causing the front-end drive PWM control circuit to stop working.

[0052] The AC fault indication circuit is connected to the second chip U2 and the third chip U1 respectively. The AC fault indication circuit includes an optocoupler PC2. When it receives the EN signal enabled by the third chip U1 in the SPWM drive circuit, the optocoupler PC2 triggers the AC fault abnormal feedback signal and sends it to the second chip U2.

[0053] The fault indicator circuit is connected to the second chip U2 in the PWM control circuit. Pin 2 of U2 is connected to the fault light signal, which is connected to the main board circuit through CON1 to control the LED to light up.

[0054] The leakage protection circuit includes resistors R49, R50, R52, R53, R54, R57, R58, R60, R61, capacitors C31, C32, C33, diode D14, Zener diode U2, and transistor Q8. It is used to cut off the power supply to protect the main board circuit when the leakage protection signal DATA is received.

[0055] The current feedback circuit is connected to the negative terminal of the 380V high voltage DC power supply (the negative terminal of the voltage conversion module output) and the third chip U3, respectively, to collect the output current of the motherboard circuit and send it to the third chip U3.

[0056] The motherboard circuit also includes a voltage feedback circuit. The DC-DC boost module is connected to the voltage feedback circuit through a rectifier and filter circuit. The voltage feedback circuit is also connected to the first chip U1 of the PWM control circuit through a closed-loop voltage regulator circuit. The voltage feedback circuit collects the voltage signal after the DC-DC boost module has boosted the voltage and determines whether the voltage signal is normal. If there is overvoltage or undervoltage, it indicates that the battery voltage is too high or too low, meaning the voltage signal is outside the preset range. A voltage signal higher or lower than the preset range indicates overvoltage or undervoltage, respectively. This triggers the closed-loop voltage regulator circuit to output a PU-1 signal, which is fed back to the first chip U1 of the PWM control circuit. After receiving the PU-1 signal, the first chip U1 stops working, thus stopping the DC-DC conversion section. Specifically, Figure 4b In the circuit, the voltage feedback circuit includes capacitors C7, C14, C22, resistors R12, R13, R14, R15, R16, R17, R18, R19, R28, R31, transistor Q4, and Zener diode U1.

[0057] The motherboard circuit also includes a first EMC absorption circuit and a second EMC absorption circuit, namely respectively Figure 2 The EMC snubber circuits in the DC-DC converter section and the DC-AC converter section are described. The input of the first EMC snubber circuit is connected to the power supply module via a fuse, and its output is connected to the DC boost module and the ACC switch, respectively. Figure 4a In the first EMC snubber circuit, common-mode inductors T3 and T4, and capacitors C15, C16, C41, C42, C43, and C44 are used to filter and remove noise from the input power supply. The input terminal of the second EMC snubber circuit is connected to the voltage conversion module, and the output terminal is connected to a socket. Figure 4b In the second EMC absorption circuit, capacitors C11, C5, C8, C9, C12, C13, and C40 are used to filter out electromagnetic radiation from the output voltage of the voltage conversion circuit.

[0058] like Figure 5As shown, the PWM control circuit includes a first chip U1, a second chip U2, and MOSFETs Q1, Q2, Q3, Q5, and Q7. MOSFET Q1 is connected to both the closed-loop voltage regulator circuit and the first chip U1. The gates of MOSFETs Q5 and Q7 are connected to pin 11 of the first chip U1, and the gates of MOSFETs Q2 and Q3 are connected to pin 14 of the first chip U1, forming two sets of totem-pole circuits. When the inverter starts working, the first chip U1 and the second chip U2 of the PWM control circuit are powered on and reset, running the initialization program. The second chip U2 acquires and processes various signals through an AD converter. These signals include leakage protection signal DATA, AC fault feedback signal, etc. The AC fault feedback signal also includes short circuits and overloads in the vehicle inverter. Preferably, the second chip U2 includes multiple AD modules (analog-to-digital conversion acquisition modules). Figure 6 As shown, the initialization program first checks if the inverter is faulty. If not, the mainboard circuit outputs 220VAC. If a fault occurs, it checks if the inverter has returned to normal. If not, the output remains off, and the fault indicator light displays the fault. The program then returns to continue acquiring signals from each channel via AD converter. If the inverter returns to normal, it outputs 220VAC. This fault control process performs a check during startup; if no fault is found, the output is started. During operation, the system continuously checks for faults, and any fault will cause the vehicle inverter to stop working.

[0059] If the motherboard circuit outputs 220VAC normally, then check for overload, excessively high battery voltage, excessively low battery voltage, and / or excessively high machine temperature in sequence. If any of these conditions are present, shut down the output, display a fault indicator light, and return to continue AD acquisition of each signal. If all conditions are normal, display a normal indicator light and return to continue AD acquisition of each signal.

[0060] Furthermore, if the second chip U2 determines that the vehicle inverter is fault-free, the first chip U1 operates. Chip U1 generates a set of complementary square wave drive signals, which amplify the drive capability through two sets of totem-pole circuits (Q2, Q3 and Q5, Q7). This drives the two MOSFETs Q1 and Q5 on the main board circuit to conduct alternately, activating the DC-DC conversion section of the vehicle inverter's main board circuit. Specifically, the transformer T1 boosts the 12V DC input voltage of BT+ and BT- to 380V DC. In addition, the auxiliary power circuit also starts operating, followed by the SPWM drive circuit, which controls the DC-AC conversion section of the main board circuit to output 220V AC power.

[0061] When the PWM control circuit receives the PU-1 signal, the drive control MOSFET Q1 stops conducting, the first chip U1 stops working, there is no drive signal output, and finally the DC-DC conversion part of the motherboard circuit stops working.

[0062] By acquiring various signals through AD converters, the system can determine whether the product is in a faulty state. If a fault occurs, the product shuts down its output, thus protecting the electrical equipment and improving the safety and reliability of the vehicle inverter.

[0063] like Figure 7 As shown, the SPWM drive circuit includes a third chip U1, a first signal drive amplifier chip U3, a second signal drive amplifier chip U4, and an amplifier circuit. The third chip is an MCU, and the SPWM drive circuit is... Figure 2 The MCU control circuit and SPWM drive circuit are connected to the first signal drive amplifier chip U3 and the second signal drive amplifier chip U4, respectively. The first signal drive amplifier chip U3 and the second signal drive amplifier chip U4 are also connected to an amplifier circuit. The MCU generates two sets of H-bridge drive signals: a first drive signal and a second drive signal. The first drive signal is amplified by the first signal drive amplifier chip U3 and the amplifier circuit, respectively. The second drive signal is amplified by the second signal drive amplifier chip U4 and the amplifier circuit, respectively. This drives the four MOSFETs Q2, Q3, Q6, and Q7 in the DC-AC conversion section of the main board circuit to conduct alternately, converting the 380V DC voltage to a 220V AC voltage output. Specifically, as shown... Figure 4 As shown, the drains (D) of MOSFETs Q2 and Q7 are close to the 380V positive terminal, forming the "upper bridge," while the drains of MOSFETs Q3 and Q6 are close to ground, forming the "lower bridge." Under unipolar modulation, the Q2 and Q6 sides form the high-frequency arm (23kHz modulation wave, SPWM high-frequency sine wave), and the Q3 and Q7 sides form the low-frequency arm (50Hz square wave, PWM low-frequency square wave). The output after high and low frequency mixing and modulation is approximately a sine wave (with high-frequency components), which is then modulated by an LC circuit to become a sine wave. The direction of the alternating current changes continuously. The full-bridge circuit composed of Q2, Q3, Q6, and Q7 converts DC to AC. When Q2 and Q7 are conducting, sides 3 of the common-mode inductor T2 are positive, and sides 4 of the common-mode inductor T2 are negative. When Q3 and Q6 are conducting, the three sides of the common inductor T2 are negative, and the four sides of the common inductor T2 are positive. Alternating current is generated on both sides, and 220V AC power is output. The 220V AC power output is processed by the second EMC absorption circuit and then output to the socket for external use.

[0064] The amplifier circuit includes amplifier U2A and amplifier U2B. Amplifiers U2A and U2B amplify the SPWM and PWM signals input to the U3 and U4 driver chips via SPWM-SD and PWM-SD, respectively.

[0065] like Figure 8As shown, the vehicle inverter also includes an input connector and input line N1, a waterproof ring for the output hole and a lower housing N2, an insulating sheet N3, a waterproof ring N4, a PCB board N5, PCB board screws N6, an upper housing N7, upper and lower housing screws N8, and output lines and output connectors N9. During assembly, the insulating sheet N3 is installed at the bottom of the lower housing in the waterproof ring for the output hole and the lower housing N2; the waterproof ring N4 is installed on the four mounting edges of the lower housing in the waterproof ring for the output hole and the lower housing N2; the circuit components on the PCB board N5 are soldered; and the input lines and output lines in the input connector and input line N1 are... The output wires in output connector N9 are soldered to PCB board N5. Then, the soldered PCB board N5 is assembled onto the waterproof ring at the outlet hole and the lower shell of lower shell N2, and secured with PCB board screw N6. Next, the upper shell N7 is assembled. When assembling the upper shell N7, the input wires and output wires in input connector N1 and output connector N9 must be placed on the outlet holes of the lower shell of lower shell N2, along with the waterproof ring at the outlet hole. Finally, the upper shell N7, the waterproof ring at the outlet hole, and the lower shell of lower shell N2 are secured with upper and lower shell screws N8. Furthermore, the circuit components on PCB board N5 are the components of the various circuits described above.

[0066] Furthermore, such as Figure 9 As shown, the vehicle inverter also includes a power socket, which includes a cover C1, a connecting rod C2, a panel and an upper shell C3, an LED light C4, a PCB board C5, a lower shell C6, and connecting screws C7 between the upper and lower shells. During assembly, the cover C1 is assembled onto the upper shell via the connecting rod C2. The cover C1 is rotated and opened and closed via the connecting rod C2 as an axis. The terminals are soldered onto the PCB board C5, and the LED light C4 is fixed onto the PCB board C5. Then, the PCB board C5 is assembled into the upper shell of the panel and upper shell C3. Then, the lower shell C6 is assembled, and the upper shell C3 and the lower shell C6 are fastened together and secured with the connecting screws C7 between the upper and lower shells.

[0067] Power is drawn from the low-voltage DC 12V battery in the automotive electronic and electrical architecture, converted to AC 220V 50Hz mains power, and then output through the vehicle inverter socket to match the plugs of household appliances for customer convenience.

[0068] LED C4 is connected to the fault indicator circuit on the main board to display the operating status of the vehicle inverter. When the inverter is in a fault state, it displays different indicator states based on the different fault conditions. For example, the different fault signals and indicator light states are shown in Table 1.

[0069] Table 1 Relationship between Fault Status and Indicator Light Status

[0070]

[0071] When a fault occurs, the MCU controls the output to shut down and simultaneously controls the LEDs to display the fault status. By displaying the fault status through the LEDs, the efficiency of troubleshooting the vehicle inverter is improved, and the application reliability of the vehicle inverter is enhanced.

[0072] Furthermore, the vehicle inverter is protected according to the fault status. Specifically, regarding the output voltage: please check if the rated power of the electrical equipment is greater than 150W. If the power is greater than 150W, it cannot be used normally.

[0073] Short circuit protection: Please remove the electrical equipment, check if the equipment is damaged, and then turn the inverter back on.

[0074] Overload protection: Please check if the rated power of the electrical equipment is greater than 150W. If the power is greater than 150W, it cannot be used normally.

[0075] Over-temperature protection: If the inverter overheats, please move it to a normal temperature environment to dissipate heat before turning it on.

[0076] Overvoltage protection: Battery input overvoltage. Please check if the input battery or generator is faulty.

[0077] Undervoltage protection: The battery input voltage is low. Please start the engine to charge the battery before using it.

[0078] Leakage protection: The inverter output high voltage leakage occurs. Please check whether the inside of the inverter or the output wire is damaged or short-circuited to the vehicle body.

[0079] Inverter malfunction: After powering on, check if there is 220VAC voltage at the inverter output. If not, the inverter is damaged. Please check if the inverter input and output terminals are properly connected. If the connection is good, please replace the inverter and return it for further analysis.

[0080] 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; and 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 vehicle-mounted inverter, characterized in that, The circuit includes a power supply module, a mainboard circuit, a PWM control circuit, and an SPWM drive circuit connected in sequence. The mainboard circuit includes a DC-DC boost module and a voltage conversion module. The power supply module is connected to both the DC-DC boost module and the PWM control circuit. The PWM control circuit is also connected to the DC-DC boost module. The SPWM drive circuit is connected to both the PWM control circuit and the voltage conversion module. The power supply module is used to provide power input; The PWM control circuit includes a first chip and a second chip. The second chip is used to collect various signals from the motherboard circuit and determine whether the collected signals are normal. The first chip is used to drive the DC boost module to start working if the signals collected by the second chip are normal. The motherboard circuit is used to collect its own output voltage, output current and MOSFET temperature signals, and send them to the SPWM drive circuit. The SPWM drive circuit is used to determine whether there is a short circuit, overload, and / or excessive machine temperature in the motherboard circuit based on the output voltage, output current, and / or MOSFET temperature signal. If so, the drive voltage conversion module stops working, and the AC fault abnormality feedback signal is fed back to the PWM control circuit, causing the second chip to control the first chip to stop working, and finally causing the DC boost module to stop working.

2. The vehicle-mounted inverter according to claim 1, characterized in that, The power supply module is connected to the PWM control circuit through an ACC switch. The power supply module includes a battery, a transistor Q6, and a MOSFET Q4. When the ACC signal is turned on, the transistor Q6 is turned on, which in turn turns on the MOSFET Q4. The positive terminal of the battery can supply 14.9V power to the vehicle inverter through the MOSFET Q4. The battery is a DC 12V low-voltage battery for a low-voltage power system, wherein the DC 12V low-voltage battery for the low-voltage power system includes one of the following: flooded lead-acid battery, enhanced flooded lead-acid battery, glass fiber valve-regulated battery, lithium iron phosphate battery, ternary lithium battery, lithium manganese oxide battery, and sodium-ion battery.

3. The vehicle-mounted inverter according to claim 1 or 2, characterized in that, The motherboard circuit also includes a voltage feedback circuit, which is connected to the rectifier and filter circuit. The voltage feedback circuit is also connected to the first chip of the PWM control circuit via a closed-loop voltage regulator circuit. The voltage feedback circuit is used to collect the voltage signal after the DC boost module boosts the voltage and determine whether the voltage signal is normal. If there is overvoltage or undervoltage, it means that the battery voltage is too high or too low. Then, the PU-1 signal is output through the closed-loop voltage regulation circuit and fed back to the first chip of the PWM control circuit.

4. The vehicle-mounted inverter according to claim 3, characterized in that, The PWM control circuit also includes MOSFETs Q1, Q2, Q3, Q5, and Q7. MOSFET Q1 is connected to both the closed-loop voltage regulator circuit and the first chip. The gates of MOSFETs Q5 and Q7 are connected together and then connected to the first chip. The gates of MOSFETs Q2 and Q3 are also connected together and then connected to the first chip, forming two sets of totem-pole circuits. The PWM control circuit is also used to amplify the drive signal through two sets of totem-pole circuits using MOSFETs Q2, Q3, Q5, and Q7, thereby driving the DC boost module in the mainboard circuit; and, When the PU-1 signal is received, the drive control MOSFET Q1 stops conducting, the first chip stops working, and the DC boost module stops working.

5. The vehicle-mounted inverter according to claim 4, characterized in that, The SPWM drive circuit includes a third chip, a first signal drive amplifier chip, a second signal drive amplifier chip, and an amplifier circuit. The third chip is connected to both the first and second signal drive amplifier chips. The first and second signal drive amplifier chips are also connected to the amplifier circuit. The third chip generates a first drive signal and a second drive signal. The first drive signal is amplified by the first signal drive amplifier chip and the amplifier circuit, respectively. The second drive signal is amplified by the second signal drive amplifier chip and the amplifier circuit, respectively. The amplified first drive signal and the second drive signal drive the voltage conversion module in the motherboard circuit to work.

6. The vehicle-mounted inverter according to claim 5, characterized in that, The motherboard circuit also includes an auxiliary power supply circuit, an AC fault indication circuit, a leakage protection circuit, a fault indicator circuit, and a current feedback circuit. The auxiliary power supply circuit is connected to transformer T1 and the third chip respectively, and is used to output 15V and 5V auxiliary power to the third chip respectively; The AC fault indication circuit is connected to the second chip and the third chip respectively. The AC fault indication circuit includes a second optocoupler. When the enable signal of the third chip in the SPWM drive circuit is received, the second optocoupler triggers the AC fault abnormality feedback signal and sends it to the second chip. The fault indicator circuit is connected to the second chip in the PWM control circuit. It is used to control the fault indicator light to turn on when the second chip receives the AC fault abnormality feedback signal and the leakage protection signal. The leakage current protection circuit is used to cut off the power supply to protect the main board circuit when a leakage current protection signal is received. The current feedback circuit is connected to the negative terminal of the voltage conversion module output and the third chip respectively, and is used to collect the output current of the motherboard circuit and send it to the third chip.

7. The vehicle-mounted inverter according to claim 6, characterized in that, The motherboard circuit includes a first EMC snubber circuit and a second EMC snubber circuit, wherein... The input of the first EMC absorption circuit is connected to the power supply module via a fuse, and the output is connected to the DC boost module and the ACC switch respectively, which are used to filter the input power supply to remove noise. The input of the second EMC absorption circuit is connected to the voltage conversion module, and the output is connected to the socket. It is used to filter out the electromagnetic radiation of the output voltage of the voltage conversion module.

8. The vehicle-mounted inverter according to claim 7, characterized in that, It also includes an input connector and input cable N1, a waterproof ring for the output hole and a lower shell N2, an insulating sheet N3, a waterproof ring N4, a PCB board N5, PCB board screws N6, an upper shell N7, upper and lower shell screws N8, and an output cable and output connector N9; among which, During assembly, install the insulating sheet N3 at the bottom of the lower housing in the outlet waterproof ring and lower housing N2, and install the waterproof ring N4 on the four mounting edges of the lower housing in the outlet waterproof ring and lower housing N2. Solder the components on the PCB board N5, and solder the input wires and output wires in the input connector and input line N1 and the output wires in the output connector N9 to the PCB board N5. Then, assemble the soldered PCB board N5 onto the lower housing in the outlet waterproof ring and lower housing N2, and tighten the PCB board N5 with the PCB board screw N6. Then, assemble the upper housing N7. When assembling the upper housing N7, the input wires and output wires in the input connector and input line N1 and the output wires in the output connector N9 should be placed on the outlet holes of the lower housing in the outlet waterproof ring and lower housing N2. Then, tighten the upper housing N7 and the lower housing in the outlet waterproof ring and lower housing N2 with the upper and lower housing screws N8.

9. The vehicle-mounted inverter according to claim 8, characterized in that, It also includes a power socket, which comprises a cover C1, a connecting rod C2, a panel and upper shell C3, an LED light C4, a PCB board C5, a lower shell C6, and connecting screws between the upper and lower shells C7; among which, During assembly, the cover C1 is assembled onto the upper shell via the connecting rod C2. The cover C1 is rotated and opened and closed via the connecting rod C2 as an axis. The terminal is soldered onto the PCB board C5, and the LED light C4 is fixed onto the PCB board C5. Then, the PCB board C5 is assembled into the front panel and the upper shell C3. Next, the lower shell C6 is assembled, and the upper shell C3 and the lower shell C6 are fastened together and secured with the connecting screw C7 between the upper and lower shells.

10. The vehicle-mounted inverter according to claim 9, characterized in that, LED C4 is connected to the fault indicator circuit of the main board circuit. It is used to display the working status of the vehicle inverter and to display different indication statuses based on different fault states when there are abnormal signals in the various signals collected by the second chip.

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