Portable off-grid inverter

Abstract

The utility model provides a portable off-grid inverter which comprises a single chip microcomputer, the single chip microcomputer is connected with an LCD display circuit unit, a clock circuit unit and a voltage stabilizing circuit unit, and the voltage stabilizing circuit unit comprises a first voltage stabilizing circuit and a second voltage stabilizing circuit. Wherein the output end of the first voltage stabilizing circuit is respectively connected with the input end of the second voltage stabilizing circuit and the display screen; the output end of the second voltage stabilizing circuit is grounded and connected with the single-chip microcomputer. According to the utility model, a novel inverter circuit layout scheme is provided, so that the length and width of the inverter are both less than 10cm, the size of the inverter is greatly reduced, and the inverter has the advantages of compact structure and small size.

Description

Technical Field

[0001] The utility model belongs to the technical field of inverters, and particularly relates to an off-grid inverter which is easy to carry. Background Art

[0002] An off-grid inverter, also called a stand-alone inverter or self-contained inverter, is a power conversion device used to convert direct current (DC) power to alternating current (AC) power in order to provide power to an independent system that is not connected to the main power grid.

[0003] An off-grid inverter accepts DC power from a battery bank, solar panel, or other DC energy source and converts it to AC power through electronic circuits inside.

[0004] The inverter is usually composed of a DC input power supply, an inverter circuit, and an output filter circuit. The logic control principle of the inverter is to generate the required AC waveform by controlling the switching state of the switching devices in the inverter circuit to achieve the conversion of DC power to AC power. This process requires the use of high-frequency switching elements (such as transistors or MOSFETS); their complex structure makes the existing inverters large and inconvenient to carry.

[0005] In view of this, how to solve the defects existing in the above technical solutions has become one of the problems to be solved urgently in the field of inverter technology. Utility Model Content

[0006] In view of the problems existing in the background technology, the purpose of the present invention is to overcome the shortcomings of the prior art and provide a portable off-grid inverter to solve the problem that the existing inverter needs to involve a large number of switching elements (such as transistors MOSFETS) in the process of converting direct current into alternating current; the structure is complex, resulting in the existing inverter being large in size and inconvenient to carry.

[0007] The utility model is implemented by the following technical solutions. The utility model discloses a portable off-grid inverter, comprising:

[0008] Single chip microcomputer;

[0009] An LCD display circuit unit is connected to the single chip microcomputer, wherein the LCD display circuit unit includes a display screen;

[0010] A clock circuit unit, connected to the single chip microcomputer;

[0011] It is characterized by further comprising:

[0012] A debugging unit is connected to the single-chip microcomputer and is provided with a program download interface; two sets of SPWM signals are provided to the single-chip microcomputer via the program download interface;

[0013] A voltage stabilizing circuit unit; the voltage stabilizing circuit unit comprises a first voltage stabilizing circuit,

[0014] The voltage stabilizing circuit unit further includes a second voltage stabilizing circuit, wherein

[0015] The output end of the first voltage stabilizing circuit is respectively connected to the input end of the second voltage stabilizing circuit and the display screen;

[0016] The output end of the second voltage stabilizing circuit is respectively connected to the ground and the single chip microcomputer;

[0017] A direct current power supply unit, connected to the voltage stabilizing circuit unit and the amplifying driving circuit unit, respectively, to supply power to the voltage stabilizing circuit unit;

[0018] The amplifying driving circuit unit is connected to the inverter circuit unit, the inverter circuit unit is connected to the AC voltage measuring circuit unit, and is connected to the single chip microcomputer through the AC voltage measuring circuit unit.

[0019] Optionally, the first voltage stabilizing circuit includes a three-terminal voltage stabilizer.

[0020] The first voltage stabilizing circuit further includes a diode D2 and a capacitor C4, and the capacitor E1 is connected in parallel across the voltage stabilizing diode D2.

[0021] Optionally, the second voltage stabilizing circuit includes a three-terminal linear regulator.

[0022] The second voltage stabilizing circuit further includes a voltage stabilizing diode D3 and a capacitor C5, and a resistor R5 and an LED lamp are connected to the circuit close to the capacitor C5, and the output end of the LED lamp is grounded;

[0023] The circuit branch arranged between the first voltage stabilizing circuit and the second voltage stabilizing circuit is connected to the USB1 port and the USB2 port respectively.

[0024] Optionally, the amplifying driving circuit unit includes a dual operational amplifier, a diode D13 and a diode D14, and the diode D13 and the diode D14 are respectively connected to two low-voltage SPWM1 and SPWM2 pins generated by the single-chip microcomputer;

[0025] The amplifying driving circuit unit further includes a resistor R13, a resistor R14, a resistor R22 and a resistor R21, and the resistor R13 is connected to the IN1+ pin of the dual operational amplifier, wherein one end of the resistor R14 is grounded;

[0026] The resistor R21 is connected to the IN2+ pin of the dual operational amplifier, and the resistor R22 is grounded.

[0027] Optionally, the IN2- pins of the dual operational amplifier are connected to resistor R19 and resistor R20 respectively;

[0028] The IN1-pins of the dual operational amplifier are connected to resistors R17 and R18 respectively;

[0029] The other end of the resistor R18 is connected to the pin OUT1 of the dual operational amplifier, and the other end of the resistor R19 is connected to the pin OUT2 of the dual operational amplifier, so that a negative feedback circuit is formed in the amplifying driving circuit unit.

[0030] Optionally, the other end of the dual operational amplifier OUT2 pin is connected to the resistor R15 of the inverter circuit unit;

[0031] The other end of the pin OUT1 of the dual operational amplifier is connected to the resistor R16 of the inverter circuit unit.

[0032] Optionally, the inverter circuit unit includes an LC filter circuit, the LC filter circuit includes a MOS tube N1 and a resistor R7, the MOS tube N1 is connected to the resistor R15, and

[0033] The two ends of the MOS tube N1 are connected in parallel with a resistor R9 and a capacitor C6, and

[0034] One end is connected to pin 1 of the inverter.

[0035] Optionally, the LC filter circuit further includes a MOS tube N2 and a resistor R6, and

[0036] Connect the inverter to pin 3, and

[0037] The other end of the resistor R6 is grounded; and

[0038] The two ends of the MOS tube N2 are connected in parallel with a resistor R910 and a capacitor C7.

[0039] Optionally, pin 5 of the inverter is connected to a rectifier bridge circuit unit, and

[0040] The rectifier bridge circuit unit is composed of a diode D6, a diode D7, a diode D4 and a diode D5, a group of leads are drawn out from the circuit of the diode D4 and the diode D5 to connect the capacitor C8, the two ends of the capacitor C8 are connected in parallel with the capacitor E3, and the other end of the capacitor E3 is connected to the resistor R11 of the AC voltage measurement unit 40;

[0041] The voltage output end of the diode D6 is connected to the pin 1 of the power transformer P1, and the pin 2 of the power transformer P1 is connected to the pin 4 of the inverter.

[0042] Optionally, the other end of the resistor R11 is connected to the resistor R12 and the single chip computer 60 respectively, and the other end of the resistor R12 is grounded.

[0043] The two ends of the resistor R12 are connected in parallel with a diode D8.

[0044] In summary, the beneficial effects of the utility model are:

[0045] (1) The utility model provides a new inverter circuit layout scheme to replace the use of transistors or MOSFETS, so that the length and width of the inverter of the utility model are less than 10 cm, thereby greatly reducing the size of the inverter, and having the advantages of compact structure and small size.

[0046] (2) The utility model connects a group of LED lights in series on the branch of the second voltage stabilization circuit. When the three-terminal linear voltage regulator is operating normally, the LED lights light up and emit red light, thus serving as a warning.

[0047] (3) The debugging pin (SWDIO) of the single-chip microcomputer of the utility model is connected to the debugging pin (SWDIO) of the debugging unit, and a program download interface is provided; two sets of SPWM signals are provided to the single-chip microcomputer through the program download interface, and the resistor R18 and the resistor R19 are both circuits between the IN pin of the dual operational amplifier and the OUT pin of the dual operational amplifier, forming a negative feedback circuit in the dual operational amplifier, and when the two low-voltage SPWM signals generated enter the dual operational amplifier, two high-voltage SPWM signals can be output; thereby replacing the existing off-grid inverter using a dedicated integrated circuit to generate SPWM signals, the circuit layout is optimized, and the size of the off-grid inverter is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 A circuit diagram provided for an embodiment of a portable off-grid inverter of the utility model;

[0049] Figure 2 For the utility model Figure 1 The inverter circuit diagram shown in;

[0050] Figure 3 For the utility model Figure 2 The LC filter circuit diagram shown in;

[0051] Figure 4 For the utility model Figure 1 The amplifying driving circuit unit diagram shown in ;

[0052] Figure 5 For the utility model Figure 1 The voltage stabilizing circuit unit diagram shown in .

[0053] Reference numerals:

[0054] 10. LCD display circuit unit;

[0055] 20. Clock circuit unit;

[0056] 30. Program download interface;

[0057] 40. AC voltage measurement circuit unit;

[0058] 50. Inverter circuit unit;

[0059] 60. Single chip microcomputer;

[0060] 70. Debugging unit;

[0061] 80. A first voltage stabilizing circuit;

[0062] 90. A second voltage stabilizing circuit;

[0063] 100. an amplifying driving circuit unit;

[0064] 110. Voltage stabilizing circuit unit;

[0065] 130. Display screen;

[0066] 140. DC power supply unit. DETAILED DESCRIPTION

[0067] In the description of this specification, the description with reference to the terms "certain embodiments", "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0068] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0069] In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. Although exemplary embodiments are disclosed in the accompanying drawings, it should be understood that the utility model can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to facilitate a thorough understanding of the utility model and to fully convey the concept of the utility model to those skilled in the art.

[0070] The utility model is mainly used in areas without access to the public power grid, such as remote areas, mobile facilities, backup power systems, mobile phone charging and renewable energy systems.

[0071] See also Figures 1 to 5 As shown, an embodiment of the utility model provides a portable off-grid inverter, including a single-chip microcomputer 60, wherein the single-chip microcomputer 60 is respectively connected to an LCD display circuit unit 10, a clock circuit unit 20 and a voltage stabilizing circuit unit 110, wherein the clock circuit unit 20 is connected to an OSCIN pin and an OSCOUT pin of the single-chip microcomputer 60; the LCD display circuit unit 10 includes a display screen 130, and information is displayed through the display screen 130, and the display screen 130 is preferably a KD display screen;

[0072] The DC power supply unit 140 supplies power to the voltage stabilizing circuit unit 110. The DC power supply unit 140 uses a 12V DC power supply.

[0073] The voltage stabilizing circuit unit 110 includes a first voltage stabilizing circuit 80 and a second voltage stabilizing circuit 90, wherein the output end of the first voltage stabilizing circuit 80 is connected to the input end of the second voltage stabilizing circuit 90 and the display screen 130 respectively;

[0074] The output terminals of the second voltage stabilizing circuit 90 are respectively connected to the ground and the single chip microcomputer 60 .

[0075] Furthermore, the output port of the DC power supply unit 140 is connected to the amplifying driving circuit unit 100, and is connected to the inverter circuit unit 50 through the amplifying driving circuit unit 100. The output end of the inverter circuit unit 50 is connected to the AC voltage measuring circuit unit 40, and is connected to the single-chip microcomputer through the AC voltage measuring circuit unit 40.

[0076] The amplifying driving circuit unit 100 further includes a diode D13 and a diode D14, and the diode D13 and the diode D14 are respectively connected to two low-voltage SPWM1 and SPWM2 pins generated by the single-chip microcomputer 60;

[0077] Furthermore, the first voltage stabilizing circuit 80 includes a three-terminal voltage regulator, and the three-terminal voltage regulator adopts a 5V 7805 three-terminal voltage regulator, the input and output terminals of the three-terminal voltage regulator are respectively connected to a voltage stabilizing diode D2 and a capacitor C4, and capacitor E1 is connected in parallel at both ends of the voltage stabilizing diode D2.

[0078] In this embodiment, 12V DC power is input through the DC power supply unit. At this time, the 12V DC power passes through the first voltage stabilizing circuit, so that the output voltage of the first voltage stabilizing circuit is 5V, so that it supplies power to the display screen.

[0079] In this embodiment, since the first voltage stabilizing circuit 80 will generate a certain degree of voltage fluctuation and high-frequency noise during actual operation, the low-pass filtering characteristics of capacitor E1 are utilized. When the voltage change in capacitor E1 is small, the electric energy charged and discharged will be much smaller than the electric energy in the first DC power supply unit, thereby suppressing high-frequency noise and voltage fluctuation; the circuit is filtered and noise reduced by connecting capacitor E1 in parallel across the voltage stabilizing diode D2.

[0080] Furthermore, the second voltage stabilizing circuit 90 includes a three-terminal linear regulator, which is preferably a 3.3V AMS117 three-terminal linear regulator, and the input and output ends of the three-terminal linear regulator are respectively connected to a voltage stabilizing diode D3 and a capacitor C5, and a resistor R5 and an LED lamp are connected to the circuit close to the capacitor C5, and the output end of the LED lamp is grounded.

[0081] In actual application, the 5V DC output by the first voltage stabilizing circuit passes through the second voltage stabilizing circuit to make its output voltage 3.3V, so that it supplies power to the microcontroller 60; the output voltages are both stable DC voltages through the first voltage stabilizing circuit 80 and the second voltage stabilizing circuit 90.

[0082] In this embodiment, by connecting a group of LED lights in series on the branch of the second voltage stabilizing circuit 90, when the three-terminal linear voltage regulator is operating normally, the LED lights will light up and emit red light, thus serving as a warning.

[0083] Furthermore, the circuit branch arranged between the first voltage stabilizing circuit 80 and the second voltage stabilizing circuit 90 is connected to the USB1 port and the USB2 port respectively; specifically,

[0084] The circuit branch arranged between the first voltage stabilizing circuit 80 and the second voltage stabilizing circuit 90 is connected to the diode D10 and the diode D11 respectively, and the output ends of the diode D10 and the diode D11 are connected to the USB1 port and the USB2 port respectively; then the 5V power supply output by the first voltage stabilizing circuit 80 is used to power the USB1 port and the USB2 port.

[0085] See also Figure 1As shown, the debugging unit 70 is provided with four groups of pins, wherein the SWDCLK pin is connected to the SWDCLK pin of the single-chip microcomputer, and the other two groups of pins are grounded and connected to the 3V3 port respectively; the debugging pin (SWDIO) of the single-chip microcomputer is connected to the debugging pin (SWDIO) of the debugging unit 70, and the program download interface 30 is connected to the circuit branch connecting the SWDCLK pin of the debugging unit and the SWDCLK pin of the single-chip microcomputer; the program is input through the program download interface 30 to provide two groups of SPWM signals for the single-chip microcomputer.

[0086] In this embodiment, the debugging pin (SWDIO) of the single-chip microcomputer is connected to the debugging pin (SWDIO) of the debugging unit 70, and a program download interface 30 is provided; two sets of SPWM signals are provided to the single-chip microcomputer through the program download interface 30, replacing the existing off-grid inverter using a dedicated integrated circuit to generate SPWM signals, thereby optimizing its circuit layout and reducing the size of the off-grid inverter.

[0087] The amplifying driving circuit unit 100 includes a dual operational amplifier, and the dual operational amplifier is preferably a LM358 dual operational amplifier.

[0088] The amplifying driving circuit unit 100 further includes a diode D13 and a diode D14, and the diode D13 and the diode D14 are respectively connected to two low-voltage SPWM1 and SPWM2 pins generated by the single-chip microcomputer 60;

[0089] The output end of the diode D13 is connected to the resistor R13, and is connected to the IN1+ pin of the dual operational amplifier through the resistor R13;

[0090] A resistor R14 is connected to the circuit branch between the diode D13 and the resistor R13, and the other end of the resistor R14 is grounded;

[0091] The output end of the diode D14 is connected to the resistor R21, and is connected to the IN2+ pin of the dual operational amplifier through the resistor R21;

[0092] A resistor R22 is connected to the circuit branch between the diode D14 and the resistor R21, and the other end of the resistor R22 is grounded.

[0093] Furthermore, the IN2- pins of the dual operational amplifier are respectively connected to resistor R19 and resistor R20, and the other end of the resistor R20 is grounded, the other end of the resistor R19 is connected to the OUT2 pin of the dual operational amplifier, and the other end of the dual operational amplifier OUT2 is connected to the resistor R15 of the inverter circuit unit 50.

[0094] Furthermore, the IN1-pin of the dual operational amplifier is respectively connected to resistor R17 and resistor R18, and the other end of the resistor R17 is grounded, and the other end of the resistor R18 is connected to the dual operational amplifier OUT1 pin; and the other end of the dual operational amplifier OUT1 pin is connected to the resistor R16 of the inverter circuit unit 50.

[0095] In this embodiment, the resistor R18 and the resistor R19 are both circuits between the IN pin of the dual operational amplifier and the OUT pin of the dual operational amplifier, forming a negative feedback circuit in the dual operational amplifier, so that OUT2 / IN2=R19 / R20; OUT1 / IN1=R18 / R17; when the two low-voltage SPWM signals generated enter the dual operational amplifier, two high-voltage SPWM signals can be output.

[0096] Furthermore, the pin VCC of the dual operational amplifier is connected to the DC power supply unit 140. In this embodiment, the amplification drive circuit unit provides 12V DC power to the MOS tube of the inverter circuit unit 50 to control the on-off of the circuit.

[0097] See also Figure 2 and Figure 3 As shown, the inverter circuit unit 70 includes an LC filter circuit, and the LC filter circuit includes a MOS tube N1. The MOS tube N1 is connected to the resistor R15 to realize the connection between the LC filter circuit and the amplifying drive circuit unit OUT2, thereby ensuring that the MOS tube N1 is driven by the amplifying drive circuit unit OUT2.

[0098] Furthermore, a resistor R7 is connected to the circuit between the MOS tube N1 and the resistor R15, and the other end of the resistor R7 is grounded; and a resistor R9 and a capacitor C6 are connected in parallel at both ends of the MOS tube N1, and one end of each is connected to the pin 1 of the inverter; and the pin 2 of the inverter is input with 12V;

[0099] And the pin 3 of the inverter is connected to the MOS tube N2.

[0100] The LC filter circuit further includes a MOS transistor N2, and the MOS transistor N2 is connected to the amplifying driving circuit unit OUT1 through a resistor R16, thereby ensuring that the driving amplifying circuit OUT1 drives the MOS transistor N2;

[0101] A resistor R6 is connected to the circuit between the MOS tube N2 and the resistor R16, and the other end of the resistor R6 is grounded; and two ends of the MOS tube N2 are connected in parallel with a resistor R910 and a capacitor C7.

[0102] In this embodiment, the MOS transistor N2 is driven by the driving amplifier circuit OUT1; the MOS transistor N1 is driven by the amplifying driving circuit unit OUT2, thereby ensuring that a 12V sine wave voltage is generated at the left end of the inverter.

[0103] Pin 5 of the inverter is connected to a rectifier bridge circuit unit, and the rectifier bridge circuit unit is composed of four groups of diodes, namely: diode D6, diode D7, diode D4 and diode D5; a group of leads are drawn out from the circuit located between the diode D4 and the diode D5 to connect to capacitor C8, and the other end is connected to the circuit located between the diode D6 and the diode D7; capacitor E3 is connected in parallel at both ends of the capacitor C8, and the other end of the capacitor E3 is connected to the resistor R11 of the AC voltage measuring unit 40, and is connected to the single-chip microcomputer through the AC voltage measuring unit 40.

[0104] Furthermore, the voltage output end of the diode D6 is connected to the pin 1 of the power transformer P1, and the pin 2 of the power transformer P1 is connected to the pin 4 of the inverter.

[0105] In this embodiment, the resistors (R6, R7, R9, R10, R15, R16) used in the inverter circuit unit 70 are protection circuits. By adding resistors, excessive current is prevented from being generated in the inverter circuit unit, the service life of components is increased, and damage to components is prevented;

[0106] The capacitors (C6, C7, E3, C8) used in the inverter circuit unit 70 are all filter capacitors. The capacitors (C6, C7) ensure the output of a sine wave and reduce interference. The capacitors (E3, C8) ensure the output of a stable DC voltage.

[0107] Those skilled in the art should be able to understand that the utility model produces a 220V DC voltage through a rectifier bridge circuit unit and capacitors C8 and E3 at the right end of the inverter, and inputs it into the single-chip microcomputer through an AC voltage measurement unit.

[0108] The other end of the resistor R11 is connected to the resistor R12 and the single chip computer 60 respectively, and the other end of the resistor R12 is grounded.

[0109] The two ends of the resistor R12 are connected in parallel with a diode D8, thereby reducing the equivalent resistance of the diode D8.

[0110] Those skilled in the art should be able to understand that the existing off-grid inverter involves the use of high-frequency switching elements (such as transistors or MOSFETS) and control logic to generate the required AC waveform in the process of converting DC power into AC power; its structure is complex, resulting in a large volume. The length and width of the existing off-grid inverter are both greater than 20cm, making it inconvenient to carry. To this end, the utility model provides 5V and 3.3V power supplies respectively by adding two voltage stabilizing circuits; wherein the 3.3V DC voltage provided by the second voltage stabilizing circuit 90 directly supplies power to the single-chip microcomputer 60; the 5V DC voltage provided by the first voltage stabilizing circuit 80 directly supplies power to the display screen; and the single-chip microcomputer provides two spwm signals through the program, replacing the existing method of providing spwm signals through integrated circuits. In this embodiment, the MOS tube of the inverter circuit unit is powered by the amplifying driving circuit unit to control the on and off of the circuit, and the driving MOS tube ensures that the left end of the transformer generates a 12V sine wave voltage, and at the same time, a 220V DC voltage is generated at the right end of the inverter through a rectifier bridge and a filter capacitor, thereby supplying power to the electrical appliances. In actual application, whether the single chip microcomputer is started or not is controlled by a key signal (this is the existing technology and will not be described in detail here).

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model and are not restrictive. Although the utility model is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solution of the utility model does not deviate from the spirit and scope of the technical solution of the utility model, and should be included in the scope of the claims of the utility model.

Claims

1. A portable off-grid inverter, characterized in that: include: Single chip microcomputer; An LCD display circuit unit is connected to the single chip microcomputer, wherein the LCD display circuit unit includes a display screen; A clock circuit unit, connected to the single chip microcomputer; It is characterized by further comprising: A debugging unit is connected to the single-chip microcomputer and is provided with a program download interface; two sets of SPWM signals are provided to the single-chip microcomputer via the program download interface; A voltage stabilizing circuit unit; the voltage stabilizing circuit unit comprises a first voltage stabilizing circuit, The voltage stabilizing circuit unit further includes a second voltage stabilizing circuit, wherein The output end of the first voltage stabilizing circuit is respectively connected to the input end of the second voltage stabilizing circuit and the display screen; The output end of the second voltage stabilizing circuit is respectively connected to the ground and the single chip microcomputer; A direct current power supply unit, connected to the voltage stabilizing circuit unit and the amplifying driving circuit unit, respectively, to supply power to the voltage stabilizing circuit unit; The amplifying driving circuit unit is connected to the inverter circuit unit, the inverter circuit unit is connected to the AC voltage measuring circuit unit, and is connected to the single chip microcomputer through the AC voltage measuring circuit unit.

2. The portable off-grid inverter according to claim 1, characterized in that: The first voltage stabilizing circuit comprises a three-terminal voltage stabilizer. The first voltage stabilizing circuit further includes a diode D2 and a capacitor C4, and the capacitor E1 is connected in parallel across the voltage stabilizing diode D2.

3. The portable off-grid inverter according to claim 1, characterized in that: The second voltage stabilizing circuit includes a three-terminal linear voltage regulator. The second voltage stabilizing circuit further includes a voltage stabilizing diode D3 and a capacitor C5, and a resistor R5 and an LED lamp are connected to the circuit close to the capacitor C5, and the output end of the LED lamp is grounded; The circuit branch arranged between the first voltage stabilizing circuit and the second voltage stabilizing circuit is connected to the USB1 port and the USB2 port respectively.

4. The portable off-grid inverter according to claim 1, characterized in that: The amplifying driving circuit unit includes a dual operational amplifier, a diode D13 and a diode D14, and the diode D13 and the diode D14 are respectively connected to two low-voltage SPWM1 and SPWM2 pins generated by the single-chip microcomputer; The amplifying driving circuit unit further includes a resistor R13, a resistor R14, a resistor R22 and a resistor R21, and the resistor R13 is connected to the IN1+ pin of the dual operational amplifier, wherein one end of the resistor R14 is grounded; The resistor R21 is connected to the IN2+ pin of the dual operational amplifier, and the resistor R22 is grounded.

5. The portable off-grid inverter according to claim 4, characterized in that: The IN2- pins of the dual operational amplifier are connected to resistors R19 and R20 respectively; The IN1-pins of the dual operational amplifier are connected to resistors R17 and R18 respectively; The other end of the resistor R18 is connected to the OUT1 pin of the dual operational amplifier, and the other end of the resistor R19 is connected to the OUT2 pin of the dual operational amplifier, so that a negative feedback circuit is formed in the amplifying driving circuit unit.

6. The portable off-grid inverter according to claim 5, characterized in that: The other end of the dual operational amplifier OUT2 pin is connected to the resistor R15 of the inverter circuit unit; The other end of the dual operational amplifier OUT1 pin is connected to the resistor R16 of the inverter circuit unit.

7. The portable off-grid inverter according to claim 1, characterized in that: The inverter circuit unit includes an LC filter circuit and a capacitor C8. The LC filter circuit includes a MOS tube N1 and a resistor R7. The MOS tube N1 is connected to the resistor R15. The two ends of the MOS tube N1 are connected in parallel with a resistor R9 and a capacitor C6, and One end is connected to pin 1 of the inverter.

8. The portable off-grid inverter according to claim 7, characterized in that: The LC filter circuit also includes a MOS tube N2 and a resistor R6, and Connect the inverter to pin 3, The other end of the resistor R6 is grounded; and The two ends of the MOS tube N2 are connected in parallel with a resistor R910 and a capacitor C7.

9. The portable off-grid inverter according to claim 7, characterized in that: Pin 5 of the inverter is connected to the rectifier bridge circuit unit, and The rectifier bridge circuit unit is composed of a diode D6, a diode D7, a diode D4 and a diode D5.

10. The portable off-grid inverter according to claim 9, characterized in that: The two ends of the capacitor C8 are connected in parallel with the capacitor E3, and the other end of the capacitor E3 is connected to the resistor R11 of the AC voltage measurement unit 40; The voltage output end of the diode D6 is connected to the pin 1 of the power transformer P1, and the pin 2 of the power transformer P1 is connected to the pin 4 of the inverter; The other end of the resistor R11 is connected to the resistor R12 and the single chip microcomputer respectively, and the two ends of the resistor R12 are connected in parallel with a diode D8.

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