Auxiliary power supply circuit system of photovoltaic inverter

Abstract

The invention belongs to the technical field of photovoltaic inverters, and discloses a photovoltaic inverter auxiliary power supply circuit system, which comprises a BAT auxiliary power supply circuit, a high-voltage auxiliary power supply circuit, a PV micro auxiliary power supply circuit and a switching circuit, and is characterized in that the PV micro auxiliary power supply circuit is electrically connected with and controls the switching circuit, the switching circuit is electrically connected with the high-voltage auxiliary power supply circuit, and the switching circuit is electrically connected with the high-voltage auxiliary power supply circuit. The high-voltage auxiliary power supply circuit is electrically connected with the BAT auxiliary power supply circuit, the high-voltage auxiliary power supply circuit reduces the voltage of a photovoltaic panel or the voltage of an alternating-current power grid and outputs the voltage and activates and starts the BAT auxiliary power supply circuit under the cooperation of the switching circuit, the PV micro auxiliary source is designed to have a minimum power capacity, and the high-voltage auxiliary power supply circuit is designed to have a small power capacity; according to the invention, the high-voltage-to-low-voltage auxiliary power supply for the voltage of the photovoltaic panel and the voltage of the alternating-current power grid is combined into one through switching circuit multiplexing, so that the circuit is simpler, the total power capacity of the auxiliary power supply is reduced, and the component specification, the circuit size, the weight and the like are designed to be smaller.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic inverters, and more specifically, relates to an auxiliary power supply circuit system of a photovoltaic inverter. Background Art

[0002] High-voltage photovoltaic input voltage (such as 100V-400Vdc) is the mainstream input parameter configuration requirement for small photovoltaic inverters on the market. Its main circuit structure is that the photovoltaic PV input voltage is boosted by the Boost circuit to transmit solar energy to the inverter bus, and the inverter converts the DC bus voltage into AC output voltage through the H-bridge and other inverter circuits. When the AC grid voltage is input to the inverter, the inverter can switch to the bypass state to directly transmit the grid energy to the load. When the inverter and battery pack are in sleep mode or shut down due to low power, when a call is received from any input port of the photovoltaic voltage or the grid voltage, the inverter and the battery pack need to be activated to automatically enter the charging state to store energy or convert energy to transmit to the load.

[0003] To achieve this activation function, the existing general solution is: design three DC-DC isolation circuits respectively, one PV auxiliary power supply (usually called: PV auxiliary source) is used to convert the energy of PV input into a DC voltage (such as 24Vdc) to supply the BAT auxiliary power supply circuit as input (that is, the auxiliary power supply at the battery end, an isolated DC-DC power supply circuit, which is used to isolate and convert the battery voltage or other DC input voltage to output 12V, 5V, 3.3V and other voltages to supply the inverter functional circuits to achieve the purpose of activating the system), and the other AC auxiliary power supply (usually called: AC auxiliary source) is used to convert the energy of the AC input port, and its purpose and utility are the same as those of the PV auxiliary power supply.

[0004] However, this solution has the following problems: First, the PV auxiliary power supply and AC auxiliary power supply in this solution have common circuit characteristics, both of which are high-voltage isolation conversion and low-voltage output, with similar input ranges and consistent output voltages. The hardware device selection and parameter design are basically the same, and the design is redundant, occupying circuit board space and wasting material costs; Second, in the existing solution, the above three DC-DC power supply circuits are a "2+1" pyramid-shaped stacking structure, and each auxiliary power supply needs to be designed with a larger power capacity to achieve full power load (that is, the output power of the PV and AC auxiliary power supplies must meet the load of the BAT auxiliary power supply circuit. For example: If the BAT auxiliary power supply circuit requires a 50W power output design, then the PV auxiliary power supply and AC auxiliary power supply must be designed and selected according to a 60W output power, and a total auxiliary power supply with a power capacity of 170W needs to be designed), the device cost is high, and the reactive power loss is large, which wastes resources and energy.

[0005] To this end, the present invention provides a photovoltaic inverter auxiliary power supply circuit system. Summary of the invention

[0006] In view of the above-mentioned defects and shortcomings of the existing technology, a circuit design scheme with high efficiency, simplicity and cost advantage is needed. The object of the present invention is to provide a photovoltaic inverter auxiliary power supply circuit system.

[0007] The purpose of the present invention can be achieved by the following technical solutions: A photovoltaic inverter auxiliary power supply circuit system, comprising a BAT auxiliary power supply circuit, a high-voltage auxiliary power supply circuit, a PV micro-auxiliary power supply circuit and a switching circuit, wherein the PV micro-auxiliary power supply circuit is electrically connected to and controls the switching circuit, the switching circuit is electrically connected to the high-voltage auxiliary power supply circuit, and the high-voltage auxiliary power supply circuit is electrically connected to the BAT auxiliary power supply circuit; It also includes a BAT port, a PV port, an AC input port and an AC output port. The BAT auxiliary power supply circuit is electrically connected to the battery through the BAT port. The PV micro auxiliary power supply circuit is connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is also connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is connected to the AC grid voltage Vac through the AC input port. The high-voltage auxiliary power supply circuit, in coordination with the switching circuit, steps down the photovoltaic panel voltage Vpv or the AC grid voltage Vac to output Vdc, and activates and starts the BAT auxiliary power supply circuit.

[0008] As a further preferred technical solution of the present invention, the PV micro-auxiliary power supply circuit is provided with a control chip U1, and the control chip U1 has a built-in MOS tube and a feedback loop. The control chip U1 has at least 8 pins, and pins 5 to 8 of the control chip U1 are drains of the built-in MOS, pins 1 to 2 of the control chip U1 are GND grounded, pin 3 of the control chip U1 is an NC floating pin, and pin 4 of the control chip U1 is the VDD working voltage.

[0009] As a further preferred technical solution of the present invention, the PV port is provided with a connection terminal PV+ and a connection terminal PV-; Pins 5 to 8 of the control chip U1 are connected to terminal PV+, and pins 5 to 8 of the control chip U1 are also electrically connected to capacitor CE2, and pin 4 of the control chip U1 is electrically connected to diode D1, and pin 4 of the control chip U1 is electrically connected to capacitor C1, and pins 1 to 2 of the control chip U1 are electrically connected to each other, and pins 1 to 2 of the control chip U1 are electrically connected to inductor L1, and pins 1 to 2 of the control chip U1 are also electrically connected to diode D2, and capacitor C1 is also electrically connected to diode D2 and inductor L1, and diode D1 is also electrically connected to inductor L1 and capacitor CE1, and capacitor CE1, diode D2 and capacitor CE2 are electrically connected to each other and connected to terminal PV-; The control chip U1 and its surrounding electronic devices form a high-voltage BUCK circuit to convert the photovoltaic panel PV voltage and output the VCC1 voltage to the switching circuit.

[0010] As a further preferred technical solution of the present invention, the switching circuit is provided with a relay RY1, the relay RY1 is provided with at least 8 pins, a coil is provided between pins 1 and 8 of the relay RY1, pin 1 of the relay RY1 is electrically connected to the wiring point D of the MOS tube Q1, pin 8 of the relay RY1 is electrically connected to the resistor R1, the resistor R1 is electrically connected to the resistor R2, one end of the resistor R2 is electrically connected to the wiring point S of the MOS tube Q1, the other end of the resistor R2 is electrically connected to the wiring point G of the MOS tube Q1, the resistor R2 is connected in parallel with the capacitor C2, and the resistor R1 is connected to the VCC1 voltage.

[0011] As a further preferred technical solution of the present invention, the AC input port is provided with a connection terminal AC-L and a connection terminal AC-N; Pins 3 and 6 of the relay RY1 are common terminals of the relay, the pin 3 is electrically connected to the terminal V1-, the pin 6 is electrically connected to the terminal V1+, a capacitor EC1 is electrically connected between the terminal V1- and the terminal V1+, the pin 7 of the relay RY1 is connected to the terminal PV+, the pin 2 of the relay RY1 is connected to the terminal PV-, the pins 4 and 5 of the relay RY1 are both electrically connected to the rectifier bridge REC1, the rectifier bridge REC1 is electrically connected to the terminal AC-N, the rectifier bridge REC1 is also electrically connected to the fuse F1, and the fuse F1 is electrically connected to the terminal AC-L; The switching circuit converts the AC grid voltage Vac connected to the AC-N terminal and the AC-N terminal into a high-voltage DC voltage Vrec after being rectified by the rectifier bridge REC1. Vrec= Vac, the switching circuit outputs high-voltage direct current V1 to the high-voltage auxiliary power supply circuit through the wiring terminal V1- and the wiring terminal V1+, V1=Vpv or Vrec.

[0012] As a further preferred technical solution of the present invention, the high-voltage auxiliary power supply circuit is a flyback isolated DC-DC power supply circuit, which is used to isolate and convert the high-voltage direct current V1 into a low-voltage direct current voltage Vdc, and supply the direct current voltage Vdc to the BAT auxiliary power supply circuit. The high-voltage auxiliary power supply circuit is composed of a control chip, a terminal, a resistor, a MOS tube, a transformer, a voltage regulator diode, a transistor, a capacitor and a diode electrically connected.

[0013] As a further preferred technical solution of the present invention, the high-voltage auxiliary power supply circuit is provided with a control chip U2, and the control chip U2 is provided with a plurality of groups of pins. The control chip U2 is electrically connected to the terminal V1- through the pins, and the control chip U2 is electrically connected to the resistor R7 through the pins. The control chip U2 is also electrically connected to the MOS tube Q3 through the pins. Specifically, the control chip U2 is electrically connected to the wiring point G of the MOS tube Q3 through the pins, and one pin of the control chip U2 is the VDD working voltage. The resistor R7 is also electrically connected to the wiring point S of the MOS tube Q3, and the wiring point of the MOS tube Q3 is electrically connected to the transformer TX1. Specifically, the wiring point of the MOS tube Q3 is electrically connected to the winding taps 5 and 6 of the transformer TX1; The winding taps 5 and 6 of the transformer TX1 are also electrically connected to the terminal V1+, and the terminal V1+ is electrically connected to the resistor R4 and the resistor R5 respectively. The resistor R4, the resistor R3, the resistor R6, the Zener diode ZD1 and the Zener diode ZD2 are connected in series in sequence, the resistor R5 is electrically connected to the transistor Q2, the Zener diode ZD1 and the Zener diode ZD2 are electrically connected to the transistor Q2, the transistor Q2 is also electrically connected to the capacitor C3, the Zener diode ZD2 is also electrically connected to the capacitor C3, one end of the capacitor C3 is electrically connected to the winding taps 8 and 10 of the transformer TX1, the other end of the capacitor C3 is electrically connected to the diode D5, the diode D5 is also electrically connected to the winding taps 8 and 10 of the transformer TX1, the transistor Q2 and the capacitor C3 are electrically connected to the pin VDD, and the Zener diode ZD2 and the capacitor C3 are electrically connected to the terminal V1-.

[0014] As a further preferred technical solution of the present invention, the BAT port is provided with a wiring terminal BAT+ and a wiring terminal BAT-, and the voltage of the BAT port is Vbat; One end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the diode D3, the other end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the capacitor EC2, the diode D3 is electrically connected to the other end of the capacitor EC2, one end of the capacitor EC2 is electrically connected to the diode D4, the other end of the capacitor EC2 is electrically connected to the BAT auxiliary power supply circuit, the other end of the diode D4 is electrically connected to the BAT auxiliary power supply circuit, Vbat is connected between the diode D4 and the BAT auxiliary power supply circuit, and the capacitor EC2 and the BAT auxiliary power supply circuit are electrically connected to the wiring terminal BAT-; The high-voltage direct current V1 is input into the high-voltage auxiliary power supply circuit through the terminal V1+ and the terminal V1-, and is transmitted to its winding taps 1 and 3 through the transformer TX1 for isolation, and then rectified and filtered by the diode D3 and EC2 to output Vdc.

[0015] As a further preferred technical solution of the present invention, the BAT auxiliary power supply circuit is electrically connected to the inverter main power circuit, and the BAT auxiliary power supply circuit is a flyback type isolated DC-DC power supply circuit. The BAT auxiliary power supply circuit is used to isolate and convert the BAT port voltage Vbat or the DC voltage Vdc to output 12V, 5V, 3.3V and other voltages to supply the inverter main power circuit, and the DC voltage Vdc is less than or equal to the minimum value of the battery port voltage Vbat.

[0016] As a further preferred technical solution of the present invention, the AC output port is provided with a connection terminal L and a connection terminal N; The inverter main power circuit is provided with a first DC / DC circuit, the first DC / DC circuit is electrically connected to the wiring terminal BAT+ and the wiring terminal BAT- of the BAT port, the first DC / DC circuit is also electrically connected to the second DC / DC circuit through an isolation transformer, the second DC / DC circuit is electrically connected to the DC / AC circuit, a third DC / DC circuit is electrically connected between the second DC / DC circuit and the DC / AC circuit, the DC / AC circuit is electrically connected to the wiring terminal AC-L and the wiring terminal AC-N of the AC input port to access the AC grid voltage Vac, the DC / AC circuit is also electrically connected to the wiring terminal L and the wiring terminal N of the AC output port, and the third DC / DC circuit is electrically connected to the wiring terminal PV+ and the wiring terminal PV- of the PV access port to access the photovoltaic panel voltage Vpv; An automatic switching circuit is provided between the DC / AC circuit and the AC input port, and an automatic switching circuit is also provided between the DC / AC circuit and the AC output port.

[0017] As described above, the photovoltaic inverter auxiliary power supply circuit system provided by the present invention has the following beneficial effects: 1. The present invention utilizes the above-mentioned photovoltaic inverter auxiliary power supply circuit system. Compared with the prior art, through the multiplexing setting of the switching circuit, the photovoltaic panel voltage Vpv and the auxiliary power supply for converting the high voltage to low voltage of the AC power grid Vac are combined into one, the circuit is more streamlined, the total power capacity of the auxiliary power supply is greatly reduced, some components can be selected with smaller specifications, the circuit volume, weight, etc. can be designed to be smaller, the cost advantage is more obvious, and the product competitiveness is strong.

[0018] 2. The present invention utilizes the above-mentioned photovoltaic inverter auxiliary power supply circuit system. Compared with the prior art, the photovoltaic inverter auxiliary power supply circuit system consumes solar clean energy first, grid energy second, and battery energy last through the coordinated cooperation of the PV micro-auxiliary power supply circuit, the switching circuit, the high-voltage auxiliary power supply circuit, the BAT auxiliary power supply circuit and the automatic switching circuit of the inverter main power circuit. This is environmentally friendly and improves battery life.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 A schematic diagram of a photovoltaic inverter auxiliary power supply circuit system applied for by the present invention; Figure 2 A circuit structure diagram of a PV micro-auxiliary power supply circuit and a switching circuit of a photovoltaic inverter auxiliary power supply circuit system applied for by the present invention; Figure 3 A circuit structure diagram of a high-voltage auxiliary power supply circuit of a photovoltaic inverter auxiliary power supply circuit system applied for by the present invention; Figure 4 A partial circuit framework diagram of an inverter main power circuit of a photovoltaic inverter auxiliary power supply circuit system applied for by the present invention. DETAILED DESCRIPTION

[0022] The following is a description of the implementation of the present invention by means of specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0023] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that the present invention can be implemented, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects that the present invention can produce and the purposes that can be achieved. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantial changes in the technical content. The specific structure can be described with reference to the drawings of the patent application.

[0024] The present invention provides a photovoltaic inverter auxiliary power supply circuit system, please refer to Figures 1 to 4 As shown, it includes a BAT auxiliary power supply circuit, a high-voltage auxiliary power supply circuit, a PV micro-auxiliary power supply circuit and a switching circuit, wherein the PV micro-auxiliary power supply circuit is electrically connected to and controls the switching circuit, the switching circuit is electrically connected to the high-voltage auxiliary power supply circuit, and the high-voltage auxiliary power supply circuit is electrically connected to the BAT auxiliary power supply circuit; It also includes a BAT port, a PV port, an AC input port and an AC output port. The BAT auxiliary power supply circuit is electrically connected to the battery through the BAT port. The PV micro auxiliary power supply circuit is connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is also connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is connected to the AC grid voltage Vac through the AC input port. The high-voltage auxiliary power supply circuit, in coordination with the switching circuit, steps down the photovoltaic panel voltage Vpv or the AC grid voltage Vac to output Vdc, and activates and starts the BAT auxiliary power supply circuit; The PV micro auxiliary power supply circuit is designed for extremely small power capacity; The high-voltage auxiliary power supply circuit is designed for low power capacity; The BAT auxiliary power supply circuit is designed for full power load.

[0025] Specifically, the specific circuit structure of the PV micro auxiliary power supply circuit is shown below. Figure 2As shown, the PV micro-auxiliary power supply circuit is provided with a control chip U1, and the control chip U1 has a built-in MOS tube and a feedback loop. The control chip U1 is provided with at least 8 pins, and pins 5 to 8 of the control chip U1 are drains of the built-in MOS, pins 1 to 2 of the control chip U1 are GND grounded, pin 3 of the control chip U1 is an NC floating pin, and pin 4 of the control chip U1 is a VDD working voltage.

[0026] The PV port is provided with a connection terminal PV+ and a connection terminal PV-; pins 5 to 8 of the control chip U1 are connected to the connection terminal PV+, and pins 5 to 8 of the control chip U1 are also electrically connected to the capacitor CE2, pin 4 of the control chip U1 is electrically connected to the diode D1, and pin 4 of the control chip U1 is electrically connected to the capacitor C1, pins 1 to 2 of the control chip U1 are electrically connected, pins 1 to 2 of the control chip U1 are electrically connected to the inductor L1, and pins 1 to 2 of the control chip U1 are also electrically connected to the diode D2, the capacitor C1 is also electrically connected to the diode D2 and the inductor L1, the diode D1 is also electrically connected to the inductor L1 and the capacitor CE1, the capacitor CE1, the diode D2 and the capacitor CE2 are electrically connected and connected to the connection terminal PV-; the control chip U1 and its surrounding electronic devices form a high-voltage BUCK circuit to convert the photovoltaic panel PV voltage and output the VCC1 voltage to the switching circuit, VCC1=12V.

[0027] It should be noted that: in this embodiment, the control chip U1 is the OB2235RASP chip of On-bright, the capacitor CE2 is the PV input capacitor, the diode D2 is the BUCK circuit freewheeling diode, the inductor L1 is the BUCK circuit energy storage inductor, the C capacitor E1 is the micro-auxiliary power supply output voltage VCC1 filter capacitor, the diode D1 and the capacitor C1 form a bootstrap power supply circuit and an output voltage detection feedback circuit. It can be seen that the circuit structure of the PV micro-auxiliary power supply circuit is simple, the required power capacity design is extremely small, the device specifications are small, and the cost advantage is obvious.

[0028] Specifically, the specific circuit structure of the switching circuit is shown below. Figure 2 As shown, the switching circuit is provided with a relay RY1, the relay RY1 is provided with at least 8 pins, a coil is provided between pins 1 and 8 of the relay RY1, the pin 1 of the relay RY1 is electrically connected to the connection point D of the MOS tube Q1, the pin 8 of the relay RY1 is electrically connected to the resistor R1, the resistor R1 is electrically connected to the resistor R2, one end of the resistor R2 is electrically connected to the connection point S of the MOS tube Q1, the other end of the resistor R2 is electrically connected to the connection point G of the MOS tube Q1, the resistor R2 is connected in parallel with the capacitor C2, and the resistor R1 is connected to the VCC1 voltage.

[0029] The AC input port is provided with a terminal AC-L and a terminal AC-N; pins 3 and 6 of the relay RY1 are common terminals of the relay, the pin 3 is electrically connected to the terminal V1-, the pin 6 is electrically connected to the terminal V1+, a capacitor EC1 is electrically connected between the terminal V1- and the terminal V1+, the pin 7 of the relay RY1 is connected to the terminal PV+, the pin 2 of the relay RY1 is connected to the terminal PV-, the pins 4 and 5 of the relay RY1 are both electrically connected to the rectifier bridge REC1, the rectifier bridge REC1 is electrically connected to the terminal AC-N, the rectifier bridge REC1 is also electrically connected to the fuse F1, and the fuse F1 is electrically connected to the terminal AC-L; The switching circuit converts the AC grid voltage Vac connected to the AC-N terminal and the AC-N terminal into a high-voltage DC voltage Vrec after being rectified by the rectifier bridge REC1. Vrec= Vac, the switching circuit outputs high-voltage direct current V1 to the high-voltage auxiliary power supply circuit through the wiring terminal V1- and the wiring terminal V1+, V1=Vpv or Vrec.

[0030] It should be noted that: when the photovoltaic inverter auxiliary power supply circuit system has PV voltage alone or PV and AC voltage exist at the same time, the switching circuit will preferentially connect the PV voltage to the common end to supply power to the high-voltage auxiliary power supply circuit, so as to deliver clean energy to the auxiliary power consumption of the inverter; When PV is present, the non-isolated BUCK buck circuit outputs VCC1=12V. Due to the presence of VCC1, MOS tube Q1 is turned on, and the VCC1 voltage is applied to the coil of relay RY1, so that the relay common terminals Pin3 and Pin6 are adsorbed and connected to Pin2 and Pin7 respectively, so that the PV voltage is connected to V1, and the common terminal V1 is connected to the filter capacitor EC1, so that the energy of the subsequent high-voltage auxiliary power supply circuit is taken from the PV solar energy; When there is AC voltage alone or PV voltage is powered off, U1 does not work, VCC1 has no voltage, MOS tube Q1 does not conduct, relay RY1 does not work and is in a naturally open state, and the common terminals Pin3 and Pin6 are connected to Pin4 and Pin5 respectively. Since the relay of the switching circuit is in a non-attracted state, the common terminal of the relay is often connected to Vrec after the rectification of the AC grid voltage, and the high-voltage auxiliary power supply circuit is activated and extracts energy from Vrec to convert and output Vdc, so that the energy of the subsequent high-voltage auxiliary power supply circuit is taken from the AC grid; Therefore, the power required by the switching circuit to drive the relay to close is relatively small (only a small relay RY1 needs to be driven to close, for example, closing the relay consumes 3W of power). Therefore, the design power capacity of the PV micro-auxiliary power supply circuit is very small, and the corresponding device specifications and volume are extremely small. In addition, non-isolated circuits can be used, which greatly reduces the design cost.

[0031] The high-voltage auxiliary power supply circuit is a flyback isolated DC-DC power supply circuit, which is used to isolate and convert the high-voltage direct current V1 into a low-voltage direct current voltage Vdc, and supply the direct current voltage Vdc to the BAT auxiliary power supply circuit. The high-voltage auxiliary power supply circuit is composed of a control chip, a terminal, a resistor, a MOS tube, a transformer, a voltage regulator diode, a transistor, a capacitor and a diode electrically connected.

[0032] Specifically, the specific circuit structure of the high-voltage auxiliary power supply circuit is shown below. Figure 3 As shown, the high-voltage auxiliary power supply circuit is provided with a control chip U2, and the control chip U2 is provided with a plurality of groups of pins. The control chip U2 is electrically connected to the terminal V1- through the pins, and the control chip U2 is electrically connected to the resistor R7 through the pins. The control chip U2 is also electrically connected to the MOS tube Q3 through the pins. Specifically, the control chip U2 is electrically connected to the wiring point G of the MOS tube Q3 through the pins, and one pin of the control chip U2 is the VDD working voltage. The resistor R7 is also electrically connected to the wiring point S of the MOS tube Q3, and the wiring point of the MOS tube Q3 is electrically connected to the transformer TX1. Specifically, the wiring point of the MOS tube Q3 is electrically connected to the winding taps 5 and 6 of the transformer TX1; The winding taps 5 and 6 of the transformer TX1 are also electrically connected to the terminal V1+, and the terminal V1+ is electrically connected to the resistor R4 and the resistor R5 respectively. The resistor R4, the resistor R3, the resistor R6, the Zener diode ZD1 and the Zener diode ZD2 are connected in series in sequence, the resistor R5 is electrically connected to the transistor Q2, the Zener diode ZD1 and the Zener diode ZD2 are electrically connected to the transistor Q2, the transistor Q2 is also electrically connected to the capacitor C3, the Zener diode ZD2 is also electrically connected to the capacitor C3, one end of the capacitor C3 is electrically connected to the winding taps 8 and 10 of the transformer TX1, the other end of the capacitor C3 is electrically connected to the diode D5, the diode D5 is also electrically connected to the winding taps 8 and 10 of the transformer TX1, the transistor Q2 and the capacitor C3 are electrically connected to the pin VDD, and the Zener diode ZD2 and the capacitor C3 are electrically connected to the terminal V1-.

[0033] The BAT port is provided with a wiring terminal BAT+ and a wiring terminal BAT-, and the voltage of the BAT port is Vbat; one end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the diode D3, and the other end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the capacitor EC2, the diode D3 is electrically connected to the other end of the capacitor EC2, one end of the capacitor EC2 is electrically connected to the diode D4, the other end of the capacitor EC2 is electrically connected to the BAT auxiliary power supply circuit, the other end of the diode D4 is electrically connected to the BAT auxiliary power supply circuit, Vbat is connected between the diode D4 and the BAT auxiliary power supply circuit, and the capacitor EC2 is electrically connected to the wiring terminal BAT- between the BAT auxiliary power supply circuit; The high-voltage direct current V1 is input into the high-voltage auxiliary power supply circuit through the terminal V1+ and the terminal V1-, and is transmitted to its winding taps 1 and 3 through the transformer TX1 for isolation, and then rectified and filtered by the diode D3 and EC2 to output Vdc.

[0034] It should be noted that: in this embodiment, the control chip U2 is the UC3845 chip of ON Company, and the high-voltage direct current V1 is divided and stabilized by current-limiting resistors R3, R4, R6 and voltage-stabilizing diodes ZD1 and ZD2 to drive the transistor Q2 to turn on. The high-voltage direct current V1 charges the capacitor C3 through R5 and Q2 and supplies it to the UC3845 chip. After reaching the turn-on voltage, the high-voltage auxiliary power supply circuit chip module is activated to output a PWM control signal to drive the MOS tube Q3 to work, and while the high-voltage direct current V1 steps down and outputs Vdc, a small part of the energy is transferred to VDD, capacitor C3 and diode D5 through winding 10-8 for rectification and power supply, so that the high-voltage auxiliary power supply circuit chip can continue to work and control the flyback power supply circuit to continuously output Vdc. Resistor R7 is a current sampling resistor used to take the current flowing through Q3 for chip control and protection. After Vdc is output, it is transmitted to Vbat through the unidirectional conducting diode D4.

[0035] The BAT auxiliary power supply circuit is electrically connected to the inverter main power circuit. The BAT auxiliary power supply circuit is a flyback isolated DC-DC power supply circuit. The BAT auxiliary power supply circuit is used to isolate and convert the BAT port voltage Vbat or the DC voltage Vdc to output 12V, 5V, 3.3V and other voltages to supply the inverter main power circuit (such as the power consumption of the inverter control system, the cooling fan, the relay control, etc., for example: the system requires 50W of power at full power). The BAT auxiliary power supply circuit is designed for full power load, and the DC voltage Vdc is less than or equal to the minimum value of the battery port voltage Vbat.

[0036] It should be noted that: the BAT auxiliary power supply circuit has two energy sources, and the higher voltage is preferentially used by the BAT auxiliary power supply circuit: 1. from the BAT port voltage Vbat; 2. from the output voltage of the upper auxiliary power supply (here refers to the output voltage Vdc of the high-voltage auxiliary power supply circuit); and the Vbat voltage can come from battery power supply, or from the inverter power circuit working in reverse to charge the PV or AC energy to the battery port (regardless of whether the battery is connected, it will be charged to this battery connection port), and the circuit design Vdc≤Vbat_min, so the BAT auxiliary power supply circuit preferentially consumes the Vbat port voltage, and the high-voltage auxiliary power supply circuit enters the no-load state after only working at low power for a short time. The high-voltage auxiliary power supply circuit only needs a small power capacity design, the circuit volume is greatly reduced, and the cost advantage.

[0037] The AC output port is provided with a terminal L and a terminal N; the inverter main power circuit is provided with a first DC / DC circuit, the first DC / DC circuit is electrically connected to the terminal BAT+ and the terminal BAT- of the BAT port, the first DC / DC circuit is also electrically connected to the second DC / DC circuit through an isolation transformer, the second DC / DC circuit is electrically connected to the DC / AC circuit, a third DC / DC circuit is electrically connected between the second DC / DC circuit and the DC / AC circuit, the DC / AC circuit is electrically connected to the terminal AC-L and the terminal AC-N of the AC input port to access the AC grid voltage Vac, the DC / AC circuit is also electrically connected to the terminal L and the terminal N of the AC output port, and the third DC / DC circuit is electrically connected to the terminal PV+ and the terminal PV- of the PV access port to access the photovoltaic panel voltage Vpv; An automatic switching circuit is provided between the DC / AC circuit and the AC input port, and an automatic switching circuit is also provided between the DC / AC circuit and the AC output port.

[0038] It should be noted that: the first DC / DC circuit and the second DC / DC circuit cooperate with the isolation transformer to form the battery boost DC / DC circuit part, which is usually a full-bridge + full-bridge circuit or a push-pull + full-bridge circuit. The energy flows from left to right for battery discharge inversion, and from right to left for battery charging; the DC / AC part circuit is usually an H-bridge circuit, which is an H-bridge inverter working state during inversion discharge and a bridgeless PFC working state during AC charging; the third DC / DC circuit is usually a Boost type boost circuit Example 1

[0039] When the battery at the inverter battery port is normally powered, no matter the inverter is in standby or normal operation, when voltage is connected to the PV port or AC port, the high-voltage auxiliary power supply circuit will start automatically and isolate the conversion output Vdc. The input of Vdc will make the BAT auxiliary power supply circuit start automatically and isolate the conversion output 12V, 5V, 3.3V and other voltages to supply the inverter functional circuits. Due to the presence of PV or AC, the inverter controls the main power circuit to change from the inverter state to the charging state to charge the battery port. Since Vdc≤Vbat, the BAT auxiliary power supply circuit will give priority to consuming the energy of Vbat converted from PV or AC through the power circuit. Example 2

[0040] When the battery at the inverter BAT port is in a disconnected or dormant state, the high-voltage auxiliary power supply circuit will be automatically started after the PV voltage or AC voltage is connected (the PV micro-auxiliary power supply circuit will be started first when the PV is connected) to output Vdc, and then the BAT auxiliary power supply circuit can be activated and started. The inverter main control chip controls the energy of the main power circuit to be transmitted from right to left, charging the BAT port and outputting Vbat (that is, the voltage between BAT+ and BAT-). Since Vbat≥Vdc, the main energy source of the BAT auxiliary power supply circuit is provided by Vbat, and the high-voltage auxiliary power supply circuit enters a no-load state.

[0041] It can be seen from Examples 1 and 2 that the high-voltage auxiliary power supply circuit only needs to work for a short time and with low power (only the inverter control system consumes power, for example, 15W of power is required) to supply the BAT auxiliary power supply circuit so that after the inverter is activated and starts to enter the charging state, the input source of the BAT auxiliary power supply circuit is converted to Vbat converted by the power circuit, and the high-voltage auxiliary power supply circuit is immediately converted to a no-load state. Therefore, the high-voltage auxiliary power supply circuit only needs a small power capacity design, and the device specifications, transformer volume, circuit board area, etc. of the high-voltage auxiliary power supply circuit can be halved in design, the heat sinks of the MOS tube and the diode can be removed, and the design cost is greatly reduced.

[0042] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A photovoltaic inverter auxiliary power supply circuit system, characterized in that: It includes a BAT auxiliary power supply circuit, a high-voltage auxiliary power supply circuit, a PV micro-auxiliary power supply circuit and a switching circuit, wherein the PV micro-auxiliary power supply circuit is electrically connected to and controls the switching circuit, the switching circuit is electrically connected to the high-voltage auxiliary power supply circuit, and the high-voltage auxiliary power supply circuit is electrically connected to the BAT auxiliary power supply circuit; It also includes a BAT port, a PV port, an AC input port and an AC output port. The BAT auxiliary power supply circuit is electrically connected to the battery through the BAT port. The PV micro auxiliary power supply circuit is connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is also connected to the photovoltaic panel voltage Vpv through the PV port. The switching circuit is connected to the AC grid voltage Vac through the AC input port. The high-voltage auxiliary power supply circuit, in coordination with the switching circuit, steps down the photovoltaic panel voltage Vpv or the AC grid voltage Vac to output Vdc, and activates and starts the BAT auxiliary power supply circuit.

2. A photovoltaic inverter auxiliary power supply circuit system according to claim 1, characterized in that: The PV micro-auxiliary power supply circuit is provided with a control chip U1, and the control chip U1 has a built-in MOS tube and a feedback loop. The control chip U1 is provided with at least 8 pins, pins 5 to 8 of the control chip U1 are the drains of the built-in MOS, pins 1 to 2 of the control chip U1 are GND grounded, pin 3 of the control chip U1 is an NC floating pin, and pin 4 of the control chip U1 is the VDD working voltage.

3. A photovoltaic inverter auxiliary power supply circuit system according to claim 2, characterized in that: The PV port is provided with a connection terminal PV+ and a connection terminal PV-; Pins 5 to 8 of the control chip U1 are connected to terminal PV+, and pins 5 to 8 of the control chip U1 are also electrically connected to capacitor CE2, and pin 4 of the control chip U1 is electrically connected to diode D1, and pin 4 of the control chip U1 is electrically connected to capacitor C1, and pins 1 to 2 of the control chip U1 are electrically connected to each other, and pins 1 to 2 of the control chip U1 are electrically connected to inductor L1, and pins 1 to 2 of the control chip U1 are also electrically connected to diode D2, and capacitor C1 is also electrically connected to diode D2 and inductor L1, and diode D1 is also electrically connected to inductor L1 and capacitor CE1, and capacitor CE1, diode D2 and capacitor CE2 are electrically connected to each other and connected to terminal PV-; The control chip U1 and its surrounding electronic devices form a high-voltage BUCK circuit to convert the photovoltaic panel PV voltage and output the VCC1 voltage to the switching circuit.

4. A photovoltaic inverter auxiliary power supply circuit system according to claim 3, characterized in that: The switching circuit is provided with a relay RY1, and the relay RY1 is provided with at least 8 pins. A coil is provided between pins 1 and 8 of the relay RY1, and pin 1 of the relay RY1 is electrically connected to a connection point D of the MOS tube Q1, and pin 8 of the relay RY1 is electrically connected to a resistor R1, and the resistor R1 is electrically connected to a resistor R2, and one end of the resistor R2 is electrically connected to a connection point S of the MOS tube Q1, and the other end of the resistor R2 is electrically connected to a connection point G of the MOS tube Q1, and the resistor R2 is connected in parallel with a capacitor C2, and the resistor R1 is connected to a VCC1 voltage.

5. A photovoltaic inverter auxiliary power supply circuit system according to claim 4, characterized in that: The AC input port is provided with a connection terminal AC-L and a connection terminal AC-N; Pins 3 and 6 of the relay RY1 are common terminals of the relay, the pin 3 is electrically connected to the terminal V1-, the pin 6 is electrically connected to the terminal V1+, a capacitor EC1 is electrically connected between the terminal V1- and the terminal V1+, the pin 7 of the relay RY1 is connected to the terminal PV+, the pin 2 of the relay RY1 is connected to the terminal PV-, the pins 4 and 5 of the relay RY1 are both electrically connected to the rectifier bridge REC1, the rectifier bridge REC1 is electrically connected to the terminal AC-N, the rectifier bridge REC1 is also electrically connected to the fuse F1, and the fuse F1 is electrically connected to the terminal AC-L; The switching circuit converts the AC grid voltage Vac connected to the AC-N terminal and the AC-N terminal into a high-voltage DC voltage Vrec after being rectified by the rectifier bridge REC1. Vrec= Vac, the switching circuit outputs high-voltage direct current V1 to the high-voltage auxiliary power supply circuit through the wiring terminal V1- and the wiring terminal V1+, V1=Vpv or Vrec.

6. A photovoltaic inverter auxiliary power supply circuit system according to claim 5, characterized in that: The high-voltage auxiliary power supply circuit is a flyback isolated DC-DC power supply circuit, which is used to isolate and convert the high-voltage direct current V1 into a low-voltage direct current voltage Vdc, and supply the direct current voltage Vdc to the BAT auxiliary power supply circuit. The high-voltage auxiliary power supply circuit is composed of a control chip, a terminal, a resistor, a MOS tube, a transformer, a voltage regulator diode, a transistor, a capacitor and a diode electrically connected.

7. A photovoltaic inverter auxiliary power supply circuit system according to claim 6, characterized in that: The high-voltage auxiliary power supply circuit is provided with a control chip U2, and the control chip U2 is provided with a plurality of groups of pins. The control chip U2 is electrically connected to the terminal V1- through the pins, and the control chip U2 is electrically connected to the resistor R7 through the pins. The control chip U2 is also electrically connected to the MOS tube Q3 through the pins. Specifically, the control chip U2 is electrically connected to the wiring point G of the MOS tube Q3 through the pins, and one pin of the control chip U2 is the VDD working voltage. The resistor R7 is also electrically connected to the wiring point S of the MOS tube Q3, and the wiring point of the MOS tube Q3 is electrically connected to the transformer TX1. Specifically, the wiring point of the MOS tube Q3 is electrically connected to the winding taps 5 and 6 of the transformer TX1; The winding taps 5 and 6 of the transformer TX1 are also electrically connected to the terminal V1+, and the terminal V1+ is electrically connected to the resistor R4 and the resistor R5 respectively. The resistor R4, the resistor R3, the resistor R6, the Zener diode ZD1 and the Zener diode ZD2 are connected in series in sequence, the resistor R5 is electrically connected to the transistor Q2, the Zener diode ZD1 and the Zener diode ZD2 are electrically connected to the transistor Q2, the transistor Q2 is also electrically connected to the capacitor C3, the Zener diode ZD2 is also electrically connected to the capacitor C3, one end of the capacitor C3 is electrically connected to the winding taps 8 and 10 of the transformer TX1, the other end of the capacitor C3 is electrically connected to the diode D5, the diode D5 is also electrically connected to the winding taps 8 and 10 of the transformer TX1, the transistor Q2 and the capacitor C3 are electrically connected to the pin VDD, and the Zener diode ZD2 and the capacitor C3 are electrically connected to the terminal V1-.

8. A photovoltaic inverter auxiliary power supply circuit system according to claim 7, characterized in that: The BAT port is provided with a wiring terminal BAT+ and a wiring terminal BAT-, and the voltage of the BAT port is Vbat; One end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the diode D3, the other end of the winding taps 1 and 3 of the transformer TX1 is electrically connected to the capacitor EC2, the diode D3 is electrically connected to the other end of the capacitor EC2, one end of the capacitor EC2 is electrically connected to the diode D4, the other end of the capacitor EC2 is electrically connected to the BAT auxiliary power supply circuit, the other end of the diode D4 is electrically connected to the BAT auxiliary power supply circuit, Vbat is connected between the diode D4 and the BAT auxiliary power supply circuit, and the capacitor EC2 and the BAT auxiliary power supply circuit are electrically connected to the wiring terminal BAT-; The high-voltage direct current V1 is input into the high-voltage auxiliary power supply circuit through the terminal V1+ and the terminal V1-, and is transmitted to its winding taps 1 and 3 through the transformer TX1 for isolation, and then rectified and filtered by the diode D3 and EC2 to output Vdc.

9. A photovoltaic inverter auxiliary power supply circuit system according to claim 6 or 8, characterized in that: The BAT auxiliary power supply circuit is electrically connected to the inverter main power circuit. The BAT auxiliary power supply circuit is a flyback type isolated DC-DC power supply circuit. The BAT auxiliary power supply circuit is used to isolate and convert the BAT port voltage Vbat or the DC voltage Vdc to output 12V, 5V, 3.3V and other voltages to supply the inverter main power circuit. The DC voltage Vdc is less than or equal to the minimum value of the battery port voltage Vbat.

10. A photovoltaic inverter auxiliary power supply circuit system according to claim 9, characterized in that: The AC output port is provided with a connection terminal L and a connection terminal N; The inverter main power circuit is provided with a first DC / DC circuit, the first DC / DC circuit is electrically connected to the wiring terminal BAT+ and the wiring terminal BAT- of the BAT port, the first DC / DC circuit is also electrically connected to the second DC / DC circuit through an isolation transformer, the second DC / DC circuit is electrically connected to the DC / AC circuit, a third DC / DC circuit is electrically connected between the second DC / DC circuit and the DC / AC circuit, the DC / AC circuit is electrically connected to the wiring terminal AC-L and the wiring terminal AC-N of the AC input port to access the AC grid voltage Vac, the DC / AC circuit is also electrically connected to the wiring terminal L and the wiring terminal N of the AC output port, and the third DC / DC circuit is electrically connected to the wiring terminal PV+ and the wiring terminal PV- of the PV access port to access the photovoltaic panel voltage Vpv; An automatic switching circuit is provided between the DC / AC circuit and the AC input port, and an automatic switching circuit is also provided between the DC / AC circuit and the AC output port.

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