阅读说明：本技术 一种有稳定性能的光伏逆变器 (Photovoltaic inverter with stable performance ) 是由 梁凯 徐大伟 张飞阳 王艳 刘卫东 李勇敢 陈伟 陈冬 刘健 于 2021-09-29 设计创作，主要内容包括：本发明公开了一种有稳定性能的光伏逆变器；包括保护箱,所述保护箱内设有逆变器本体,所述保护箱内还设有漏电电流保护系统,所述漏电电流保护系统包括DSP控制模块、信号检测及采样模块、逆变电路驱动模块以及保护和控制信号模块,所述DSP控制模块与信号检测及采样模块连接,所述DSP控制模块与逆变电路驱动模块连接,所述DSP控制模块通过I/O端口与保护和控制信号模块连接。通过对逆变模块加以改进和控制,能够使其保证中点电压基本不再悬浮不定,共模电压基本保持为定值,从而达到消除漏电流的目的,保证了光伏逆变器的稳定运行,并通过温度调节组件能够对逆变器本体的温度进行调节,从而能够进一步提高逆变器的稳定性。(The invention discloses a photovoltaic inverter with stable performance; including the guard box, be equipped with the dc-to-ac converter body in the guard box, still be equipped with leakage current protection system in the guard box, leakage current protection system includes DSP control module, signal detection and sampling module, inverter circuit drive module and protection and control signal module, DSP control module and signal detection and sampling module are connected, DSP control module and inverter circuit drive module are connected, DSP control module passes through the IO port and is connected with protection and control signal module. Through improving and controlling the contravariant module, can make it guarantee that midpoint voltage basically no longer suspends indefinitely, the common mode voltage keeps for the definite value basically to reach the mesh of eliminating the leakage current, guaranteed photovoltaic inverter's steady operation, and can adjust the temperature of dc-to-ac converter body through the temperature regulation subassembly, thereby can further improve the stability of dc-to-ac converter.)

1. A photovoltaic inverter having stable performance; including guard box (1), its characterized in that, be provided with inverter body (2) in guard box (1), still be provided with in guard box (1) and be used for inverter body (2) earth leakage protection's leakage current protection system, leakage current protection system includes DSP control module (3), signal detection and sampling module, inverter circuit drive module and protection and control signal module, DSP control module pass through the ADC port with signal detection and sampling module connect, signal detection and sampling module are used for detecting and gathering the voltage of inverter body (2) input and the electric current of output, DSP control module still with inverter circuit drive module connects, DSP control module pass through the IO port with protection and control signal module connect.

2. The photovoltaic inverter with the stable performance according to claim 1, wherein an input end of the inverter body (2) is electrically connected with the photovoltaic cell panel through a dc bus capacitor, an output end of the inverter body (2) is electrically connected with a power grid through a filter circuit, the signal detection and sampling module comprises a dc voltage signal detection and sampling sub-module and an ac current signal detection and sampling sub-module, the dc voltage signal detection and sampling sub-module is used for collecting voltage at two ends of the dc bus capacitor, and the ac current signal detection and sampling sub-module is used for collecting current at an output end of the filter circuit.

3. The pv inverter of claim 2, wherein the signal detection and sampling module further comprises a zero crossing detection circuit for detecting the number of zero crossings in the ac sampling circuit.

4. The photovoltaic inverter with the stable performance as claimed in claim 3, characterized in that the topological circuit inside the inverter body (2) comprises a photovoltaic direct current module, an inversion module and a filtering module, wherein the photovoltaic direct current module comprises a photovoltaic cell panel and a direct current bus capacitor, the inversion module is used for completing the conversion of voltage from direct current to alternating current, and the filtering module is used for suppressing the harmonic waves of the inverted output current.

5. The pv inverter as claimed in claim 4, wherein the inverter module comprises eight power switches and two diodes, the power switches adopt IGBTs as inverter control switching elements, and the diodes adopt fast recovery diodes of type MUR3040 PT.

6. The photovoltaic inverter with the stable performance as claimed in claim 5, wherein the DSP control module controls the power switch tube in the inverter module to be turned on and off through an inverter circuit driving module.

7. The pv inverter with stabilized performance according to claim 1, characterized in that a temperature regulation assembly is further disposed in the protection box (1), and the temperature regulation assembly is used for regulating the temperature of the inverter body (2).

Technical Field

The invention belongs to the technical field of photovoltaic inverters, and particularly relates to a photovoltaic inverter with stable performance.

Background

The photovoltaic inverter converts dc power into ac power through an inverter circuit, and a device for implementing the inversion process is called an inverter, which has a core of a process of converting dc voltage (photovoltaic module) into ac voltage (grid-connectable).

The transformer-free inverter directly connected to the grid can obtain more stable performance. The transformer converts electrical energy into magnetic energy, which is then converted into electrical energy, and the electrical isolation device installed between the input and output ends results in an energy loss of up to 1%, and even up to 2%. Therefore, the operation efficiency of the transformer-less inverter is higher than that of the transformer-type inverter. This technique has many other advantages such as low material consumption, light weight, stability and reliability. In summary, a transformerless inverter is advantageous over a transformer inverter in many respects.

In the leakage current in the normal operation state, in the process of converting the voltage from the photovoltaic module by adopting high frequency (20kHz), the high frequency voltage is equal to the voltage peak value of a power grid; these voltages are considered as disturbances inside the inverter and the filter can block these disturbances from entering the grid. In theory, however, it is not possible to completely prevent the dc component from the mains side from entering the ac grid, so that a certain dc voltage component to ground is also present in the ac output. This dc voltage component will generate a "leakage current" that flows through the parasitic capacitance to the battery pack ground.

The varying common mode voltage is the root cause of leakage current. In order to suppress the leakage current, it is necessary to keep the common mode voltage stable, and if the common mode voltage can be made to be a constant value or have only a low frequency ripple phenomenon, the leakage current can be substantially eliminated.

The solution to the leakage current problem of the transformerless inverter is mainly by improving the topology in this way. However, in the prior art, two modes of direct current decoupling and alternating current decoupling are mostly adopted to suppress leakage current, but complete elimination cannot be achieved, and the existing midpoint voltage suspension cannot stabilize common mode voltage, so that leakage current is caused.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a photovoltaic inverter with stable performance, which can ensure that the midpoint voltage is basically not suspended indefinitely and the common-mode voltage is basically kept at a fixed value by improving and controlling an inverter module, thereby basically eliminating leakage current, ensuring the stable operation of the photovoltaic inverter and adjusting the temperature of the inverter through a temperature adjusting component,

thereby, the stability of the inverter can be further improved.

The invention provides the following technical scheme:

a photovoltaic inverter having stable performance; including the guard box, be provided with the dc-to-ac converter body in the guard box, still be provided with in the guard box and be used for dc-to-ac converter body earth leakage protection's leakage current protection system, leakage current protection system includes DSP control module, signal detection and sampling module, inverter circuit drive module and protection and control signal module, DSP control module pass through the ADC port with signal detection and sampling module connect, signal detection and sampling module are used for detecting and gathering the voltage of dc-to-ac converter body input and the electric current of output, DSP control module still with inverter circuit drive module connects, DSP control module pass through the IO port with protection and control signal module connect.

Preferably, the input end of the inverter body is electrically connected with the photovoltaic cell panel through a direct current bus capacitor, the output end of the inverter body is electrically connected with a power grid through a filter circuit, the signal detection and sampling module comprises a direct current voltage signal detection and sampling submodule and an alternating current signal detection and sampling submodule, the direct current voltage signal detection and sampling submodule is used for collecting voltages at two ends of the direct current bus capacitor, and the alternating current signal detection and sampling submodule is used for collecting current at the output end of the filter circuit.

Preferably, the signal detecting and sampling module further includes a zero-crossing detecting circuit, and the zero-crossing detecting circuit is used for detecting the number of zero crossings in the ac sampling circuit.

Preferably, the topology circuit inside the inverter body includes a photovoltaic direct current module, an inversion module and a filtering module, the photovoltaic direct current module includes a photovoltaic cell panel and a direct current bus capacitor, the inversion module is used for completing the conversion of voltage from direct current to alternating current, and the filtering module is used for suppressing the harmonic wave of the inversion output current.

Preferably, the inverter module includes eight power switching tubes and two diodes, the power switching tubes adopt IGBTs as inverter control switching elements, and the diodes adopt fast recovery diodes with the model number MUR3040 PT.

Preferably, the DSP control module controls the power switch tube in the inverter module to be turned on and off through the inverter circuit driving module.

Preferably, a temperature adjusting assembly is further arranged in the protection box and used for adjusting the temperature of the inverter body.

Preferably, the temperature adjusting assembly comprises a gas temperature adjusting box, a liquid storage box and a temperature sensor, the gas temperature adjusting box is located on the outer side of the protection box, the liquid storage box is located inside the protection box, the temperature sensor is located inside the protection box and used for detecting the temperature inside the protection box and feeding the temperature back to the DSP control module in a signal form, a semiconductor refrigerating sheet is vertically arranged inside the gas temperature adjusting box, a first cavity is formed between the cold end surface of the semiconductor refrigerating sheet and the gas temperature adjusting box, a second cavity is formed between the hot end surface of the semiconductor refrigerating sheet and the gas temperature adjusting box, a first gas inlet pipe is arranged in the first cavity, the other end of the first gas inlet pipe is located in the liquid storage box, and a plurality of first gas inlets are further arranged at the position of the first cavity of the gas temperature adjusting box, the air temperature adjusting box is characterized in that a cooling fan is arranged in the second chamber, the air temperature adjusting box is located at the second chamber, a plurality of heat dissipation holes are further formed in the position of the second chamber, the first air inlet pipe is located at one end of the liquid storage box and located below the liquid level of the liquid storage box, a first air outlet is formed in the upper end of the liquid storage box, and a first one-way air outlet valve is arranged at the first air outlet.

Preferably, the temperature regulation assembly further comprises an exhaust mechanism, the exhaust mechanism comprises a first mechanism, a second mechanism and a third mechanism, the first mechanism, the second mechanism and the third mechanism are all connected with a crankshaft, one end of the crankshaft is connected with a motor, a second air outlet is formed in the left side of the third mechanism, the second air outlet is communicated with the outside of the protection box, and a second one-way air outlet valve is arranged at the position of the second air inlet.

Preferably, the first mechanism and the second mechanism are symmetrically arranged on two sides of the third mechanism, the first mechanism and the second mechanism are identical in structure, the crankshaft penetrates through the second mechanism and is connected with the second mechanism in a rotating mode, the crankshaft penetrates through the first mechanism and is connected with the first mechanism in a rotating mode, and the motor drives the crankshaft to rotate.

Preferably, first mechanism includes first barrel, the bent axle sets up the position that is close to the right side in first barrel inside, be equipped with first bearing on the bent axle, first bearing with the bent axle rotates to be connected, the lateral wall of first bearing is connected with first connecting rod, the other end of first connecting rod rotates through the third bearing and is connected with first push rod, the other end of first push rod is connected with first piston piece, first piston piece passes through rubber pad sliding seal with first barrel inner wall and is connected, the lateral wall of first barrel is equipped with the second air inlet, second air inlet department is equipped with first one-way admission valve, the lateral wall of first barrel is close to left position and is provided with the second intake pipe, the other end and the third mechanism of second intake pipe are connected.

Preferably, the third mechanism includes the second barrel, the right side at the second barrel outside is established to the bent axle, be connected with the second bearing on the bent axle, the lateral wall of second bearing is connected with the second connecting rod, the second connecting rod runs through the right side wall of second barrel, the other end of second connecting rod is connected with the second push rod, the other end of second push rod is connected with the second piston piece, the second piston piece passes through rubber pad sliding seal with second barrel inner wall and is connected, the lateral wall of second barrel is close to left end position symmetric connection and has second intake pipe and third intake pipe, the second intake pipe is connected with first mechanism, the third intake pipe is connected with second mechanism, the left end of second barrel runs through the lateral wall and the external world intercommunication of guard box.

Preferably, the second intake pipe corresponds with the second barrel junction and is equipped with the third air inlet, the third intake pipe corresponds with the junction of second barrel and is equipped with the fourth air inlet, third air inlet, fourth air inlet all are equipped with the one-way admission valve of second.

Preferably, the bottom is provided with the protective assembly in the guard box, the protective assembly includes wooden spacer and damping anti-impact pad, the dc-to-ac converter body is located on the wooden spacer, the lower extreme of wooden spacer pass through damping anti-impact pad with the guard box is connected, the inside align to grid of damping anti-impact pad has cellular hexagonal thin wall hollow cylinder, be equipped with the air chamber between the adjacent hollow cylinder.

Preferably, the inner wall of guard box still is provided with the insulating layer, the insulating layer is aramid fiber insulated paper layer, the outer wall of guard box still is provided with the insulating layer.

Preferably, the filtering module includes a filter, and in order to further improve the stability of the photovoltaic inverter and further reduce the influence caused by the magnitude of the grid-connected current ripple, the dc bus voltage Upv, the grid output maximum amplitude voltage Ugm, the current ripple amplitude Δ Imax, the switching frequency P, the current peak value Igmax, and the inductance value D of the filter should satisfy the following relationship:

in the above formula, Upv, Ugm unit, V; imax, Igmax units, a; alpha is a relation coefficient and has a value range of 0.87-3.55.

Preferably, in order to further improve the stability of the photovoltaic inverter and ensure that the inverter body is always in a reasonable temperature environment when working, the invention also provides a method for adjusting the temperature of the inverter, which comprises the following steps:

s1, the temperature sensor collects the temperature inside the protection box in real time and sends the temperature to the DSP control module in a signal form;

s2, setting five working modes in the DSP control module, namely a primary cooling mode, a secondary cooling mode, a primary heating mode, a secondary heating mode and a standby mode, wherein the four working modes have respective value intervals, and the DSP control module calculates the temperature difference delta W between the temperature difference delta W and a preset threshold value according to the temperature value sampled by the temperature sensor;

and S3, the DSP control module determines the working mode of the semiconductor chilling plate according to the temperature difference delta W and controls the rotation and stop of the motor.

Preferably, in step S3, when the temperature difference Δ W is within the value range of the primary cooling mode, the DSP control module controls the semiconductor cooling plate to operate at low power by controlling the input current, and causes the motor to rotate at low speed; when the value of the temperature difference delta W is in the value range of the secondary cooling mode, the DSP control module controls the semiconductor refrigerating sheet to work at high power by controlling the input current and enables the motor to rotate at high speed; when the temperature difference delta W is in a value range of the first-stage heating mode, the DSP control module realizes the reversal of the anode and the cathode of the semiconductor chilling plate through the H-bridge driving circuit, controls the low-power work of the semiconductor chilling plate through the control of input current and enables the motor to rotate at a low speed; when the temperature difference delta W is in the value range of the secondary heating mode, the DSP control module realizes the reversal of the anode and the cathode of the semiconductor refrigerating sheet through the H-bridge driving circuit, controls the high-power work of the semiconductor refrigerating sheet through the control of the input current and enables the motor to rotate at a high speed.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the photovoltaic inverter with the stable performance, the inverter module is improved and controlled, so that the neutral point voltage is basically not suspended indefinitely, the common mode voltage is basically kept at a fixed value, the aim of eliminating leakage current is fulfilled, the stable operation of the photovoltaic inverter is guaranteed, the temperature of the inverter body can be adjusted through the temperature adjusting assembly, and the stability of the inverter can be further improved.

(2) According to the photovoltaic inverter with the stable performance, the gas temperature adjusting box is arranged, the semiconductor refrigerating sheet can heat or cool the gas in the first cavity, the gas in the first cavity can enter the protection box through the first gas inlet pipe and the liquid storage box, the exhaust mechanism can exhaust the gas in the protection box to the outside, negative pressure can be formed in the protection box, the gas in the first cavity can conveniently enter the protection box, the liquid storage box can also process the entered gas, the gas is mixed with water, and the possibility that sundries such as dust and the like enter the protection box can be reduced.

(3) According to the photovoltaic inverter with the stable performance, in the process of the exhaust mechanism, the first connecting rod in the first cylinder drives the first push rod to move rightwards, gas in the protection box enters the first cylinder through the first one-way air inlet valve, then the first connecting rod in the first cylinder drives the first push rod to move leftwards, the first piston block extrudes the gas in the first cylinder, the gas can rapidly enter the second cylinder through the second air inlet pipe and the second one-way air inlet valve, the second connecting rod drives the second push rod to move leftwards, the second piston block extrudes the gas in the second cylinder, and the gas is exhausted to the outside through the second one-way air outlet valve.

(4) According to the photovoltaic inverter with the stable performance, the stability of the photovoltaic inverter can be further improved and the influence caused by the size of grid-connected current ripples can be further reduced by limiting the voltage Upv of a direct current bus, the maximum amplitude voltage Ugm output by a power grid, the current ripple amplitude delta Imax, the switching frequency P, the current peak value Igmax and the inductance value D of a filter.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic view of the overall structure of the present invention.

Fig. 2 is a block diagram of the architecture of the present invention.

Fig. 3 is a voltage sampling circuit diagram of the present invention.

Fig. 4 is a current sampling circuit diagram of the present invention.

Fig. 5 is a zero crossing detection circuit diagram of the present invention.

Fig. 6 is a circuit diagram of an IGBT driving circuit of the invention.

Fig. 7 is a circuit diagram of an inversion module topology of the present invention.

FIG. 8 is a schematic view of the structure of the gas temperature adjusting tank and the liquid storage tank of the present invention.

Fig. 9 is a schematic view of the structure of the exhaust mechanism of the present invention.

Fig. 10 is a schematic structural diagram of a first mechanism of the present invention.

Fig. 11 is a schematic structural view of a third mechanism of the present invention.

In the figure: 1. a protection box; 2. an inverter body; 3. a DSP control module; 4. a gas temperature regulating box; 41. a semiconductor refrigeration sheet; 42. a first chamber; 43. a second chamber; 44. a first air inlet; 45. a heat radiation fan; 46. heat dissipation holes; 5. a first intake pipe; 6. a liquid storage tank; 7. a first one-way outlet valve; 81. a first mechanism; 82. a second mechanism; 83. a third mechanism; 84. a crankshaft; 85. a second intake pipe; 86. a third intake pipe; 811. a first cylinder; 812. a first bearing; 813. a first link; 814. a first push rod; 815. a first piston block; 816. a second air inlet; 817. a first one-way intake valve; 831. a second cylinder; 832. a second bearing; 833. a second link; 834. a second push rod; 835. a second piston block; 836. a second air outlet; 837. a second one-way outlet valve; 838. a third air inlet; 91. wood lining strips; 92. a vibration-damping cushion pad; 93. a hollow cylinder; 94. an air chamber.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described in detail and completely with reference to the accompanying drawings. It is to be understood that the described embodiments are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The first embodiment is as follows:

referring to fig. 1-7, a photovoltaic inverter with stable performance; the protection box comprises a protection box 1, an inverter body 2 is arranged in the protection box 1, a leakage current protection system for leakage protection of the inverter body 2 is further arranged in the protection box 1, the leakage current protection system comprises a DSP control module 3, a signal detection and sampling module, an inverter circuit driving module and a protection and control signal module, the DSP control module is connected with the signal detection and sampling module through an ADC port, the signal detection and sampling module is used for detecting and collecting voltage at the input end of the inverter body 2 and current at the output end of the inverter body to realize closed-loop control of a current loop, the DSP control module is further connected with the inverter circuit driving module, the DSP control module is connected with the inverter circuit driving module through e PWM, ePWM is used for a motor control system and a power conversion device, and in the inverter system, and the DSP control module is connected with the protection and control signal module through an I/O port. In order to control the dc voltage of the photovoltaic bus and the grid-connected ac current, the dc side capacitor voltage, the inverter side current and the grid current need to be detected, and in order to control the output current of the inversion link in real time, the grid ac current needs to be sampled and detected.

The input of inverter body 2 is connected with the photovoltaic cell board electricity through direct current bus electric capacity, the output of inverter body 2 passes through filter circuit and is connected with the electric wire netting electricity, signal detection and sampling module include direct current voltage signal detection and sampling submodule, alternating current signal detection and sampling submodule piece, direct current voltage signal detection and sampling submodule piece are used for gathering the voltage at direct current bus electric capacity both ends, alternating current signal detection and sampling submodule piece are used for gathering the electric current of filter circuit output.

The signal detection and sampling module further comprises a zero-crossing detection circuit, and the zero-crossing detection circuit is used for detecting the zero-crossing times in the alternating current sampling circuit. The zero-crossing detection has the function of detecting the passing zero potential when the current or voltage waveform changes from a positive half period to a negative half period in an alternating current system, and the frequency of the detected waveform of the system can be obtained according to the times of passing the zero point. When a photovoltaic system is connected to the grid, the voltage feedforward compensation in the DSP controller needs to use the amplitude of the grid voltage, and generates a reference current with the same frequency and phase as the grid voltage, and needs to capture the phase zero point of the grid voltage.

The topological circuit in the inverter body 2 comprises a photovoltaic direct current module, an inversion module and a filtering module, the photovoltaic direct current module comprises a photovoltaic cell panel and a direct current bus capacitor, the inversion module is used for completing the conversion of voltage from direct current to alternating current, and the filtering module is used for suppressing the harmonic waves of the inversion output current.

The inversion module comprises 8 power switch tubes and two diodes, wherein the power switch tubes adopt IGBTs as inversion control switch elements, and the diodes adopt fast recovery diodes with the type MUR3040 PT. Referring to fig. 7, the topology circuit guides the clamp unit from the midpoint of the freewheeling arm to the midpoint of the voltage-dividing capacitors C1 and C2 to form a T-shaped path, so that the problem of unstable clamping voltage caused by slow reverse recovery of the body diode is avoided while conducting in both directions.

The IGBT is an electronic device compositely formed by combining the characteristics of two switching tubes of a BJT (bipolar junction transistor) and a MOSFET (metal-oxide-semiconductor field effect transistor), has the advantages of high switching action speed, low driving energy consumption and low saturation voltage drop, and is generally used as a switching module in a high-voltage high-capacity system.

The DSP control module controls the on and off of a power switch tube in the inverter module through an inverter circuit driving module. Because the PWM signal pulse generated by the DSP controller can not directly drive the IGBT switch tube, a driving circuit is required to be connected with the main control chip and the IGBT, an intelligent gate driver with the model of ACPL-331J is adopted as an inverter circuit driving module, the intelligent gate driver has the advantages of meeting the requirement of isolating input and output signals, avoiding the delay of the signals in the transmission process, keeping the smoothness of the signals and ensuring the stability of the system, in addition, the IGBT can generate common-mode interference when being switched on at high frequency in the working process, and the driver has certain common-mode rejection capability and avoids serious electromagnetic interference.

The filtering module comprises a filter, in order to further improve the stability of the photovoltaic inverter and further reduce the influence caused by the magnitude of grid-connected current ripples, the direct-current bus voltage Upv, the maximum amplitude voltage Ugm of the power grid output, the current ripple amplitude delta Imax, the switching frequency P, the current peak value Igmax and the inductance value D of the filter should satisfy the following relationship:

in the above formula, Upv, Ugm unit, V; imax, Igmax units, a; alpha is a relation coefficient and has a value range of 0.87-3.55.

Example two:

referring to fig. 1 to 11, on the basis of the first embodiment, a temperature adjusting assembly is further disposed in the protection box 1, and the temperature adjusting assembly is used for adjusting the temperature of the inverter body 2.

The temperature adjusting assembly comprises a gas temperature adjusting box 4, a liquid storage box 6 and a temperature sensor, the gas temperature adjusting box 4 is positioned outside the protection box 1, the liquid storage box 6 is positioned inside the protection box 1, the temperature sensor is positioned inside the protection box and used for detecting the temperature inside the protection box and feeding back the temperature to the DSP control module 3 in a signal form, a semiconductor refrigerating sheet 41 is vertically arranged inside the gas temperature adjusting box 4, a first cavity 43 is formed between the cold end surface of the semiconductor refrigerating sheet 41 and the gas temperature adjusting box 4, a second cavity 44 is formed between the hot end surface of the semiconductor refrigerating sheet 41 and the gas temperature adjusting box 4, a first gas inlet pipe 5 is arranged in the first cavity 43, the other end of the first gas inlet pipe 5 is positioned in the liquid storage box 6, and a plurality of first gas inlets 44 are further arranged at the first cavity of the gas temperature adjusting box 4, be provided with radiator fan 45 in the second chamber, gas temperature regulation case 4 is located second chamber department still is provided with a plurality of louvres 45, first intake pipe 5 is located the one end of liquid reserve tank is located the liquid level below of liquid reserve tank, the upper end of liquid reserve tank 6 is provided with first gas outlet, first gas outlet department is provided with first one-way air outlet valve 7. Through this setting, can guarantee that the semiconductor refrigeration piece can heat or cool down the gas of first cavity, gas in the first cavity can be through first intake pipe, the liquid reserve tank enters into the guard box inside, exhaust mechanism can arrange the outside with the inside gas of guard box, can make the interior negative pressure that forms of guard box, the gas in the first cavity of being convenient for gets into in the guard box, the liquid reserve tank can also handle the gas that gets into, gas and water liquid mix, can reduce debris such as dust and get into the possibility in the guard box.

Temperature regulation subassembly still includes exhaust mechanism 8, exhaust mechanism 8 includes first mechanism 81, second mechanism 82, third mechanism 83, first mechanism, second mechanism, third mechanism all are connected with bent axle 84, the one end of bent axle 84 is connected with the motor, the left side of third mechanism is provided with second gas outlet 836, second gas outlet 836 with the outside intercommunication of guard box 1, second gas inlet department is provided with the one-way air outlet valve 837 of second.

First mechanism 81 is in with the setting of second mechanism 82 symmetry the both sides of third mechanism 83, just the structure of first mechanism and second mechanism is the same, bent axle 84 runs through the second mechanism, and constitutes to rotate with the second mechanism and be connected, the bent axle runs through first mechanism simultaneously, and constitutes to rotate with first mechanism and be connected, the motor drive bent axle rotates.

First mechanism 81 includes first barrel 811, bent axle 84 sets up the position that is close to the right side in first barrel 811 is inside, be equipped with first bearing 812 on the bent axle, first bearing with the bent axle rotates to be connected, the lateral wall of first bearing is connected with first connecting rod 813, the other end of first connecting rod rotates through the third bearing and is connected with first push rod 814, the other end of first push rod 814 is connected with first piston block 815, first piston block passes through rubber pad sliding seal with first barrel inner wall and is connected, the lateral wall of first barrel is equipped with second air inlet 816, second air inlet department is equipped with first one-way admission valve 817, the lateral wall of first barrel is close to left position and is provided with the second intake pipe, the other end and the third mechanism of second intake pipe are connected.

Third mechanism 83 includes second barrel 831, bent axle 84 establishes the outside right side at the second barrel, be connected with second bearing 832 on the bent axle, the lateral wall of second bearing is connected with second connecting rod 833, the second connecting rod runs through the right side wall of second barrel, the other end of second connecting rod is connected with second push rod 834, the other end of second push rod is connected with second piston block 835, second piston block passes through rubber pad sliding seal with second barrel inner wall and is connected, the lateral wall of second barrel is close to left end position symmetric connection and has second intake pipe 85 and third intake pipe 86, the second intake pipe is connected with first mechanism, third intake pipe 86 is connected with second mechanism, the left end of second barrel runs through the lateral wall and the external world intercommunication of guard box 1.

The junction of the second air inlet pipe 85 and the second cylinder 831 is correspondingly provided with a third air inlet 838, the junction of the third air inlet pipe 86 and the second cylinder 831 is correspondingly provided with a fourth air inlet, and the third air inlet and the fourth air inlet are both provided with second one-way air inlet valves.

By arranging the exhaust mechanism, the crankshaft 84 can be driven to rotate when the motor works, and in the rotating process of the crankshaft, when the crankshaft in the first cylinder drives the first connecting rod and the first push rod to move rightwards, because the first one-way air inlet valve of the second air inlet is under the action of negative pressure, the crankshaft is in an open state, air in the protection box enters the first cylinder, and the second one-way air inlet valve arranged at the second air inlet pipe is under the action of negative pressure, and is in a closed state; the second mechanism is in the same state as the first mechanism; meanwhile, a second connecting rod and a second push rod in the second cylinder move leftwards under the action of the crankshaft, in the process, because a second one-way air inlet valve is in a closed state under the action of negative pressure, a second one-way air outlet valve 837 arranged at a second air outlet at the left side of the second cylinder is in a more open state under the action of pressure, and air in the second cylinder is quickly exhausted to the outside under the action of pressure; when the crankshaft drives the second connecting rod and the second push rod to move rightwards, the second one-way air inlet valve at the second air inlet pipe and the third air inlet pipe is opened under the action of negative pressure, the second one-way air inlet valve is closed under the action of negative pressure, at the moment, the first connecting rod in the first cylinder drives the first push rod to move leftwards, the first piston block extrudes air in the first cylinder, the air enters the second cylinder quickly through the second one-way air inlet valve in the opened state, timely supplement of air in the second cylinder is completed, the replacement rate of air in the protection box can be further improved through the arrangement, the temperature regulation efficiency is further improved, and external dust and sundries can be effectively prevented from entering the protection box.

The bottom is provided with the protective assembly in the guard box 1, the protective assembly includes wooden filler strip 91 and damping anti-impact pad 92, inverter body 2 is located on the wooden filler strip, the lower extreme of wooden filler strip through damping anti-impact pad with the guard box is connected, the inside align to grid of damping anti-impact pad has cellular hexagonal thin wall hollow cylinder 93, be equipped with air chamber 94 between the adjacent hollow cylinder. Through this setting, the vibrations that slow down the inverter body that can be fine.

The inner wall of the protection box 1 is further provided with an insulating layer, the insulating layer is an aramid fiber insulating paper layer, and the outer wall of the protection box 1 is further provided with a heat insulation layer.

In order to further improve the stability of the photovoltaic inverter and ensure that the inverter body is always in a reasonable temperature environment when working, the invention also provides a method for adjusting the temperature of the inverter, which comprises the following steps:

s1, the temperature sensor collects the temperature inside the protection box in real time and sends the temperature to the DSP control module in a signal form;

s2, setting five working modes in the DSP control module, namely a primary cooling mode, a secondary cooling mode, a primary heating mode, a secondary heating mode and a standby mode, wherein the four working modes have respective value intervals, and the DSP control module calculates the temperature difference delta W between the temperature difference delta W and a preset threshold value according to the temperature value sampled by the temperature sensor;

and S3, the DSP control module determines the working mode of the semiconductor chilling plate according to the temperature difference delta W and controls the rotation and stop of the motor.

In step S3, when the temperature difference Δ W is within the value range of the primary cooling mode, the DSP control module controls the semiconductor cooling plate to operate at low power by controlling the input current, and causes the motor to rotate at low speed; when the value of the temperature difference delta W is in the value range of the secondary cooling mode, the DSP control module controls the semiconductor refrigerating sheet to work at high power by controlling the input current and enables the motor to rotate at high speed; when the temperature difference delta W is in a value range of the first-stage heating mode, the DSP control module realizes the reversal of the anode and the cathode of the semiconductor chilling plate through the H-bridge driving circuit, controls the low-power work of the semiconductor chilling plate through the control of input current and enables the motor to rotate at a low speed; when the temperature difference delta W is in the value range of the secondary heating mode, the DSP control module realizes the reversal of the anode and the cathode of the semiconductor refrigerating sheet through the H-bridge driving circuit, controls the high-power work of the semiconductor refrigerating sheet through the control of the input current and enables the motor to rotate at a high speed.

Other technical solutions not described in detail in the present invention are prior art in the field, and are not described herein again.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention; any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.