1. Remote maintenance: Remote maintenance can be carried out through the software of the PV inverter collector management system V1.0.

2. Local maintenance: The software "PBOXConfigToool" can be used for local maintenance through serial port.

3. WIFI parameter maintenance: AP mode is supported for WIFI module, which can be configured through OpticalWIFI.

Configure the maintenance tool on the cloud and APP

Cloud configuration (State Grid Cloud photovoltaic Poverty Alleviation Agreement)

Procedure of APP configuration tool:

Configuration video

4.1 Serial port parameters are 9600,8, N, 1.

4.2. Set the IP address (domain name) and port number to be connected.

4.3. Set Apn, User name, and password.

4.4. Set the serial number and password of the device.

4.5 Set the device model. Select a frequency converter model from the table below.

4.6 Smart electricity meters are set on the power generation side and the Internet access side.

4.7. Click Set.

According to the inverter output AC voltage phase number, can be divided into single-phase inverter and three-phase inverter; According to the type of semiconductor devices used by the inverter, it can be divided into transistor inverter, thyristor inverter and thyristor inverter can be turned off. According to the different principle of inverter line, it can also be divided into self-excited oscillation inverter, step wave superimposed inverter and pulse width modulation inverter. According to the application in the grid-connected system or off-grid system can be divided into grid-connected inverter and off-grid inverter. In order to facilitate photoelectric users to choose the inverter, here only to the inverter for different occasions for classification.

1. Centralized inverter

Concentrated inverter technology is a number of parallel photovoltaic series are connected to the DC input of the same concentrated inverter, the general power of the use of three-phase IGBT power module, the use of smaller power field effect transistor, while the use of DSP conversion controller to improve the quality of power output, so that it is very close to the sine wave current, Generally used in large photovoltaic power stations (> 10kW) in the system. The biggest feature is the high power and low cost of the system. However, because the output voltage and current of different photovoltaic arrays are often not completely matched (especially when the photovoltaic arrays are partially blocked due to cloudy, shade, stains and other reasons), the centralized inverter will lead to the reduction of the efficiency of the inverter process and the decrease of the energy of the battery. At the same time, the power generation reliability of the whole photovoltaic system is affected by the bad working state of a photovoltaic unit group. The latest research direction is the use of space vector modulation control and the development of new inverter topology connection to achieve high efficiency under partial load.

2. Group and string inverter

Series inverter is based on the modular concept, each PV series (1-5kw) through an inverter, the DC end has the maximum power peak tracking, parallel grid in the AC end, has become the most popular inverter in the international market.

Many large photovoltaic power plants use series inverters. The advantage is that it is not affected by the module difference and shading between the group and the series, and at the same time reduces the best working point of the photovoltaic module and the inverter does not match, so as to increase the power generation. These technical advantages not only reduce the system cost, but also increase the reliability of the system. At the same time, the concept of "master-slave" is introduced between the groups, so that the system can connect several groups of photovoltaic groups together, so that one or several of them can work, so as to produce more electric energy.

3. Micro inverter

In the traditional PV system, the DC input end of each series inverter will be connected by about 10 photovoltaic panels in series. When one of the 10 panels in series doesn't work well, it affects all of them. If the inverter multiple input uses the same MPPT, then all inputs will be affected, greatly reducing the power generation efficiency. In practical applications, clouds, trees, chimneys, animals, dust, snow and ice can cause these factors, which is very common. In the PV system of micro inverter, each panel is connected to a micro inverter. When one of the battery panels does not work well, only this one will be affected. All the other photovoltaic panels will operate at their best, making the system more efficient overall and generating more power. In practice, if the series inverter failure, will cause several kilowatts of panels can not play a role, and the impact of microinverter failure is quite small.

4. Power optimizer

Solar power system installation power OptimizEr (OptimizEr) can greatly improve the conversion efficiency, and the Inverter (Inverter) function simple cost reduction. For smart solar power systems, a power optimizer allows each solar cell to perform at its best and monitor battery depletion at any time. The power optimizer is a device between the power generation system and the inverter, the main task is to replace the original optimal power point tracking energy of the inverter. By simplifying the circuit and matching a single solar cell to a single power optimizer, the power optimizer performs a very fast analog scan of the optimal power point tracking, so that every solar cell can achieve the optimal power point tracking. In addition, it can also monitor the status of the cell anytime and anywhere by placing a communication chip. Immediate return problems allow relevant personnel to repair as quickly as possible.

Three, the function of photovoltaic inverter

The inverter not only has the function of direct AC conversion, but also has the function of maximizing the performance of the solar cell and the function of system fault protection. Summed up, there are automatic operation and shutdown function, maximum power tracking control function, anti-independent operation function (for grid-connected systems), automatic voltage adjustment function (for grid-connected systems), DC detection function (for grid-connected systems), DC grounding detection function (for grid-connected systems). The functions of automatic operation and shutdown and maximum power tracking control are briefly introduced here.

(1) Automatic operation and shutdown function

After sunrise in the morning, the intensity of solar radiation gradually increases, and the output of solar cells increases accordingly. When the output power required by the inverter is reached, the inverter automatically starts to run. After entering operation, the inverter will monitor the output of the solar cell module from time to time. As long as the output power of the solar cell module is greater than the output power required by the inverter, the inverter will continue to run; Until sunset shutdown, even in rainy weather the inverter can run. When the output of the solar cell module becomes smaller and the output of the inverter is close to 0, the inverter will be in standby state.

(2) Maximum power tracking control function

The output of the solar cell module varies with the intensity of solar radiation and the temperature of the solar cell module itself (chip temperature). In addition, the solar cell module has the characteristic of voltage decreasing with the increase of current, so there is an optimal operating point to obtain the maximum power. The intensity of solar radiation varies, and obviously so does the optimal working point. Relative to these changes, the operating point of the solar cell module is always at the maximum power point, and the system always obtains the maximum power output from the solar cell module. This control is the maximum power tracking control. The most important feature of the inverter used in solar power system is that it includes the function of maximum power point tracking (MPPT).

Four, the main technical indicators of photovoltaic inverter

1. Stability of the output voltage

In the photovoltaic system, the electric energy produced by the solar cell is first stored by the battery, and then converted into 220V or 380V alternating current by the inverter. However, the output voltage of a battery varies widely due to its own charging and discharging. For example, for a nominal 12V battery, its voltage can vary between 10.8 and 14.4V (exceeding this range may cause damage to the battery). For a qualified inverter, when the input voltage varies within this range, the steady-state output voltage shall not change by more than the rated value. 5%, and when the load changes, the output voltage deviation should not exceed ± 10% of the rated value.

2. Waveform distortion of output voltage

For sine wave inverter, the maximum allowed waveform distortion degree (or harmonic content) should be specified. It is usually expressed as the total waveform distortion of the output voltage, which should not exceed 5% (l0 % is allowed for single-phase output). Because the high harmonic current output of the inverter will produce eddy current and other additional losses on the inductive load, if the inverter waveform distortion is too large, it will lead to serious heating of the load components, which is not conducive to the safety of electrical equipment, and seriously affect the operating efficiency of the system.

3. Rated output frequency

For loads including motors, such as washing machines, refrigerators, etc., because the optimal frequency of the motor operating point is 50Hz, too high or too low frequency will cause equipment heating, reduce the operating efficiency and service life of the system, so the output frequency of the inverter should be a relatively stable value, usually the power frequency of 50Hz, Under normal working conditions, the deviation should be in. Within l %.

4. Load power factor

Characterizes the ability of the inverter to carry inductive or capacitive loads. The load power factor of sine wave inverters is 0.7 to 0.9, and the rating is 0.9. In the case of a certain load power, if the power factor of the inverter is low, the capacity of the inverter is required to increase, on the one hand, resulting in an increase in cost, at the same time, the apparent power of the AC circuit of the photovoltaic system increases, the loop current increases, the loss will increase, and the system efficiency will be reduced.

5. Inverter efficiency

The efficiency of the inverter refers to the ratio of the output power and the input power under the specified working conditions, expressed as a percentage. In general, the nominal efficiency of the photovoltaic inverter refers to the pure resistance load, the efficiency of 80% of the load. Due to the high overall cost of photovoltaic system, it is necessary to maximize the efficiency of photovoltaic inverter, reduce the system cost, and improve the cost performance of photovoltaic system. At present, the nominal efficiency of mainstream inverters is between 80% and 95%, and the efficiency of low-power inverters is not less than 85%. In the actual design process of photovoltaic system, not only should choose the high efficiency inverter, but also through the reasonable configuration of the system, as far as possible to make the photovoltaic system load work near the best efficiency point.

6. Rated output current (or rated output capacity)

Represents the rated output current of the inverter within the specified load power factor range. Some inverter products give a rated output capacity, expressed in VA or kVA. The rated capacity of the inverter is the product of the rated output current when the output power factor is 1 (i.e., pure resistive load).

7. Protection measures

An inverter with excellent performance should also have complete protection functions or measures to cope with various abnormal situations in the actual use process, so that the inverter itself and other parts of the system from damage.

(1) Input undervoltage insured:

When the input terminal voltage is lower than 85% of the rated voltage, the inverter should be protected and displayed.

(2) Input overvoltage insured:

When the input terminal voltage is higher than 130% of the rated voltage, the inverter should be protected and displayed.

(3) Overcurrent protection:

The overcurrent protection of the inverter should be able to ensure timely action when the load occurs short circuit or the current exceeds the allowable value, so that it will not be damaged by the surge current. When the working current exceeds the rated 150%, the inverter should be able to protect itself.

(4) output short circuit protection

The short circuit protection operation time of the inverter should not exceed 0.5s.

(5) Input backconnection protection:

When the input is correct and the negative pole is reversed, the inverter should have protective function and display.

(6) Lightning protection:

Inverter should have lightning protection.

(7) over temperature protection

In addition, for the inverter without voltage stability measures, the inverter should also be output overvoltage protection measures, so that the load from overvoltage damage.

8. Starting characteristic

To characterize the ability of the inverter to start with load and its performance in dynamic operation. The inverter shall be guaranteed to start reliably under rated load.

9. noise

Noise is generated by transformer, filter inductor, electromagnetic switch and fan in power electronic equipment. When the inverter is running normally, its noise should not exceed 80dB, and the noise of small inverter should not exceed 65dB.

Five, selection skills

Inverter selection, the first consideration should be sufficient rated capacity, in order to meet the maximum load of the equipment on the electrical power requirements. For the inverter with a single device as the load, the rated capacity selection is relatively simple.

When the electrical equipment is a pure resistive load or the power factor is greater than 0.9, select the rated capacity of the inverter to be 1.1 to 1.15 times the capacity of the electrical equipment. At the same time, the inverter should also have the ability to resist capacitive and inductive load impact.

For general inductive loads, such as motors, refrigerators, air conditioners, washing machines, high-power water pumps, etc., when starting, its instantaneous power may be 5 to 6 times its rated power. At this time, the inverter will bear a large instantaneous surge. For this kind of system, the rated capacity of the inverter should be left with sufficient margin to ensure that the load can be started reliably. The high performance inverter can be started continuously at full load without damaging the power components. For the safety of small inverter, sometimes soft starting or current limiting starting mode is needed.