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1.Using environmental conditions
Solar off grid inverters normal use conditions: altitude is not more than 1000m, air temperature of 0～+40℃.

2.DC input power supply condition
Input DC voltage fluctuation range: ±15% of battery rated voltage.

3.Rated output voltage
Under the specified input power supply conditions, when output the rated current, the rated voltage of the inverter should be output.

4.Rated output current
Under specified output frequency and load power factor, the rated current of the inverter should be output.

5.Rated output frequency
Under the specified conditions, the rated output frequency of the fixed frequency inverter is 50Hz:

6.Maximum harmonic content
When the pure sine wave inverter under resistive load, the maximum harmonic content of output voltage should be less than or equal to 10%.

7.Overload capacity
Under specified conditions, in a relatively short period of time, the capacity of the output of the inverter over the rated current value. The overload capacity of the inverter should meet certain
requirements under the specified load power factor.

8.Efficiency
Under the rated output voltage, the output, the current and the prescribed load power factor, the output power of the inverter is compared with that of the input active power (or DC power).

9.Load power factor

The allowable variation range of the load power factor of the inverter, the recommended value of 0.7 – 1.0.

10.The non symmetry of load

In the 10% asymmetric load, the non-symmetry of fixed frequency three-phase inverter output voltage should be less than or equal to 10%.

11.The non-symmetry of output voltage

Under normal operating conditions, the load is symmetric, the non-symmetry of output voltage should be less than or equal to 5%.

12.Starting characteristics
Under normal operating conditions, the inverter can normally start 5 times in full load and no load operation.

13.Protection function
Solar inverter should be set: short circuit protection, over current protection, over voltage protection, under voltage protection and lack of phase protection.

14.Interference and anti interference
Solar inverter should be able to stand the general environment of electromagnetic interference under the normal working conditions. The anti interference performance and electromagnetic
compatibility of the solar inverter should meet the requirements of the relevant standards.

15.Noise

The inverter which not often operation, monitor and maintain should be less than 95db;
The inverter which operate, monitoring and maintenance regularly should be less than 80db.

16.Display
The solar energy inverters should be provided with the data of AC output voltage, output current and output frequency, and there are input live, power and fault status of the signal display.

Determine the technical conditions of the solar inverter:
When the photovoltaic / wind power system is selected, firstly need to determine the main technical parameters of the inverter:
Input DC voltage range, such as DC24V, 48V, 110V, 220V, etc.;
Rated output voltage, such as three phase 380V, or single phase 220V;
Output voltage waveform, such as sine wave, trapezoidal wave or square wave.

Temperature and humidity are the two main reasons for the failure of outdoor rated UPS. The electronic systems may does not contain the design of against harsh environmental conditions, in order to meet the protection of electronic equipment in the indoor and the outdoor environment, the industry invested a lot of time in dealing with the problem of cooling treatment. The cooling treatment of outdoor UPS systems has become a very important issue. In fact, it is only necessary to eliminate the problem of internal heat which is caused by the size limitation and the light radiation in the face, so it can solve the heat dissipation problem of outdoor electronic equipment.

The heat management of the outdoor AC UPS must make a choice for the environmental conditions of the equipment. The equipment is usually divided into indoor equipment and outdoor equipment. Indoor equipment including installation in the central office (CO) or client switching equipment (for different application circuit board), server, router, modem and batteries, depending on end use and decide. Outdoor equipment includes all the equipment that can be seen in the central computer room, but they are installed in a controlled environment.

In addition to ensuring that the device is in the best temperature and humidity conditions, and the telecom engineers must ensure that the equipment to maintain proper heating conditions in a short period of time to the power supply interruption or cooling device failure, until the outdoor UPS cooling device recovery work. Therefore, in the design of appropriate heat dissipation systems, designers must consider the heat dissipation problems may be encountered while in the normal state (steady state) and emergency state.

The above guidelines apply to the central computer room and client equipment as well as outdoor equipment. In addition to the general exchange and processing equipment, the battery device for providing power supply during power outages is also very important. Battery equipment also need to heat dissipation, but also put in a proper ventilation conditions in the house.

In the process of using IGBT UPS, often by the impact of capacitive or inductive load, overload and even short circuit, etc., as well as the wrong operation of UPS, may cause IGBT damage. IGBT in the use of the main reasons for the failure of the following conditions:

1.Over current damage

IGBT has a certain anti over current capacity, but must pay attention to prevent the current damage. IGBT composite device has a parasitic thyristor, so has the latching effect. After the latching effect occur, the drain current cause excessive high power consumption, and finally lead to the damage of the device.

In order to avoid the IGBT happens latching effect and damage, the circuit design should ensure the IGBT maximum working current should not exceeding the IDM value of the IGBT. Also note that may be appropriate to increase the driving resistance Rg to extend the shutdown time, reduce the di / dt of IGBT. Driving voltage size will also affect IGBT latching effect, low driving voltage, under over current in long time and IGBT must be applied with negative bias voltage, IGBT manufacturers generally recommend with about 5V reverse bias voltage. In a negative bias voltage, the driving voltage is between 10 and 15V, and the drain current is 4 to 10 times higher than the rated current in the 5~10μs, so the driver IGBT must be designed with a negative bias voltage. Due to each IGBT based UPS load impact characteristic is not identical, and powered devices may occur short circuit fault, so take measures to limit the flow of IGBT current in the UPS design is necessary, consider using driving thick film circuit provided by IGBT manufacturers.

2.Over voltage damage
Due to the inductive components in the inverter circuit, IGBT will generate spike voltage in the moment of turn off, if the peak voltage is too high, may cause damage to the IGBT even breakdown. Prevent voltage damage methods: optimization of process structure of main circuit, by narrowing the large loop current path to reduce the circuit parasitic inductance; appropriately increase the IGBT driving resistance Rg to slow down the speed of the switch (but switching losses also increased); buffer circuit design, suppression of spike voltage. The diode used in the buffer circuit must be a fast recovery diode, the capacitor must be the film capacitor which is high frequency, low loss, good frequency characteristics. So as to achieve a good absorption effect. The common circuit divide into energy dissipation type and feedback buffer type. Feedback buffer type divide into passive type and active type.

3.Bridge arm damage
In IGBT online UPS, the two drivers of the same arm branch of the inverter bridge must be locked, and the dead time (i.e. common non conducting time) should be set. If common conduction happens, IGBT will soon be damaged. In the control circuit, the control timing of the driving problem should be considered in various operating conditions.

4.Overheat damage and electrostatic damage
Can be used to increase the amount of heat sink, heat conductive adhesive coating, forced fan cooling, set over temperature protection and other methods to solve the problem of overheating damage. In addition to pay attention to the electrostatic damage in installation process, the operator and tools must be protected against static electricity.

1.After the intention to purchase an EV, check the installation conditions
Before the installation of EV charging piles, the first thing you need to do is to survey whether you have matched the installation conditions, such as whether there is a fixed parking spaces, how far from the power grid lines, etc.. The simplest method is to ask residential property for the situation. Property mustknow some simple relevant installation issues, such as the installation of the program, the use of electricity, installation area and so on. In fact, you don’t have to worry about that, because themanufacturers will send personnel to solve the professional problems later.

2.Go to 4S shop to apply for the survey of installation field, select the type of charging piles
When the staff survey the site, it is best to ask the property together to deal with the installation issues, thus can not only have the professionals to answer questions about the property, but also improve the installation efficiency. And the property will also give some suggestions to the installation staff, such as parking spaces are in line with the installation conditions, whether meet the requirements of the line and so on.
As for charging pile types, at present home charging pile can be divided into vertical type and wall mount type electric vehicle charger. The advantage of wall mount type is saving space, low price, but must be installed in the wall which can be wired. The price of vertical type is higher, and it will occupy a larger space, but can be installed in the open parking lot.

SOROTEC wall mount type electric vehicle charger.

3.Find out what type of residential power supply is
After the investigation and consultation of the construction site, the problem you need to solve is the power supply. In fact, the most common power supply of charging pile is ordinary residents electricity, we need to apply box power supply wire from the state power grid, after the approval of qualified, the state power grid will send corresponding staff to wire. In addition, there are both advantages and disadvantages if use small commercial electric pressure. Its shortage is more electricity cost, the advantage is to avoid the cumbersome process of dealing with the state power grid, you can directly ask property to solve the problems.

4.Confirm the installation scheme of charging pile, start construction
A few days after the survey and installation site, the construction side will give the corresponding installation program, generally is the installation costs and details, as well as the construction effect chart. After property confirm the price and the material is correct, you can let the workers to install charging pile. If the wiring has been completed at this time, then you can connect to the charging pile and use normally. Due to the charging pile can be considered as the necessary supporting equipment for the electric vehicle, so now many electric vehicle manufacturers with different charging pile installation policy, some manufacturers responsible for free installation, the other may require customers pay a few cost.

5.If charging pile is not completed, can use a portable charger in emergency
Because it involves multi-party negotiation, so the speed of construction will be a little slower, the cycle is generally 1 months. So within a period of no private charging pile, in addition to charge in the public charging stations and 4S shop, the by portable ev charger is also possible under the premise of ensuring the safety, but do not recommend use for a long time.

Test the main circuit DC voltage and output current, calculate the output power of the solar array, and achieve the maximum power point tracking. Disturbance resistance R and MOSFET series together, under the conditions of the output voltage is basically stable, by changing the duty cycle of MOSFET, to change the average current through the resistance, and the current disturbance is generated. At the same time, the output current and voltage of the photovoltaic cell will be changed. By measuring the change of the output power and voltage of the photovoltaic cell before and
after the disturbance, the disturbance direction of the next cycle will be determined. When the disturbance direction is correct, the output power of the solar energy board is increased, and the next cycle continues to move in the same direction. In this case, the disturbance and observation of the solar photovoltaic panels output up to the maximum power point.

12V 24V 48V MPPT Solar charge controller