Power Inverter buy points

How to choose the correct ups power inverter mainly pay attention to the following points .
1 , the rated output voltage: within a predetermined fluctuation range of the input DC voltage is allowed , it means that the rated voltage of the inverter should be output . The stability of rated output voltage accuracy is generally defined as follows : In steady-state operation , the voltage fluctuation range should be a limit , such as the deviation does not exceed the rating of ± 3% or ± 5%. Under load mutations or other interfering factors affecting the dynamics of the output voltage deviation should not exceed the rating of ± 8% or ± 10%.
2 , the output voltage imbalance : Under normal operating conditions, the inverter output phase voltage unbalance ( reverse component of the ratio of positive sequence component ) should not exceed a specified value , usually expressed in% as 5 % or 8 %.
3 , the output voltage waveform distortion : When the  220 volt power inverters   output voltage is sinusoidal , shall specify the maximum allowable waveform distortion ( or harmonic content ) . Usually to a total distortion of the output voltage waveform that its value should not exceed 5% ( 10% single phase output enable ) .
4 , rated output frequency of the inverter output AC voltage frequency should be a relatively stable value , usually frequency 50Hz. Under normal operating conditions the deviation should be within ± 1 %.
5 , the load power factor : the ability to characterize the capacitive load inverter with inductive load or . In the sine condition, the load power factor of 0.7 to 0.9 ( hysteresis ) , the rating is 0.9 .
6, rated output current : Indicates the inverter within the specified range of the rated output power factor of the load current . Some inverter products given is rated output capacity , the unit in VA or KVA said . The rated capacity of the inverter when the output power factor of 1 ( ie, purely resistive load ) , the rated output voltage of the rated output current of the product.
7 , rated output efficiency: The efficiency of the AC power inverters inverter under specified operating conditions , the output power to input power ratio , in%. Inverter efficiency at rated output capacity for full load efficiency of 10% at rated output capacity efficiency at low load efficiency.
8 , Protection: over-voltage protection : No voltage stabilization measures for the inverter output over-voltage protection measures due to the negative output cut from overvoltage damage.
Overcurrent protection : inverter over-current protection , should be able to ensure that a short circuit in the load current exceeds the allowable value or action from time to time , so from inrush current damage.
9 , starting characteristics : characterizing the performance of the inverter starting with a load capacity and dynamic work. The inverter should ensure reliable starting at rated load .
10 , the noise : the transformer power electronic device , the filter inductor , electromagnetic switches and other components are the fan noise is generated . Normal operation of the inverter , the noise should not exceed 80dB, small inverter noise should not exceed 65dB.

The working principle of the inverter

1 . Full-controlled inverter works: Figure 3 shows , for the full-bridge inverter main circuit commonly used single-phase output figure, the AC components using
the IGBT Q11, Q12, Q13, Q14. Controlled by the PWM pulse width modulation IGBT tube turned on or off .
   When the  4000 watt power inverter  circuit connected to a DC power source , first Q11, Q14 is turned on , Q1, Q13 is turned off, the current from the positive output of theDC
power supply , via Q11, L or sense transformer primary winding 1-2, back to Q14
to the negative power supply . When Q11, Q14 after the deadline , Q12, Q13 is
turned on , current flows from the positive power supply through Q13, electrical
transformer primary winding 2-1 am Q12 back negative power . In this case, the
transformer primary winding , has formed an alternating positive and negative
square wave , the use of high frequency PWM control , two pairs of IGBT tube
alternately repeated , generating an AC voltage on the transformer . Since LC AC
filter effect, so that the output AC voltage sine wave form .
   When Q11, Q14 off when , in order to release the stored energy in the IGBT
diode in parallel at D11, D12, so that energy back to the DC power supply to go.Th2 is triggered according conduction, because reverse biased anode Th2 , Th1
off, return the blocking state . Thus , Th1 and Th2 commutation , and then charge the capacitor C and reverse polarity . So turn triggered thyristors ,
alternating current flows transformer primary , the secondary of the transformer
to get the AC .
   In the circuit, the inductance L can be limited for the discharge current of
the capacitor C , to extend the discharge time to ensure that the circuit is
greater than the turn-off time of the  220 volt power inverters  turn-off time without a large
capacity capacitor . D1 and D2 are two feedback diode , inductor L can be the
energy release , it will be returned to the remaining energy supply , completethe feedback energy.

Solar inverter centralized inverter

Concentrated photovoltaic  sine wave power inverters  and is commonly used in large power stations (> 10 kw) system, a lot of parallel photovoltaic group of string is connected to a single centralized inverter dc input, the use of the general power three-phase IGBT power modules, the use of smaller power field effect transistor, at the same time using DSP conversion controller to improve the quality of the output power, making it very close to the sine wave current. Biggest characteristic is the system of high power, low cost. But the pv group string matching and part of the covering film, lead to the efficiency and capacity of the whole solar system. At the same time, the whole pv system reliability of generating a photovoltaic cell set of adverse effects of work status. The latest research direction is using space vector modulation control, as well as the development of new  grid inverters  topology connection, to get part of the load cases of high efficiency.
In SolarMax (sory & middot; mike) focused on the inverter, you can attach a photovoltaic array interface box, to monitor each string of strings of photovoltaic panels, such as one group work is not normal, the system will put this information on to the remote controller, at the same time can through the remote control will stop working, and the line which will not be reduced because of a string of photovoltaic (pv) list of fault and affect the entire solar system work and energy output.

Reducing the power inverter system operation and maintenance costs

 Integrated automation substation is now running in the background monitoring computer generally located, mostly for microwave communications equipment and optical machines, monitoring and grid inverters communications equipment such as AC power supply operating power to achieve uninterrupted power supply to meet the requirements of four remote different uninterruptible power supply equipment shall be installed 220v inverters  separately (UPS) and batteries. The installation of substation power inverter can be directly used in DC power systems use large-capacity battery provides AC power, UPS power supply scheme savings than investment costs, avoid duplication of investment in battery, reducing the maintenance workload, reducing the operating costs.

Power Inverter prospects

Power Inverter in foreign markets was generally welcomed. Abroad due to the higher prevalence of motor vehicles, there is no occasion when they go out in the mains work or travel to connect car battery with an  2500 watt power inverter   electrical appliances and power tools to drive to work. After China's entry into WTO, more and more private buyers in the domestic market, therefore, as a DC power inverter for use in the car on the move to AC power converter will bring convenience to your life, but also the essential car owners supplies.