1. What is an inverter and its function?
   
2. What constitutes an Inverter?
   
3. What is PWM based Mosfet technology?
   
4. What constitutes a Good Inverter?
   
5. What is Quasi Sine Wave (stepped sine wave), Sine wave and Square Wave?
   
6. What are the essential protections & features for a good Inverter?
   
7. What is the difference between Mosfet based power Inverters vs. other Inverters?
8. How is this increase in efficiency obtained?

A: Mains Power sensing circuit: When the AC Power comes below 110VAC or above 280VAV or if there is a total mains failure, the system automatically switches to the back-up source of power.
B. Battery charger: A module that charges the battery when AC comes and prepares battery to give back energy in case of mains power failure.
C. Inverter (DC-to AC converter): A system that would convert the energy stored in the battery/batteries to give back-up power to appliances i.e 230VAC 50Hz.

The smooth DC power (battery power) is inverted by two channels of Mosfets (switching device) in Push-Pull/ bridge configuration. The switching device (Mosfets, IGBTs or Transistors) is used and controlled by a sophisticated control circuit. A closed loop voltage feedback control is used to keep the output voltage constant even under widely varying DC voltage (Batteries) conditions and the load on Inverter. A proportional increase in the width of the pulses causes an increase in voltage and a proportional reduction in width decreases the voltage. This means the voltage control action of variable gain is normally accomplished by varying pulse width to the power.

This method of varying pulse width is known as Pulse width Modulation (PWM) controls. All models of Genus - Power Inverters provide regulated output voltage (PWM Controlled) on battery mode a per the load distribution voltage standard.

Operating a Microwave with a Power Inverter.

The power rating used with microwave ovens is the "cooking power" which refers to the power being "delivered" to the food being cooked. The actual operating power requirement rating is higher than the cooking power rating (for example, a microwave with "advertised" rating of 600 watts usually corresponds to almost 1100 watts of power consumption). The actual power consumption is usually stated on the back of the microwave. If the operating power requirement cannot be found on the back of the microwave, check the owner's manual or contact the manufacturer.

• Fast Mains Power sensing circuits: In case of power failure, a good inverter would switch to battery for backup so fast that the time of switching is not to be perceptible. As a result some appliances that required a higher start current, like the refrigerator can be driven using Inverter.
  
• Battery charger System: Battery is the life of the Inverter. An Inverter lives on battery so it is the responsibility of the Inverter to protect the battery and use it optimally and enhance its life. Inverter battery lifetime is maximized if the battery is always powered from a constant current charger. Genus power Inverter gives constant charging current to batteries irrespective of the A.C Voltage i.e. whether the AC Voltage is 150 or 270V, the battery gets nearly the same charging current. This protects the battery plates from damage and Genus power Inverter has an advanced trickle charging mechanism built in the system to prevent batteries from overcharging and to increase the battery life.
  

Inverter (DC to AC Inverter): The main part of the Inverter system, one that converts battery energy to backup power must be designed to deliver high grade power most efficiently. Genus's power Inverter is designed to perform this function in the absence of power.

The power from the mains is a sinusoidal wave (Sine wave) of frequency 50Hz. Ideal backup power source would be one that generates the equivalent sine wave of the same as that of the mains. Genus range of power Inverters give power in the form of stepped Sine wave (Quasi Sine wave) voltage so that the bulbs & Tubelights glows at an optimal brightness without any humming sound.

In fact most of the times it is difficult to realize the absence of main power. Genus inverters voltage regulations in the inverter is very good. So the output voltage (on battery mode) would remain nearly constant irrespective of battery condition and load on the Inverter.

Square Wave produce the humming sound and reduce the life of the appliances. In most of the Transistor power inverter, output is the square wave on battery mode.

Genus power Inverter produces the stepped Sine Wave (Quasi Sine Wave) which is nearly equivalent of the AC Main Sine wave and gives the same results.

Overload protection with Auto-resetting:

As you apply load (bulb, fan,tubes etc.) more than invereter capacity (during Inverter ON condition), it will warn you with Beep Sound & LED Indication, in this situation the system will shut down Output for a few seconds and then start to check the load on Inverter, and do this process again & again until you don't reduce the load & when the loads become within the capacity of the Inverter, the Inverter will stop beep sound anf off the OVERLOAD indication and will supply the power to your appliances automatically.

Low battery/deep discharge protection:

The battery must be protected from discharging completely. Lead Acid batteries / SMF / Tubular batteries should not be discharged below a certain threshold level. The battery deep discharge protection is required because a deeply discharge battery is difficult to recharge. Genus's range of power Inverters have the low Battery / deep discharge.

Battery over charge Protections:

Overcharging occurs when battery continues to get charged with high value of current after getting fully charged. Such charging corrodes the battery plates and reduce the battery life.

Hence battery-overcharging protections is necessary because if battery is getting over charged frequently, then it will reduce the life of battery. Genus's power Inverter models have the Battery overcharge protection.

Short circuit protection:

A good Inverter must also protect itself from damage. Since an Invereter is a consumer product and is connected on house wiring , chance of risk must be minimized. It must have a built-in short circuit protection, so that if any equipment connected across it were to be short circuited, the Inverter itself should not get damaged due to drawing high current.

The Genus inverters come with a fuse free, Electronic short circuit protection. This would prevent damage to the Inverter as well as the other appliance attached to it.

Reverse battery protection:

It means when the batteries to Inverter connected in reverse (i.e. +of battery to -ve of Inverter and -ve of batteries to +ve of Inverter), The system should not damage. Genus's power inverters have the same protections.

Frequency stability:

Many appliances are by design dependent on the frequency of the Input power (normal Input Supply Frequency (50Hz +/- 5%). The output wave from the Inverter should be stable (50Hz) for proper functioning of these equipment's.

The Frequency stability of Genus Inverters is achieved by PWM ( Pulse width Modulation) controller, which delivers stable high grade of power. This controller also ensures frequency stability with temperature to the tune of 2%.

CCCV Battery charger:

Inverter battery life time is maximized if the battery is always powered from a constant current constant voltage (CCCV) charger.

All Genus power Inverters is designed for the hostile Indian power conditions. The charger of Inverter is designed on the silicon controlled rectifier Technology (acknowledged as the best technology for battery charging), because of which power consumption is minimum and give constant charging current to batteries irrespective of A.C Voltage. Whether the A.C Voltage is 145 or 270V, the battery gets nearly the same charging current through the CCCV charger.

High efficiency of system:

The efficiency of the Inverter system is calculated by comparing the Input power with the Output power in the Inverter/Battery mode of operation. A device that has a high switching speed can only achieve maximum efficiency. MosFet is a high speed-switching device.

Genus's 'Mech' power Inverter design is based on MosFets. The design has an Inverter efficiency of 95% and overall efficiency of nearly 92%. This results in more backups with less stress on batteries.

The Inverter usually comprises of a power circuit which is 'switched' at a pre-determined frequency to generate a stepped wave. There are various types of devices used in the inverter power circuit. Earlier technologies used bipolar junction transistors or BJTs (1960's) and power transistor (1970s). The latest generation devices are power MOSFETs which have revolutionized the inverter technology and offer unique advantages over conventional devices.

MOSFETs are majority carrier, voltage-driven devices and their construction and principles of operation are fundamentally different from BJTs, which are minority carrier, current-driven devices.

MOSFETs offer several significant advantages over thyristors as well, which include the ability to operate at frequencies above the audible range, low output distortion, high overload capability, negligible switching and snubber circuit losses, fast response and simple drive circuitry.

Device characteristics limit the use of BJTs for high-frequency switching applications. Minority carrier delay times limit the switching speed to the 500 to 5,000 nanosecond ranges. MOSFETs on the other hand, are majority carrier devices and switch in the 20-to-100 nanosecond range. Conventional Inverter systems have an efficiency range of 60-to-80 %. MOSFET-based systems with inverter efficiency as high as 92.5%.

Losses in the inverter circuit are primarily switching losses, snubber losses and I2R losses. Use of MOSFETs practically eliminates the first two losses. Unlike BJTs MOSFETs are a majority carrier devices having no storage time effects. Switching losses are directly proportional to turn-on and turn-off times, which, for MOSFETs, are in the nanosecond range, practically eliminating switching losses. Further, in MOSFETs switching performance is essentially independent of operating temperature, unlike BJTs wherein efficiency drops as temperature increases with switching times.

Snubbers are resistive devices used in inverter power circuits to control the rate of rise of voltage caused by rapid switching. MOSFETs have a very high dv/dt rating (in the range of 1000 to 2000 volts/microsec) eliminating the need for snubbers altogether. BJTs, on the other hand , have dv/dt limited to about 200 volts/micro sec. Such turn-off times need very heavy snubbers across the devices, resulting in losses.

As a result of this increase in efficiency, for the same capacity battery, MOSFET-based inverters ensure longer backup time and lower AH batteries can be used, thereby reducing battery cost.

Surge currents are normally generated at the time of switching on equipment, sudden changes in load, etc. For instance, a refrigerator draws up to eight times its normal current draw during start-up. MOSFET-based inverters can handle higher inrush currents.

Genus inverter design is based on MOSFETs. The design has an inverter efficiency of nearly 92%. This results in more backup with less stress on the batteries.