The inverter is an electrical device, which is used to convert the DC power to an AC power. The inverter for home is used for emergency backup power and used in some aircraft systems to convert a portion of the aircraft DC power to AC. The alternating current mainly used for electrical devices used in homes like radio, lights, motor, etc. Inverter types are classified into many based on application like a sine wave, modified sine wave, square wave, voltage source inverter, multilevel inverter, etc.
These inverters can suit for various electricity needs, The voltage source inverters produce an output voltage or a current to required ranges and frequencies. These ranges are either positive or negative, it is known as two-level inverters. Multilevel inverter is to synthesize a near sinusoidal voltage from several levels of DC voltages. Multi level inverter main advantage is minimum harmonic distortion.
Domestic Inverter Types with Practical Examples
The domestic inverter is mainly used for household electric devices, the rating of domestic inverter mainly depends on the home applications, which are available in different load capacities. The basic construction of the inverter is, the input terminals of the inverter connect to the output terminals of the DC battery, and connected to a transformer through the center tap of the primary winding. The contact switch is rapidly switched back and forth to allow current to flow back to the battery following two alternate paths through one end of the primary winding and then the other. The alternation of the voltage of the primary winding of the transformer produces alternating voltage in the secondary circuit. This will be normally maintained by 230v/110 volts AC and can all home made application devices.
Most of the Home appliance alternating electrical power is observed. However AC power is not always available and the need for mobility and simplicity has given in batteries Thus, for portable AC power, for this purpose inverter is needed. Inverters take a DC voltage from an input terminal of a battery or a solar panel as input.
These inverters are classified by depending on their output as three types that is a square wave, modified-sine wave and pure sine wave. Normally Off-the-shelf inverters are generally either square wave or modified-sine wave and sine wave inverter. These 3 types of inverters less expensive and it is modified though delivering the same average voltage to a load, it is not appropriate for delicate electronic devices on the precise timing. Most of the pure sine wave inverter offer having good accuracy it is very high load capacity, but they are more complex in design and more expensive.
Pure sine wave inverters will power devices with more accuracy less power loss, and less heat generation. Pure sine wave inversion process is accomplished by taking a DC voltage source and switching it across a load using an H-bridge parameter. If this voltage needs to be boosted from a DC source, It can be accomplished before the AC stage by using a DC-DC boost converter or after the AC stage by using a boost transformer. The inverted signal itself is composed of a pulse-width-modulated (PWM) signal the PWM signal is encodes a sine wave. The duty cycle of the sine wave output signal is changed such that the sine wave power is transmitted. This output power can be used alternatively.
Square Wave Inverters
The conversion of DC to AC is most commonly done through the use of MOSFET inverter circuits which can switch the voltage across the load, providing a digital approximation of the desired AC signal. The simplest variant of this inversion is the production of a square wave conversion of a sine wave. In the form of square wave, The load voltage must be switched majorly from high voltage to low Voltage, without using for an intermediate step (0V). In order to deliver the same power as the sine wave to be approximated, the amplitude value of the square wave value and sine wave’s RMS value is same.
Therefore, the average voltages, and the power delivered will be the same for the two waveforms. Square wave inverters are very rarely used in practice, as many devices which utilize timing circuits that on something close to the sine wave from the power company cannot operate with such a rough. In addition, a square wave has relatively large 3rd and 5th harmonic components which burn power and severely cut down on the efficiency of devices using such inverters as a power source. In this bellow diagram op-amp is the main part of the square wave signal diagram.
Applications of square wave inverter
Majorly square wave inverter applications voltage source inverter having many applications in many low cost AC motor drives, That is like as an uninterrupted power supply and circuits utilizing electrical resonance between an inductor and capacitor.Some examples of circuits utilizing like resonance phenomenon are induction heating units and electronic ballasts for fluorescent lamps.
Modified Sine Wave Inverters
The operation of the Modified sine wave inverters will same a square wave inverter. In this we are majorly produce these square waves because of the 555 timers. Most of a power some equipment 555 timers generally need a 1kW and a 1MW resistor to achieve a 50% duty cycle and adjust the frequency with the capacitor. An adjustable capacitor or capacitors in series and parallel, It can enable you to get the right frequency. So that any multivibrator set for a 50% duty cycle will get for the first signal, and from where I live, AC is 60hz cycle, In my signal generator the multivibrator is set to120 cycles. However, where you live AC may be 40 or 50 cycles, And you may need to set the multivibrator for 80 or 100 cycles.
Everything after the transistors is a compressed version of the circuit board I built the signal generator The flip-flop should have a negative transition clock, it is so the And the gates are not on when the flip-flop toggles. The Opto-couplers are used as IGBT/Mosfet gates , Industrial inverters, gate logic inputs, microprocessor inputs just to name a few appellations. These protect one part of the circuit from the power in the rest of the circuit.
A very common upgrade to the modified square wave inverter is also known as a the modified sine wave inverter. These are having three voltage levels in the output waveform, high, low, and zero with a dead zone between the high and low sine wave pulses. The modified sine wave is a closer, An approximation of a true sine wave it is acts like a square wave, These modified sine waves can be used by most household electrical devices. As such, It is extremely common to see this type of inversion in industrial quality inverters. Being much more varied than a simple square wave.
The modified sine wave has some minor drawbacks. Like the square wave, modified sine waves have a large amount of power efficiency loss due to significant harmonic frequencies, inverter devices that rely on the input power waveform for a clock timer will not work properly. Many devices can work while powered by a modified sine source. This makes it an affordable design option for such implementations as household uninterruptible power supplies.
Modified sine wave is also called as a step wave, it acts like a pure sine wave, modified sine waves are main purposes is mainly used for very high efficiency. Such as microwaves, drills and clocks or motors will apply for using the modified sine wave inverter.
Applications of the Modified Sine Wave Inverter
- Output wave form is pure sine wave is a very low harmonic distortion compare to the other wave forms.
- Inductive loads like micro ovens and motors run correctly, That’s will quieter and cooler.
- Reduces audible and electrical noise in fans and fluorescent lights , audio amplifiers,TVs, game consoles, fax and answering machines .
- Prevent crashes in computers, unreadable print outs, and glitches and noice in moniters.
Pure Sine Wave Inverters
Most of the power source for most applications is a 60Hz,230v AC sine wave, Identical to the 120V Vrms Source available. It is majorly available from some developed companies.Most of the low power electronic household plug-in devices are designed to work with this source (high power devices such as cooking ovens use a 240V source). These electronic equipments will be Most likely to work properly and most efficiently on such a voltage and current sources. The full sine wave source is produced Most easily for high power applications through rotating electrical machinery such as naval gas-turbine machinerys, home made applications of diesel or gasoline backup generators or other types of generators employed by power companies that employs a shaft torque to create an AC current.
These power sources provides a relatively clean, pure sine waves (lacking significant harmonics and high frequency noise) thanks to their analog rotational things. Such as rotating machinery can be an appropriate for low-power backup supply usage due to their high cost, Huge size and required maintenance. There are mainly useful for pure sine wave applications.
The Non sinusoidal waveform generated is also called as a relaxation oscillator. The op amp relaxation oscillator is also called as a square wave generator. The frequency of the oscillator is f=1/T. Here T is also known as a Time and f is a frequency of the oscillator. In this op amp generator both Z1 and Z2. The unsymmetrical square wave can be had by different square waves.
Advantages of the Pure Sine Wave Inverter
Office buildings considering a backup power inverter, a true sine wave model will allow proper function of all electronic office equipment and fluorescent tube lighting. And some of electronic equipments like a Toyostove, battery chargers, electric drills, digital clock radios or other sensitive electronics should consider a true sine wave inverter to ensure proper functioning of all household appliances.
It can applicable many power applications like electric tube light, kitchen appliances, power tools, Tvs, radios, computers and many more electronics gadgets we are using.
Various inverters may have different features making them better suited for different specific applications. Very small inverters are available that connect to a car cigarette lighter, with a single three-prong AC outlet as the output. Large inverters are generally designed to be hardwired into a building electrical system. Some inverters offer 240 volts output. The right inverter for any specific use can be found with the help of an experienced inverter dealer.
It’s will be useful in all electronic applications,when using pure sine wave power. True sine wave inverters will produce AC power as well as a better than utility power, Ensuring that even the most sensitive equipment will run properly. While sine wave inverters are more expensive than modifying sine wave models, The quality of their waveform can be a definite advantage.
The common and popular technique of digital pure-sine wave generation is pulse-width modulation (PWM) technique. Major operation of the PWM technique will convert analogue waveform Generation to a digital waveform by using pulse width modulation, The duty cycle is modulated such that the average voltage of the waveform corresponds to a pure sine wave by using PWM technique. The simplest way of producing the PWM signal is through the comparison of a low-power reference sine wave with a triangle waveform.
By sing these two signals as input to a comparator, these PWM output will be a three level PWM signal. This PWM signal can be used to control switches connected to a high voltage bus, these PWM techniques will replicate this signal at the appropriate voltage signal, connect through a line RC filter. This PWM signal will clean up into a close approximation of a pure sine wave signal. Though this technique produces a much cleaner AC power source than either the square or modified sine waves. The PWM technique wave forms are shown in below
The micro inverter is also also called AC module, It is the integration of Photo voltaic and inverter into one electrical device. With only one PV to control, there is no PV mismatch. MPP tracking can be done at individual PV level, maximizing possible efficiency. As it is modularized, the micro inverter is good for mass production. This technology is also very appropriate for residential applications with low power requirements and where partial shading is a critical issue. This type of inverter is also designed with a plug and play feature so that it can be installed without a deep electrical knowledge.
However, if implemented by a large number of Industries for industrial applications, due to the distributed installation, the maintenance requirements can increase the cost and discourage wide usage. Keeping inverter boxes watertight and using components that have large temperature, ambient are the two major concerns. It will be necessary to develop a system that can detect failure of any micro inverter and isolate it immediately. This type of inverter has recently become an emerging product and promised a remarkable market share in future. Which Potentially leads to low manufacturing cost and low retail prices.
This is all about domestic inverter types with practical examples.Domestic Inverters comprising of Sine Wave Inverters and Solar Inverters. Which are highly efficient and are known for their long functional life and hassle free operations.We believe that you have got a better understanding about this domestic inverter types.Furthermore, any queries regarding this article, or electrical and electronic projects please visit www.edgefxkits.com