Evaluation of Inverter usage in India
Evaluation is systematic determination of merit, worth, and significance of something or someone using criteria against a set of standards. Evaluation often is used to characterize and appraise subjects of interest in a wide range of human enterprises. Evaluation is a methodological area that is closely related to, but distinguishable from more traditional social research.
Evaluation is the systematic acquisition and assessment of information to provide useful feedback about some object. Evaluation is a systematic endeavor and both use the deliberately ambiguous term 'object' which could refer to a program, policy, technology, person, need, activity, and so on. The latter definition emphasizes acquiring and assessing information rather than assessing worth or merit because all evaluation work involves collecting and sifting through data, making judgments about the validity of the information and of inferences we derive from it, whether or not an assessment of worth or merit results.
An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. An inverter is essentially the opposite of a rectifier.
Static inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.
Electricity is divided into two types of currents, alternating current(AC) and direct current (DC). AC, a more common current for home use, works by allowing electrons to flow in two different directions. In DC currents, electrons flow only one way.
An inverter takes existing power that comes in the form of DC current and converts it to AC current. This is a popular option for those wanting to run home electronics in automobiles. Such cars often produce on DC current, which is not compatible with most electronics meant to run off standard outlets. Therefore, an inverter becomes necessary.
A generator, on the other hand, is a machine that converts mechanical energy into energy in an electrical form. In most cases, electric generators are responsible for the energy a home receives. Large-scale electrical generators may be powered by coal, natural or nuclear energy. A portable generator commonly uses gasoline, which is burned to create electrical energy. Generators usually produce AC electricity.
Simply stated, the difference between the two is that an inverter is only effective if there is already a source of electrical energy. It cannot generate its own. It can simply convert electrical energy that is already there. On the other hand, a traditional generator cannot make AC current into DC current.
On the other hand, there are things known as inverter generators. These are like traditional generators in that they convert some other form of energy into electrical energy. However, they produce AC power, which is then converted to DC power before being converted back to AC. The reason for this conversion is that the power gained during the process. It allows the generator to be more fuel efficient, as well as operate more quietly than standard generators.
Some people also confuse an inverter with a power converter, even using the terms interchangeably. However, a converter is used to change voltage from one level to another. For example, in Europe, a converter may be used to convert the voltage from 220 to 120, for electrical components meant to run on a lower voltage, such as those in the United States.
Since early transistors were not available with sufficient voltage and current ratings for most inverter applications, it was the 1957 introduction of the thyristor or silicon-controlled rectifier (SCR) that initiated the transition to solid state inverter circuits
In applications where inverters transfer power from a DC power source to an AC power source, it is possible to use AC-to-DC controlled rectifier circuits operating in the inversion mode. In the inversion mode, a controlled rectifier circuit operates as a line commutated inverter. This type of operation can be used in HVDC power transmission systems and in regenerative braking operation of motor control systems.
Another type of SCR inverter circuit is the current source input (CSI) inverter. A CSI inverter is the dual of a six-step voltage source inverter. With a current source inverter, the DC power supply is configured as a current source rather than a voltage source. The inverter SCRs are switched in a six-step sequence to direct the current to a three-phase AC load as a stepped current waveform. CSI inverter commutation methods include load commutation and parallel capacitor commutation. With both methods, the input current regulation assists the commutation. With load commutation, the load is a synchronous motor operated at a leading power factor.
As they have become available in higher voltage and current ratings, semiconductors such as transistors or IGBTs that can be turned off by means of control signals have become the preferred switching components for use in inverter circuits.
Power inverter
A power inverter converts DC power or direct current to standard AC power or alternating current, which allows you to run electrical equipment off your car or marine battery for mobile applications, emergencies or simple convenience.
Power inverters are small rectangular devices that have a trailing wire with a jack that plugs directly into the cigarette lighter on the dashboard. They might also come with jumper-like cables for connecting directly to a battery. The device normally has one or two outlets for standard electrical cords. Your laptop, small-screen television, video game player or portable DVD theater are all examples of devices that will get you through a long ride, assuming you're not the one driving!
Power inverters are great for camping at parks that do not provide electricity. The toaster, blender, and boom box can all still be used. On your boat you can plug in the digital movie camera to capture those great water-skiing videos you might have missed after the camera's battery ran low!
In a utility outage a power inverter can be used for emergency electricity. Just run an extension cord from your car into the house, or if you have a charged spare battery you can connect the power inverter directly. Plug in a radio to tune into important alerts, run essential medical equipment, lights, or whatever else you need that falls within the inverters power limits.
Power inverters come in many models that vary in watts. The amount of wattage you will require on yours depends on the total draw of the devices you'd like to use. If you have a two-outlet inverter and will be plugging in 2 devices at once, add up the total wattage of both devices then add at least 50% more to account for peaks or spikes in the power draw. For example if your DVD Theater draws 100 watts and your laptop another 100 watts, a minimum 300-watt inverter is recommended.
Solar Power Inverter
The solar inverter is a critical component in a solar energy system. It performs the conversion of the variable DC output of the Photovoltaic (PV) module(s) into a clean sinusoidal 50- or 60 Hz AC current that is then applied directly to the commercial electrical grid or to a local, off-grid electrical network. Typically, communications capability is included so users can monitor the inverter and report on power and operating conditions, provide firmware updates and control the inverter grid connection. Depending on the grid infrastructure wired (RS-485, CAN, Power Line Communication, Ethernet) or wireless (Bluetooth, ZigBee/IEEE802.15.4, 6loWPAN) networking options can be used.
At the heart of the inverter is a real-time microcontroller. The controller executes the very precise algorithms required to invert the DC voltage generated by the solar module into AC. This controller is programmed to perform the control loops necessary for all the power management functions necessary including DC/DC and DC/AC. The controller also maximizes the power output from the PV through complex algorithms called maximum power point tracking (MPPT). The PV maximum output power is dependent on the operating conditions and varies from moment to moment due to temperature, shading, soilage, cloud cover, and time of day so tracking and adjusting for this maximum power point is a continuous process. For systems with battery energy storage, the controller can control the charging as well as switch over to battery power once the sun sets or cloud cover reduces the PV output power. The controller contains advanced peripherals like high precision PWM outputs and ADCs for implementing control loops. The ADC measures variables, such as the PV output voltage and current, and then adjusts the DC/DC or DC/AC converter by changing the PWM duty cycle.
The C2000 in particular is designed to read the ADC and adjust the PWM within a single clock cycle, so real time control is possible. Communications on a simple system can be handled by a single processor, more elaborate systems with complex displays and reporting on consumption and feed-in-tariff pay back may require a secondary processor, potentially with Ethernet capability like the Stellaris Cortex M3 parts. For safety reasons, isolation between the processor and the current and voltage is also required, as well as on the communications bus to the outside world.
Evaluation is the systematic acquisition and assessment of information to provide useful feedback about some object. Evaluation is a systematic endeavor and both use the deliberately ambiguous term 'object' which could refer to a program, policy, technology, person, need, activity, and so on. The latter definition emphasizes acquiring and assessing information rather than assessing worth or merit because all evaluation work involves collecting and sifting through data, making judgments about the validity of the information and of inferences we derive from it, whether or not an assessment of worth or merit results.
An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits. An inverter is essentially the opposite of a rectifier.
Static inverters have no moving parts and are used in a wide range of applications, from small switching power supplies in computers, to large electric high-voltage direct current applications that transport bulk power. Inverters are commonly used to supply AC power from DC sources such as solar panels or batteries.
The electrical inverter is a high-power electronic oscillator. It is so named because early mechanical AC to DC converters were made to work in reverse, and thus were "inverted", to convert DC to AC.
DC power source utilization
An inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.
Grid tie inverters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch off automatically in the event of a blackout.
Micro-inverters convert direct current from individual solar panels into alternating current for the electric grid.
A variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.
Air conditioning Main article: Inverter (air conditioning)
An air conditioner bearing the inverter tag uses a variable-frequency drive to control the speed of the motor and thus the compressor.
DC power source utilization
An inverter converts the DC electricity from sources such as batteries, solar panels, or fuel cells to AC electricity. The electricity can be at any required voltage; in particular it can operate AC equipment designed for mains operation, or rectified to produce DC at any desired voltage.
Grid tie inverters can feed energy back into the distribution network because they produce alternating current with the same wave shape and frequency as supplied by the distribution system. They can also switch off automatically in the event of a blackout.
Micro-inverters convert direct current from individual solar panels into alternating current for the electric grid.
Uninterruptible power supplies
An uninterruptible power supply (UPS) uses batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier is used to supply DC power to recharge the batteries.Induction heating
Inverters convert low frequency main AC power to a higher frequency for use in induction heating. To do this, AC power is first rectified to provide DC power. The inverter then changes the DC power to high frequency AC power.HVDC power transmission
With HVDC power transmission, AC power is rectified and high voltage DC power is transmitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC.Variable-frequency drives
Main article: variable-frequency driveA variable-frequency drive controls the operating speed of an AC motor by controlling the frequency and voltage of the power supplied to the motor. An inverter provides the controlled power. In most cases, the variable-frequency drive includes a rectifier so that DC power for the inverter can be provided from main AC power. Since an inverter is the key component, variable-frequency drives are sometimes called inverter drives or just inverters.
Electric vehicle drives
Adjustable speed motor control inverters are currently used to power the traction motors in some electric and diesel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles such as the Toyota Prius. Various improvements in inverter technology are being developed specifically for electric vehicle applications. In vehicles with regenerative braking, the inverter also takes power from the motor (now acting as a generator) and stores it in the batteries.Air conditioning Main article: Inverter (air conditioning)
An air conditioner bearing the inverter tag uses a variable-frequency drive to control the speed of the motor and thus the compressor.
The general case
A transformer allows AC power to be converted to any desired voltage, but at the same frequency. Inverters, plus rectifiers for DC, can be designed to convert from any voltage, AC or DC, to any other voltage, also AC or DC, at any desired frequency. The output power can never exceed the input power, but efficiencies can be high, with a small proportion of the power dissipated as waste heat. History
The origins of electromechanical inverters explain the source of the term inverter. Early AC-to-DC converters used an induction or synchronous AC motor direct-connected to a generator (dynamo) so that the generator's commutator reversed its connections at exactly the right moments to produce DC. A later development is the synchronous converter, in which the motor and generator windings are combined into one armature, with slip rings at one end and a commutator at the other and only one field frame. The result with either is AC-in, DC-out. With an M-G set, the DC can be considered to be separately generated from the AC; with a synchronous converter, in a certain sense it can be considered to be "mechanically rectified AC". Given the right auxiliary and control equipment, an M-G set or rotary converter can be "run backwards", converting DC to AC. Hence an inverter is inverted converter. Controlled rectifier inverters
Difference between generator and invertorsEarly inverters
From the late nineteenth century through the middle of the twentieth century, DC-to-AC power conversion was accomplished using rotary converters or motor-generator sets (M-G sets). In the early twentieth century, vacuum tubes and gas filled tubes began to be used as switches in inverter circuits. The most widely used type of tube was the thyratron.The origins of electromechanical inverters explain the source of the term inverter. Early AC-to-DC converters used an induction or synchronous AC motor direct-connected to a generator (dynamo) so that the generator's commutator reversed its connections at exactly the right moments to produce DC. A later development is the synchronous converter, in which the motor and generator windings are combined into one armature, with slip rings at one end and a commutator at the other and only one field frame. The result with either is AC-in, DC-out. With an M-G set, the DC can be considered to be separately generated from the AC; with a synchronous converter, in a certain sense it can be considered to be "mechanically rectified AC". Given the right auxiliary and control equipment, an M-G set or rotary converter can be "run backwards", converting DC to AC. Hence an inverter is inverted converter. Controlled rectifier inverters
Electricity is divided into two types of currents, alternating current(AC) and direct current (DC). AC, a more common current for home use, works by allowing electrons to flow in two different directions. In DC currents, electrons flow only one way.
An inverter takes existing power that comes in the form of DC current and converts it to AC current. This is a popular option for those wanting to run home electronics in automobiles. Such cars often produce on DC current, which is not compatible with most electronics meant to run off standard outlets. Therefore, an inverter becomes necessary.
A generator, on the other hand, is a machine that converts mechanical energy into energy in an electrical form. In most cases, electric generators are responsible for the energy a home receives. Large-scale electrical generators may be powered by coal, natural or nuclear energy. A portable generator commonly uses gasoline, which is burned to create electrical energy. Generators usually produce AC electricity.
Simply stated, the difference between the two is that an inverter is only effective if there is already a source of electrical energy. It cannot generate its own. It can simply convert electrical energy that is already there. On the other hand, a traditional generator cannot make AC current into DC current.
On the other hand, there are things known as inverter generators. These are like traditional generators in that they convert some other form of energy into electrical energy. However, they produce AC power, which is then converted to DC power before being converted back to AC. The reason for this conversion is that the power gained during the process. It allows the generator to be more fuel efficient, as well as operate more quietly than standard generators.
Some people also confuse an inverter with a power converter, even using the terms interchangeably. However, a converter is used to change voltage from one level to another. For example, in Europe, a converter may be used to convert the voltage from 220 to 120, for electrical components meant to run on a lower voltage, such as those in the United States.
Since early transistors were not available with sufficient voltage and current ratings for most inverter applications, it was the 1957 introduction of the thyristor or silicon-controlled rectifier (SCR) that initiated the transition to solid state inverter circuits
The commutation requirements of SCRs are a key consideration in SCR circuit designs. SCRs do not turn off or commutate automatically when the gate control signal is shut off. They only turn off when the forward current is reduced to below the minimum holding current, which varies with each kind of SCR, through some external process. For SCRs connected to an AC power source, commutation occurs naturally every time the polarity of the source voltage reverses. SCRs connected to a DC power source usually require a means of forced commutation that forces the current to zero when commutation is required. The least complicated SCR circuits employ natural commutation rather than forced commutation. With the addition of forced commutation circuits, SCRs have been used in the types of inverter circuits described above.
Another type of SCR inverter circuit is the current source input (CSI) inverter. A CSI inverter is the dual of a six-step voltage source inverter. With a current source inverter, the DC power supply is configured as a current source rather than a voltage source. The inverter SCRs are switched in a six-step sequence to direct the current to a three-phase AC load as a stepped current waveform. CSI inverter commutation methods include load commutation and parallel capacitor commutation. With both methods, the input current regulation assists the commutation. With load commutation, the load is a synchronous motor operated at a leading power factor.
As they have become available in higher voltage and current ratings, semiconductors such as transistors or IGBTs that can be turned off by means of control signals have become the preferred switching components for use in inverter circuits.
Power inverter
A power inverter converts DC power or direct current to standard AC power or alternating current, which allows you to run electrical equipment off your car or marine battery for mobile applications, emergencies or simple convenience.
Power inverters are small rectangular devices that have a trailing wire with a jack that plugs directly into the cigarette lighter on the dashboard. They might also come with jumper-like cables for connecting directly to a battery. The device normally has one or two outlets for standard electrical cords. Your laptop, small-screen television, video game player or portable DVD theater are all examples of devices that will get you through a long ride, assuming you're not the one driving!
Power inverters are great for camping at parks that do not provide electricity. The toaster, blender, and boom box can all still be used. On your boat you can plug in the digital movie camera to capture those great water-skiing videos you might have missed after the camera's battery ran low!
In a utility outage a power inverter can be used for emergency electricity. Just run an extension cord from your car into the house, or if you have a charged spare battery you can connect the power inverter directly. Plug in a radio to tune into important alerts, run essential medical equipment, lights, or whatever else you need that falls within the inverters power limits.
Power inverters come in many models that vary in watts. The amount of wattage you will require on yours depends on the total draw of the devices you'd like to use. If you have a two-outlet inverter and will be plugging in 2 devices at once, add up the total wattage of both devices then add at least 50% more to account for peaks or spikes in the power draw. For example if your DVD Theater draws 100 watts and your laptop another 100 watts, a minimum 300-watt inverter is recommended.
Solar Power Inverter
The solar inverter is a critical component in a solar energy system. It performs the conversion of the variable DC output of the Photovoltaic (PV) module(s) into a clean sinusoidal 50- or 60 Hz AC current that is then applied directly to the commercial electrical grid or to a local, off-grid electrical network. Typically, communications capability is included so users can monitor the inverter and report on power and operating conditions, provide firmware updates and control the inverter grid connection. Depending on the grid infrastructure wired (RS-485, CAN, Power Line Communication, Ethernet) or wireless (Bluetooth, ZigBee/IEEE802.15.4, 6loWPAN) networking options can be used.
At the heart of the inverter is a real-time microcontroller. The controller executes the very precise algorithms required to invert the DC voltage generated by the solar module into AC. This controller is programmed to perform the control loops necessary for all the power management functions necessary including DC/DC and DC/AC. The controller also maximizes the power output from the PV through complex algorithms called maximum power point tracking (MPPT). The PV maximum output power is dependent on the operating conditions and varies from moment to moment due to temperature, shading, soilage, cloud cover, and time of day so tracking and adjusting for this maximum power point is a continuous process. For systems with battery energy storage, the controller can control the charging as well as switch over to battery power once the sun sets or cloud cover reduces the PV output power. The controller contains advanced peripherals like high precision PWM outputs and ADCs for implementing control loops. The ADC measures variables, such as the PV output voltage and current, and then adjusts the DC/DC or DC/AC converter by changing the PWM duty cycle.
The C2000 in particular is designed to read the ADC and adjust the PWM within a single clock cycle, so real time control is possible. Communications on a simple system can be handled by a single processor, more elaborate systems with complex displays and reporting on consumption and feed-in-tariff pay back may require a secondary processor, potentially with Ethernet capability like the Stellaris Cortex M3 parts. For safety reasons, isolation between the processor and the current and voltage is also required, as well as on the communications bus to the outside world.
