Inverter
1 Introduction
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 u of appropriate transformers, switching, and control circuits.Solid-state inverters have no moving parts and are ud in a wide range of applications, from small switching power supplies in computers, to large electric utility high-voltage direct current北大考研成绩查询 applications that transport bulk power. Inverters are commonly ud to supply AC power from DC sources such as solar panels or batteries.
There are two main types of inverter. The output of a modified sine wave inverter is similar to a square wave output except that the output goes to zero volts for a time before switching positive or negative. It is simple and low cost and is compatible with most electronic devices, except for nsitive or specialized equipment, for example certain lar printers. A pure sine wave inverter produces a nearly perfect sine wave output (<3% total h
armonic distortion) that is esntially the same as utility-supplied grid power. Thus it is compatible with all AC electronic devices. This is the type ud in grid-tie inverters. Its design is more complex, and costs 5 or 10 times more per unit power The electrical inverter is a high-power electronic oscillator. It is so named becau early mechanical AC to DC converters were made to work in rever, and thus were "inverted", to convert DC to AC.The inverter performs the opposite function of a rectifier.
2 Applications
2.1 DC power source utilizationkayak
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 voltageGrid tie inverters can feed energy back into the distribution network becau 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. They are grid tie designs by default.
2.2 Uninterruptible power supplies
An uninterruptible power supply (UPS) us batteries and an inverter to supply AC power when main power is not available. When main power is restored, a rectifier supplies DC power to recharge the batteries.
2.3 控件是什么Induction heating
Inverters convert low frequency main AC power to a higher frequency for u 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.
2.4 HVDC power transmission
With HVDC power transmission, AC power is rectified and high voltage DC power is trans
mitted to another location. At the receiving location, an inverter in a static inverter plant converts the power back to AC.
2.5 李阳疯狂英语Variable-frequency drives
高中英语说课稿模板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 cas, 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.
2.6 Electric vehicle drives
外国文学小说Adjustable speed motor control inverters are currently ud to power the traction motors in some electric and diel-electric rail vehicles as well as some battery electric vehicles and hybrid electric highway vehicles such as the Toyota Prius and Fisker Karma. Various improvements in inverter technology are being developed specifically for electric vehicle applications.[2] In vehicles with regenerative braking, the inverter also takes power from the motor (now acting as a generator) and stores it in the batteries.
清明节英语2.7 The general ca
A transformer allows AC power to be converted to any desired voltage, but at the same fr
equency. 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.
3 Circuit description
3.1 Basic designs
In one simple inverter circuit, DC power is connected to a transformer through the centre tap of the primary winding. A switch is rapidly switched back and forth to allow current to flow back to the DC source following two alternate paths through one end of the primary winding and then the other. The alternation of the direction of current in the primary winding of the transformer produces alternating current (AC) in the condary circuit.
The electromechanical version of the switching device includes two stationary contacts and a spring supported moving contact. The spring holds the movable contact against on
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e of the stationary contacts and an electromagnet pulls the movable contact to the opposite stationary contact. The current in the electromagnet is interrupted by the action of the switch so that the switch continually switches rapidly back and forth. This type of electromechanical inverter switch, called a vibratorstaff是什么意思 or buzzer, was once ud in 上周vacuum tube automobile radios. A similar mechanism has been ud in door bells, buzzers and tattoo guns.
