Electricity is indispensable important energy in modern society.Power of sustainable development in the 21st century, has become the basis of social and economic sustainable development, and in the development of social economy, energy and environment coordination plays an important balance
In the modern society of all the power resources, electricity use the most convenient, the most widely application scope.Electricity in different areas of the deep application, as well as to the high efficiency, high power density, high reliability electricity transformation needs, driving the power transformation technology, theory, circuit, the development of material and process.The efficient power conversion applications series, namely, from the perspective of "energy transformation" technology application and discuss ways to obtain the best power supply, save energy and protect the environment at the same time to seek for high effective electricity can transform device.As we know, unprocessed and regulate the original power is the initial state of electric energy effectively.'s electrical grid is a column, fuel generator is against power failure or away from emergency and supplement of the power grid, solar cells, wind power, tidal power generation is an effective way of to nature can exchange for power, fuel cells, lead-acid batteries, lithium ion battery, dry is a renewable, such as electric pool or one-off energy carrier.
For most of the electric field in modern society, the original ecological energy, in a sense is "thick".Use "coarse electricity" will be disappointing.According to different users, for example, it is not good on the grid electricity.Is public power grid, power grid in high peak and trough of voltage difference.Due to the timing of the different users to power grid for the electricity and the uncertainty of electric quantity and chance, especially the starting and braking of large equipment, can give a neighboring grid when random instantaneous impact and pattern divide;Thunder and lightning, storms, grid turbulence caused by the natural factors such as heat, and even instantaneous interruption of power supply, sensitive user will also get in trouble: equipment dysfunctional, low system efficiency, computer data loss, confusion of logical functions, serious when will also cause damage of the system hardware, paralyzed the system work.To do this, you need in the upstream of the grid With flexible transmission and distribution control and the downstream in the grid voltage stabilizer and UPS for coarse downloaded from grid electricity integration and repair.
Because the battery itself has, capacitive voltage instantaneous fluctuation may be smaller than the grid.But the battery for some problems in the work, the most common problem is the battery with the extension of working hours or increase of electricity consumption will gradually decline Use up.In addition, low voltage of battery monomer, rarely can be directly used in a natural form, majority is to use series or parallel combination, this way of using it is difficult to ensure series or string and combination of the characteristics of each monomer.Therefore, reasonable charge, discharge and regulation must be carried out.
Solar cells can convert sunlight into electricity, but the sun will for consistency, rain or shine, day and night, seasons and not balanced, therefore need to convert electrical energy to collect storage, then through DC - DC or DC - AC transformation, stability of direct current (DC) and alternating current (AC).Nature can power also affected by natural factors such as wind, with the help of wind the forces of nature, such as transmission of generator output power is often in a state of flux, also must implement adjust control.......
On the power supply and utilization of the big stage, electricity transformation plays an extremely important role;In the field of electrical energy transformation, with high frequency inverter technology as the core of the PWM switch control can make many ask Bin solved the above, it is lower than that of the traditional frequency electricity transformation has more advantages.For example, high frequency inverter can make the power transformation equipment into ten times reduced volume and weight, also can significantly reduce energy consumption and electromagnetic interference, and gives digital equipment, intelligent features, and so on.Here the so-called high frequency, it is relative to the 50 hz frequency transformation as well as in the 1960 s of 20 kHz frequency conversion variable in higher frequency: tens of kHz, hundreds of kHz and even a few MHz.High frequency conversion device power density increase with the frequency increases, the switch loss components and materials also increasingly prominent, pushing a small loss at high frequency power devices and materials for continual improvement.As a result, small loss at high frequency soft switching PWM circuit in nearly a decade has obtained the fast development.All of these make high electric energy conversion device.
Whether power grid and battery or relatively independent power supply system, electromagnetic environment problems.Namely in the electricity line for electromagnetic interference environment (such as lightning, ignition), or a Shared power bus load equipment electromagnetic interfered with, or DC DC, DC to AC conversion device's own electromagnetic interference, get "upset" neighbourhood.Therefore, the electromagnetic compatibility in all have to face the complicated problem of power supply and utilization.Facing the grid of modern society carry very harsh.Due to the long-term development of the power semiconductor switching devices, advanced control technology, increasingly, increase the level of a power converter equipment very fast;And because of the variable flow move load equipment Increasing, its complex load properties of the negative effects of outstanding.Based on these factors the grid power factor is low, waveform distortion, as well as the surge, phase loss situation.Therefore, it is very urgent to power quality control, such as power compensating, active filtering between conversion technology in the electric power grid and the user can have better buffer matching effect.
Energy problems in the outstanding position in this century, people in the pursuit of saving energy has remarkable contribution to the highly efficient power supply equipment and utilization method.In reality, a considerable part of energy consumption in the form of the drive motor, such as machine tools, electric tools, electric vehicles, urban light rail, transmission system, robot, fan, water chestnut, textile machinery, air conditioning, etc, etc.With extensive directly the original electric drive, will attract series impedance or impedance in parallel, in order to control and regulate the operation of the electric machine, and the necessity of impedance will all be electric consumption.In order to put these wasted very considerable power "jian" come back, using the modern electrical energy conversion technology of motor frequency conversion control, has the very good energy saving potential.
Light is said to have overall electricity large proportion in the world, electricity saving potential is tremendous, originated in Europe and the United States of green lighting Wave a worldwide trend.Green lighting the subject: minimum power consumption to produce maximum lumen.In addition to the new type electric source and the new luminous medium, with new high frequency electric energy conversion technology and equipment of electronic ballast is an important means of implementing green according to Ming.
The development of the productivity, technology progress, increasingly prominent environmental problems.Electricity production, transformation, use to a great extent, affect the environment.Electricity production generally associated with carbon dioxide, sulfur dioxide emissions, the former is the earth's greenhouse gases, which is the cause of acid rain, both are great damage to the environment.But a bit less electricity production can change a bit less environmental degradation.Production development is bound to increase the demand of the electric power, the key is to save electricity, reduce the waste of electricity.This requires our power supply units, power transformation system increases efficiency.In addition, the electromagnetic environment of clean power transformation equipment in the electromagnetic compatibility standards.Save power, electromagnetic compatibility, no environmental pollution of green power is imperative.