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Delve deeply and work diligently to achieve new heights
All colleagues unite and focus their efforts to write a new chapter of developmentDevelopment Trends of High-Power High-Voltage Power Supplies and Switching Power Supplies
所属分类： Industry News
发布时间：2020-07-14
Reports indicate that China’s switching power supply industry has grown rapidly in recent years. During the first decade of this century, annual sales expanded by more than 10%, with annual shipments exceeding 20 million units. Upon closer examination, however, it becomes clear that this figure includes low‑power switching supplies—typically below a few hundred watts—such as those used in personal computers and household appliances. This paper focuses exclusively on switching power supplies operating in the kilowatt‑class and above. It is worth emphasizing that the development of high‑power switching power supplies is likely to proceed in leaps and bounds.
I. Classification of High-Power High-Voltage Power Supplies
Generally speaking,
High-power power supply They can be classified into linear power supplies and switching power supplies.
(1) Linear power supplies primarily comprise a mains-frequency transformer, a high-power rectifier circuit, an output rectifier‑filter, a control circuit, and a protection circuit. This approach steps down the AC voltage via the transformer, rectifies and filters it to produce a DC voltage, and then regulates the output voltage through voltage feedback, thereby achieving high‑precision DC output.
(2) Switch-mode power supplies are implemented using electronic technology. First, the AC input from the mains is rectified into DC. The switching transistor is driven by a high-frequency pulse-width modulation signal generated by an inverter, producing a high-frequency sawtooth‑shaped AC voltage that is applied to the primary winding of the switch-mode transformer. The secondary winding of the transformer induces a high-frequency voltage, which is then rectified and filtered to supply the load with the required DC output while suppressing high-frequency noise from interfering with the load. The output stage feeds back through a dedicated circuit to the control circuit, adjusting the duty cycle of the pulse‑width modulation to achieve stable output regulation.
Its characteristic is that, at the same power level, the higher the switching frequency, the smaller the size of the switching transformer; however, this also places stricter demands on the switching transistors. The secondary winding of the switching transformer may comprise multiple windings, or a single winding may have several taps, to achieve the desired output.
In fact, highly integrated specialized chips are already available, which simplify the peripheral circuitry to such an extent that debugging is often unnecessary. For example, a switch-mode power‑supply chip (or module) can be configured into a basic switching power supply simply by selecting appropriate resistor–capacitor components and a switching transformer.
(3) Depending on the specific requirements, DC power is used in different applications. Linear power supplies provide a linear DC output; this technology is highly mature and can deliver high stability, excellent quality, low ripple, and zero interference or noise, making it suitable for demanding applications. Its drawbacks include large size, heavy weight, high power consumption, and relatively low conversion efficiency. Such power supplies are not well suited to the needs of computers and other devices and are gradually being replaced by switching-mode power supplies. This represents the traditional linear power supply that was commonly used in the past. Next come switching-mode power supplies, which generate significant peak‑to‑peak interference and substantial output ripple during operation—measures to mitigate these issues are necessary. Their advantages include light weight, high capacity, high efficiency, compact size, and reduced thermal losses. Their disadvantages are higher noise levels and electromagnetic interference, though modern shielding technologies have largely addressed these concerns.
II. Current Status of Switching Power Supplies
In the 1990s,
Switching power supply They have successively penetrated various sectors of electronic and electrical equipment. Switching power supplies are now widely used in program-controlled switches, telecommunications, power supplies for electronic testing instruments, and control‑system power supplies. However, they also suffer from drawbacks such as circuit complexity and significant radio‑frequency and electromagnetic interference. With advances in electronic technology, these limitations are being gradually overcome. The overall circuit is divided into a main circuit and a control circuit; the main circuit comprises input rectification and filtering, power conversion, and output rectification and filtering. Demand for high‑capacity power products is growing rapidly, driving steady expansion of the switching power supply market. As the nation places increasing emphasis on energy conservation and environmental protection, structural adjustments in the power industry have become imperative. Along with progress in power electronics, switching power supplies are playing an increasingly vital role in energy efficiency, consumption reduction, and environmental sustainability. High‑efficiency, large‑capacity units are steadily becoming the market’s dominant force, effectively boosting demand in the power‑supply sector. Consequently, this shift in China’s power‑supply market is closely linked to the country’s macroeconomic policy direction and the broader dynamics of the power industry. Influenced by national macro policies, China’s power‑industry structure has undergone restructuring: small thermal‑power units have been retired one after another, while large, highly efficient units have been brought online. This structural transformation has significantly amplified market demand for high‑capacity power supplies, thereby underpinning the stable growth of the switching power‑supply market.
Market concentration remains relatively low, and competition among manufacturers is equally intense. China is home to nearly 1,000 power‑supply manufacturers, widely dispersed across the country, resulting in a fairly balanced market structure. No single manufacturer commands a market share exceeding 10%. Consequently, the switching‑mode power‑supply market exhibits low concentration, with fierce competition among players having become one of its defining characteristics. As rivalry intensifies, power‑supply companies are placing greater emphasis on economies of scale and R&D capabilities to bolster brand visibility and enhance their competitive edge.
Technological advances drive product innovation. Power‑supply products are closely linked to the progress and evolution of electronic technologies. In recent years, with the rapid development of power‑electronics in China, switch‑mode power supplies have evolved toward higher frequencies, greater power density, improved power factor, enhanced efficiency, increased reliability, and greater intelligence. This technology‑driven product innovation has been widely recognized by the market. The emergence of “green” power supplies and modular power systems has played a crucial role in energy conservation, reduced consumption, and environmental protection, significantly contributing to alleviating China’s energy and environmental challenges.
In summary, switch-mode power supplies are an inevitable outcome of power electronics development and align with the trends of our times. Their advent has spurred technological innovation. Today, both domestically and internationally, switch-mode power supplies are being actively developed, and their prospects are exceptionally promising. To a significant extent, the replacement of traditional power supplies by switch-mode designs is an unavoidable trend.
III. Development Trends of Switching Power Supplies
Among the various power supply systems in power electronics, switch-mode power supply technology stands at the core. For large-scale electroplating power supplies, conventional circuits are typically bulky and heavy. By adopting advanced switch-mode power supply technology, it is possible to significantly reduce both size and weight, markedly improve power‑supply efficiency, conserve materials, and lower costs. In electric vehicles and variable‑frequency drives, switch-mode power supply technology is indispensable. It enables the frequency of power consumption to be adjusted, thereby achieving near‑ideal load matching and precise drive control. High‑frequency switch-mode power supply technology serves as the cornerstone for a wide range of high‑power applications, including inverter welding machines, communication power supplies, high‑frequency heating systems, laser power sources, and power‑operated equipment. The technological goals and development trends of switch-mode power supplies in the 21st century can be summarized into the following three key areas.
(1) High-frequency theoretical analysis and practical experience show that the volume and weight of transformers, inductors, and capacitors in electrical equipment are inversely proportional to the square root of the supply frequency. Consequently, when we increase the frequency from 50 Hz to 20 Hz and then further raise it by a factor of 400, the volume and weight of electrical equipment typically decrease to about one-twentieth of their original values.
(2) Modularity has two meanings: first, the modularity of power supply equipment; second, the modularity of power supply equipment.
(3) Digital signals and digital circuits are becoming increasingly important. Digital signal processing technologies are steadily improving and maturing, demonstrating growing advantages. Consequently, for intelligent switching power supplies, digital technology is indispensable when computer control is required.
(4) The greening of green power supply systems has two implications: first, significant energy savings can reduce environmental pollution; second, these energy sources do not (or less) pollute the power grid. Switching power supplies must be green.