**Using Wide Bandgap Semiconductors:** Wide bandgap semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) can significantly reduce switching and conduction losses, improving efficiency. For example, SiC-based designs offer high robustness and efficiency over a wide temperature range, significantly reducing switching and conduction losses compared to silicon (Si)-based designs.<sup>1</sup> **Optimizing Circuit Design:** Optimizing circuit design, such as using multi-stage buck converters, can effectively reduce on-state voltage drop and improve conversion efficiency. For example, by performing voltage conversion in two steps, an intermediate voltage can be set, thereby reducing inductor peak current and power loss.<sup>2</sup> **Efficient Cooling Technology:** Efficient cooling technology can help reduce equipment operating temperature, reduce efficiency losses due to overheating, and thus improve the overall system stability.<sup>1</sup> Power electronic efficiency is crucial for the efficient operation of power systems. High-efficiency power electronic devices can reduce energy waste, lower operating costs, and reduce greenhouse gas emissions, meeting the requirements of sustainable development. Furthermore, high-efficiency power electronic devices can improve system reliability and lifespan, reduce maintenance costs, and thus improve the overall economic and environmental friendliness of power systems.<sup>34</sup>
The concept of power electronics has evolved and is now associated with technologies related to power conversion, its control, and relative efficiency. This sector is also closely related to all electrical and electronic systems suitable for energy conversion. Circuit research in power electronics focuses primarily on efficiency. Energy is a very precious resource and must be used in the cheapest possible way. It is for this reason that heat dissipation and power losses in electronic devices must be minimized.
In other words, the energy transferred from the input to the output of a device should not decrease or be reduced. The application of power electronic systems is increasingly spanning various fields. DC/DC, AC/DC and AC/AC converters, uninterruptible power supplies, battery chargers, and power supplies are just some examples of how power factor correction and insulation concepts come into play. In businesses, factories, and even homes, many devices consume significant amounts of energy. They must be designed optimally to ensure extremely high safety and reliability, but most importantly, to exceed the specifications set by governments and authorities for certification. The purpose of power electronics is to save electricity, reduce operating costs, and improve the safety of electrical systems. They must be designed optimally to ensure extremely high safety and reliability, but most importantly, to exceed the specifications set by governments and authorities for certification.
Power electronics technology is the application of semiconductor electronics in power control and conversion [2]. These semiconductors are power transistors and diodes, which turn the input voltage on and off, forming a passive component network that converts it into different voltage levels. Advances in power semiconductor technology have led to further improvements in power processing efficiency.
To ensure the proper operation of the power conversion system, it needs to be controlled by an embedded digital computer employing complex algorithms that run thousands of times per second. This computer monitors the system's operation and adjusts its behavior based on various parameters and set targets. This adjustment capability is embedded in digital algorithms that incorporate system and application knowledge.
Power electronics technology integrates digital bytes (information) with electron flow to operate in an optimal manner. The combination of power electronics and digital technologies is a key factor enabling the power grid to become the backbone of a carbon-neutral energy system.
The purpose of power electronics is to save electricity, reduce operating costs, and improve the safety of electrical systems. They must be designed optimally to ensure extremely high safety and reliability, but most importantly, to exceed the specifications set by governments and authorities for certification. The full-load efficiency of power electronics is the efficiency level of a power electronic device at rated current or rated power. This indicator is one of the important parameters describing the energy utilization rate of power electronic devices or circuits under maximum load conditions. In practical applications, the level of power electronics full-load efficiency directly affects the energy efficiency level of the entire power system. Power electronics full-load efficiency is usually expressed as a percentage, calculated by dividing the output power by the input power and then multiplying by 100%. The higher the power electronics full-load efficiency, the less energy loss and the higher the energy conversion efficiency. Therefore, improving the power electronics full-load efficiency can effectively save energy and reduce environmental impact. In practical work, improving the power electronics full-load efficiency requires optimization from multiple aspects, such as selecting appropriate devices and circuit structures, and optimizing control algorithms. It is worth noting that the operating states of power electronic devices often change. Therefore, in addition to full-load efficiency, attention should also be paid to their energy efficiency characteristics under different operating conditions to achieve optimal energy utilization. In actual production and energy management, the emphasis on the full-load efficiency of power electronics has also promoted the development and application of energy-saving technologies, driving the sustainable development of the entire energy industry.
Energy conversion efficiency is a crucial metric, and manufacturers are vying to improve upon it beyond 95%. To achieve this, increasingly complex conversion topologies are being adopted, such as phase-shifted full-bridge (PSFB) and LLC converters. Furthermore, diodes are gradually being replaced by lower-power MOSFETs, and wide-bandgap (WBG) devices, with their astonishing switching speeds, are hailed as the future of the semiconductor industry.
However, end users take a holistic view, focusing on the efficiency of the entire system or process—maximizing profits while fulfilling environmental obligations. They understand that gradually reducing small losses in the energy conversion process doesn't necessarily lead to a significant increase in overall cost or environmental benefits when considering total lifecycle costs. On the other hand, integrating more energy conversion devices into smaller packages—increasing "power density"—can more effectively utilize factory or data center footprints and create more value with existing management costs.
In power electronics, efficiency is a term that's easily conceptualized—100% is good, 0% is bad. But it depends on your perspective. For example, for data centers, overall power efficiency is near zero, meaning almost all the electricity drawn from the grid is converted into heat generated by blade servers, power supplies, and cooling system electronics. But if this heat can be effectively used to generate revenue for the data center, the effect is entirely different, a method widely adopted in many industries. So if you want to save costs and space while maximizing profits, the real question is how to minimize total power consumption while maximizing productivity.
Data center managers are well aware of this and need to consider daily how to maximize data processing power and speed while minimizing electricity costs and reaping a return on capital investment. They have no choice but to add servers, even if it means increasing power consumption by several kilowatts, because they can calculate the monetary value gained and offset the additional energy and capital costs. In industry, adding a 100kW motor inevitably increases the load on the motor drive and power supply, while generating more net output. In all industries, power itself adds no commercial value, yet it is indispensable; therefore, every operating expense and every bit of power loss in the power supply is seen as a reduction in profits. This implicitly puts more pressure on power electronics manufacturers to reduce losses by improving power efficiency.
Energy conversion equipment suppliers may compete with each other over claimed efficiencies under very specific conditions, but for end users, what matters is productivity and profitability. Saving a few dollars by consuming less energy is good, but the gains from increasing equipment density in racks or cabinets and improving productivity per cubic foot are likely more attractive. There's a concept of "dollar density" in data center and manufacturing floor space—a monetary value, measured in thousands of dollars per square foot, that's necessary to generate revenue. Therefore, scaling down electronic equipment to provide more productive space is where the real benefits lie. If this means no longer needing to purchase full-size additional racks when expansion is required, then the cost savings will be greater in both the short and long term.
Achieving higher electronic density through relevant energy converters is prompting system architects to view "power density" as an increasingly important metric. However, unlike end-to-end electrical efficiency, the power density of a complete system is very difficult to compare because there are too many factors to consider. For example, a typical industrial cabinet may contain switching equipment, connectors, electromagnetic interference (EMI) filters mounted on the chassis, AC/DC converters that generate intermediate voltages, high-current buses, DC/DC converters at the loads, fans and their own power supplies and mounting hardware, and even air conditioning units. In a control cabinet, the load may be external, such as an electric motor. In this case, the volume of the energy conversion equipment occupies a large portion of the overall space, and any space saved can be used to install more control electronics. However, the benefits are reduced because adding equipment consumes more power. Control cabinets may also be limited by the requirement to use standardized hardware (such as DIN rails for equipment mounting), while suppliers are offering increasingly narrower products, and the availability of input/output connector sizes often defines minimum requirements. A 30W AC/DC connector is now only about 21mm wide, while a 480W component can be as small as 48mm wide x 124mm high. The cooling system within the rack (if any) may consist only of fans with indefinite inlet temperatures, so the power converter ratings are often determined only under the premise of operating in a hot airflow without chassis cooling. This results in relatively low power conversion density values, approximately 10 to 20 watts per 25 cubic millimeters.
