TOPICS

Realizing Compact, High-Efficiency Power Conversion Modules

Power Electronics

Alps Alpine in Pursuit of Compactness and Efficiency with Original Materials and Preempting Needs with Platform Design

Electric power keeps the world running… industry, infrastructure, business and everyday living… and its management is increasingly essential for modern society. The Strategic Energy Plan of the Japanese government presents the issues we need to address as “3E+S,” calling for balanced achievement of energy security, economic efficiency, environmental suitability and safety.
One domain the plan singles out is power electronics. The technology holds potential both for greater efficiency and stability in energy supply through power conversion and control, and as a contributing factor in tackling global warming and other environmental issues. Next-generation power electronics boasting enhanced convenience and marketability are sought in many different fields to help adapt to society’s needs, represented by rapid growth of energy saving, energy generation and energy storage markets, trends in business continuity planning (BCP) and life continuity planning (LCP) for dealing with disasters or emergency situations, and the spread of environmentally friendly vehicles.

Power electronics plays a role in diverse areas

Activities in the Power Electronics Domain

Armed with technology and know-how accumulated through automotive electronics and consumer devices business, Alps Alpine is advancing unique activities in a new sphere – power electronics. Efforts are particularly focused on the area of renewable energy, encompassing energy storage systems, charge-discharge systems for electric vehicles and plug-in hybrids, and photovoltaic systems.
Our power conversion modules are both compact and lightweight while maintaining high efficiency. They consist of two power conversion units and a control board. As power semiconductor devices, we use SiC MOSFETs with a trench construction, and we also employ coils made with Liqualloy™, an original magnetic material developed by Alps Alpine. Though SiC MOSFETs were deemed hard to work with, Alps Alpine was quick to adopt them and chalked up success in the market in terms of performance and reliability.

Original Material Liqualloy™ and SiC MOSFETs Realize Size Reduction to One Third and 95% Conversion Efficiency

As a technical requirement, and a basic premise for incorporation into all kinds of equipment, next-generation power electronics would have to realize further size and power loss reductions to fully draw out their outstanding energy-saving effects. Alps Alpine’s power conversion modules achieve groundbreaking compactness and high efficiency making use of our original material Liqualloy™.
Liqualloy™ is an amorphous alloy with a supercooled liquid region, meaning crystallization does not take place at freezing point. Its superior characteristics include: 1) low iron loss (low core loss); 2) high saturated flux density; 3) easy to pulverize; and 4) stable characteristics at high temperatures. As illustrated below, losses with high switching frequencies are extremely low compared to other core materials and saturation flux density is higher than ferrite, which is often used as a magnetic material. Liqualloy™ is therefore ideal for helping to reduce the size of power electronics.

Characteristics remain stable in low to high temperatures

Saturation Flux Density and Core Loss Comparison of Core Materials

Saturation flux density (Bs(T)) Core loss
(kW/m³@100kHz, 100mT)
Liqualloy™ 1.1 200 - 400
FeNi (High Flux) 1.35 550 - 1100
Silicon steel 1.55 1400 - 2100
MnZn ferrite 0.35 - 0.5 100 -

Taking advantage of Liqualloy™ characteristics under high-speed switching conditions, Alps Alpine opted to use SiC MOSFETs in its power conversion modules to reduce the size of capacitors and inductors, while integration of charging and discharging in a bidirectional power circuit provides synergistic effects that also contribute to major downsizing – a decrease in volume to around one third of earlier models. As well as tapping expertise accumulated over the years in high-frequency switching control to ensure consistent quality, Alps Alpine also pursues greater efficiency, which runs counter to size and weight reductions, managing to maintain a high conversion efficiency of at least 95%. As a result, it is possible to design easy-to-use layouts, helping to realize slimmer, more compact equipment. This leads to potential advantages, for example, in slimming down charge-discharge systems for electric vehicles and plug-in hybrids, allowing larger parking spaces and better use of freed-up space.

More about Liqualloy™
Power Inductor Products

Anticipating Customer Needs with Platform Design

Alps Alpine’s activities in the power electronics domain are not limited to enhancing product functionality and developing materials. We also adopt a customer’s perspective with a focus on convenience, deploying a lineup of six basic power conversion circuit platforms for applications in the 1.5kW – 5kW capacity range. There are three types of inverter circuit on offer – single-phase two-wire DC-AC inverter, single-phase three-wire DC-AC inverter, and three-phase three-wire DC-AC inverter – and three types of converter circuit – non-isolated bidirectional DC-DC converter, isolated bidirectional DC-DC converter, and DC-DC converter with MPPT*. By selecting the most suitable platform for their application, customers are able to shorten development lead time and keep initial costs down.

*MPPT: Maximum power point tracking

Alps Alpine’s power conversion modules and other power electronics products are making a difference in more and more scenarios, incorporated into such diverse products as energy storage systems, charge-discharge systems for electric vehicles and plug-in hybrid vehicles, power conditioners for photovoltaic systems, and fuel cell systems. Harnessing the advantages of original materials and our ability to put forward recommendations closely attuned to the customer’s activities, Alps Alpine will continue to build on and refine its unique solutions.