The importance of semiconductors in the clean energy sector is nimble, as Semiconductor solutions are getting miniaturized, reliable, power-efficient and yes smart. Conditioning power from solar arrays and wind turbines to help energy for electric equipment to get into electric grids is critically important. Semiconductors help harness, convert, transfer, stores and also make sure that the grid is responsive and efficient. To less known, Semiconductors are also helping in harvesting power optimally. Now IoT-Powered and advance power semiconductors are all coming into a successful GigaWatt drive for the clean energy sector. Harnessing further on the changing paradigm of clean energy and utility of semiconductors, this article brings along Raghavan Nagarajan, T&D and Wind Application Expert and Suresh Thangavel, Global Application Manager from Infineon Technologies AG | Ali Husain, Senior Manager, Corporate Strategy & Marketing, ON Semiconductor | MORNSUN Marketing Department to further infer on the role and the growing importance of semiconductors for clean energy.
Semiconductor, The Vital Element for Clean Energy?
Stating on what makes semiconductors such an important element for clean energy, Raghavan cited, without semiconductor-based power electronics systems, harnessing clean renewable energy such as wind energy would not be simply possible. Therefore, semiconductors are the heart of any clean energy generation technology. This way, there would be increasing demand for efficient and reliable power semiconductors to perform all this conversion with as low losses as possible.
Whereas Suresh further elaborates by giving an example on solar application, the photovoltaic (PV) module provides D-C current. However, we need to have a grid compatible A-C voltage to consume locally or for efficient transmission of the power that comes from the module. This is possible thanks to the solar inverter, which are build up with power semiconductors. Thus, power electronic devices make the modern P-V system widely usable. Solar energy, unlike their fossil-fuel alternatives, cannot be relied upon to provide the necessary fast response to plug load gaps in power generation. Instead, it makes more sense to collect and store this energy when it is generated, making it available for use later. For this purpose, Energy Storage Solutions (ESS), large and small, are being developed, providing power for everything from charging electric vehicles to power cities.
Inscribing on the eminence of Power Semiconductors, Ali said, to use clean energy, it has to be converted – increase the voltage or go from DC to AC – in order to feed into the grid and travel to the homes, businesses, and factories which depend on it. Power semiconductors are the key to this power conversion. Without them, we could not deliver clean energy to those who need it. Power electronics also is critical to smaller, distributed generation like solar panels on homes and businesses. Even the storage and release of energy from batteries is mediated by power semiconductor devices. It’s all about efficiency: the more efficient the power conversion, the more of which can be used.
Whereas, Mornsun states, clean and renewable energy has increasingly become a critical resource to solve the shortage of conventional energy worldwide, however, due to the cost, efficiency, reliability and other factors, it has been restricting the prevalence of renewables applications. Semiconductors, as the basis of high-tech products and technology revolution, is playing a significant role in all walks of life to help space-saving, cost-saving, energy-saving, etc., such as IoT, communications, medical care, etc.
Similarly, the renewable energy area can’t thrive without the help of semiconductors. As a technological mover, semiconductors play a key role in how to effectively harness, convert, transfer, store, or distribute electricity, and to improve efficiency or to reduce the demand or reliance for current energy. Solar and wind source are the fastest-growing clean, renewable energy. Semiconductors form the basis of the photovoltaic (PV) system. Semiconductor devices are widely used to convert power from solar arrays and wind turbines so the energy can be used by electric equipment and fed onto the electric grid. By increasing the capacity proportion of clean and renewable energy in the power grid, semiconductors have their huge potential to make more contributions to boost up the efficiency, stability of energy conversion, enable large-scale applications, and meet the increasing demand for more energy-saving semiconductor equipment.
How Renewable Companies Can Make The Best Out Of Semiconductors?
With new possibilities and benefits emerging, Renewable companies are tapping the benefits of semiconductor technologies in their process cycle. Ali emphasizes, when designing the power conversion stages, be sure to take into account the total cost of ownership. It may seem to make sense to reduce the cost of the converter as much as possible, but you may end up wasting many multiples of that cost in energy burned up as heat instead of delivered to customers. Semiconductors can also be used to monitor and protect the renewable power generation and also to measure and optimize the local and regional grid system as a whole.
Suresh starting with an example and sharing the importance of SiC devices, noted; in utility application, lighter weight string inverter for solar applications is gaining popularity. The key requirements are to attain greater design flexibility, easy transportation, quick and easy replaced by two people. Further, the high operation voltage of 1500 V results in the requirement of a low cosmic radiation-induced failure rate, at the same time with higher system efficiency for the power devices. Because of these contradictory requirements, A-NPC multilevel topologies are the preferred solutions today due to its highest efficiency over the full range of power factor operation. Where the inverter is designed for both solar and battery storage applications. A cost-effective way for a special adaptation of the A-NPC topology is optimally combined Infineon’s CoolSiCTM 1200-Volt MOSFET with TRENCHSTOP IGBT technology. In this way, switching losses only occurs in the fast and highly efficient SiC MOSFETs and hence the IGBTs are optimized for lower conduction losses. Thus, the amount of SiC devices is reduced to a minimum, achieving an optimal cost-performance ratio.
Sharing a purview on Infineon’s expertise, Raghavan underlines, Infineon enables an unlimited world of energy by not only providing semiconductor solutions (discrete & modules) for renewable energy generation. But, we also provide battery management system solutions, which enable battery-based energy storage systems to store the generated renewable energy and to reuse it on demand. Renewable companies need to find a good balance between system performance, system reliability and system cost on a high level. The key to success is to find the optimal devices with short design time to market.
Benefited from semiconductor technology and integrated storage solutions, renewables companies enable more economical, eco-friendly energy production, and explore the potential to continuously increase the current generation of renewable energy said Mornsun.
Mornsun further stated, many renewables companies in solar, wind, hydro, and biomass energy and some companies engaged in the market business of LED lighting and solar cell energy-saving technology are strengthening their cooperation with semiconductor companies. Some PV companies, for example, hope to create new designs or devices by leveraging their own proprietary solar cell technology, patents, and equipment to combine with conventional silicon solar cells manufactured by semiconductor companies. By doing these, both of them aim to achieve cost reduction, efficiency improvement for PV, and further progress on less cost in high volumes for manufacturing.
Semiconductor Technologies Empowering Renewable Sector
Some applied material companies are taking advantage of the strong associations between PV and semiconductors to research and develop new processing technologies and semiconductor materials such as thin-film semiconductor material. They are using their expertise in the semiconductor field and the material production technology, and trying to address material and production challenges to reduce the usage cost of renewables emphasized Mornsun.
Suresh highlighted on two technologies silicon carbide and the newest chip technology IGBT7. With CoolSiC™ MOSFETs, the power of a string inverter can be doubled at the same inverter weight. CoolSiC™ MOSFETS allows a power density increase by a factor of 2.5, e.g. from 50 kW (Si) to 125 kW (SiC) at a weight of less than 80 kg, so it can be lifted by two installers. Furthermore, the efficiency reduction at high operating temperatures is significantly lower compared to a Si solution. You can achieve a maximum efficiency of over 99% by using CoolSiC™ MOSFET solutions from Infineon.
The IGBT7 chip technology comes with a short-time overload operation that reaches up to 175 degrees junction temperature, in order to cope with short-term overcurrent operations, which occur during grid ride through events. This enables the possibility to increase the junction’s operating temperature as close as possible to its allowed maximum. This may allow the increase of the inverter’s power, since it will be operated with lower safety margin limits under nominal operation said Suresh.
Ali accentuating on Gallium Nitride (GaN) and Silicon Carbide (SiC) power semiconductor materials, said, these enable smaller and more efficient power conversion. Also, the packaging is becoming more and more important. Removing heat from power electronics is a very important part of the reliability and safety of the system. Semiconductor packaging is very important to heat removal. The fast switching capabilities of GaN and SiC also demand innovative packaging, to reduce parasitic inductance which can cause ringing and system instability.
Mornsun elaborated, the types of semiconductors used in the field of renewable energy mainly include semiconductor materials, discrete devices, sensors, analog and mixed signal devices, and digital integrated circuits. Silicon is the most efficient and by far the most common semiconductor material for clean energy. It is widely used for all integrated circuits and in approximately 90% of all PV modules.
PV cells consist of a large-area Silicon (Si) wafers, which are the basic components of PV panels, accounting for more than 70% of the cost of the entire photovoltaic (PV) system. Therefore, the demand and supply of semiconductor materials in the field of renewable energy, PV industry, in particular, have been continuously on a rise. PV cells mainly use single-crystal Si wafers and multi-crystal Si wafers. And poly silicon was originally made for PV applications. In recent years, the demand for poly silicon for PV has been increasing, which has directly led to an increase in its price as well. The crystalline silicon used in PV has the advantage of high purity, high efficiency with a long lifespan of around 25 years, but the high material cost and high manufacturing consumption also put a limit on its plentiful use for PV.
Mornsun also cited, another new material is organic PV materials. These materials have the potential to provide electricity at a lower cost, but they are about 50 per cent as efficient as silicon cells. In addition, organic PV materials can’t last long because of their limited operating lifetime. The efficiency and stability of these materials need to be improved before they are commercially viable. So, what is the future of semiconductor materials? Many researchers are studying a semiconductor material called perovskite. This material has a special crystalline structure and can be composed of different materials including lead which is used as a common option. It has the potential to boost power output by converting some parts of the solar spectrum into electricity more efficiently than silicon. However, it has a short lifespan, and the substitution for the toxic lead is also a big concern.
With the understanding of fundamentals of semiconductors and the increasing investment in applied research, today’s researchers and engineers are constantly striving to break through the cutting-edge semiconductor technology. Renewable energy will be able to be widely used at a lower cost, more efficiently. Most significantly, it will continue to innovate the utility of clean energy in tomorrow’s businesses and consumer area concluded Mornsun.
Semiconductor Companies Enabling Intelligent Future
With new advanced technologies complementing and honoring clean energy, semiconductors are driving the future. Ali believes with the intelligence coming from powerful embedded processors, inexpensive sensors and communication technologies, and expanding artificial inelegance (AI) algorithms, we are enabling a new model where the household can become a consumer and producer (prosumer) at the same time. People will be able to optimize their use of the grid, make some money, and have resiliency when the grid fails. Intelligence will manage all of it for us in a seamless way.
Underlining example of centralized energy generation is utility-scale, Suresh cited, at least over 20 megawatts or even over 100-megawatt solar power plants. A 100-megawatt solar plant can be installed with over 36 times 3 megawatt or 50 times 2-megawatt central inverters. The central inverter with increased power will significantly reduces the system quantities. In the business model of centralized energy generation, companies are not selling central inverters but 50-megawatt energy, for example. A 50% power output increase of each system translates into cost savings of at least 14 central inverters. It is a huge saving. Those utility-scale solar plants first require large tracts of land and are commonly placed in rural agricultural areas. Projects of this size are designed to last for decades. Therefore, maintenance and installation costs play a central role on the cost.
Quoting on the development of IoT technology, Mornsun said, technology progress is leading renewables to forward-looking intelligent future. The industry coupling between renewables companies and semiconductor companies will also play a key role in achieving this goal. These companies can expand their digital capabilities and meet the challenges and opportunities both in cost, reliability, efficiency and intelligent management. Driven by data, on the energy supply side, the realization of intelligence can produce more valuable results, including increased power generation capacity, resource optimization, integration of operations and maintenance with energy management and remote intelligence. On the demand side, allowing demand management to match the loads to the power capacity on a real-time basis can make a big difference in optimizing the distribution and efficiency of energy in a more reasonable way continued Mornsun.
For semiconductor companies, they will likely place many chips in solar cells, wind turbines, combiners, inverters, smart grid equipment, energy storage BMS, various sensors, drives, and home energy management equipment, etc. These smart devices and programming software are combined to form a smart renewable energy network with computing and communication capabilities, covering smart home appliances, electric vehicles, charging stations, transportation, factories, and medical care and more areas. Such intelligence is expected to change multiple industries and markets and create an energy-saving, clean, and eco-friendly future noted Mornsun.
Renewables and Emerging GaN, SiC Power Semiconductor Market
As aforementioned in the article by Suresh *(Read How Renewable Companies Can Make The Best Out Of Semiconductors). Suresh here mentions, solar PV is becoming cheaper than ever. Our Customers face huge price pressure and consolidation in the market. We see a trend towards high power density to reduce to $/W for PV systems. Our Customers need to combine suitable topologies and devices to balance the reliability, efficiency and cost. GaN could play a role in future for 1000V string inverter and MPPT for micro-inverter. This technology is in validation, and could be leveraged to further reduce the size and weight of the inverter.
Whereas Ali stating on the benefits, said, SiC and GaN offer much lower losses than traditional silicon power electronics, which means more power for us to use. These Wide bandgaps (WBG) devices also have much faster switching performance than silicon. This allows higher frequency switching which leads to smaller passive devices like inductors and capacitors. In many power converters, the passive elements constitute the most weight, largest cost, and biggest size in the system. WBG devices can allow these all to shrink.
Mornsun concluded, Meanwhile, compound semiconductors are poised to revolutionize clean energy innovations. Such as, Silicon carbide (SiC), gallium nitride (GaN) and Zinc Oxide (ZnO), the very promising wide bandgap (WBG) semiconductor materials. They enable WBG-based components smaller, faster, more reliable and with higher efficiency than the silicon-based components. WBG-based inverters, for example, are able to convert the DC electricity generated by solar and wind energy into AC electricity that can be used for homes and businesses, while integrating the power onto the grid through reducing transmission losses by about 50%. However, challenges are still there in cost reduction and mass manufacturing. An endeavor in developing the newer technologies that use semiconductor materials and understanding of their behavior is continuing. Thin-film semiconductor material with a lower cost is becoming more prevalent. Amorphous silicon and Copper Indium Gallium Selenium (CIGS), for example, are such materials. Their cost is lower than that of crystalline silicon, but their efficiency for PV panel is not as high as it is for crystalline solar cells. The advantage of these materials lies in the potential to provide much lower cost solutions for PV.\
Individual Leadership and Expertise in this Domain
Our portfolio comprises a broad selection of inverters ranging from just a few watts and kilowatts for residential use to several megawatts for the commercial and utility-scale markets. It includes best-in-class discrete OptiMOS™, CoolMOS™ and CoolSiC™ MOSFETs and IGBTs as well as highly integrated 3-level Easy 1B/2B modules, functionally integrated EiceDRIVER™ gate driver ICs, XENSIVTM current sensors TLI4971 and XMC™ controllers. Backed by our end-to-end application expertise, we offer the best chip combinations to achieve leading power density levels and best-in-class efficiency.
Discrete CoolSiC™ MOSFET switches, CoolSiCTM Schottky Diodes, IGBT TRENCHSTOP™ 5 and IGBT Highspeed 3 can cover applications as far as 30 kW, whereas power modules from the CoolSiC™ MOSFET Easy 1B/2B, 3-Level EasyPACKTM 1B/2B and Booster EasyPACKTM 1B/2B should start being considered for systems beyond 30 kW.
Thangavel: Central inverters make use of power modules, with 3-level NPC topologies turning to the 62 mm, EconoDUAL™ 3 and PrimePACK™ 3/3+ families.
Common to all solar inverter solutions are drivers, and here design engineers have a range of high-side (1ED) and half- bridge (2ED) products in the EiceDRIVER™ family. With SiC MOSFETs switching at up to 50 V/ns or above, it is essential that gate driver strength matches the switch’s needs, as well as providing accurate timing and tight tolerances. Negative gate voltages or a Miller clamp may also be required, along with fast short-circuit protection, as SiC devices are less short- circuit capable than IGBT alternatives. EiceDRIVER™s to match the CoolSiC™ range are available, with devices such as the 1EDC20I12MH being UL 1577 certified for 2.5 kV(rms) for one minute.
Current sensing within the inverter solution can be implemented optimally using XENSIV™ devices, such as the TLI4971. Everything from simple monitoring and system feedback to central control systems, to control of the switching inverters can be covered by programmable devices such as the XMC™ 4000 range of Arm® Cortex®-M4 microcontrollers. Finally, the auxiliary supply is optimally implemented using AC/DC integrated power stage devices such as those in the CoolSET™ family.
Additionally, Infineon offers hardware security solutions. Our OPTIGA™ Trust authentication chips give effective protection against counterfeit products. This helps avoiding damage to user devices as a result of non-original, sub-standard accessories or parts.
Security is of critical importance within an isolated production plant and even more so in an interconnected value chain. Our high-quality industrial security solutions, which are easy to integrate, enable the monitoring of whether or not only authorized people, machines and renewables are communicating. They also reliably reveal if a system has been manipulated, helping avoid unnecessary downtime. Finally, yet importantly, they enable secured software updates to devices in the field.
ON Semiconductor designs and fabricates the full range of power electronic devices for clean energy conversion. We have workhorses like IGBTs and power diodes, a range of Superjunction MOSFETs for any switching profile, new SiC diodes and MOSFETs, and ICs for gate drivers, auxiliary power supply controllers and galvanic isolation. Many of these devices are packaged together in modules for topologies from a simple half-bridge to complex multilevel inverters. Outside of power, ON Semiconductor supports a variety of communication technologies such as Zigbee, Bluetooth, and WiFi to monitor and optimize the renewable assets.
MORNSUN, a manufacturer provides one-stop solutions of power supplies, has a line of products for renewables
applications engineered to meet the challenges of the latest in power generation technology. Included in this product line are power converters that support a 1500V PV system, which reduces the quantities of strings, inverters, combiners, and DC- side cables, while significantly increasing the power density and power-per-array. With the right conversion components, overall system losses associated with 1500V designs can be significantly reduced. At Mornsun, we are constantly updating our power solutions, allowing our customers to take advantage of the latest technology in renewable energy, including power generation and distribution of solar and wind energy. If you are looking to harness and control power for a renewable energy source, then Mornsun has the solutions for you, offers everything from isolation converters, voltage regulators and integrated IGBT drivers to power management ICs, which are UL 1741, CSA-C22.2 No.107.1, EN62109 safety approved.
1. Ballentine, Paul Duran, Lindsay Anderson, Emily (2008). The Role of Semiconductors in Clean Energy, found at: https:// repositories.lib.utexas.edu/handle/2152/47379
2. U.S. Department of Energy (2013). Wide Bandgap Semiconductors: Pursuing the Promise, found at: https:// www.energy.gov/eere/amo/downloads/wide-bandgap- semiconductors-pursuing-promise
3. Kerry Taylor-Smith (2018), Solar Panels and Semiconductor Materials, found at: https://www.azocleantech.com/article. aspx?ArticleID=747
4. Accenture (2020). Applied Intelligence for renewables, found at: https://www.accenture.com/mu-en/insights/utilities/ renewables-applied-intelligence