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I recently had the chance to test drive a Tesla. Not like any Tesla, the super-powered one: S85PD.

The one that has an “Insane” mode and can beat a Ferrari at traffic lights. Even though there was no Ferrari at the traffic light we stopped at, I can trust the fact that it can compete with many supercars.

And as a power electronics market analyst, I had to ask the sale guy about inverter and power modules. He did not know much about that. It’s not really his job, and he is not a design engineer. He knew a lot about the car and its features (which is enough to sell it) but not about the inside of the inverter, the power train, or the car…

So I asked Siri Google, and I had answers. I ended up on a Tesla car owners forum. I looked into it, and I found pictures and description of the inverter. Like the the picture down here.

Fig.1: 2×14 IGBTs in parallel is one leg of inverter—All packaged in discrete TO247 – From Tesla Roadster and Model S inverter

All about Tesla and power semiconductor packaging

That’s the truth. Don’t go for a reverse engineering on a Tesla inverter. Engineers just made an awesome car with very simple off-the-shelf products. Do not look for any highly special package for power modules International Rectifier (now-Infineon) would have made specially for Elon Musk (just because he is Elon Musk). There is no such thing. The inverter is made of TO-247 packages (Figure 1), derived from TO-220 in the 1990’s in order to handle more power and heat.

They used 20-year-old power module packaging technology to build the fastest electric luxury car on earth. It’s that simple.

I was shocked again! (The first shock was experiencing the acceleration of “Insane” mode.) I wanted to share that with someone. So I went on the internet and asked a very dumb question on the Power electronics group of LinkedIn.

A question that sounded like that:

Linkedinquestion

And many comments, questions and reactions (and “likes”. There are “likes” in LinkedIn too… But you cannot “poke” anyone. I wish we had that feature).

And for those of us who are not hanging out in this virtual professional world of LinkedIn, I wanted to summarize discussions here.

What you get from these discussions

1. “Module or discrete?” is still a 2015 question.

The first power module packaging design question is to know if you are going to use a power module or not. And that is a question that Tesla engineers had to ask themselves and that JB Straubel, CTO of Tesla, asked himself designing the model S. He talked about it during 2010 APEC conference, and I wish I was there :-(

But according to the attendees, the choice of going for TO-series package rather than well-marketed EV series of power modules were:

  1. Simplicity of assembly
  2. Heat dissipation (and thus easy cooling)

Which is in total accordance to any engineer mind designing a product to:

  1. Work
  2. Be efficient

As the rest of the design is not engineering work … most of the time.

2. Power modules & IGBT packaging preconception

Most comments agree on the fact that a power module is a great thing, with a lot of room for innovation and many great features.

But they also agree on the fact that there are other factors to think about, when going for a design in power electronics, depending on the applications.

You still need to think about:

  • Volumes of production
  • Total cost of the solutions
  • Heat spreading and cooling requirements
  • Peak currents, ripples and other EMC stuffs
  • Size

Still you have interesting feedback putting down some preconception on power modules:

  • “The TO series are indeed very tough little beasts and I have been told by a senior semiconductor reliability engineer in some ways more reliable than a module, with respect to bond wires. Not something they usually advertise as the same company also makes modules targeted at EV/HEV”
  • “The TO-series package are really quite outstanding and I’ve used them a lot”
  • “That design allows Tesla to ‘insanely’ run 1500A through the inverter IGBTs and then the motor”

3. Theories on why Tesla made unexpected IGBT packaging choices

For most of the participants in the discussion, the choice of TO-247 totally made sense, but not always for the same reasons:

It could be because:

  • “The design was done when they were not sure about the volumes”
  • “There was no suitable module available at that time” (then what about today?)
  • “They wanted to reduce the risk of failure for this new product”

The point is not actually to try to find the right one, but to think about it.

We are in 2015, and we still find so many reasons why discrete TO-247 packaging could be a very good choice.

Tesla Model S inverter

Tesla Model S inverter – 3 phase represented by the triangle, having each two switches of 14 IGBTS in parallel

4. Power module packaging for EV/HEV—What’s next?

The state of the art and what would be the best choice in the future has also been discussed.

An interesting comment points out that:

the state of the art in power device packaging […] will most probably be in the higher volume, mass manufactured electric vehicles—from Ford, Toyota, GM, etc., There are definitely higher performance packages—with better characteristics in terms of thermal, inductance, tolerance to vibration, etc.

or that:

Tesla might not have the volume to drive custom power electronics packaging.

Which totally makes sense and proves that Toyota has a huge knowledge of how to build a power converter and hybrid car. They started Prius back in 1994 and have all the feedback and experience since then. On the other side, and that is Point The Gap comment: Is power electronics for Hybrid cars and Power electronics for full electric cars the same thing?

You get rid of a lot of constraints, starting with space and cooling restrictions when you design for a full electric car. (e.g.: Tesla’s cars have a rear and front trunk, with batteries under the car and inverters/motor group not taking much space).

4.1 .XT, SKiN and other IGBT packaging innovations

There is also a reminiscence of .XT Technology (Infineon) and SkiN (Semikron). These two technologies have been in one of our articles about PCIM 2015.

From Point The Gap point of view, these are all very interesting innovations. It’s just that they have been presented 2 to 4 years ago, and we are still waiting for available products. Remember the marketing campaign from Semikron in 2013 about SKiN technology. According to them, it may be ready in 2016. Why so much communication 3 years before availability…

And finishing with something that sounds very true to us:

“According to Tesla’s website the Power Electronics Module uses 84 IGBTs to power the 3-phase induction motor, or 14 IGBTs in parallel per switch. Is it the best solution? I seriously doubt it, although it may be the ‘lowest cost’ solution based solely on the bill of materials.”

4.2 Is best power semiconductor packaging “no-packaging”?

A parallel discussion also emerged on discrete packaging innovations. You must know EPC’s WLP (Wafer Level Package). The innovation here is that there is no package. The die has a protection coating on one side and bumps on the other. No wires, no wire bonding issues.

Of course this reduces the risks of failures. But as pointed in a comment: “Chipscale packages/no-packages are exciting at lower voltage and power for converters, power supplies, etc., but PCB interconnects bring back resistance and inductance.” An affirmation that is disputed by no-package manufacturers.

Conclusion: Join the conversation

If you have comments on this, join us in the group. We would be happy to have your feedback. It’s an interesting discussion.

Sources: http://insideevs.com/; https://teslamotorsclub.com

Toshiba Mitsubishi-Electric Industrial Systems Corp (TMEIC) established a company that manufactures and sells PV inverters for large-scale solar power generation systems in Yancheng, Jiangsu Province, China.

This is the first time that the company has formed an overseas base dedicated to manufacturing PV inverters. The name of the new company is “Yancheng TMEIC Power Electronics Corp. Its capital is Rmb18.8 million, which was wholly invested by TMEIC. The new company will start operations in February 2015.

The site area of the manufacturing plant is 6,000m2. At the plant, the 500kW and 630kW models of the “Solarware” PV inverter will be manufactured. TMEIC aims at an yield equivalent to 1GW.

China is already the largest market for solar power generation in the world, and TMEIC considers it as the most important region for its overseas strategy.

Yancheng, where TMEIC formed the new company, has many advantages in the development of mega (large-scale) solar power plants. For example, it enjoys a large amount of sunlight and has a large amount of land. Also, it is located near a power grid and areas where a large amount of electricity is used. Therefore, many solar plants are expected to be built in the city.

TMEIC has passed the “Zero Voltage Ride Through” performance test, which was conducted at State Grid Corporation of China, for the first time as a Japanese manufacturer. And it will establish a system to supply PV inverters by forming the new company.

The SuperGrid Institute is one of several energy-transition projects promoted and part funded by the French government. It is a collaborative research institute bringing together public and private organisations to develop new technologies for supergrids.

The SuperGrid Institute’s work will make an important contribution to the transition to low-carbon energy. To dramatically increase the share of renewable energy in the energy mix, future transmission grids will have to offer a special combination of capabilities not available today: long-distance transmission (to connect remote renewable energy sources), subsea or underground energy transport, the ability to handle unpredictable fluctuations in renewable energy generation, and more. Meshed HVDC grids are a promising solution to these issues, but they require that a number of technological challenges be overcome. And that is the ambition of the SuperGrid Institute.

Supergrid institute smartgrid grid HVDC Alstom

“Today, the institute is hosted primarily at the Alstom complex at Villeurbanne, France. However, we are in the process of building
our own campus with buildings, equipment and test facilities. In fact, we envisage making our test facilities commercially available to
third parties. The same is true of the intellectual property (IP) we generate.”

“We already have some patents in the pipeline and we shall leverage our IP assets to forge new partnerships and generate licence income.”

Says Philippe Auriol, retired professor of the Ecole Centrale Lyon and former director of a CNRS laboratory

“A key point for universities and students is the proximity of test and measurement facilities on high-power, high-voltage prototypes. Very few university labs have access to this type of equipment – anywhere in the world. These tests and measurements will then constitute the starting point for new basic research projects.
Some PhD research projects are currently under way. For example, a ‘fail-to-short’ project – a packaging technique to ensure that a failed electronic module is seen as a short circuit. Another is focusing on the control of high-voltage power electronics to ensure a high level of insulation.”

Says Hervé Morel, Senior Scientist at Université de Lyon

Jean-François Ballet, Managing Director of the SuperGrid Institute and Vice-President Industry Projects at Alstom Grid, explains:

“We have structured the SuperGrid Institute into five key programmes to achieve our ambitious goals.”

  • Programme 1: Supergrid system architecture, operation and control
  • Programme 2: Technologies for breaking, insulation and measurement
  • Programme 3: Power conversion technologies
  • Programme 4: Supergrid cables and lines
  • Programme 5: Stabilisation and storage

 

Source

SBE is designing a fully size-and-performance compatible DC Link system for the HP Drive IGBT module in collaboration with Infineon. Both vertical and horizontal connection systems will be available. The vertical system is designed to occupy the same footprint as the HP Drive itself and the horizontal system will respect the shorter length of the new HP Drive. This way, customers will be able to take full advantage of the size reduction offered by the improved Infineon technology and trust in the demonstrated performance and lifetime capability of the SBE Power Ring Film Capacitor technology.

 

The SSBE Capacitor on IGBT PackBE DC Link system is fully capable of supporting the voltage and current options that can be used with the new Infineon HP Drive module. Yet the size is greatly reduced from conventional DC Link systems used today with the larger HP2 module systems. The SBE system insures that the customer can actually realize the potential inverter power density improvement which can be facilitated by the Infineon HP Drive.

SBE is known in the industry as providing the highest ripple current density available. There is no need to sacrifice the capability of this exciting product development by Infineon by using standard technology offerings for the required DC Link system.

SBE will have sample systems available at the time of release of the Infineon HP Drive and prototype and preproduction systems over the coming months. Starting in 1Q15, you will be able to order these products on the SBE on line store. However, as we expect demand for these initial prototypes to be high, you are welcome to pre-order by contacting customer service at jaimeb@sbelectronics.com.

Source: http://www.sbelectronics.com/2014/12/collaboration-infineon-optimized-dc-link-designfor-new-hp-drive-6-pack-igbt-module/

The global AC drives manufacturer Vacon is now part of the Danfoss Group, effective 1 December 2014. In September 2014, Danfoss announced a public tender offer to acquire all the shares of Vacon. By the end of November, Danfoss obtained approvals from all the relevant authorities, and has now acquired more than 90% of Vacon shares and voting rights in Vacon.

Danfos and Vacon logos

The combination of Vacon and Danfoss will create one of the world’s leading players in the drives market, leveraging the best of the two companies.

“The clear ambition is to be a leading player in the drives market. We see that true value is created together. This is why we will create a new business, where people work together to develop the best products, applications and services for our customers,” says Niels B. Christiansen, President and CEO of Danfoss.

“Combining two strong and innovative AC drives companies will give customers an even more competitive, innovative and attractive offering of AC drives. Joining forces also means that the new business will be able to invest further in both R&D and in the sales force, which is a key success factor in our business,” says Vesa Laisi, President and CEO of Vacon.

Vesa Laisi will be the President of the new business segment, named Danfoss Drives.

“The dedicated drives focus unites both Vacon and Danfoss and distinguishes the two companies from competitors.”

“Vesa has spent most of his career in the drives industry and he possesses very deep insights into the business. He will use this experience to guarantee world-leading product portfolio and customer service,” says Niels B. Christiansen.

Danfoss also announces a reorganization of the rest of the Group. The closing of the Vacon deal now paves the way for establishing four strong and global segments.

“Today, we have very strong businesses and with the new structure, we can unite these in even stronger entities to further strengthen our market positions.”

“This is the right outset for the next part of our strategic journey with a strong focus on growth,” says Niels B. Christiansen.

 

Source

The electric truck supplier of control systems to the growing electric truck market, Motiv Power Systems, raised $7.3 million in growth capital from investors led by Colorado’s Magness Investment Group. The funding comes as the second Motiv-equipped all-electric school bus is delivered to Kings Canyon Unified School District.

“Motiv has cracked the code on electric trucks,” said Gary Magness, Manager of the Magness Investment Group. “We are impressed with how Motiv’s approach leverages the existing truck and bus builder ecosystem to achieve scalability. I’m pleased to be a part of this revolution in trucking that brings environmental sustainability and significant fuel savings to an industry that’s the backbone of our economy.”

The Motiv electric Powertrain Control System (ePCS) is unique in the industry as a single product suite that can electrify any truck or bus chassis with a variety of commercially-available battery packs and motors. The Motiv ePCS, battery packs and motor are installed to replace the engine and transmission of a new incomplete chassis such as the Ford E450 in a ship-through modification.  This process, common in the truck industry, is similar to a Compressed Natural Gas ship-through modification and means minimal changes between the fossil fuel and electric versions of the final vehicle.  Existing truck and bus builders who already use these incomplete chassis can build and sell electric versions of their existing truck and bus models.

“It’s an honor to have the support of an investor like Mr. Magness,” said Motiv CEO Jim Castelaz.  “Not only does he see the potential in the market we are addressing, he understands our approach and believes in our vision of breaking the complete dependence trucks and buses currently have on fossil fuel.”

About Motiv Power Systems

Founded in 2009 and based in Foster City, CA, Motiv Power Systems designs and builds an electric Powertrain Control System (ePCS) for commercial truck and bus builders who use it to create all-electric versions of vehicles such as box trucks, flat-/stake-bed trucks, refrigerated trucks, utility/service trucks, shuttle buses, school buses, delivery vehicles and refuse trucks.

The Red Oak Park, a neighborhood in Boulder, CO, features renewable energy design. (Photo by Dennis Schroeder / NREL)

Enphase Energy, Inc. today announced its fourth-generation Enphase® System is shipping in Europe. The Enphase System now includes the M250 Microinverter, which produces 250-Watts rated AC output power. In addition, the Envoy Communications Gateway, with a Wi-Fi option, connects to the Enlighten software platform to deliver a new standard in solar system intelligence and reliability.

Enphase is the number one inverter used in residential solar in the Americas, according to an IHS report. The company has accelerated business momentum in its international markets as well, most notably in the UK, France and the Netherlands.

“We are excited to introduce the fourth-generation Enphase System to our customers across the UK and our core European markets,” says Olivier Jacques, managing director, EMEA, for Enphase Energy. “Leveraging the successful introduction of our fourth-generation System in the U.S. last year, we continue to set the bar for inverter quality, performance and reliability in EMEA.”

Enphase M250 Microinverter:

Optimized for high-power solar modules, the M250 Microinverter produces 250-Watts rated AC output power and pairs with modules up to 310W. The M250 is rated at 95.7 percent EU efficiency and has been built to withstand the harshest environmental conditions. It is IP67 rated and has undergone over one million hours of testing in extreme temperature and humidity environments prior to launch. This level of quality testing and assurance is unprecedented amongst microinverters, setting a new standard for reliability in the industry. In addition, the new Enphase System continues to be supported by an industry-leading 20-year warranty.

The new fourth-generation Enphase M250 Microinverter is available now through authorized distribution in the UK, France, Benelux, Switzerland, Germany (<4kWp) and Italy (<3kWp). The current M215 Microinverter will remain available for European customers in addition to the introduction of the M250.

For more information about the fourth-generation Enphase System, visit: enphase.com/uk countries. To sign up for new training available for the M250, visit our WEBEX PAGE.