 Hello and welcome to this on 24 webinar about what silicon control rectifier can do for EV charging. I'm Jean-Pierre Pro and I'm here today with Benoît Ronard. So here is the agenda for today. So we start first the introduction to evaluate the market size. What are the silicon control rectifiers key features for this application and what is the STM ranking in the thyristor market. Then second we will look at the different EV charging topologies including power factor correction trends, how to limit the inrush current and what are the SCR benefits to limit the inrush current. The third party would be the bi-directional EV charger, the vehicle to grid, V2G or vehicle to load, V2L operation, how to benchmark the SCRs, how to control and layout SCR in this application and we will present different evaluation boards available at ST.com. Then we will conclude presenting the SCR product roadmap. What about the competition in the thyristor market and what are the takeaways for this webinar. We will end up the session with question and answers. Here you can see the EV charging market size evaluation by strategy analytics. These numbers in million units include the plug-in hybrid vehicle and also the battery electrical vehicles. And this growing market of 27% growth rate within the next five years for onboard charger will reach about 40 million units by 2028. Also in pink color you can see the growth rate of 35% for the charging points including the private and the public charging station. If we look now by battery voltage, the 800 volt battery represents about 5% of the total battery in 2022. And this will increase to 25% by 2030 and the remaining 75% would be for 100 volt batteries. Now if we look at the content for thyristors in this market, we can estimate today this available market for thyristors to be in 2022 about 50 million dollars. And that will double by 2030 to 100 million dollars silicon control rectifiers in EV charging. What you can see here in this slide is the battery electrical vehicle car segmentation from class A, B and C and the sports car from Porsche. The different power of these cars are ranging from 100 kilowatts for the Renault Zoe to 150 kilowatts for ID3 from Volkswagen, 286 kilowatts for the Tesla Model 3 and up to 560 kilowatts inverter power for the Porsche Taycan. The maximum battery size is also increasing according to the range of car from 52 kilowatt hour up to 83 kilowatt hour for the sports car. The battery voltage are mainly 400 volts for all the cars like the Renault Zoe, the ID3 and the Tesla Model 3, but it's raising to 800 volts for the Porsche Taycan. And then how much power would be required to charge those batteries is depending on the car. Like it is required to provide 50 kilowatts of charging energy for the Renault Zoe, 125 kilowatts for the ID3, the Tesla will support a battery charge up to 250 kilowatts and the Porsche Taycan supports a fast charge up to 350 kilowatts, which is a lot of power that the EV charge station will have to provide to charge these cars. There are different types of EV charger station. Here in this table, you can see from bottom up the Type 1, which is about 20 amp or less than 4 kilowatt single phase. And this is available everywhere and it's, for instance, the domestic charger that you will have at your home. Then the Type 2 is rising up to 22 kilowatt, about 80 amperes, single phase or three phase. It's less available, but you can see you can find them now in most of the charging station or domestic wallbox. And this will allow to charge the car, let's say in hours, like between two hours to 24 hours to get to full charge, depending on what type of charger you are using. If you want to charge faster, you have to go to Type 3, which will be power ranging from 50 kilowatts up to 200 and even higher, 300 kilowatt of power for the Porsche Taycan, for instance. And this will input directly a 400 volt DC, like in the supercharger from Tesla, which is 150 kilowatt. And this is available, but not as frequently as the Type 1 and Type 2. And then we can see now some higher voltages charger, like the Porsche Taycan 800 volt, which has a booster to boost the 400 volt input up to 800 volt to charge the battery. They can see also that there are different types of connectors, AC input or DC input to charge the car. And they will have either proprietary connection or the service provider will have different plugs to charge the cars. There is also optional support for the three phase AC in the EV charging. And for sure, the trend is to support bidirectional charging for vehicle to grade or vehicle to load. So what are the challenges for EV charging, and especially the onboard charger, the one that is included inside the car? First of all, we can mention the vibrations in the car. This is a source of early failures, especially for the relays and the other mechanical components inside the car. Energy saving is particularly important, and this translates to longer distance range for the car. So we have to maximize the conversion efficiency and limit the off-state standby losses. Electromagnetic interference is also increasing the complexity of electronics and making the qualification difficult, especially when you consider the IEC standard at 61,000-3-3, 4-4 and 4-5, which relates to in-rush current limitation, burst test and lightning strikes. Then the charging is also a challenge for the car. And one of the challenges in charging the battery is the in-rush current limitation that will slow down the charging and also will limit the component laugh time, especially for the passive components. And then the last point would be the automotive standard, the automotive electronic impulse reinforced qualification processes and higher reliability levels for the car industry. So what are the Silicon Control rectifier characteristics in the Switch device family? Here in this graph you can see the different Switch devices, including IGBTs, MOSFETs, white band gap devices like silicon carbide or gallium nitride. There are switches capable of switching currents up to megahertz of frequency for the latest white band gap devices. Contrary to this, silicon thyristors are only switches that can operate at 50 hertz or 60 hertz or a few kilohertz at the maximum. But the characteristic of Silicon Control rectifiers is that they are able to conduct a lot of peak currents. They have a very high current density compared to other switches. And this makes the devices very suited for application like EV charging that has to control a lot of current and requires very efficient devices. Also in the Switch family, the thyristors is quite unique because it can block voltage in both directions. Whereas the other switches, they always have some kind of diodes that are conducting in one direction. Thyristor control rectifiers is blocking voltage in both directions. And these characteristics make the SCR very interesting for EV charging application. Here in this slide you can see the SCR market and the STM ranking in this market. On the top left graph, this is the Omnia evaluation of the market with on the y-axis the size of the supplier and on the x-axis the growth from 2020 to 2021. With 30% growth last year, ST is now ranked number two, second supplier of thyristors worldwide. On the bottom left, WSTS is splitting the market in two. The device is below 55 ampere in blue and the device is above 55 ampere in gray. ST is supplying devices on less than 55 ampere and the market share that we have is rising from 27% in 2016 up to 30.5% in 2021. And devices that we are supporting are SMD devices and now including modules for power up to 50 kilowatts. The total available market above 55 ampere include devices that are ranging from 30 kilowatts of power up to 300 kilowatts of power. And now I end over to Benoit Ronard for a more detailed presentation on EV charging topologies. Let's go now deeper on EV charger topologies. The mega trend for charging topologies is to go from unidirectional power to bidirectional power transfer. What does it mean? It means that you need to charge the EV battery from the grid. This is what we call the charging mode and also you need to inject battery energy from the car to the grid. This is what we call inverter mode. This is the case of course for automotive applications such as on board chargers and off board chargers or charging stations. And also more and more for industrial applications such as photovoltaic solar box or UPS. There are three different modes to achieve the bidirectional transfer. The first one is the charging mode. What we call here G to V mode grid to vehicle. This is where you charge the battery from the grid. The two other modes are the inverter mode, vehicle to grid and vehicle to load. Vehicle to grid means you inject the energy from the battery to the grid and vehicle to load means you inject the energy to a specific application. You plug into the EV. For example you can supply a laptop, you can supply power tools or if you want a barbecue. Now let's focus on PFC topology trends. In the first row you have PFC topologies. The first one is conventional PFC. This is standard PFC with rectifier bridge. The second one is bridge less PFC. You have better efficiency here compared to conventional PFC. Then you have total PFC also with better efficiency and compact power density. And the last one is Vienna PFC. We are focusing total PFC as this is the most used solution today. Here regarding the power devices parts, the high frequency leg is composed by two MOSFETs and the low frequency leg is composed by two SCRs. SCRs mean silicon controlled rectifiers working at 50 or 60 Hz. Now if you want to add the bidirectional features you need to implement two more SCRs in antiparallel of the two others. Then here in the schematic in the second row you have in green the two SCRs to bring the inverter mode. The two SCRs in blue for inrush current limitation of the topology and the two MOSFETs for the high frequency switching. The two SCRs in the blue box are used to manage the inrush current limitation. Each application must comply with IEC 61000-3-3 standard. This standard gives the limitation of voltage changes, voltage fluctuations and flickers of the grid. What does it mean? It means that when you plug in an application, when you plug in AC-DC converters with bulk capacitors, you need to limit the inrush current you think from the grid to the bulk capacitors. And this standard is asking to limit the RMS current at startup. On the right you can see how with SCRs you can manage, thanks to a fast shift control, you can manage the voltage of the output capacitors up to the full charge of these capacitors at startup. There are two use solutions to manage this inrush current. Here with a comparison, on the left side of the slide, we are using NTC resistors to manage the inrush current at startup. Once the capacitor is fully charged, the resistor is bypassed by a mechanical relay to avoid any power losses inside the NTC in steady state. The drawback is that the electro-mechanical relay causes some audible noise when switching. This is not usable with system with vibration because this is mechanical device. There is edging of the metal contact of the relay with very poor number of cycles specified. And the charging time is very low. Here in the waveform, we are charging a capacitor at 6 amps of RMS current with a charging time of 400 ms. On the right side of the slide, here the inrush current is controlled with SCRs, Silicon Control Rectifier, and this is rectifier with a gate to smartly charge the output capacitors. With the same examples of RMS current limited at 6 amps, the charging time is only 120 ms, because you can charge very accurately the output capacitors. Here there is an advantage, there is no more electro-mechanical parts. This is faster, only you need to implement a smart control of the device. This is not a big deal in a full PFC. There are also a few other advantages to switch from relay to SCR. One of them is the PCB size. Then here we have an example where you remove two electro-mechanical relays with the bulky power resistors to limit the inrush current, buy two SCRs in TO220 with a smaller sink. Also, another advantage is the lifetime. As we said previously, there is an edging of the contact of the relay. We can see in the picture on the bottom some contacts with the metallization. After a few cycles, there is some arcing between contacts that lead to metallization edging. And one of the other advantages is the overall efficiency of the PFC. Then on the right side of the slide, on the curve, you can see the efficiency of the PFC. In blue, this is efficiency using SCRs and in pink, this is efficiency when you use the relay, including the coil consumption and the resistor contact of the relay. Then you can see good improvement in terms of efficiency from 0.5% at 10% load for a 1 kW PFC to 0.2% gain at peak efficiency at 50% load. Now let's go deeper on bidirectional PFC function. Here is the principle of operation working in inverter mode, V2G or V2L. The first row shows operations when grid voltage is positive and second row shows operations when grid voltage is negative. The MOSFETs are switching high-frequency, few tens of kHz, few hundreds of kHz, when the SCRs is switching only 50Hz, 60Hz. This is what we can see in the drawing on the right side, where we can see in pink the current through the SCRs and in green the current switching by the two MOSFETs in positives and same in negative for the other SCRs. Now we can see in the literature IGBTs to manage bidirectionality. Here is a comparison of power losses of IGBTs compared to SCRs. In the graph you can see efficiency assuming PFC at 99% and the impact of the leg to ensure the bidirectionality if you use SCRs in blue and if you use IGBTs in pink. Because of the IGBTs, it is very saturated at high current and the SCRs thanks to its voltage current characteristics with very low dynamic resistors is able to manage better efficiency for the overall PFC. We can see also MOSFETs for this kind of function, but here the saturation mode is worth at high current. Here is an example with 45mAh of RDS on, you can decrease the RDS on but it becomes more and more expensive compared to IGBTs and SCRs. Now let's see how to implement the SCRs in the charger. ST is offering a large panel of packages for power devices. From through all vertical cooling, TO220, TO220 full pack, TO247 or TOP3 high where TO220 and TO247 are automotive grade for onboard charger but also in SMD packages for higher power density with automated assembly keeping in mind the compromise with thermal dissipation through the PCB. This is a discrete approach with packages up to D2 pack that is automotive grade or even bigger D3 pack with very low RTH junction to case. The other solution is to use the module approach. Module means multiple dice in one package. Here we are proposing topside cooling packages to have a single head sink for the whole bomb of power devices of the PFC. This is through HU3 pack, ASPEC SMEET and DMT32, all our automotive grade of course. Now let's have a look on the portfolios to reach EV chargers. Thanks to the large offers of packages, we can have scalable products range to fit all automotive and industrial applications. One of the topic here is to manage in rush current. Then we need a high current capability for the SCRs. Then we have a product offers from 30A to 80A. All are rated at 150°C of junction temperature to reach requirements of automotive onboard chargers. And then, as we have seen in the last slide, it includes through all devices in discrete surface mount, in discrete and in modules. With two modules released today in ASPEC SMEET, one is two SCRs in series, one is two SCRs and two rectifiers to make a bridge in a conventional PFC. Now that we have chosen the right SCRs, let's go on the control circuit. SCRs are gate current control devices. Then it means you need to apply a gate current around 50mA to trigger the device. Here are some examples of control circuits. On the left there is an opto transistor control circuit. Here there is the advantage, this is very simple to implement, but the opto cells can be a blocking point for automotive applications. The second one is pulse transformer control circuits. This is really simple also to implement and fully compatible with automotive grid applications. And the last one is the transformers too, but this is double output transformers. This is maybe the best solution as we have several SCRs inside the applications. Here is an example when you drive four SCRs with two pulse transformers with double outputs. Now that the control circuit is fixed, let's see how to implement the SCRs in a few configurations of PCB and packages. First considering application with passive cooling. A TO247 rule package is considered. The main drawback is the height of the package either the head sink, even if the application case can be used if insulation is provided between TO247 and the case. The rule package has the main advantage to allow single side PCB for easier implementation. On the right side, D2PAC SMD package is considered. Here with an insulated metal substrate IMS for a better power density than TO247. The drawbacks are the two PCBs and the price gap between FR4 epoxy PCB and IMS PCB. We are now considering here leaking cooling, most of the time used in OBC. The HU3PAC package is used as discrete SCR. It's SMD package with topside non-insulated frame for cooling. Here both of the compactness and the thermal performance are optimized. On the right side, ACEPAC SMD is also SMD package with topside cooling capability. This is the most optimized assembly as it allows the module approach with two or four SCRs in the same package. Here the package is already insulated, making easier the assembly of a set of ACEPAC SMD for all power devices. ST has developed a 3.6 kilowatt totem pole evaluation board for designers. It is unidirectional chargers with inrush control thanks to SCRs and it brings automotive-grade 1200V SCRs but also 650V SIG MOSFETs, gate drivers for MOSFETs, 32-bit STM32 microcontrollers and flyback converter with Viper. This evaluation board is fully compatible with EMC standard. Here is an example of conducted noise measurements. And the efficiency of the board can reach 98.7% at peak efficiency. This picture shows how you can improve the overall board efficiency from 97.7% to 98.7%. 98.7% means you can reach standards for titanium SMPS. In total, ST has developed 8 evaluation boards to demonstrate inrush current solutions with SCRs. Not only for automotive but also for industrial applications from 0.8 kilowatt to 7 kilowatt. There are some plug-and-play boards to use to bypass NTC unconventional topologies or with totem pole topologies where we have seen we can use SCRs in low-frequency leg or in conventional PFC with mixed bridge to SCRs and to rectifier to manage inrush current limitation. So thank you very much Benoit and let's now move to the conclusion. So let's start first by summarizing the product range STMicroelectronics is proposing for silicon control rectifier. Here in this slide you can see the range of product ranging from 30 ampere, 40 ampere, 60 and 80 ampere. Yellow colors is industrial grade product whereas the blue color is automotive grade products and the products are 800 volt or 1200 volt capable. The range of discrete product are packaged in D-square pack, TO220, D3 pack or TO247 or the more advanced HU3 pack which is a top-side cooling packages. And then we also have modules in the A-SPAC-SMIT product family combining two theristors in series or a full bridge of control rectifiers plus diodes. This makes the product range of ST very scalable for all range of power for industrial and automotive application. The product range we have is also very robust against inrush currents and we provide high reliability up to 150 degrees Celsius of junction temperature. And as you can see in this slide the package choice includes SMD, discrete modules and top cooled power devices. Now let's look at the product roadmap that STMicroelectronics will introduce in the coming month. First of all we will introduce a half leg configuration of theristors. The first one would be rated 60 amp and they would be one unidirectional devices with two SCRs and two diode and a bi-directional devices with four SCRs. These two products 60 amp will be complemented by the same devices rated 30 amps for lower power application and all devices will be packaged in one A-SPAC-SMIT devices. Then for higher power we are going to introduce a three phase bridge in the DMT32 package and this device will combine three SCRs and three diodes for the three phase configuration. As you have seen STMicroelectronics is proposing SCRs with the industrial grade or the automotive grade. Here in this slide is a summary of what is specific for the automotive grade product. As far as standards and processes are concerned, first of all the manufacturing site has to be automotive certified for an automotive grade product according to EATF 16949. The wafer process and the package has to be compliant with automotive which includes the use of part average testing, PAT and also a better control process which is visible here with the CPK greater than 1.67 for automotive grade product whereas standard industrial product will have a CPK greater than 1.33. Also the automotive grade product requires a specific AECQ101 qualification compliance. For instance thermal cycling has to be done up to 1000 cycles from minus 55°C to plus 150°C and we are also doing operating life tests on automotive grade products and the number of devices that we are testing is 77 pieces and up to 3 lots compared to the standard 30 pieces 3 lot for industrial grade product. As far as documentation is concerned automotive grade product also comes with the P-PAP level 3 documentation and the traceability is also specific as the path number will always have a Y in the suffix and there is also a PCN procedure that is different for the automotive grade product. Let's now look at the four reasons why customers are selected SCR from SCR Microelectronics compared to AXIS SCRs and Latifuse company. First of all SCR has a complete range of SCR products but also provides microcontrollers, power devices and sense and control devices. The second reason is the system solution that ST proposed that includes evaluation board, reference design, schematic, layout and firmware. The third reason is the innovative product range of ST macroelectronics including advanced packages for higher power density and the fourth reason is that ST has an integrated high volume production capability for automotive and industrial grade products. Let's now summarize the takeaway for this on 24 webinar about what SCR can do for EV charging. On the main challenges that we face like in-rush current limitation the solution is to use SCR in phase control and the benefit would be to have a smart control of the in-rush current and a fast startup of the PFC. When the challenge is to increase efficiency the solution is to reduce the conduction losses in the 50 hertz leg of the PFC stage and the benefit of the SCR would be to lower the voltage drop compared to IGBTs and increase efficiency even with temperature. Talking about temperature, the challenge of the EV charging is to work at 125 degrees of operating ambient temperature and the solution would, as ST proposed, is to use a 150 degree Celsius maximum junction temperature and 1,200 volt rated SCRs that will allow to shrink the cooling heat sink and that will be compatible also with 800 volt battery. The last challenge will be time to market and the solution is to design flexible converters from 3 kilowatt up to 22 kilowatt uni or bi-directional and the benefit in using ST SCR is that the SCR is a scalable solution and it is provided in either discrete form or package module devices. So thank you very much for attending the webinar and for more information you can consult www.st.com