Hitachi Suijin Series of Power Modules for Electric Vehicles


Chris White at Hitachi Europe Limited

Hitachi’s Suijin series of automotive power modules provide a range of high power, high-performance power modules to meet the most demanding automotive applications.

Electric vehicles are receiving ever-greater attention from vehicle manufacturers, governments, regulators and consumers and the pressure is increasing on vehicle designers to deliver on the technology’s promise.

Hitachi’s Suijin series of automotive power modules are here to help. Building on Hitachi’s long history in producing power modules for electric and hybrid-electric vehicles the Suijin series provides a range of high power, high-performance power modules to meet the most demanding automotive applications from 600V to 1200V.

 

The Suijin Series Package

The Suijin Series provides high function 6in1 power modules incorporating direct water-cooling for maximum cooling efficiency, power cycle life and output power and temperature sensing for optimum design performance.

The series offers a single package outline for the full range of voltage and current ratings allowing for a common mechanical design and high level of design re-use for converters with different ratings. The compact form factor, high power density facilitate and robust construction enables the designer to realize industry-leading converter designs.

 

Figure 1. Suijin Series Direct Water Cooled Module

 

Product Line up

The Suijin Series product line up covers from 650V, 750V and 1200V rated modules with current ratings up to 1000A. All products are available now as samples or in mass production:

  • 650V, 600A – MBB600TV6A
  • 650V, 800A – MBB800TW6A
  • 750V, 1000A – MBB1000UW1A
  • 1200V, 400A – MBB400TX12A

 

Evaluation Kits

To assist with initial evaluation and design activities Hitachi can supply a comprehensive evaluation kit to support each module. The Evaluation kit includes:

  • Gate Drive with all key IGBT drive and protection features and temperature sensing for each arm.
  • DC Link Capacitor designed to connect directly to the DC connections of the module and provide a low inductance DC link
  • Water cooling jacket for connection to a cooling system during testing.

 

Latest Technology

Hitachi continues to apply the latest technology breakthroughs to the Suijin series to continue extending the performance envelope. The application of latest generation Side Gate IGBT, on-chip temperature sensing and Copper Sintering for improved die attach ensure the best output power, energy losses, control, and lifetime.

 

Low loss, High Controllability

The latest generation Hitachi Side Gate IGBT reduces energy losses and improves controllability compared to conventional trench IGBT. The loss trade-off can be improved with up to 35% reduction in turn off energy or 15% reduction in saturation voltage as shown in Figure 2a.

Low gate charge reduces the load on the gate driver and low reverse recovery dV/dt and voltage overshoot allow optimization of the turn-on to lower switching losses further and enable easy integration into a converter as shown in Figure 2b.

The reduced reverse transfer capacitance (Cres) of Side Gate IGBT leads to improved Short Circuit performance with a better-controlled gate voltage and lower peak collector current. This provides a power module that is more robust under short circuit conditions and reduces the current that must be handled in the converter design.

 

Figure 2. Side Gate IGBT performance. Left: Vce - Eff tradoff, Right: Eon+Err - reverse recover dV/dt.

 

Maximum Lifetime and Power Density

The application of Copper Sintering to replace the solder layer between the IGBT chip and the substrate greatly increases the robustness of the module, in particular increasing the power cycle life by 10 times compared to standard solder. It also increases the available output power of the module, providing the highest possible power density. This is particularly suited to high-performance vehicle designs requiring aggressive acceleration and highly dynamic mission profiles while ensuring total reliability throughout the lifetime of the vehicle.

 

On-Chip Temperature Sensing

To enable dynamic and accurate converter optimization Hitachi is embedding temperature sensors into the IGBT chips allowing the converter control system to read directly the chip temperature. This enables more accurate dynamic control of the converter to optimize performance over the lifetime of the vehicle.

 

Future Developments

Hitachi continues to innovate and bring new technology to market to improve the performance of power modules including wide band gap devices, next-generation silicon IGBT, and new packaging technologies.

 

Next Generation Silicon IGBT

Hitachi’s innovative dual side gate IGBT breaks through the conventional performance limitation of silicon. By applying dynamic carrier control, the turn off loss can be reduced by 45% compared to conventional trench IGBTs and the Eoff – Vce(sat) tradeoff approaches that of SiC MOSFETs but using standard silicon processes.

 

SiC TEDMOS

Hitachi is also bringing SiC MOSFETs to automotive applications to support the next generation of automotive inverters, drive up efficiency and further improve performance. Hitachi’s trench SiC MOSFET technology “TEDMOS” uses a special trench structure to offer leading performance with low energy losses and improved short circuit durability.

The structure of TEDMOS ensures a robust and reliable chip that is easy to control. Both Drain-Source resistance and switching losses are reduced compared to SiC DMOS structures. The electric field around the trench is reduced compared to conventional trench structures giving a more reliable chip. Short circuit current is also better controlled, resulting in short circuit durability that is similar to standard IGBTs without compromising normal operational performance.

 

Figure 3. Hitachi SiC TEDMOS performance compared to conventional SiC DMOS. From left to right: on-state resistance, switching loss, and short circuit durability.

 

New Packaging Technology

Key to maximizing the full benefit of the semiconductor innovations is the packaging and Hitachi continues to innovate in this field. Future developments will bring improved cooling, reduced stray inductance and improved module lifetime. These will combine to allow the semiconductors to be operated to their full potential and provide converter designers and vehicle designers with new levels of performance and design flexibility to meet ever more challenging requirements.

 

Conclusion

Hitachi is supporting the development of electric and hybrid electric vehicles by applying innovation and advanced technology to a range of automotive-focused power modules. The modules are well suited to high-performance applications that demand the highest levels of efficiency, lifetime and power output.

The common module outline for the Suijin series facilitates a high level of design reuse and common design across converter power ranges to suit a wide range of applications.

Hitachi’s focus on bringing the best performance to the market through innovation and advanced technology is evident in the future roadmap for the Suijin series. The latest generation silicon IGBTs available now will be followed by further silicon and SiC MOSFET generations to continue the push for higher efficiency and better performance.

More information:    Source: Bodo's Power Systems, June 2018