“The integration that we have experienced in the past few years mainly includes electrified power architecture, which mainly includes power systems such as on-board charger (OBC), high voltage DC/DC (HV DCDC), inverter (ACDC) and power distribution unit (PDU). Terminal device. Due to the relatively large number of these components, in consideration of platform development, integration can be applied at the mechanical, control, or power system level.
From 2007 to 2021, China’s auto industry has been vigorously developing, and auto sales peaked in 2018. In this process, we have seen the rapid development of joint ventures, the rise of independent brands, and the growth of emerging companies in electric vehicles. At present, in the era of great changes in the automotive industry, completely different design and development requirements have been put forward for electrification, intelligence, networking, and sharing of multiple tracks. This has made vehicle companies in the most competitive Chinese market have begun to break the original ” With the development pace of “one replacement in five years and one model change in three years,” the current auto companies are all based on the sales of fuel vehicles, implementing large-scale investments into electrification transformation, and transforming on the software side.
As shown in the figure below, we can see that a very important feature is that the powertrain and thermal management system, including the drive system, battery system, charging and power electronics, and thermal management system have begun to further integrate and develop to some extent. Highly integrated stage. These gray parts will be used as the basic components of future smart electric vehicles and will be developed on the road of focusing on scale and integration.
Figure 1 The foundation and expansion of the development of electric vehicles
The first part of the combination of powertrain direction?
The integration that we have experienced in the past few years mainly includes electrified power architecture, which mainly includes power systems such as on-board charger (OBC), high voltage DC/DC (HV DCDC), inverter (ACDC) and power distribution unit (PDU). Terminal device. Due to the relatively large number of these components, in consideration of platform development, integration can be applied at the mechanical, control, or power system level. There is already a clear approach, one is modular integration: 3+3+3: drive system (motor, inverter, reducer three-in-one drive) + battery system (battery + OBC + DCDC integration), thermal management Integration (PTC, compressor and pipeline, valve), we are already familiar with this, this has become a routine practice. Going to the top for more integration, as shown in the figure below, GM’s “8-in-1” highly integrated electric drive unit on the Ultium platform includes a motor, inverter and reducer, vehicle controller, integrated PDU, OBC and two DCDC.
Figure 2 General Motors “8 in 1” highly integrated electric drive unit
We can see that with the increasingly fierce competition, if you want to achieve a certain height in scale, car companies need to make in-depth simplifications on the basis of the original modularization, and integrate these components into a whole component. Can bring many benefits:
Optimizing the characteristics and efficiency of the three power and electric vehicle architectures can improve the manufacturability of the final assembly by reducing the number of parts that need to be assembled; through the structural system, it is possible to reduce the wiring harness for high-voltage connections, merge the structure and reduce the brackets to achieve overall weight reduction The purpose, the most important thing is to reduce the complexity of vehicle-level management and consider the future, standardize and modularize each component, so that in the integration process, reuse and optimize the cost as much as possible. The integration process makes the cost very Big space
Here we see two directions. One is the different stages of integration in terms of chip and circuit directions. As mentioned earlier, from the perspective of different electrical, structure, and control levels, there are different stages of integration. Take the integration of charger and DCDC as an example, these two components are completely independent. Our ultimate goal is to achieve a certain degree of reuse of two highly integrated components at the component level through functional merging, and to simplify the cost by changing a certain structure of the circuit through detailed design. Remarks: This block diagram is from TI’s official website TI.COM.CN, and there is a selection list of these devices. Among them, TI’s ultra-low latency C2000™ MCU helps to achieve higher switching frequencies (up to 1 to 2 MHz), and wide band gap switches made of GaN and other materials and optimized high-speed gate drivers can be Significantly reduce the size of components and improve system efficiency. The first stage: OBC and DCDC, just physically put together, the two are independent, that is, as shown in the following figure, the overall two parts of the second stage: the two parts use a structural shell, sharing the cooling flow The third stage: control level integration, integrating the circuits of the control logic parts of the two components. The fourth stage: at the power topology level, multiplexing some of the circuit devices (switching devices and magnetic devices)
Figure 3 The integration of different levels of OBC and high-voltage DC/DC converters
It is from this point of view that, from the perspective of power device integration, considering that the car charger and the high-voltage DC/DC full bridge have the same rated voltage, they can be used in combination, and the two components reuse the full bridge to share the power switch. become possible. Integrating two transformers together can achieve magnetic integration. They have the same rated voltage on the high-voltage side, so they may eventually become a three-terminal transformer. Under this design, the performance of DCDC low-voltage output will be limited, and it can be considered to add a built-in step-down converter.
Figure 4 Power level multiplexing of OBC and DCDC
The second direction is centralized processing at the control level and the algorithm level.
Taking the previous design direction of integrated thermal management of a certain brand, not only component integration is used here, but the physical parts of all components are concentrated. The 12 components in the traditional thermal management system are integrated into one, and the original intercommunication pipeline is replaced by a substrate. The number of pipes in the thermal management system has been reduced by 40%, and the number of components has been reduced by 10%. The most important thing is the control integration. The control of all components is centralized. The control systems of key components such as compressors and pumps are all integrated into the EDU (Electric Drive Unit). The advantage lies in the expansion, upgrade and function optimization of the software, which reduces the Electronic control of the components. Failure probability, enhanced diagnosis and maintenance of the life cycle of each component. Most importantly, this is in line with the general technical direction of the centralized management and release of automotive software in the future.
Figure 5 Integrated thermal management system
Summary: Smart electric vehicles will disrupt the entire industry in the future. In the entire process, the integration and sharing of electrified components is the foundation. The advantages in terms of the number of parts and the simplicity of the system are very significant, and from the initial structure integration to the integration of electrical and electronic aspects. With the gradual development of software control, the overall pace of development of smart cars will be faster, and the core support of chips and software in the three-electric system will be more needed.
1) Achieving High Efficiency and Enabling Integration in EV Powertrain Subsystems Using C2000™ Real-Time MCUs
2) A High-Performance, Integrated Powertrain Solution: The Key to EV Adoption
3) Reduce EV cost and improve drive range by integrating powertrain systems