When charging piles are included in the seven major projects of new infrastructure in 2020, people seem to see that a trillion-yuan market is about to be leveraged, and more than 26 provinces and cities have launched more than 50 projects and charging facilities. related policies. But the reality is that according to the data provided by Zhiyan Consulting, although the shipment of charging piles has increased significantly in the past year (from 120,000 to nearly 300,000), there has not been the expected blowout.
The development of the market has not been satisfactory. Although there is a problem of coordination of interests of all parties, there are also various obstacles from a technical point of view. Among them, the most urgent need to solve is the charging experience that is very important to the user. Time, and the real-time interaction of charging pile information, all of which focus on high-power DC charging piles.
Anxiety charging in progress
In order to solve the problem of charging anxiety of electric vehicles, faster charging speed has become a clear requirement of fast charging stations. It is a common requirement in the industry to achieve charging for 5 minutes and travel 200 kilometers. The DC module of the charging pile can be upgraded by increasing the power density and increasing the charging voltage. The former requires high-performance real-time microcontrollers and power devices that support higher switching frequencies, while the latter requires higher withstand voltage and higher power devices. High conversion efficiency, the third generation wide bandgap semiconductor power device will be a good choice. Moreover, with the increase of the switching frequency of the third-generation semiconductors, more complex power supply topologies and control algorithms are required, so the demand for real-time controllers is further increased.
When it comes to the main control part of the DC charging pile, we must mention the Texas Instruments (TI) C2000™ microcontroller, which has a high market share. In fact, the C2000 microcontroller has a long-standing reputation in the Chinese market and has long been widely used in the field of power electronic control and provides advanced digital signal processing in industrial and automotive applications. The C2000 microcontroller has been at the forefront of the analog-to-digital control revolution for more than 20 years. After continuous development, the third generation is now even better: with more computing power and richer peripheral resources.
The C2000 microcontroller implementation controller has the dual advantages of a microcontroller and a digital signal processor due to the built-in C28x math-optimized core. With a variety of high-efficiency computing cores, the C2000 microcontroller can achieve μs-level loop computation times. For example, in a bidirectional high-density GaN CCM totem-pole PFC, using the TMU, the C2000 microcontroller can reduce the PWM calculation from 10 μs to less than 0.5 μs, ensuring a cycle-by-cycle adaptive dead-time calculation for the most accurate and efficient GaN FET control.
The integration of more advanced peripherals is another advantage of the C2000 microcontroller for complex topologies. By integrating 3.6M SPS sampling rate and ADC with 12-bit to 16-bit resolution, higher-speed current sampling and voltage sampling are realized; there is also 150ps resolution PWM, which can meet the higher switching frequency of third-generation semiconductors, Enables highly dynamic charging modules with significantly improved efficiency and reduced size.
Complex multilevel topologies are becoming more common as bus voltages are increased in pursuit of higher efficiency. NPC and ANPC topologies are the two most popular topologies for bidirectional PFC/inverters, which can limit the voltage stress on switching devices to half the bus voltage. However, these topologies require more PWM channels from the MCU and also require a special protection scheme to maintain voltage balance across the power switches during any shutdown. C2000 microcontroller third-generation devices offer a unique Configurable Logic Block (CLB) that implements an on-board fault protection scheme to ensure real-time protection under all operating conditions without any external logic circuitry, similar to FPGAs / CPLDs are as flexible. An example is presented in the TIDA-010210 6.6kW Three-Phase Three-Level ANPC Inverter/PFC Bidirectional Power Stage Reference Design.
On the other hand, aiming at the design goals of high-efficiency, high-power-density power electronics and very high power density for fast charging piles, the third-generation semiconductors (including SiC, GaN, etc.) The most important semiconductor technology for peaking, carbon neutrality. Compared with the previous two generations, it has unique properties such as large band gap, high breakdown electric field, high thermal conductivity, high electron saturation drift speed, and small dielectric constant, so it can reduce the system heat dissipation cost and passive device size, and can Provide higher energy efficiency or higher power density and lower total system cost.
Due to the early launch of SiC, the user coverage is wider. However, “it is still too early to draw conclusions on whether SiC and GaN are better or worse. In the long run, there will be more room for cost reduction of silicon-based GaN.” Fu Yang, technical support manager of Texas Instruments North China, said. In any case, with the increasing maturity of the third-generation semiconductor process in the future, the overall cost advantage will become more prominent.
TI has a layout in both directions, with SiC improving system robustness and reliability, reducing form factor and easily meeting EMI standards by providing drivers with integrated capacitive isolation. TI’s layout on GaN can be traced back to 2010, and in 2017, it launched the first 10-kilowatt cloud-connected power grid converter with Siemens. And by constantly trying new architectures, GaN is adapted to a wider voltage range, such as 800V, 1000V (for reference), which also brings greater possibility to see GaN on charging piles in the future. To ensure high reliability, TI has conducted more than 40 million hours of device reliability testing and more than 5 GWh of power conversion application testing on GaN FETs. At the same time, in order to further improve reliability and integration, TI has introduced devices that integrate GaN and drivers. What is even more eye-catching is that TI has its own process and factory in GaN, so it can ensure the stability of product quality and supply.
In addition to the charging time, the most painful thing for users is that they cannot know the usage of the charging pile in front of them when they need to charge, which requires remote access and control using secure wireless connection technology. TI can provide various secure wireless connection products ranging from short-range near-field communication (identification, information protection) to long-distance private protocol communication, and is also compatible with commonly used BLE and WiFi communication technologies. These allow the charging pile to update its status in real time, and users to know its usage.
Data security is increasingly valued by users and operators, so the solution requires functions such as secure identity authentication and data communication. For WiFi products, TI has added information security protection mechanisms a long time ago, such as verifying the data integrity of external Flash, preventing unauthorized access and protecting sensitive data, and improving security mechanisms such as encrypted channels and key management.
need more
In fact, a safer, smarter, and faster charging pile involves far more technology than the ones mentioned above. For example, because the super charging pile is a high-power and high-voltage outdoor scene, it has special safety and reliability requirements. Therefore, the stability and intelligence of the isolation device and gate device used in this scenario can protect the power device. , which is a prerequisite for the DC module to operate in a safer state.
According to Fu Yang, technical support manager of Texas Instruments North China, TI is conducting innovative research in various aspects to meet various challenges in the charging pile market. One of them is how to improve user experience with more intelligent charging piles, which will require the help of Edge computing and AI technologies.
In terms of traditional products, it is also advancing in an orderly manner. For example, TI’s highly integrated next-generation power products integrate current sampling, isolation, and isolation power management chips into a smaller chip to help customers save PCB area and cost; and on the basis of existing silicon devices , through more complex topologies to achieve higher power densities without using more advanced power devices…
In addition to its advanced technology, TI provides multiple product lines and different cooperation methods for different users and needs. The most important thing is that, as an enterprise with corporate social responsibility that has been deeply rooted in China for 35 years, TI is willing to pass the Comprehensive local support to help Chinese companies succeed and integrate into the tide of China’s information industry development.
Along with carbon peaking and carbon neutrality, which were first written into the “Government Work Report”, there are also “increase parking lots, charging piles, power stations and other facilities, and speed up the construction of a power battery recycling system.” The new energy vehicle industry development plan (2021~2035)” draft for comments, it is expected that the number of new energy vehicles in my country will reach 64.2 million in 2030. Even if the vehicle-to-pile ratio cannot be achieved at 1:1, it means that the future charging pile market will achieve leapfrog development. The secret to moving with the trend and being able to stand at the forefront is to find a partner who can solve it one problem at a time, one step at a time. TI has always insisted on this and is committed to creating a better future. TI will always be there to meet future challenges hand in hand with you!