This article is mainly to talk about the latest development of electric vehicle power management technology. Electric vehicle systems consist of electric motors, power converters, and energy storage devices such as lithium-ion batteries. This new architecture system must be optimized to maximize system efficiency, enabling the car to achieve maximum travel distance on a single charge. These developments in electronic technology have created conditions for reducing the emissions from transportation. Save our planet and keep the earth away from pollution! This is a consensus voice among scientists and people of insight around the world to reduce greenhouse gas emissions. Vehicles powered by fossil fuel combustion engines are the culprit. Although there are many alternative technologies to promote car travel, the only feasible solution at present is: electric cars. Catalog I Electric vehicles (EV) and hybrid electric vehicle (HEV) II Silicon carbide (SiC) power supply for electric vehicles III GaN power supply for electric vehicles IV Utilizing hybrid vehicle transmission system to reduce greenhouse gas emissions V Automotive inverter VI Dual-voltage battery system VII Delphi integration and wiring VIII Electric wheel drive system IX Conclusion FAQ I Electric vehicles (EV) and hybrid electric vehicle (HEV) An electric vehicle (EV) runs on a battery, as does a hybrid electrical vehicle (HEV), except that it also uses a fossil-fueled internal combustion engine as an aid. The technologies that power these cars need to be successful and have a bright future. Energy efficiency is the key. Therefore, intelligent power management mechanisms are needed to maximize the efficiency of converting battery energy into wheel mechanical driving force, thereby increasing single-charge charging. Travel distance, while not increasing carbon emissions, is ideally a significant reduction in carbon emissions. This video describe the operational characteristics of a hybrid vehicle drive train: Introduction to hybrid-electric vehicle energy monitor II Silicon carbide (SiC) power supply for electric vehicles The weight, size, and cost of an electric vehicle, and the distance travelled by a single charge, are directly related to the efficiency of the power conversion system. SiC power components are ideal for working in the high temperature environments that are common in automobiles. Let us take a closer look at the role of silicon carbide power components in improving system efficiency. Lighter weight means longer mileage. A typical way to reduce the weight, cost, and size of a power conversion system is to increase the switching frequency of the switching regulator. We know that the size and weight of active components such as inductors, capacitors, and transformers can be reduced when operating at higher frequencies. Embrace the silicon carbide (SiC) solution. Although silicon (Si) power devices can also operate at high frequencies, the advantage of SiC is the ability to handle much higher voltages than Si. SiC is a wide band gap semiconductor device, and a wider band gap means a higher critical electric field (a critical electric field is a blocking voltage in an off state). The high voltage capability of wide bandgap (WBG) SiC devices allows them to have lower on-resistance, resulting in faster switching speeds and unipolar operation. Part of the principle is that their carrier frequencies need to be accelerated to much higher speeds (more High kinetic energy) to overcome wider band gaps. Although gallium arsenide (GaAs) and gallium nitride (GaN) also have high critical electric fields and are also improved devices for high-power solutions, SiC has other advantages, such as higher maximum operating temperatures. High Debye temperature, high thermal conductivity (in polycrystalline SiC), rapid switching and high resistivity saturation with low resistivity in the electric field, facilitated generation of lower silica (SiO2) The production cost, as well as the higher threshold energy brings more robust radiation resistance. SiC devices have many key applications in electric vehicles. The existing electric traction drive can convert 85% of the electrical energy into mechanical energy to drive the wheels. This efficiency is quite high, but SiC can also help improve efficiency. The power converter can benefit from improved efficiency because it transfers battery power to the engine and can be used in the battery charger circuit and any needed auxiliary power (Figure 1). Figure 1. SiC power devices have many uses in electric vehicles The SiC power supply that converts 750V to 27V for low-voltage electric vehicles is a good example of using SiC power devices to improve the efficiency of electric vehicles. This architecture increases efficiency from 88% to a staggering 96%, reduces size and weight by 25%, and does not require fans to cool excess heat compared to Si solutions. Table 1 shows some important applications of SiC power devices for electric vehicles. The reference information mentioned in the table can be found by referring to Reference 1 at the end of this article. Table 1. Some SiC applications in the electric vehicle electronics architecture III GaN power supply for electric vehicles Gallium nitride (GaN) also contributed to the improvement of the power supply of electric vehicles. IGBTs widely used in motor drive and DC/DC control have been silicon-based products. These designs typically have switching times on the order of 10kHz to 100kHz, while GaN devices can switch nanoseconds and can easily operate in a 200°C automotive environment. Like SiC, GaN devices can also reduce the size of inductors, capacitors, and transformers in power supply architectures due to their higher switching speeds. They can also reduce the overall size and weight due to the shrinking size of passive components. We will analyze their efficacy based on the chemical composition of electric vehicle batteries, such as lithium-based chemistry and NiMH with high energy density. As described in the previous SiC device section, the efficiency of the power conversion architecture also needs to be improved in order to enable longer distances for a single charge. The switching speed and minimum on-resistance of silicon devices have reached their maximum limit, and GaN seems to be a viable solution that exceeds these limits. Experiments show that if the switching frequency can be increased by 5 times, the inductor and capacitor can be reduced to one-fifth the size. Today's GaN technology can support very high speeds. GaN power devices perform quite well in four key areas: high temperature operation, higher breakdown voltage, low on-resistance, and nanoscale switching speeds for higher operating frequencies. GaN is similar to SiC in terms of these advantages. There are two differences between them: LEDs and RF transistors always use GaN; many silicon manufacturing processes are compatible with GaN processes, which reduces wafer costs and processes compared to the higher substrate costs of SiC. cost. Since the reliability problem was solved as early as 2003, today's technology has achieved the first batch of GaN high electron mobility transistor (HEMT) devices already in production. These are normal conduction devices, so the gate voltage of 0V will become conductive, and any voltage less than 0V will turn the device off. The SiC substrate was used early. Once the Si substrate is perfectly integrated with GaN, the production cost can be significantly reduced. The new cascaded architecture implemented in 2014 changed the ever-changing devices into normally-off devices. Since then, the drive technology has made great progress, the integration is getting higher and higher, and the power inverter has also made significant progress. GaN devices also perform well in battery chargers for electric vehicles, which consist of AC/DC converters plus DC/DC converters. This combination is a power factor controller (PFC) (Figure 2). Figure 2: A typical electric vehicle power architecture With GaN, coupled with higher switching speed GaN HEMTs, smaller passive devices can be realized. At higher frequency conditions, using a smaller inductor can make the ripple current of the power supply architecture lower, improve the power factor, and get a capacitor with a smaller size and lower cost. Lower ripple currents also have less stress on the capacitors, increasing their reliability and lifetime. Over the past few years, the reliability of GaN has been raised to a very high standard, which is the key to the use of GaN in automobiles. IV Utilizing hybrid vehicle transmission system to reduce greenhouse gas emissions At present about 72% of traffic emissions are generated by cars driving on the road. Improving the design of the hybrid powertrain drive system to increase its efficiency is the primary means of reducing emissions. One approach is to increase the efficiency of the DC-link voltage control architecture, which means that first it is necessary to increase the power converter efficiency of the series hybrid electric vehicle drive system. The DC-link is usually connected to three drive systems: a primary power supply consisting of a three-phase rectifier; a secondary power supply consisting of a dual active bridge (DAB) DC/DC converter; and a propulsion load consisting of a three-phase inverter ( Figure 3). They relate to tandem hybrid cars. Figure 3: Block diagram of the drive train of a hybrid vehicle In a design topology where the DC-link and battery voltages are not equal, an intermediate DC/DC converter solution is required. The paper "Voltage Control Methods for Improving Efficiency of Power Circuits in Series Hybrid Electric Vehicles" (Reference 3) describes many methods for studying different architectures and solutions for various DC-link voltage and DC/DC converter control. . The following will discuss the proportional control law that controls the dynamic DC-link voltage to achieve the phase shift between the waveforms of the gate switching of the DAB DC/DC converter bridge. This converter is located between the DC-link and the battery of a series hybrid vehicle drivetrain, as shown in Figure 4. In this case, the controller lowers the power consumption of the DC/DC converter and the entire drive system. Figure 4: Hybrid driveline interconnection diagram in the control schematic In this model, the diesel engine is the main power source of the hybrid vehicle, and the DC battery is the secondary power source. The supervisory control system (SCS) controls the ratio of power provided by the two power sources based on battery state of charge (SOC) and motor load. In fact, in this series hybrid vehicle, the DC-link voltage imposes restraint conditions on the ideal working area of PMSM and PMSG corresponding to the unit modulation index, so that the system can avoid signal distortion and reduce system efficiency. Overshoot state. Keeping the modulation index close to 1 can increase the total efficiency of the power circuit in the drive system, thereby maximizing the efficiency of the inverter and the rectifier, and the switching process is the main factor of its efficiency loss. Therefore, reducing the switching voltage can improve efficiency. This permanent zero pressure switch (PZVS) mechanism that minimizes power loss is best suited for cars with high mixing factors, especially in urban environments. The mixing factor (HF) is the ratio of the installed power from the power source to the total installed power. This mixing factor affects the fuel consumption in hybrid vehicles. V Automotive inverter The main power inverter controls the electric motor in the electric drive system and is an important component in the hybrid/electric vehicle. Power inverters, like engine management systems (EMS) in internal combustion engine cars, determine driving behavior. This inverter is suitable for any motor, such as synchronous, asynchronous or brushless motor, controlled by an integrated electronic PCB board. This PCB is specifically designed by automotive manufacturers to minimize switching losses and maximize thermal efficiency. The other function of the inverter is to capture the energy released by the regenerative brake and feedback to charge the battery. The distance traveled by hybrid/electric vehicles is directly related to the efficiency of the main inverter (Figure 5). Figure 5: Infineon main inverter block diagram in a hybrid/electric vehicle VI Dual-voltage battery system Managing batteries in hybrid and electric vehicles requires high-voltage technology. Dual-voltage systems incorporating 12V and 48V batteries require bi-directional DC/DC conversion, as shown in Figure 6, with the goal of protecting the circuit and supporting architectural functions. Figure 6: Bidirectional DC/DC converters from 48V to 12V In addition, automotive architecture designs typically have a single-phase 3.5kW or 7kW on-board charger module (OBCM) for charging an electric vehicle or plug-in hybrid electric vehicle (PHEV) from the grid. In contrast, electric vehicles and plug-in hybrid vehicles can be used as energy sources, and can also be used as energy storage devices in smart grids that integrate renewable energy. Smart grid work takes into account the smart charging and discharging of electric vehicles and plug-in hybrid vehicles. This is why OBCM must be a bi-directional DC/DC charger. The best architecture for this design is a boost series of resonant bi-directional topologies, as shown in Figure 7. It operates above the resonant frequency, has a zero-voltage switching function, and has maximum power transfer performance at the minimum switching frequency point. Compared to unidirectional power converters, this technology replaces diode rectifiers with MOSFET rectifiers. This solution also has higher efficiency and wider battery capacity. One of the major drawbacks of this architecture shown in Figure 7 is that the rectifier bridge has large losses when it is turned off. This problem must be addressed in future designs. Figure 7: Designers sometimes use a modulated DAB converter to control simple high-frequency isolation VII Delphi integration and wiring It is amazing that Delphi integrates all of the components discussed in this article and some of the other hybrid electric vehicle power electronics (Figure 8). Figure 8. Delphi achieves high integration in hybrid/electric vehicles It is also important to use suitable internal connectors in hybrid/electric vehicles (Figure 9). Figure 9. The key element of a hybrid/electric car is to minimize the quality VIII Electric wheel drive system “Design and implementation of electric drive systems for in-vehicle electric vehicle applications” (Reference 8) proposes a hub drive system for hybrid and electric vehicles, and a hub-drive hybrid vehicle that provides computing performance. The SIMULINK model has been successfully developed. Two 14kW DC brushless DC (BLDC) motors are manufactured according to the literature and are installed in the rim of the hybrid vehicle wheels. In addition, two independently driven rear wheels are also mounted on Fiat's Linea. By detecting the angle of the steering wheel, electronic control technology replaces the mechanical differential device. The electric drive control system of the car and the electronic control unit (ECU) communicate via the CAN bus. A successful cascade is achieved between the electrically driven rear wheel and the ICE-driven front axle. Figure 10. A rear-wheel brushless DC motor image This design chose a brushless DC motor with a concentrated coil because it has a very low power-to-weight ratio and high efficiency, and it is easy to control. Figure 11. Exploded view of a direct-drive brushless DC motor in wheel rims and motor-generator units The brushless DC motor power drive consists of an integrated power module (IPM), an 8-bit microcontroller and an electronic control system. Driver software development for IGBT converter control and motor pulse width modulation (PWM) voltage control. The system has optocoupler isolation, current and temperature protection, and the system is also embedded with speed, current and voltage sensors. In summary, this article describes some recent developments in the power management of electric vehicles and hybrid vehicles. In the future, there will certainly be more development results that will be further improved to benefit our planet. IX Conclusion Electric propulsion technology requires the integration of a completely new architecture of the powertrain in the vehicle. This newly added component requires a multidisciplinary and in-depth study of the corresponding system components. Electric vehicle systems consist of electric motors, power converters, and energy storage devices such as lithium-ion batteries. This new architecture system must be optimized to maximize system efficiency, enabling the car to achieve maximum travel distance on a single charge. These developments in electronic technology have created conditions for reducing the emissions from transportation. FAQ 1. What is energy management system in electric vehicles? Energy management strategies are the algorithms that decide the power split between engine and motor in order to improve the fuel economy and optimize the performance of HEVs. ... A lot of research work has been conducted for energy optimization and the same is extended for Plug-in Hybrid Electric Vehicles (PHEVs). 2. What is EV technology? EVs (also known as plug-in electric vehicles) derive all or part of their power from electricity supplied by the electric grid. They include AEVs and PHEVs. AEVs (all-electric vehicles) are powered by one or more electric motors. They receive electricity by plugging into the grid and store it in batteries. 3. What is the biggest challenge with electric vehicles? The major challenge is costs. Battery technology is expensive, and because batteries in electric cars need to be able to hold massive amounts of charge to make the cars practical for most drivers, they have to be built using expensive materials, most of which are tough to procure. 4. Why electric cars are bad for the environment? Nevertheless, at the end of the manufacturing process, electric cars are the ones generating more carbon emissions, according to the Union of Concerned Scientists. Why is this? Because electric cars store energy in large batteries (the larger they are, the bigger their range is) that have high environmental costs. 5. What are the main problems with electric cars? The biggest problem with EVs is range. While a plug-in hybrid can count on gasoline as a backup, EVs can't. An EV like the Tesla Model S can travel nearly 400 miles on a single charge, but not all EVs can make it quite that far. EVs like the Model S tend to be pretty expensive too. 6. What is meant by electric vehicle? An EV is a shortened acronym for an electric vehicle. EVs are vehicles that are either partially or fully powered on electric power. Electric vehicles have low running costs as they have less moving parts for maintaining and also very environmentally friendly as they use little or no fossil fuels (petrol or diesel). 7. How do electric vehicles work? Electric cars function by plugging into a charge point and taking electricity from the grid. They store the electricity in rechargeable batteries that power an electric motor, which turns the wheels. Electric cars accelerate faster than vehicles with traditional fuel engines – so they feel lighter to drive. 8. What are the types of electric vehicles? There are two basic types of EVs: all-electric vehicles (AEVs) and plug-in hybrid electric vehicles (PHEVs). AEVs include Battery Electric Vehicles (BEVs) and Fuel Cell Electric Vehicles (FCEVs). 9. Do electric cars run on AC or DC? Electric cars can use AC or DC motors: If the motor is a DC motor, then it may run on anything from 96 to 192 volts. Many of the DC motors used in electric cars come from the electric forklift industry. 10. Are there any benefits of owning an electric car? They can reduce emissions and even save you money. Fueling with electricity offers some advantages not available in conventional internal combustion engine vehicles. Because electric motors react quickly, EVs are very responsive and have very good torque.
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