6 = TimesNewRoman Power Electronic Device Application and Selection Criteria in Electric Vehicles Ma Xianminpu’an School of Science and Technology, Xi’an 710054, Shaanxi, China. The requirements for electronic devices are given. The comparison results of different devices are given. The advancement of electronic technology and power semiconductor device technology has led to the emergence of many power electronic devices with different performances. In order to achieve the highest possible efficiency of the power converter, this is a requirement worthy of research on power electronic devices. For high-power transistors, the power field effect body is made of bamboo iMOSFK insulation, bipolar transistor 108 and elbow 03 gate-controlled thyristor. After comparing and researching modern power electronic devices, they put forward their views on the selection of these devices. 1. The requirements of electric drive systems for devices In the process of controlling AC motors, power electronic devices are used as on-off switches in power converters. In order to obtain high conversion efficiency, the DC battery voltage is changed to alternating current. It is hoped that the power electronic device will have the characteristics of conceivable switching, such as zero resistance at turn-on, no power loss, and infinite resistance, no leakage current, and current at infinity. In addition, I also hope that the rated voltage and rated current of the component are large, the price is low, the driving power is small, and the resistance is strong. The rated voltage and the rated current of the electric vehicle battery pack are generally 300, the maximum voltage during charging can reach 370, and the regenerative charging process Medium, the battery voltage may rise to 4, when choosing the rated voltage around, the main consideration The factors are the end-of-charge voltage and the maximum allowable electric current. Therefore, the rated voltage of the device is generally 600. The rated current of the device is mainly determined by the output power of the motor and the number of devices in parallel. Due to the limitation of the operating temperature of the device, the rated current often passes through the peak value of the motor The power rating is true. In electric drive systems, the peak rated power of the motor is approximately 24 times the rated power of the machine. If the peak power is 1001, the corresponding rated power flow can be considered as 600, and then other safety factors are considered. It is more appropriate to select a device with a rated current of 700 people. Multiple switching devices are connected in parallel, and a device with a smaller rated current can be selected. However, in order to solve the fund project 1999153 of the key laboratory visiting scholars fund project of the Fund Project; the Shaanxi Natural Science Foundation project 200141 has the current problem. The switching parameters of the parallel devices must cause 1.2 switching frequency and switching loss. The switching rate and the motor input In terms of power, in pulse width modulation, Jiali mode, in order to eliminate noise, it is expected that the switching frequency of the device is greater than 201 out. In theory, the audio frequency can be removed when the switching frequency is greater than 18 out. Therefore, in actual operation, the switching frequency is often selected as the output, and the noise of the inverter can be tolerated at this time.
The increase in the child shut-off rate can increase the power density of the device. Reduce the size of the filter, reduce or eliminate the buffer circuit. Furthermore, the volume and weight of the entire converter are reduced, and the overall efficiency of the converter is improved. In electric vehicles, the improvement of efficiency has practical significance. For example, the extra power that can be obtained by the drive system can be used to drive electric vehicles in multiple halls before charging. 1 In the converter. With the increase of the switching frequency, the switching loss will increase proportionally, but the efficiency of the circuit will be greatly reduced. On the other hand, it will be severely turned on and off under the condition of zero voltage or zero current. In theory, the switching loss is zero. In a 1-flow bad-node resonant inverter, the Khan-off frequency can be 1 to 200 kHzJ and the switching loss is very small.
Although the resonant soft switching circuit has such significant advantages, it is still a certain distance away from actual use. At present, hard switches are still used in electric vehicles. Adding a converter from a practical point of view, the switching frequency of 101 produces efficiency noise It is more suitable for electromagnetic interference. 1.3 Dynamic characteristics and device protection. 000 and 10,000 people. The driving power of 4 devices should be very small. This requires that the input capacitance of the device should be very small, and the input impedance must be very high. The anti-parallel freewheeling diode should have the same dynamic characteristics as the main switch, such as low reverse recovery time and the same power control capability.
The reliability of the device is directly related to the reliability and safety of electric vehicles. When the device withstands the maximum allowable voltage, it should have the ability to withstand an appropriate amount of overvoltage. In addition, the device should also have the design of the most human current to constitute the device protection circuit. In any case, if the current through the device exceeds its rated maximum, the protection circuit must act to shut down the device. In order to reduce the space occupied by the converter in the car, the size of the device and the cooling system should be as small as possible. Therefore, it is best to use a power mode with a half-bridge module device package thermal impedance should be very small, preferably less than 0.03. In addition, the device should be installed on an electrically insulating heat sink 1.4 Other price requirements of the device should also be considered. Because it accounts for a large proportion of the entire converter. Due to the high cost of electric vehicles, you should choose a device with a high performance-price ratio.
In addition, electric vehicles must be accelerated and decelerated frequently, bumping up and down, and power devices should be able to work reliably under these stresses.
2 The characteristics of several power electronic devices Since the 1980s, the joint development of microelectronic technology and power electronic technology has produced a new generation of high-frequency fully-controlled power integrated devices. Modern power electronic devices are high-power products. The thyristor power field-effect product is based on the Cambodian insulated gate bipolar transistor 803 gate-controlled thyristor can turn off the thyristor 010 electrostatic induction transistor 3 order electrostatic induction thyristor order and so on.
and 1! . Given the competition, the frequency of 1 is more than 37, and the turn-off gain is small. A special shutdown circuit is needed, and the process of snin5, which is not suitable for power converters of electric vehicles, is relatively complicated, and it will take some time to be practical. It will not be considered here. 2.1 High-power transistors High-power transistors are different from ordinary Transistors, sometimes called power transistors, are called power transistors. High-power transistors are bipolar full-controllers with a layer structure. It has the advantages of easy control, short switching time, high frequency characteristics, and good on-state voltage reduction. At present, the capacity of 8 ° C has reached 1400800, the frequency of 1 is 4 to 10, and the application range is from 1 to 100 to 5, but it increases its force as the current increases. Since the leakage current when the transistor is off is 1 level, the conduction loss is less than the turn-off loss. It has a capacity of 2. It can bear 2 before the heart wears. It consumes very little power and is hardly protected by semiconductor fuses. The transistor has the characteristic of secondary breakdown. When the secondary breakdown occurs, the reverse current increases sharply. If the collector current continues to increase, the secondary breakdown will occur. The secondary breakdown is mainly caused by the excessive local temperature in the device, and it is caused by the avalanche breakdown during reverse bias. Therefore, the correct design of the safe operating area is very important for the protection of the first one.
The current gain of 8 ° C is relatively small, requiring a large base drive capability. In order to increase the current gain, Darlington tubes are often used. The Darlington structure is composed of two or more transistors, and its common emitter current is slow. The current production is already modularized. The 2.2 power half field effect transistor is a unipolar device, which is composed of most The current is conductive and there is no storage effect of the minority, so the switching time is short, and the operating frequency is high. The gate source of the factory tile 1 is separated by the layer 2 and the input is more than 40. It is a device for electric bars. The rigid pole drive circuit is very simple, its power loss is negligible, the current of 031 has a negative temperature coefficient, it is not easy to produce local hot spots, it is difficult to cause secondary breakdown, and it has the characteristics of good thermal stability and strong anti-interference ability.
When the He 05 Coding is turned on, its power loss is 5%. If the current is smaller than 315, it has a lower resistance than the magic. With the increase of temperature, the conduction loss of 051 will exceed 8%. Due to the relatively small rated current of 1 Cambodia 1 in the drive system, 8 is a tandem connection in the electric car prototype. Find 24 river lights in parallel to obtain the required rated current and on-resistance.
From, Rongjing can reach 1200200 for a long time, the off time is in the order of nanoseconds, Ding 1 is used as frequency 1 to reach more than 500 and 13 Ding modules are packaged in Ding 0247, rated voltage 600, when the current from 20 to 1 30 Some products even reach 100 2.3 Insulated Gate Bipolar Transistor Insulation Liutan Pole Transistor is a kind of composite device made by dyeing the devices with 031 and 8 in a single core. It combines the respective advantages of He03D and 8D. It has the advantages of high input impedance, high working speed, fast on-state voltage, low drive current, high withstand voltage and high current withstand. It replaces the current important direction of the development of power electronic devices in the world.
The key to 81 applications is the rational design of the drive circuit. The main reason for its bad switching characteristics and safe operating area with the characteristics of the gate drive circuit. Commonly used drive circuits are pulse transformers, direct drive Tunlu discrete drive circuits, and integrated integrated drive circuits. 81 integrated modules are currently the most advanced power switching devices. Its internal 1 products with dielectric protection functions are often American 1 series. Japan ’s Fuji 8 series and so on, its standard bar operating frequency is generally 10 fast operating frequency, before applying for 1 share is 40kHz, the maximum capacity of 0 discrete children is 3 3001200, the typical operating frequency is 201 out of 1 The maximum capacity of the two units of the Xun Ding integrated module is 600, 600 people, and 6 units is 6002004. Since the capacity of the 81 module is not large, the customer is separated in the drive system; The composite device composed of thyristor and 03 factory 1, its main components are 3, Chung Cangpu, MOSKKTmW, MCTSCI.UnMOSFKn common advantages, such as voltage high current large on-state voltage reduction current density high input impedance high drive power small switching speed It is higher than 2500 people, 8 households, and Yuyou 200008, which is an ideal. At present, He ’s products are being serialized. Its voltage level is 5001000, and its current capacity is 5,1001. The former power electronic device has the highest evaluation, and it has a good application prospect in the future electric vehicle drive system.
3 The comparison and selection criteria of device characteristics are in the design juice of electric vehicle power converter. The selection of the device mainly considers the current frequency, power loss and dynamic characteristics. Here is a kind of scoring standard for switching devices according to a 5-point scale, which is used as a device selection criterion. Very low. 9 Momentum requirements 3 = medium; 4. Small driving power circuit is complicated ; 5 = Simple driving power circuit.
Forward blocking electric music saturation voltage and current density module maximum current capacity working temperature sturdiness input impedance on gain switching frequency on time off time switching loss maximum off gain easy to parallel easy to protect price application difficulty total score Turn-on gain 2 = turn-on time = 82 = 3 = total 0.5; laugh switching loss 1 = very high; high; know moderate; know low; 5 = very low 1; turn-off gain 3 = medium; know high; 5 Very high, easy to parallel, 2 difficult; 3 = easy; knowing is easier; 5 is easy.
Easy to protect 2 = difficult; 3 = easy; knowing is easy.
Price 1 = very high; 2 = high; 4 medium; 5 = low and easy; 5 = easy to know based on the above; quasi-one evaluation of the material output port, 4 conclusions, electric power technology, core control technology of electric vehicles, The performance of power electronic devices is related to the reliability of the car, so the performance of the device must be thoroughly understood to design a system with excellent performance. From the above comparison results, in the current application of electric vehicles, State 3 is suitable for Khan Of the converters with high off frequency and low power, 8 is not likely to be eliminated by 1031, 101 is the most suitable switching device, but its driving and protection are very important. If the performance is continued to be improved and commercialized, then it is The best device to replace 1081 is Qu Wenlong. The application of power electronics in electric vehicles. Electrical Engineering Technology 7ffi. 1999.14iJffPJi9597.
Zhang Li, Zhao Yongjian. Modern power electronic technology device circuit and application M. Beijing Science and Technology Press, 1992.
Wang Cong. Soft switching power converter and its application. Beijing Science and Technology Press, 2001.
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