Introduction of large DIPIPMP conditioner inverter. application on EV bus air. Abstract: 1. Introduction

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1 chip,, generation ) Ver. Introduction of large DIIM conditioner inverter application on EV bus air Yinghua Ma, Qingdao Longertek Co., Ltd, Qingdao, China, myhsir@163.com Xiaoling Wang, Semiconductor division, Mitsubishi Electric & electronics (Shanghai) CO., Ltd, Shanghai, China, wangxl@mesh.china.meap.com Abstract: This paper presents the application of Mitsubishi electric 4 large Dual In-line ackage intelligent power module (abbr. as large DIIM on EV bus air conditioner inverter. By adopting high performance large DIIM the prototype EV bus air conditioner inverter achieved compact size, high output power, high reliability, low cost etc.. In this paper, Mitsubishi electric large DIIM features, application points, circuit design are introduced. Lastly the testing data, testing result, CB outline are given. th 1. Introduction Large DIIM has been developed by Mitsubishi Electric Co., Ltd. By applying new designed full gate type CSTBT two new functions are built in DIIM. The two functions are current sensing function and temperature sensor function. With these two functions, it is easy for engineers to design short circuit protection circuit and over temperature protection circuit with low cost and high reliability. With the improved features, large DIIM is a suitable device for appliance application and industrial application such as general inverter and servo controller etc.. Another feature for large DIIM 4 is that different current ratings are all included in one package. Modules are available with blocking voltage ratings of 600V and 1200V. Devices with nominal current ratings of 50A to 75A at 600V and 5A to 50A at 1200V are all available in the same compact package outline. The outline, package and internal circuit are shown in Fig.1., Fig.2., Fig.3.. Fig.1. Outline of large DIIM Fig.2. Structure for large DIIM Fig.3. Internal circuit of large DIIM

2 . generation th large DIIM application Although large DIIM is a device with high reliability and muti-protection functions, Engineers have to pay attention to thermal design, over temperature protection design, short circuit protection design and CB layout design to achieve the best performance of large DIIM 2.1. Thermal design consideration Thermal design for semiconductor devices is very important for inverter. In order to protect IGBT chips, the maximum junction temperature is 150 for large DIIM To ensure junction temperature of large DIIM below 150 at any working condition of inverter, power loss simulation is necessary. The simulation software for Mitsubishi electric devices is shown in Fig.4.. In the simulation result, the definition of the junction temperature is average temperature. In order to keep some margin for temperature swing with IGBT switching, In simulation software the junction temperature should not exceed 125. The power loss of each IGBT and diode can also be calculated by the simulation software. Fig. 4. Simulation software for Large DIIM Fig.5. Temperature sensor characteristic 2.2. Consideration of over temperature protection Over temperature protection for Large DIIM is also needed to protect DIIM in case of bad cooling system or over current. For Large DIIM, it is easy to realize this function with built in temperature sensor. The temperature sensor characteristic is shown in Fig.5.. As an example, 90 could be regarded as the over temperature protection point with analog voltage output about 3.76V Consideration of short circuit protection In order to avoid large power dissipation in the shunt resistor, Large DIIM equipped with IGBT chips having a current mirror emitter. With this current mirror function there is no need to use power shunt resistor in short circuit protection. Fig.6. shows the circuit of the short circuit protection for Large DIIM.

3 aincurrent IGBT4 Di4 VN1 NU IGBT5 Di5 UN LVIC IGBT6 Di6 NV VN WN Fo VOT VNC Mfiltering time μs with power 1/8 Watt NW CFO CIN Vsc Rs RC filter Recommended Current sensing resistor Fig.6. Short circuit protection diagram Fig.7. CB layout precautions 2.4. CB layout precautions Large DIIM. is the device switching at high speed. High speed switching of big current may cause high di/dt. Noise may happen due to bad CB layout. Correct CB layout may decrease the parasitic inductance and then decrease the noise. Fig. 7. is the precautions for wiring on CB. 3. 4H EV bus air conditioner inverter design 3.1. Target performance data for 4H EV bus air conditioner inverter Now days the energy saving and environmental protection requirements are growing more urgent. EV bus is more environmentally friendly than traditional bus. The power supply for EV bus air conditioner is coming from battery and air conditioner inverter is important for the air conditioner to run with high efficiency and high reliability. ower semiconductor devices are the key for the inverter to run stably. Large DIIM is a perfect device to be designed in EV bus air conditioner inverter. As an example, 50A/600V S21A79 DIIM was selected in a 4H EV bus air conditioner. The main target design data for inverter is listed in Table.1... No. Items Inverter parameters 1 Input voltage 324±20%VDC 2 Rated output power 4.5kW 3 Rated output frequency Hz 4 Carrier frequency for DIIM 5kHz 5 Maximum output phase current 25A(rms) 6 Over load ratio 1.2 Table. 1. Target design data for 4H EV bus air conditioner inverter

4 Rs value setting for short circuit protection Rs value is important for short circuit protection of Large DIIM. Fig.8. shows the curve for Rs value VS short circuit protection current for S21A79 DIIM. From the curve, Rs value should be larger than 40.2Ω. As for 4H EV bus air conditioner, 62ΩRs value was selected. Fig.8. Rs value VS short circuit current( without extra shunt resistors) 3.3. rototype machine and experimental result Fig.9. shows the picture of control CB board for inverter equipped with Mitsubishi electric S21A79 Large DIIM The control CB board is compact and high cost efficiency by applying high integration and high performance large DIIM product. Fig.10. shows the short circuit protection waveform of S21A79 large DIIM In the testing waveform, CH1 is the voltage of Rs, CH2 is Fo signal of large DIIM Fig.11. shows the driving circuit of S21A79 large DIIM From the circuit, R207 is Rs with the resistance value 62Ω. With Rs function, there is no need to use power shunt resistors served as the SC protection function. Fig.9. Control CB board picture for inverter Fig.10. Short circuit protection waveform

5 . Fig.11. The driving circuit of S21A79 large DIIM 4. Conclusion Mitsubishi electric large DIIM has series of protection function of under control supply, short circuit, analog output voltage of temperature. High reliability and high performance are realized for inverter with large DIIM EV bus air conditioner inverter has higher reliability and compact size requirements. Mitsubishi electric large DIIM could fully satisfy the requirements. The testing results of the prototype inverter showed that the EV bus air conditioner could achieve the best performance and meet the needs of end user. 5. Literature [1] Large DIIM Application Note, (Ver.1) by Mitsubishi electric.