Future Power Electronics and Motion. Electronics - SiC Choppers and Biped Robots. Atsuo Kawamura. Department of Electrical and Computer Engineering.
Future Power Electronics and Motion Electronics - SiC Choppers and Biped Robots Atsuo Kawamura
Department of Electrical and Computer Engineering Yokohama National University 79-5 Tokiwadai, Hodogaya-ku, Yokohama Japan 240-8501
might become negligible, which in turn change the system configurations ([2]).
Abstract- First, the future trends of power electronics and motion electronics are forecasted for the next decades. The several future breakthroughs such as wireless transmission of electric power and wireless actuators are summarized, and also several applications are introduced. Second, two examples of the reality are introduced among the author's research activities. The first one is the soft switching chopper circuit for FCEV using SiC devices, which have a possibility of very high power density by increasing the switching frequency. The second is the introduction of several biped walking and jumping robots at Kawamura laboratory.
C. Wireless Actuator The wireless actuator as a concept is such that it has no wire, however, it receives a low level power and accumulates it in the energy storage element, and actuates others when it is requested ([3]). D. Electric Airplane Due to the new material of NdFeB, the power density of the motors might be beyond 100kW/l in ten years. If the energy can be charged in a new energy storage elements, an electric airplane has a advantage in the less noise and stable flight due to the quick torque response.
I. INTRODUCTION The future trends of power electronics and motion electronics are forecasted in [1] by several young researchers, in which a couple of dream-like breakthroughs were listed. The table I is the keywords for these future technologies. Some of them look out of questions, and others seem to be coming soon. These ideas were results of a kind of brain storm. Extremely fast calculation
E. Sub-nano Motion Control The present HDD has 7OGb/in2, the track density 100kTPI, the head positioning 30nm, however, in ten years lTb/in2 with Inm positioning might be possible with the control and material advancements ([4]).
capability of micro-computer, continuous advancement of the communication technology, new switching devices, emerging control theory, new material and components may incubate something new in this field. However, the reality is, of course, that the dream does not easily come true. As an invited lecture, authors wish to deliver the long and middle range targets in the power electronics and motion electronics fields. In the section II, dream-like ideas are summarized, and in section III and IV, two examples of the reality toward the dream are introduced.
F Humanoid and New Robotics
The humanoid robots will be widely spread in the aged society like Japan in 20 years in future. The physical capability will be beyond the human, and the information processing ability will exceed that of human, and they will be ubiquitous existence in the society. The personal legged bus might be welcomed because it can go up and down the stairs. G. Ultra High Efficient Power Converter DR. I. Takahashi forecasted the 99.6% efficiency power converter with new switching devices, and very high power density power conversion equipments. ([5])
II. SEVEN DREAMS ([1])
A. Microprocessor After 10 Years The most advanced key element in the past decade might be a microprocessor, and it is very difficult to forecast the new style of computers in the next ten years. Several functions should be integrated in one silicon chip, and also the calculation speed (ITOP) might be realized. 10GHz A/D, the low power dissipation, sheet circuit, wireless communication and so on make ubiquitous intelligent environment in any application.
III. THE SOFT SWITCHING CHOPPER USING SIC DEVICES
Currently, the soft switching, the higher frequency and the new switching devices technology such as SiC devices attempt to contribute to the remarkable development of size effective power converter in new energy and energy conservation technology field. Especially, the development of the new hybrid vehicle and the fuel cell electric vehicle have led to increase the power handling capability. In particular, in order to output the same traction force as
B. New Sensors The wireless communication technology changes the meaning of sensors. The cost of all kinds of sensors
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TABLE I KEYWORDS OF TEN-YEAR-FUTURE TECHNOLOGY ON PE, ME, AND IT Ultrahigh efficient, compact, and light power converter Energy transmission other than electricity (light, sound wave, heat, and super-conductivity) Electric airplane and electric rocket Completely leveling of electric power system load Simulation technology High speed for electromagnetic field FEM + circuit + control Fuel cell used in each home Artificial muscle and soft actuator Bio-motor control Wireless actuator Drive-by-wireless Computer evolution Wearable computing Thin circuits => Electronic paper Rapid improvement of communication speed (Tbit/s)
1 [MV] 1 [mA] motor Wireless power transmission about 1O[kW] level at 1 [m]. Low density energy collection Distributed nuclear fusion Sensor chips (voltage, current, and temperature) intelligent and wireless wireless controller Nano-machine Sub-nano motion controller Bio-interface and cyborg Completely automatic driving of EV Humanoid and home robots Legged bus climbs mountain Optical circuits embedded in CPU Rapid progress of artificial intelligence Ubiquitous wireless ID tag
the conventional gasoline vehicle a 100kW power range power converter is required. Viewed from the point of the high power density, three applications will be focused on: A. New Soft Switching DC Chopper Circuit SAZZ, B. Bilateral Chopper Circuit SAZZ-1, C. QRAS Chopper Using SiC Devices. A. New Soft Switching DC Chopper Circuit SAZZ The new proposed SAZZ (Snubber Assisted Zero Voltage and Zero Current Transition chopper) type soft switching DC chopper is shown in Fig. 1. The main part of proposed topology has simple configuration of 2 switches (S1 and S2), 2 diodes (D1 and D5) and a capacitor C2 (([6]). This configuration can realize the desirable properties of the ZVZCT (Zero voltage and Zero Current Transition) turn-on and ZVS (Zero Voltage Switching) turn-off. Fig.3 shows the steady-state voltage and current waveforms of the SAZZ and each operation mode is illustrated in Fig.4. Before the main switch Si is turned on, the voltage across capacitor C2 is discharged through the auxiliary switch S2, causing zero voltage and zero current in main switch Si by a resonant reverse current in auxiliary switch S2. When the switch Si is turned off, the voltage across Si starts to increase from zero voltage by capacitor C2 ([7]). 100kHz 8kW prototype-model using IGBTs was fabricated as shown in Fig.2. The specification of this prototype-model is shown in Table II. Measured waveforms of SAZZ operation (output=400V, 100kHz, 8kW) is shown in Fig.5. It is confirmed that the main switch turn on in ZVZCT modes take place and the recovery current of the output diode becomes zero. The output power of 8kW with the efficiency of 97.3% was achieved at the peak frequency of 1 OOkHz by HIOKI 3193 POWER HiTESTER ([8]).
Fig. 1. The circuit of SAZZ. Reactor Lz Reactor LIMa[in switch SlAuxiliaryy switch S2 Input ccapacitor Cl
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Fig. 2. The 100[kHz]-8[kW] prototype model SAZZ. TABLE II THE SPECIFICATION OF PROTOTYPE MODEL SAZZ.
Rating Switch Frequency Circuit type Control Cooling
= 400[V], POUT = 8[kW] 5OMT060WH, 600[V], 50[A]
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SAZZ circuit type. The boost mode in reverse direction is illustrated in Fig.7. The buck mode in reverse direction is illustrated in Fig.8. 25kW-5OkHz prototype model SAZZ-1 was fabricated for the purpose of decreasing the distributed inductors. The experimental results for buck mode in reverse direction is shown in Fig.9. 96.57% efficiency at 25kW with boost mode (input: 250V / output: 390V) in forward direction and 97.44% efficiency at 25kW with buck mode (input: 420V / output: 300V) in forward direction were obtained ([9]).
B. Bilateral Chopper Circuit SAZZ-1 The SAZZ circuit operational principle can be extended to a bidirectional buck and boost SAZZ chopper circuit. A new SAZZ bilateral buck-boost chopper circuit (SAZZ1) with buck and boost capabilities in any direction, as shown in Fig.6, was created by combining two basic
C. QRAS Chopper using SiC Devices New semiconductor devices "Silicon Carbide (SiC) schottky diodes" are now already available on the market. For eliminating the reverse recovery charges we parallel four SiC schottky diodes (CSD1012D,1200V-IOA) man26
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