구동회로
메카트로닉스시스템의구성 ECU 인터페이스회로 ( 시그널컨디셔닝 ) 마이컴 Model of 기계시스템 인터페이스회로 ( 드라이빙회로 ) 센서 액츄에이터 ( 구동기 ) 기계시스템
Power Semiconductor Device TRAC BJT http://en.wikipedia.org/wiki/power_semiconductor_device
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4] 활성모드의전류성분 B-E, B-C 를각각 PN 접합다이오드로생각할수있음. 개별 PN 다이오드에역방향바이어스가인가되면전류가흐르지못하지만, BJT 에서역방향바이어스된 B-C 접합에는이미터에서주입된전자가베이스를통과하여컬렉터로이동하므로 B-C 접합에컬렉터전류가흐른다는사실에유의.
BJT 의구조및동작모드 [4] 활성모드의전류성분 B-E 접합에순방향바이어스 이미터영역의다수캐리어인전자가베이스영역으로주입 (1 로표시 ) 베이스영역의다수캐리어인정공은이미터영역으로주입 (2 로표시 ) 이미터영역의도핑농도가베이스영역의도핑농도보다월등히높이때문에, 1 이 2 보다월등히많다. 이미터에서베이스로주입된전자중일부 (3 으로표시 ) 는베이스영역의정공 (4 로표시 ) 과재결합하여소멸된다. 이미터에서베이스로주입된전자중, 베이스에서재결합된일부를제외한나머지 (5 로표시 ) 는컬렉터로넘어가컬렉터전류 c 를형성한다.
BJT 의구조및동작모드 [4] 컬렉터전류 C 는컬렉터전압 V C 와무관하다.
BJT 의구조및동작모드 [4] C DC B DC : 공통이미터 DC 전류이득 Rizzoni Ch.10, Fig. 10.8
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4]
BJT 의구조및동작모드 [4] VCE V BE C DC B VCE V BE Rizzoni Ch.10, Fig. 10.9(b)
BJT 의 DC 해석과등가모델 [4] BJT가활성모드로동작할때, 순방향바이어스가걸린 B-E 접합은턴-온 (turn-on) 전압 V BE(on) 을갖는PN 다이오드로모델링할수있다. 활성모드의컬렉터전류는베이스전류의함수인제어전류원 β DC B 로모델링할수있다.
BJT 의 DC 해석과등가모델 [4] 부하선 (load line): 선형회로가비선형소자 ( 트랜지스터 ) 에대해나타낼수있는부하 의모든궤적을나타내는직선 트랜지스터의동작점 (Q 점 ) 이부하선상에설정된다. BJT 의경우 - B-E 특성에대해그려지는입력부하선 - E-C 특성에대해그려지는출력부하선
BJT 의 DC 해석과등가모델 [4] 입력부하선 B-E 루프에 KVL 을적용하여얻어지는다음수식에의해그려진다.
BJT 의 DC 해석과등가모델 [4] 출력부하선 E-C 루프에 KVL 을적용하여얻어지는다음수식에의해그려진다.
ntroduction to FET [4] FET (Field Effect Transistor) BJT 에비해아주작은면적으로만들수있고 전력소모도매우적어서 고집적디지털및아날로그반도체 C (ntegrated Circuit) 에폭넓게사용되고있다. 전자또는정공한종류의캐리어에의해서전류가형성되는다수캐리어소자이므로단극성 (unipolar) 트랜지스터로동작 선형증폭기뿐만아니라디지털논리회로에도폭넓게활용된다.
MOSFET 의구조및동작원리 [4] 증가형 MOSFET 의구조와기호
MOSFET 의구조및동작원리 [4] N 채널증가형 MOSFET 의구조 p 형기판에 5 가의도너불순물 (P, As 등 ) 을높은농도로주입하여 n+ 영역을형성하고이곳에금속을접촉하여소오스와드레인단자를만듦 소오스와드레인사이의기판실리콘영역이채널영역이되며, 채널영역위에는얇은 SiO 2 산화막 (oxide) 이형성되고, 그위에게이트전극이만들어짐 SiO 2 산화막은실리콘을산소와결합시킨산화실리콘으로서우수한절연체 게이트전극과채널이절연체로분리되어있는구조 개발초기에게이트전극을금속으로만들었기때문에 MOS(Metal-Oxide-Semiconductor) 라고부르게되었다.
MOSFET 의구조및동작원리 [4] 드레인 : 소오스에서공급된캐리어가채널영역을지나소자밖으로방출되는단자 게이트 : 소오스와드레인 사이의전류흐름을제어 하는역할 소오스 : 전류를운반하는 캐리어를공급
MOSFET 의구조및동작원리 [4] 증가형 MOSFET 의동작원리 게이트전극에양 (+) 의전압을인가하면, 게이트산화막아래의채널영역에전자들이모여 n 형반전층 (inversion layer) 형성 이상태를 채널 이형성되었다고함 반전층 이란? 기판의다수캐리어 ( 기판의도핑형태에의해결정됨 ) 와반대형태의캐리어가모여있는상태
MOSFET 의구조및동작원리 [4] 증가형 MOSFET 의동작원리 채널이형성된상태에서드레인에양 (+) 의전압이인가되면소오스와드레인사이에전류가흐르게됨 증가형 MOSFET 에서채널을형성하기위해필요한최소게이트전압을문턱전압 (threshold voltage) 이라고함 n 채널증가형 MOSFET 의문턱전압은 V Tn >0 이며, p 채널증가형 MOSFET 의문턱전압은 V Tp <0 임
MOSFET 의구조및동작원리 [4] 증가형 MOSFET 의전류 전압특성 게이트전압에따라차단상태와도통상태로동작하며, 도통상태에서는드레인전압의크기에따라비포화영역과포화영역으로구분 증가형 MOSFET 의세가지동작영역식 - 차단영역 : - 비포화영역 : - 포화영역 :
MOSFET 의구조및동작원리 [4] 포화영역에서의동작 2 차효과를무시하는이상적인경우에, 포화영역에서 MOSFET 의전류는드레인전압에무관하고게이트전압에만영향을받음 드레인전류 :
MOSFET 의구조및동작원리 [4] N 채널 MOSFET 의각영역에따른전류 - 전압특성 차단영역에서는드레인전류가 0 비포화영역에서는드레인전류가게이트전압과드레인전압에모두영향을받음 포화영역의드레인전류는게이트전압에의해서만영향을받음 점선으로표시된포물선은포화영역과비포화영역의경계를나타내며, 인값들의궤적임 포화영역과비포화영역의명칭이 BJT 의경우와반대이므로혼동하지 않도록유의.
FET 의바이어스와 DC 해석 [4] MOSFET 의출력특성에동작점과부하선의교점 천이점 (transition point) : MOSFET 포화영역의경계를나타내는포물선과부하선의교점
Electronically Controlled Switches, BJT and FET [4] [2] BJT B >θ ON saturation region short circuit B <θ OFF cutoff region open circuit FET V GS >θ ON ohmic region short circuit V GS <θ OFF cutoff region open circuit
부하의위치 [3]
부하의위치 [3] V BE >V BE(on) 인가?
Power Semiconductor Device: GBT The GBT(insulated gate bipolar transistor ) combines the simple gate-drive characteristics of the MOSFETs with the high-current and low saturation-voltage capability of bipolar transistors by combining an isolated gate FET for the control input, and a bipolar power transistor as a switch, in a single device. http://en.wikipedia.org/wiki/nsulated-gate_bipolar_transistor Equivalent circuit for GBT Electronic symbol for GBT Small GBT module, rated up to 30 A, up to 900 V
Power Semiconductor Device: GBT t switches electric power in many modern appliances: electric cars, trains, variable speed refrigerators, air-conditioners and even stereo systems with switching amplifiers. Since it is designed to rapidly turn on and off, amplifiers that use it often synthesize complex waveforms with pulse width modulation and low-pass filters. http://en.wikipedia.org/wiki/nsulated-gate_bipolar_transistor
Power Semiconductor Device: Thyristor The thyristor is a four-layer, three terminal semiconducting device, with each layer consisting of alternately N-type or P-type material, for example P-N-P-N. The main terminals, labelled anode and cathode, are across the full four layers, and the control terminal, called the gate, is attached to p-type material near to the cathode. Some sources define silicon controlled rectifiers (SCR). The name "silicon controlled rectifier" or SCR is General Electric's trade name for a type of thyristor. The operation of a thyristor can be understood in terms of a pair of tightly coupled bipolar junction transistors, arranged to cause the self-latching action. http://en.wikipedia.org/wiki/thyristor Equivalent circuit Circuit symbol
Power Semiconductor Device: Thyristor 사이리스터 (thyristor) 또는실리콘 - 제어정류기 (Silicon-Controlled Rectifier, SCR) 는다이오드가동작할수있는조건을제어하는게이트를가진다이오드로간주될수있다 [3]. Thyristors have three states: 1) Reverse blocking mode Voltage is applied in the direction that would be blocked by a diode 2) Forward blocking mode Voltage is applied in the direction that would cause a diode to conduct, but the thyristor has not yet been triggered into conduction 3) Forward conducting mode The thyristor has been triggered into conduction and will remain conducting until the forward current drops below a threshold value known as the "holding current" http://en.wikipedia.org/wiki/thyristor
Power Semiconductor Device: Thyristor n a conventional thyristor, once it has been switched on by the gate terminal, the device remains latched in the on-state (i.e. does not need a continuous supply of gate current to conduct), providing the anode current has exceeded the latching current ( L ). As long as the anode remains positively biased, it cannot be switched off until the anode current falls below the holding current ( H ). http://en.wikipedia.org/wiki/thyristor
Power Semiconductor Device: Thyristor Thyristors are mainly used where high currents and voltages are involved, and are often used to control alternating currents, where the change of polarity of the current causes the device to switch off automatically; referred to as Zero Cross operation. The device can be said to operate synchronously as, once the device is open, it conducts current in phase with the voltage applied over its cathode to anode junction with no further gate modulation being required to replicate; the device is biased fully on. http://en.wikipedia.org/wiki/thyristor Load voltage regulated by thyristor phase control. Red trace: load voltage Blue trace: trigger signal.
Power Semiconductor Device: Thyristor [3] 사이리스터 (thyristor) 교류전류제어 R 1 은전류제한저항, R 2 는사이리스터가트리거되는레벨을설정하는전위차계이다. 다이오드는게이트에가해지는교류전압의 부분을막아주는역할을한다. R 2 를조절함으로써인가되는교류전압의양의반사이클인 0~90 사이의어떠한지점에서도사이리스터를트리거시킬수있다.
Power Semiconductor Device: GTO A gate turn-off thyristor (GTO) is a special type of thyristor, a high-power semiconductor device. GTOs, as opposed to normal thyristors, are fully controllable switches which can be turned on and off by their third lead, the GATE lead. http://en.wikipedia.org/wiki/gate_turn-off_thyristor Equivalent circuit Circuit symbol
Power Semiconductor Device: GTO Thyristors can only be turned ON and cannot be turned OFF. Thyristors are switched ON by a gate signal, but even after the gate signal is de-asserted (removed), the thyristor remains in the ON-state until any turn-off condition occurs (which can be the application of a reverse voltage to the terminals, or when the current flowing through (forward current) falls below a certain threshold value known as the "holding current"). Thus, a thyristor behaves like a normal semiconductor diode after it is turned on or "fired". The GTO can be turned-on by a gate signal, and can also be turned-off by a gate signal of negative polarity. Turn on is accomplished by a "positive current" pulse between the gate and cathode terminals. Turn off is accomplished by a "negative voltage" pulse between the gate and cathode terminals. http://en.wikipedia.org/wiki/gate_turn-off_thyristor
Power Semiconductor Device: GTO GTO 직류전압제어 : 게이트에교류전압을인가하면, 전압의파형을초퍼하여간헐시 킬수있다. 그래서, 게이트에교류신호를가하면직류출력평균전압을변형및제어할 수있다 [3].
Power Semiconductor Device: TRAC TRAC (Triode for Alternating Current) is an electronic component which can conduct current in either direction when it is triggered (turned on), and is formally called a bidirectional triode thyristor or bilateral triode thyristor. t can be triggered by either a positive or a negative voltage being applied to its gate electrode. Once triggered, the device continues to conduct until the current through it drops below a certain threshold value, the holding current, such as at the end of a half-cycle of alternating current (AC) mains power. http://en.wikipedia.org/wiki/trac TRAC schematic symbol
Power Semiconductor Device: TRAC [3]
Power Semiconductor Device: TRAC [3]
Solenoid 의전류제어 [1] Solenoid driving circuit
Solenoid Driving [1] PWM (Pulse Width Modulation) PWM or Pulse Width Modulation refers to the concept of rapidly pulsing the digital signal of a wire to simulate a varying voltage on the wire. This method is commonly used for driving motors, heaters, or lights in varying intensities or speeds. A few terms are associated with PWM: Period - how long each complete pulse cycle takes Frequency - how often the pulses are generated. This value is typically specified in Hz (cycles per second). Duty Cycle - refers to the amount of time in the period that the pulse is active or high. Duty Cycle is typically specified as a percentage of the full period. http://www.acroname.com/robotics/info/concepts/pwm.html
Solenoid Driving [1] Solenoid driving circuit ON state OFF state
Solenoid Driving [1] di di Ri L 0 i 0 dt dt A 1 st -order source-free circuit had the form where, Ae t L R i 0 A t=0 일때, 0 A 0 i t 0 e t i 0 OFF state t
Solenoid Driving [1] Ri L di dt V BAT The complete response for 1 st -order circuit with DC forcing functions will have the form di i dt B S Ae t L where,, R S V R BAT i t t B Ae 을윗식에대입하면, ON state B Ae t t=0 일때, A e t 0 A 0 i S S B S A 0 S t t i 1 t S 0 S e 0e S e t
Solenoid Driving [1] Solenoid Driving [1] t S t t S S e e e t i 1 0 0 t S t S S t S S e e e 1 0 0 0 0 0 0 0 0 t i 0 s
Sequence of nitial Current [1] The initial current of each PWM period can be calculated recursively from the first period as below : (1) 0 0 δ : duty ratio (1) T 0 s se (2) (1 ) T T 0 e s s (2) T T TT 0 e e e e ss s s (3) (1 ) T T (1 ) TT 2T 0 e e e e s s s s (3) T T TT 2T 2TT 0 e e e e e ss s s s s (4) (1 ) T T T(1 ) T 2T 2 T(1 ) T 3T 0 e e e e e e s s s s s s...
Sequence of nitial Current [1] n th initial current is the summation of geometric series. (3) (1 ) T T (1 ) TT 2T 0 e e e e s s s s s s (3) (1 ) T T (1 ) T T T 0 e e e e e ( n1) T (1 ) T T 1 0 n s e e e T ( ) ( ) (3-1) 1 e (3) T T TT 2T 2TT 0 e e e e e ss s s s s T 1 0 ( n) s(1 e ) e (3-2) T 1 e nt
Sequence of nitial Current [1] The current integration of n th PWM ON state ON ( n1) T t (1 ) T T 1 t BAT BAT BAT e T R R e R e e e T V V V { ( ) } dt 0 1 e The current integration of n th PWM OFF state OFF nt (1 ) T T 1 t VBAT e 0 T R e e { (1 ) } dt 1 e
Average Solenoid Current [1] By dividing the summation of ON and OFF by the period T, the average solenoid current at time index n T nt T t V in ( ) BAT {1 (1 ) nt t } it ( ) {1 (1 ) } (4-2) R T e e R T e e V BAT
Average Solenoid Current [1] V BAT T t it ( ) {1 (1 ) } (4-2) R T e e 1 (1 ) x e T x x f the PWM period T is sufficiently smaller than the solenoid time constant τ, x has a very small value and the coefficient becomes 1. Ex) n our case, τ=0.003, T=0.00005 x<0.017 V BAT T t it () {1 (1 ) } (4-2) R T e e V BAT t e it () (1 ) (5-1) R
Average Solenoid Current [1] f there is non-zero initial current at first period, the average solenoid current is modified as below: t VBAT VBAT it () ( o ) R R e o t VBAT ( o) 1 (5-2) R e Envelop V BAT R o The saturated current is in linear relation with duty-ratio The envelop of solenoid current, in other words, the average current changes from the initial current to the saturated current exponentially f PWM frequency is sufficiently high, the average current has the same time constant with the instant solenoid current.
참고자료 1. H. G. JUNG, J. Y. HWANG, P. J. YOON, J. H. KM, Resistance Estimation of a PWM- Driven Solenoid, nternational Journal of Automotive Technology, Vol. 8, No. 2, pp. 249-258. 2. Giorgio Rizzoni, Principles and Applications of Electrical Engineering, Fifth Edition, McGraw Hill, 2007. 3. W. Bolton ( 노태정등공역 ), 메카트로닉스 4 판, 사이텍미디어 4. 강문식, 신경욱, T CookBook, 전자회로 : 핵심개념부터응용까지, 한빛미디어