Circuit Synthesis - An MNA Approach Timo Reis Model Reduction Seminar Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Problem Formulation Given is a descriptor system E ẋ(t) = Ax(t) + Bu(t) y(t) = Cx(t). Find an electrical circuit such that for the voltages uV (t), uI (t) of voltage and current sources and currents iV (t), iI (t) of voltage and current sources hold: – – » » i (t) u (t) and y(t) = V u(t) = V uI (t) iI (t) fulfill the given descriptor system for some state vector x(t). Arising questions: For which class of descriptor systems can we find a circuit that realizes its input-output-behaviour? Can we formulate numerical methods for the realization? tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Problem Formulation Given is a descriptor system E ẋ(t) = Ax(t) + Bu(t) y(t) = Cx(t). Find an electrical circuit such that for the voltages uV (t), uI (t) of voltage and current sources and currents iV (t), iI (t) of voltage and current sources hold: – – » » i (t) u (t) and y(t) = V u(t) = V uI (t) iI (t) fulfill the given descriptor system for some state vector x(t). Arising questions: For which class of descriptor systems can we find a circuit that realizes its input-output-behaviour? Can we formulate numerical methods for the realization? tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion History of the problem Wilhelm Cauer (1920s-1940s) Consideration of the problem from a frequency domain point of view. Single-Input-Single-Output-Systems. Discovered that impedance functions of circuit satisfy some special conditions (positive realness). Otto Brune (1930s-1940s) and Sidney Darlington (1950s-1970s) gave further realization techniques (in frequency domain) B.D.O Anderson and S. Vongpanidlerd (1960s-1990s) gave methods for the realization of multiple-input-multiple-output ODE models ẋ = Ax + Bu, y = Cx + Du. Realization based on matrix operations. We are interested in time-domain methods for differential-algebraic models! tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion History of the problem Wilhelm Cauer (1920s-1940s) Consideration of the problem from a frequency domain point of view. Single-Input-Single-Output-Systems. Discovered that impedance functions of circuit satisfy some special conditions (positive realness). Otto Brune (1930s-1940s) and Sidney Darlington (1950s-1970s) gave further realization techniques (in frequency domain) B.D.O Anderson and S. Vongpanidlerd (1960s-1990s) gave methods for the realization of multiple-input-multiple-output ODE models ẋ = Ax + Bu, y = Cx + Du. Realization based on matrix operations. We are interested in time-domain methods for differential-algebraic models! tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Let a descriptor system E ẋ(t) = Ax(t) + Bu(t) y(t) = Cx(t). be given with E, A ∈ Rn,n , B ∈ Rn,p , C ∈ Rq,n such that the pencil λE − A is regular. Definition The transfer function G ∈ R(s)q,p of this system is given by G(s) = C(sE − A)−1 B. The system is called minimal, if the state space dimension n is minimal among all descriptor systems with transfer function G(s). Lemma For i = 1, 2, let two minimal descriptor systems Ei ẋi (t) = Ai xi (t) + Bi ui (t), yi (t) = Ci xi (t) with Ei , Ai ∈ Rn×n , Bi ∈ Rn×p , Ci ∈ Rq×n be given which have the same transfer function. Then there exist unique W , T ∈ Rn,n such that E2 = WE1 T , A2 = WA1 T , B2 = WB1 , C2 = C1 T . Moreover both W , T are invertible. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Let a descriptor system E ẋ(t) = Ax(t) + Bu(t) y(t) = Cx(t). be given with E, A ∈ Rn,n , B ∈ Rn,p , C ∈ Rq,n such that the pencil λE − A is regular. Definition The transfer function G ∈ R(s)q,p of this system is given by G(s) = C(sE − A)−1 B. The system is called minimal, if the state space dimension n is minimal among all descriptor systems with transfer function G(s). Lemma For i = 1, 2, let two minimal descriptor systems Ei ẋi (t) = Ai xi (t) + Bi ui (t), yi (t) = Ci xi (t) with Ei , Ai ∈ Rn×n , Bi ∈ Rn×p , Ci ∈ Rq×n be given which have the same transfer function. Then there exist unique W , T ∈ Rn,n such that E2 = WE1 T , A2 = WA1 T , B2 = WB1 , C2 = C1 T . Moreover both W , T are invertible. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Let a descriptor system E ẋ(t) = Ax(t) + Bu(t) y(t) = Cx(t). be given with E, A ∈ Rn,n , B ∈ Rn,p , C ∈ Rq,n such that the pencil λE − A is regular. Definition The transfer function G ∈ R(s)q,p of this system is given by G(s) = C(sE − A)−1 B. The system is called minimal, if the state space dimension n is minimal among all descriptor systems with transfer function G(s). Lemma For i = 1, 2, let two minimal descriptor systems Ei ẋi (t) = Ai xi (t) + Bi ui (t), yi (t) = Ci xi (t) with Ei , Ai ∈ Rn×n , Bi ∈ Rn×p , Ci ∈ Rq×n be given which have the same transfer function. Then there exist unique W , T ∈ Rn,n such that E2 = WE1 T , A2 = WA1 T , B2 = WB1 , C2 = C1 T . Moreover both W , T are invertible. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Given a system E ẋ(t) = Ax(t) + Bu(t), y(t) = Cx(t) with E, A ∈ Rn×n , B ∈ Rn×p , C ∈ Rp×n and transfer function G(s) ∈ R(s)p×p . Definition A system is passive if for all (sufficiently smooth) u(·) ∈ L2 (R+ , Rp ) R∞ T 2 + p holds y(·) ∈ L (R , R ) with 0 u (τ )y(τ )dτ ≥ 0. A system is lossless passive if for all (sufficiently smooth) R∞ u(·) ∈ L2 (R+ , Rp ) holds y(·) ∈ L2 (R+ , Rp ) with 0 u T (τ )y(τ )dτ = 0. A transfer function G(s) ∈ R(s)p×p is positive real if it has no poles in C+ and for all s ∈ C+ holds G(s) + G ∗ (s) ≥ 0. A transfer function G(s) ∈ R(s)p×p is lossless positive real if it is positive real and for all ω ∈ R such that G has no pole is iω holds G(iω) + G T (−iω) = 0. Parseval’s identity implies: A descriptor system (∗) is (lossless) passive if and only if its transfer function is (lossless) positive real. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Given a system E ẋ(t) = Ax(t) + Bu(t), y(t) = Cx(t) with E, A ∈ Rn×n , B ∈ Rn×p , C ∈ Rp×n and transfer function G(s) ∈ R(s)p×p . Definition A system is passive if for all (sufficiently smooth) u(·) ∈ L2 (R+ , Rp ) R∞ T 2 + p holds y(·) ∈ L (R , R ) with 0 u (τ )y(τ )dτ ≥ 0. A system is lossless passive if for all (sufficiently smooth) R∞ u(·) ∈ L2 (R+ , Rp ) holds y(·) ∈ L2 (R+ , Rp ) with 0 u T (τ )y(τ )dτ = 0. A transfer function G(s) ∈ R(s)p×p is positive real if it has no poles in C+ and for all s ∈ C+ holds G(s) + G ∗ (s) ≥ 0. A transfer function G(s) ∈ R(s)p×p is lossless positive real if it is positive real and for all ω ∈ R such that G has no pole is iω holds G(iω) + G T (−iω) = 0. Parseval’s identity implies: A descriptor system (∗) is (lossless) passive if and only if its transfer function is (lossless) positive real. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Given a system E ẋ(t) = Ax(t) + Bu(t), y(t) = Cx(t) with E, A ∈ Rn×n , B ∈ Rn×p , C ∈ Rp×n and transfer function G(s) ∈ R(s)p×p . Definition A system is passive if for all (sufficiently smooth) u(·) ∈ L2 (R+ , Rp ) R∞ T 2 + p holds y(·) ∈ L (R , R ) with 0 u (τ )y(τ )dτ ≥ 0. A system is lossless passive if for all (sufficiently smooth) R∞ u(·) ∈ L2 (R+ , Rp ) holds y(·) ∈ L2 (R+ , Rp ) with 0 u T (τ )y(τ )dτ = 0. A transfer function G(s) ∈ R(s)p×p is positive real if it has no poles in C+ and for all s ∈ C+ holds G(s) + G ∗ (s) ≥ 0. A transfer function G(s) ∈ R(s)p×p is lossless positive real if it is positive real and for all ω ∈ R such that G has no pole is iω holds G(iω) + G T (−iω) = 0. Parseval’s identity implies: A descriptor system (∗) is (lossless) passive if and only if its transfer function is (lossless) positive real. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Auxiliary result: Positive real lemma for lossless descriptor systems: A minimal system E ẋ (t) = Ax(t) + Bu(t), y(t) = Cx(t) is lossless passive if and only if there exists X ∈ Rn,n such that AT X + X T A = 0, X T B − C T = 0 and E T X ≥ 0. Moreover, in the case of solvability X is invertible and unique. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Definition A transfer function G ∈ R(s)p,p is reciprocal if there exists p1 , p2 ∈ N with p1 + p2 = p such that for Σe = diag(Ip1 , −Ip2 ) and all s ∈ C where G has no pole holds G(s)Σe = Σe GT (s). The matrix Σe is called external signature of the system. A descriptor system is called reciprocal if its transfer function is reciprocal. The transfer function of a reciprocal system has the form » – G11 (s) G12 (s) G(s) = , T (s) G22 (s) −G12 T T where G11 = G11 ∈ R(s)p1 ,p1 , G22 = G22 ∈ R(s)p2 ,p2 . tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Definition A transfer function G ∈ R(s)p,p is reciprocal if there exists p1 , p2 ∈ N with p1 + p2 = p such that for Σe = diag(Ip1 , −Ip2 ) and all s ∈ C where G has no pole holds G(s)Σe = Σe GT (s). The matrix Σe is called external signature of the system. A descriptor system is called reciprocal if its transfer function is reciprocal. The transfer function of a reciprocal system has the form » – G11 (s) G12 (s) G(s) = , T −G12 (s) G22 (s) T T where G11 = G11 ∈ R(s)p1 ,p1 , G22 = G22 ∈ R(s)p2 ,p2 . tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Equations for an electrical circuit: uR (t) = R · iR (t) iC (t) = C · d u (t) dt C uL (t) = L · d i (t) dt L (resistances) (capacitances) (inductances) uTi (t) = TT · iTi (t), iTt (t) = TTT · uTi (t) (ideal transformers) AR iR (t) + AL iL (t) + ATi iTi (t) + ATt iTt (t) + AV iV (t) + AI iI (t) = 0 (Kirchhoff’s current law) ATR e(t) = uR (t), ATV e(t) = uV (t), ATL e(t) = uL (t), ATI uI (t) = e(t) ATTi e(t) = uTi (t), ATTt e(t)uTt (t), (Kirchhoff’s voltage law) where e(t): vector of node potentials R, C, L: resistance, capacitance and inductance matrix (symm. pos. def) TT : transformer gain matrix, AR , AC , AL , AI , Element incidence matrix of branches of resistances, capacitances, AV , ATi , ATt : inductances, voltage/current source and initial/terminal port of ideal transformers, tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Then modified nodal analysis leads to: 2 6 6 6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 3 0 2 ė(t) 7 6 0 7 76 i̇L (t) 74 0 5 i̇Ti (t) i̇V (t) 0 » 2 −AR R −1AT R 6 6 AT 7 6 L 7=6 5 6 T T T 4 ATi −TT ATt 3 – " −AT uI (t) I = iV (t) 0 AT V 0 0 0 0 −AL −ATi +ATtTT −AV 0 0 0 0 0 0 0 0 0 3 2 7 76 76 74 7 5 2 −AI 3 6 0 e(t) 6 6 iL (t) 7 7+6 0 iTi (t) 5 6 6 4 0 iV (t) 0 3 0 0 7 7» – 7 i (t) 7 I 0 7 7 vV (t) 0 5 −I 3 2 # e(t) 7 0 6 i (t) 6 L 7, 5 4 −I iTi (t) iV (t) tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Then modified nodal analysis leads to: 2 6 6 6 6 4 | AC C AT C 0 0 0 L 0 0 0 0 0 0 {z 0 =:E 3 0 2 ė(t) 7 0 76 i̇L (t) 76 74 0 5 i̇Ti (t) i̇V (t) 0 } 3 2 −AR R −1AT R 6 AT 7 6 L 7=6 5 6 6 AT −T T AT 4 Ti T Tt AT V =:y (t ) −ATi +ATtTT −AV 0 0 0 0 0 0 0 0 0 {z | – " −AT uI (t) I = iV (t) 0 | {z } | » −AL =:A 0 0 0 0 {z =:C 2 3 # e(t) 6 i (t) 7 6 L 7, 4 5 −I iTi (t) } iV (t) 0 3 2 7 76 76 74 7 5 | } e(t) iL (t) iTi (t) iV (t) {z 3 2 6 6 76 7+6 56 6 4 } =:x (t ) | 0 −AI 0 0 0 0 3 0 7 7» – 7 i (t) I 0 7 7 vV (t) 7 0 5| {z } =:u(t ) −I {z =:B } tu-logo Motivation Descriptor Systems Circuit Equations Example Conclusion 2 −AI 7 6 7 6 0 7 7, B = C T = 6 6 0 7 4 5 0 3 0 7 0 7 7 0 7 5 −I Circuit Synthesis Observations for the circuit descriptor system: 2 6 6 E =6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 2 −AR R −1AT R 6 7 6 AT 0 7 L 7, A = 6 6 7 6 AT −T T AT 0 5 4 Ti T Tt 0 3 0 −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 AT V 3 E and −(A + AT ) are symmetric and positive semidefinite, if the circuit does not contain resistances, then A + AT = 0, B = CT . Conclusion: The transfer function G(s) = C(sE − A)−1 B of the circuit satisfies for s ∈ C+ : G(s) + G ∗ (s) = B T (sE − A)−1 B + B T (sE − AT )−1 B = 2B T (sE − A)−1 (2 Re(s)E − (A + AT ))(sE − A)−∗ B ≥ 0, tu-logo i.e., the circuit system is positive real. Motivation Descriptor Systems Circuit Equations Example Conclusion 2 −AI 7 6 7 6 0 7 7, B = C T = 6 6 0 7 4 5 0 3 0 7 0 7 7 0 7 5 −I Circuit Synthesis Observations for the circuit descriptor system: 2 6 6 E =6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 2 −AR R −1AT R 6 7 6 AT 0 7 L 7, A = 6 6 7 6 AT −T T AT 0 5 4 Ti T Tt 0 3 0 −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 AT V 3 E and −(A + AT ) are symmetric and positive semidefinite, if the circuit does not contain resistances, then A + AT = 0, B = CT . Conclusion: The transfer function G(s) = C(sE − A)−1 B of the circuit satisfies for s ∈ C+ : G(s) + G ∗ (s) = B T (sE − A)−1 B + B T (sE − AT )−1 B = 2B T (sE − A)−1 (2 Re(s)E − (A + AT ))(sE − A)−∗ B ≥ 0, tu-logo i.e., the circuit system is positive real. Motivation Descriptor Systems Circuit Equations Example Conclusion 2 −AI 7 6 7 6 0 7 7, B = C T = 6 6 0 7 4 5 0 3 0 7 0 7 7 0 7 5 −I Circuit Synthesis Observations for the circuit descriptor system: 2 6 6 E =6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 2 −AR R −1AT R 6 7 6 AT 0 7 L 7, A = 6 6 7 6 AT −T T AT 0 5 4 Ti T Tt 0 3 0 −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 AT V 3 E and −(A + AT ) are symmetric and positive semidefinite, if the circuit does not contain resistances, then A + AT = 0, B = CT . Conclusion: The transfer function G(s) = C(sE − A)−1 B of the circuit satisfies for s ∈ C+ : G(s) + G ∗ (s) = B T (sE − A)−1 B + B T (sE − AT )−1 B = 2B T (sE − A)−1 (2 Re(s)E − (A + AT ))(sE − A)−∗ B ≥ 0, tu-logo i.e., the circuit system is positive real. Motivation Descriptor Systems Circuit Equations Example Conclusion 2 −AI 7 6 7 6 0 7 T 6 7, B = C = 6 7 4 0 5 0 3 0 7 0 7 7 0 7 5 −I Circuit Synthesis Observations for the circuit descriptor system: 2 6 6 E =6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 2 −AR R −1AT R 6 7 6 AT 7 0 7 6 L 7, A = 6 6 AT −T T AT 0 5 4 Ti T Tt 0 AT 0 3 V −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 3 For Σi = diag(Ine , −InL , −InV , −InT ), Σe = diag(InI , −InV ), the MNA matrices satisfy Σi E = Σi E T , Σi A = −Σi AT , Σi B = C T Σe , B T Σi = Σe C. Hence we have that the transfer function G(s) = C(sE − A)−1 B satisfies G(s)Σi = Σi GT (s), i.e. circuit system is reciprocal. tu-logo Motivation Descriptor Systems Circuit Equations Example Conclusion 2 −AI 7 6 7 6 0 7 T 6 7, B = C = 6 7 4 0 5 0 3 0 7 0 7 7 0 7 5 −I Circuit Synthesis Observations for the circuit descriptor system: 2 6 6 E =6 6 4 AC C AT C 0 0 0 L 0 0 0 0 0 0 0 2 −AR R −1AT R 6 7 6 AT 7 0 7 6 L 7, A = 6 6 AT −T T AT 0 5 4 Ti T Tt 0 AT 0 3 V −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 3 For Σi = diag(Ine , −InL , −InV , −InT ), Σe = diag(InI , −InV ), the MNA matrices satisfy Σi E = Σi E T , Σi A = −Σi AT , Σi B = C T Σe , B T Σi = Σe C. Hence we have that the transfer function G(s) = C(sE − A)−1 B satisfies G(s)Σi = Σi GT (s), i.e. circuit system is reciprocal. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Reformulation of the task: Given is a passive and reciprocal descriptor system with transfer function G(s). Find incidence matrices AR , AC , AL , ATi , ATt , AI , AV , positive definite matrices R, C, L, a transformer gain matrix TT such that 2 6 6 G(s) = 6 4 −AI 0 0 0 3T 2 sAC CATC + AR R −1ATR 6 7 −ATL 0 7 6 7 6 6 T 0 5 4 −ATi +TTT ATTt −I −ATV 0 AL ATi −ATt TT sL 0 0 0 0 0 AV 3−1 2 7 0 7 7 0 7 5 0 6 6 6 4 −AI 0 0 0 0 3 0 7 7 7 0 5 −I tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion First auxiliary result: Theorem Let a minimal and passive descriptor system E ẋ (t) = Ax(t) + Bu(t), y(t) = Cx(t) that is reciprocal with external signature Σe = diag(Ip1 , −Ip2 ) be given. Then, there exist W , T ∈ Gln (R) such that – – » – » » A11 A12 B1 0 E11 0 T . WAT = , WB = (CT ) = WET = 0 B2 0 E22 −AT11 0 where Eij , Aij ∈ Rni ,nj , Bi ∈ Rni ,pi with further E11 ≥ 0, E22 ≥ 0, A11 ≤ 0. If the system is moreover lossless, then we can find a transformation with A11 = 0. tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Next task: Given is a system with – » » A11 0 E11 , A= E= 0 E22 −AT12 A12 0 – , B = CT = » B11 0 0 B22 – Introduce new states and perform blockdiagonal congruence transformations – » T11 0 , such that T T ET , TAT , T T B = C T T is in desired form. T = 0 T22 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example We demonstrate the technique for the lossless case: E= » E11 0 0 E22 – , A= T Transforming T11 E11 T11 = » I 0 » – » 0 A12 B11 T , B = C = 0 −AT12 0 – – » 0 I 0 T , T22 ... E22 T22 = 0 0 0 0 B22 – tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example We demonstrate the technique for the lossless case: E= » E11 0 0 E22 – , A= T Transforming T11 E11 T11 = » I 0 » – » 0 A12 B11 T , B = C = 0 −AT12 0 – – » 0 I 0 T , T22 ... E22 T22 = 0 0 0 0 B22 – tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 I 6 0 6 E =4 0 0 0 0 0 0 0 0 I 0 2 2 3 0 B11 6 0 7 7 , B = C T = 6 B21 4 0 0 5 0 0 0 6 0 A=6 4 −AT13 −AT14 Introducing new states 0 0 −AT23 −AT24 A13 A23 0 0 3 0 0 7 7 B32 5 B42 . 3 A14 A24 7 7 0 5 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 I 6 0 6 E =4 0 0 0 0 0 0 0 0 I 0 2 2 3 0 B11 6 0 7 7 , B = C T = 6 B21 4 0 0 5 0 0 0 6 0 A=6 4 −AT13 −AT14 Introducing new states 0 0 −AT23 −AT24 A13 A23 0 0 3 0 0 7 7 B32 5 B42 . 3 A14 A24 7 7 0 5 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 6 6 6 6 6 E =6 6 6 6 4 0 0 0 0 0 0 0 0 2 0 6 0 6 0 6 6 6 0 A=6 6 0 6 6 0 6 4 I 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 AT 13 AT 14 T −B11 0 Transforming T1T A23 T2 = » I 0 0 0 0 0 I 0 0 0 0 0 0 0 −AT 23 −AT 24 T −B21 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −B32 −B42 0 I 0 0 0 0 0 0 0 0 2 I 6 0 7 6 7 6 0 7 6 7 6 0 7 7 , B = CT = 6 6 0 7 6 7 6 0 7 4 0 5 0 3 0 A13 A23 T B32 0 0 0 0 0 A14 A24 T B42 0 0 0 0 −I B11 B21 0 0 0 0 0 0 0 0 −I 0 0 0 0 0 0 0 0 0 0 0 −I 3 7 7 7 7 7 7 7 7 7 5 3 7 7 7 7 7 7. 7 7 7 7 5 – 0 and eliminating some other blocks 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 6 6 6 6 6 E =6 6 6 6 4 0 0 0 0 0 0 0 0 2 0 6 0 6 0 6 6 6 0 A=6 6 0 6 6 0 6 4 I 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 AT 13 AT 14 T −B11 0 Transforming T1T A23 T2 = » I 0 0 0 0 0 I 0 0 0 0 0 0 0 −AT 23 −AT 24 T −B21 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −B32 −B42 0 I 0 0 0 0 0 0 0 0 2 I 6 0 7 6 7 6 0 7 6 7 6 0 7 7 , B = CT = 6 6 0 7 6 7 6 0 7 4 0 5 0 3 0 A13 A23 T B32 0 0 0 0 0 A14 A24 T B42 0 0 0 0 −I B11 B21 0 0 0 0 0 0 0 0 −I 0 0 0 0 0 0 0 0 0 0 0 −I 3 7 7 7 7 7 7 7 7 7 5 3 7 7 7 7 7 7. 7 7 7 7 5 – 0 and eliminating some other blocks 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example ... leads to 2 6 6 6 6 6 6 6 E =6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 0 2 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 27 −AT 28 −AT 29 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 −AT 57 −AT −AT −AT 38 48 58 T T −A39 −A49 −AT 59 0 0 I ˆ Transforming T1T A48 T2 = I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 3 2 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 6 0 T 7, B = C = 6 7 6 0 7 6 7 6 0 7 6 0 7 6 5 4 0 0 0 0 −I 0 A27 A28 A29 0 0 A38 A39 0 0 A48 A49 0 A57 A58 A59 −I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 5 ˜ 0 and eliminating some other blocks tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example ... leads to 2 6 6 6 6 6 6 6 E =6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 0 2 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 27 −AT 28 −AT 29 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 −AT 57 −AT −AT −AT 38 48 58 T T −A39 −A49 −AT 59 0 0 I ˆ Transforming T1T A48 T2 = I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 3 2 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 6 0 T 7, B = C = 6 7 6 0 7 6 7 6 0 7 6 0 7 6 5 4 0 0 0 0 −I 0 A27 A28 A29 0 0 A38 A39 0 0 A48 A49 0 A57 A58 A59 −I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 5 ˜ 0 and eliminating some other blocks tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example ... leads to 2 6 6 6 6 6 6 6 6 E =6 6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 0 0 2 6 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 27 0 −AT 29 −AT 210 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 −AT 57 0 −I 0 T −A39 0 −AT 59 −AT 0 −AT 310 410 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A27 0 0 A57 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 2 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 T 7, B = C = 6 0 7 6 7 6 0 7 6 7 6 0 7 6 0 7 6 5 4 0 0 0 0 −I 0 0 A29 A210 0 0 A39 A310 0 I 0 0 0 0 A59 A510 −I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 7 5 Eliminating some uncontrollable/onobservable states tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example ... leads to 2 6 6 6 6 6 6 6 6 E =6 6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 0 0 2 6 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 27 0 −AT 29 −AT 210 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 −AT 57 0 −I 0 T −A39 0 −AT 59 −AT 0 −AT 310 410 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 A27 0 0 A57 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 2 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 T 7, B = C = 6 0 7 6 7 6 0 7 6 7 6 0 7 6 0 7 6 5 4 0 0 0 0 −I 0 0 A29 A210 0 0 A39 A310 0 I 0 0 0 0 A59 A510 −I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 7 5 Eliminating some uncontrollable/onobservable states tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 0 6 0 6 0 6 6 0 6 6 E =6 0 6 6 0 6 6 0 4 0 0 2 6 6 6 6 6 6 A=6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 26 −AT 27 −AT 28 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 −AT 46 −AT −AT 37 47 T −A38 −AT 48 0 I 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 3 0 7 0 7 7 0 7 7 0 7 7, B = 7 0 7 7 0 7 5 0 0 0 0 A26 A27 0 A37 A46 A47 0 0 0 0 0 0 0 0 0 0 2 I 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 0 6 6 6 6 6 6 T C =6 6 6 6 6 4 −I A28 A38 A48 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7. 7 7 7 7 7 5 Introducing a new state tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion ... leads to 2 0 6 0 6 0 6 6 0 6 6 E =6 0 6 6 0 6 6 0 4 0 0 2 6 6 6 6 6 6 A=6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 26 −AT 27 −AT 28 0 0 0 0 0 0 0 0 0 0 0 0 0 E55 E56 0 T E56 E66 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 −AT 46 −AT −AT 37 47 T −A38 −AT 48 0 I 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 3 0 7 0 7 7 0 7 7 0 7 7, B = 7 0 7 7 0 7 5 0 0 0 0 A26 A27 0 A37 A46 A47 0 0 0 0 0 0 0 0 0 0 2 I 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 0 6 6 6 6 6 6 T C =6 6 6 6 6 4 −I A28 A38 A48 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 3 7 7 7 7 7 7 7 7 7 7 7 5 7 7 7 7 7 7 7. 7 7 7 7 7 5 Introducing a new state tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example ... leads to 2 6 6 6 6 6 6 6 6 6 E =6 6 6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 0 0 0 2 6 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 6 4 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 26 −AT 27 T −A28 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 −AT 37 −AT 38 0 0 0 0 0 0 0 E55 T E56 0 0 0 0 0 0 0 0 0 0 E56 E66 0 0 0 0 0 0 0 0 0 0 0 −AT 46 −AT 47 −AT 48 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 7 2 7 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 7 , B = CT = 6 0 6 7 6 0 7 6 7 6 0 7 7 4 0 7 7 0 5 0 A26 0 A46 −I 0 0 0 0 0 0 0 A27 A37 A47 0 0 0 0 0 0 0 −I A28 A38 A48 0 0 0 0 0 0 0 0 0 0 −I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 3 7 7 7 7 7 7 7 7 7 7 7 5 3 7 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 7 5 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Column-echelon-form: » A27 A37 – ·V = » – – » R29 P29 , + R39 P39 » P29 P39 – ˆ = ei1 ··· eik ˜ ... leads to 2 2 6 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 6 4 6 6 6 6 6 6 6 6 6 E =6 6 6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 28 T T −P29 − R29 T −A210 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E66 T E67 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 T T −P39 − R39 −AT 310 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E67 E77 0 0 0 0 0 0 0 0 0 0 0 −AT 48 −AT 49 T −A410 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 3 7 2 7 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 7 , B = CT = 6 0 6 7 6 0 7 6 7 6 0 7 7 4 0 7 7 0 5 0 A28 0 A48 −I 0 0 0 0 0 0 0 P29 + R29 P39 + R39 A49 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I −I A210 A310 A410 0 0 0 0 0 0 0 3 7 7 7 7 7 7 7 7 7 7 7 5 0 0 0 −I 0 0 0 0 0 0 0 3 7 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 7 5 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example Column-echelon-form: » A27 A37 – ·V = » – – » R29 P29 , + R39 P39 » P29 P39 – ˆ = ei1 ··· eik ˜ ... leads to 2 2 6 6 6 6 6 6 6 6 A=6 6 6 6 6 6 6 6 4 6 6 6 6 6 6 6 6 6 E =6 6 6 6 6 6 6 6 4 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −AT 28 T T −P29 − R29 T −A210 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 E66 T E67 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I 0 0 T T −P39 − R39 −AT 310 0 0 0 0 0 0 0 E67 E77 0 0 0 0 0 0 0 0 0 0 0 −AT 48 −AT 49 T −A410 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 I 0 0 0 0 0 0 3 7 2 7 I 7 6 0 7 6 7 6 0 7 6 7 6 0 7 6 7 7 , B = CT = 6 0 6 7 6 0 7 6 7 6 0 7 7 4 0 7 7 0 5 0 A28 0 A48 −I 0 0 0 0 0 0 0 P29 + R29 P39 + R39 A49 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 −I −I A210 A310 A410 0 0 0 0 0 0 0 3 7 7 7 7 7 7 7 7 7 7 7 5 0 0 0 −I 0 0 0 0 0 0 0 3 7 7 7 7 7 7 7 7 7. 7 7 7 7 7 7 7 5 tu-logo Motivation 2 6 6 E =6 6 4 Descriptor Systems AC C AT C 0 0 0 L 0 0 0 0 0 0 0 Circuit Equations 2 0 6 7 6 AT 0 7 L 6 7, A = 6 7 6 AT −T T AT 0 5 T Tt 4 Ti 0 0 3 Circuit Synthesis −AL −ATi +ATt TT −AV 0 0 0 0 0 0 0 0 0 AT V Conclusion Example 3 2 −AI 7 6 7 6 0 7 T 7, B = C = 6 6 0 7 4 5 0 0 3 7 0 7 7 0 7 5 −I with 2 2 3 0 0 60 6I 7 6 6 7 AC = 607 , AL = 6−I 40 405 0 0 20 3 I 07 60 6 7 07 , ATt = 60 4 05 I 0 – 0 » E66 E67 . C = I, L = T E67 E77 2 3 0 0 07 60 6 7 0 7 , ATi = 60 40 05 I −I 0 P29 P39 0 0 2 3 2 3 0 3 −I 0 P̄29 7 607 607 6 7 6 7 7 P̄39 7 , AV = 607 , AI = 6 0 7 , 405 4I 5 5 0 0 0 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Consider Circuit Synthesis " s + s22s+1 G(s) = − s21+1 As descriptor system: 2 1 0 0 0 60 1 0 0 6 60 0 1 0 E =6 60 0 0 1 6 40 0 0 0 0 0 0 0 0 0 0 0 0 0 2 3 0 0 6−1 7 07 6 6 07 7, A = 6 0 60 07 6 7 40 15 0 0 » 0 2 1 C= 0 1 0 1 s2 +1 2s s2 +1 1 0 0 0 0 0 0 0 # Example Conclusion . 0 0 0 0 0 1 −1 0 0 0 0 –0 1 0 . 1 0 0 0 0 0 1 0 2 3 0 0 61 7 07 6 6 07 7 , B = 60 60 07 6 7 40 05 1 1 3 0 07 7 07 7, 17 7 05 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example 0 0 0 1.0653 0.1564 −0.5400 3 0 7 0 7 0 7 7, −0.54007 −0.77095 1.1901 Conclusion Bringing into block form 2 0.5570 6−0.6436 6 6−0.1587 E =6 0 6 4 0 0 2 0 0 6 6 0 6 A=6 6−0.6258 4−1.0549 1.1931 0 0 0 −1.0516 1.2702 −0.1807 −0.6436 1.9137 −0.9081 0 0 0 0 0 0 0.7625 0.2525 0.1607 −0.1587 −0.9081 1.0632 0 0 0 0.6258 1.0516 −0.7625 0 0 0 1.0549 −1.2702 −0.2525 0 0 0 0 0 0 0.1564 2.0000 −0.7709 3 −1.1931 0.1807 7 7 −0.16077 7, 0 7 5 0 0 2 −0.2120 6 1.7390 6 6 0.3937 T B =C =6 0 6 4 0 0 3 0 0 7 7 0 7 7, 0.9232 7 −1.00005 0.5371 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Realization procedure leads to 2 0 6 0 6 6 0 6 AL = 6−1 6 6 0 4 0 0 2 3 0 0 0 7 61 6 7 0 7 60 6 7 0 7 , AC = 60 6 7 0 7 60 40 5 0 0 −1 0 0 0 0 0 −1 0 » 3 C= 0 2 – 1 0 , L = 40 1 0 2 3 2 2 3 3 0 −1 0 0 61 6 0 7 607 07 6 7 6 6 7 7 17 60 6 0 7 607 6 7 6 6 7 7 07 , AV = 607 , AI = 6 0 7 , ATt = 60 6 7 6 6 7 7 07 60 6 0 7 617 40 5 4 5 4 5 0 0 0 0 0 0 0 0 1.0198 −0.1981 2 3 0.2986 0 6−0.9950 −0.19815 , T = 6 4 0 2.9802 −0.4925 0 0 1 0 0 0 0 0 0 0 1 0 0 0 −2.9851 −0.0995 0 −2.1812 2 3 0 0 60 07 6 7 07 60 6 7 07 , ATi = 60 6 7 17 60 41 5 0 0 0 3 −2.1213 0.7071 7 7 5 1 0 0 0 0 0 0 0 1 3 1 07 7 07 7 07 , 7 07 05 0 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Conclusion Example 0.7071 1 0 0 −2.1812 0 −0.4925 uV (t) −2.9851 −2.1213 1 −0.0995 1 0.2986 3 −0.9950 A realizing circuit is therefore given by iI (t) −0.1981 1.0198 2.9802 tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Outline 1 Motivation 2 Descriptor Systems 3 Circuit Equations 4 Circuit Synthesis 5 Example 6 Conclusion and Outlook tu-logo Motivation Descriptor Systems Circuit Equations Circuit Synthesis Example Conclusion Conclusion Passive and Reciprocal Descriptor Systems Transformation into MNA form Interpretation as an electrical circuit. tu-logo Thanks a lot for your attention!