solving problem with discrete events #3068
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lixiao00093
changed the title
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Is this a bug? using ModelingToolkit, DifferentialEquations, Plots
using ModelingToolkit: t_nounits as t, D_nounits as D_t
# --------system models --------
@connector AcBus begin
@variables begin
vm(t) = 1.0
va(t) = 0.0
pin(t) = 0.0, [connect = Flow]
qin(t) = 0.0, [connect = Flow]
end
end
@mtkmodel Zipload_component begin
@parameters begin
u = 1,[description = "Enable Signal"]
g
b
end
@components begin
bus = AcBus()
end
@equations begin
bus.pin ~ u * ( g * bus.vm ^2)
bus.qin ~ u * (- b * bus.vm ^2)
end
end
@mtkmodel Piline_component begin
@parameters begin
u = 1 ,[description = "Enable Signal"]
rft
xft
g0 = 0.0
b0
tap_ratio = 1.0
gft = rft/(rft^2 + xft^2)
bft = -xft/(rft^2 + xft^2)
m_real = tap_ratio
m2 = tap_ratio^2
end
@components begin
bus_fr = AcBus()
bus_to = AcBus()
end
@equations begin
bus_fr.pin*m2 ~ u*( g0/2*bus_fr.vm^2 + gft*bus_fr.vm^2
- gft*m_real*bus_fr.vm*bus_to.vm*cos(bus_fr.va - bus_to.va)
- bft*m_real*bus_fr.vm*bus_to.vm*sin(bus_fr.va - bus_to.va))
-bus_fr.qin*m2 ~ u*(b0/2*bus_fr.vm^2 + bft*bus_fr.vm^2
- bft*m_real*bus_fr.vm*bus_to.vm*cos(bus_fr.va - bus_to.va)
+ gft*m_real*bus_fr.vm*bus_to.vm*sin(bus_fr.va - bus_to.va))
bus_to.pin*m2 ~ u*( g0/2*m2*bus_to.vm^2 + gft*m2*bus_to.vm^2
- gft*m_real*bus_fr.vm*bus_to.vm*cos(bus_fr.va - bus_to.va)
+ bft*m_real*bus_fr.vm*bus_to.vm*sin(bus_fr.va - bus_to.va))
-bus_to.qin*m2 ~ u*(b0/2*m2*bus_to.vm^2 + bft*m2*bus_to.vm^2
- bft*m_real*bus_fr.vm*bus_to.vm*cos(bus_fr.va - bus_to.va)
- gft*m_real*bus_fr.vm*bus_to.vm*sin(bus_fr.va - bus_to.va))
end
end
@mtkmodel Syn2_component begin
@components begin
bus = AcBus()
end
@variables begin
delta(t), [description = "rotor angle"]
omega(t) = 1.0, [description = "rotor speed"]
vf(t)
tm(t)
p(t)
q(t)
_Id(t) = 0.0
_Iq(t) = 0.0
end
@parameters begin
time_flag
u = 1, [description = "Enable Signal"]
fn
H
Damp
ra
xd1
Kw
Kp
iM = u / (2 * H)
c1 = ra / (ra^2 + xd1^2)
c2 = xd1 / (ra^2 + xd1^2)
c3 = c2
vm0
va0
end
@equations begin
_Id ~ u*(-(bus.vm * sin(delta - bus.va) * c1) - (bus.vm * cos(delta - bus.va) * c3) + c3 * vf)
_Iq ~ u*( (bus.vm * sin(delta - bus.va) * c2) - (bus.vm * cos(delta - bus.va) * c1) + c1 * vf)
p ~ bus.vm * sin(delta - bus.va) * _Id + bus.vm * cos(delta - bus.va) * _Iq
q ~ bus.vm * cos(delta - bus.va) * _Id - bus.vm * sin(delta - bus.va) * _Iq
bus.pin ~ -p # for AcBus
bus.qin ~ -q # for AcBus
D_t(delta) ~ u * 2 * π * fn * (omega - 1)
D_t(omega) ~ iM * (tm - p - ra * (_Id^2 + _Iq^2) - Damp * (omega - 1))
D_t(tm) + (time_flag<0)* (bus.va-va0) ~ 0
D_t(vf) + (time_flag<0)* (bus.vm-vm0) ~ 0
end
end
@mtkmodel Fault_component begin
@parameters begin
u = 0,[description="fault status"]
rf
xf
yg = rf/(rf^2 + xf^2)
yb = -xf/(rf^2 + xf^2)
end
@components begin
bus = AcBus()
end
@equations begin
bus.pin ~ u * yg * bus.vm^2
bus.qin ~ -u * yb * bus.vm^2
end
end
# -------colection of instances of models--------
Bus_Dict = Dict{Symbol,ODESystem}(Symbol(1)=>AcBus(;name = Symbol("Bus 1")),Symbol(2)=>AcBus(;name = Symbol("Bus 2")))
device_list::Dict{Symbol,ODESystem} = Dict(
:line => Piline_component(;name = :line, rft = 0.01,xft = 0.01,g0 = 0,b0 = 0.01,tap_ratio = 1.0),
:syn => Syn2_component(;name = :syn1, time_flag = -1, fn = 50.0, H = 1.0, Damp = 0.8, ra = 0.01, xd1 = 0.1, Kw=1.0, Kp=1.0, va0 = 0.0 , vm0=1.0),
:zipload => Zipload_component(;name = :zipload1, g = 1.0, b = 0.0),
:fault => Fault_component(;name = :fault, rf = 0.0, xf = 0.1)
)
# -------connection of models--------
eqs = [ connect(Bus_Dict[Symbol(1)], device_list[:syn].bus),
connect(Bus_Dict[Symbol(1)], device_list[:line].bus_fr),
connect(Bus_Dict[Symbol(1)], device_list[:fault].bus),
connect(Bus_Dict[Symbol(2)], device_list[:zipload].bus),
connect(Bus_Dict[Symbol(2)], device_list[:line].bus_to)]
# -------Apply and clear fault in the models--------
u_temp_record = Dict{Int,Vector{Float64}}()
function affect1!(integ, u, p, ctx)
if integ.ps[p.u] != ctx
println("apply fault at t = ", integ.t)
integ.ps[p.u] = ctx
u_temp_record[1] = copy(integ.u[integ.differential_vars.==false])
end
end
function affect2!(integ, u, p, ctx)
if integ.ps[p.u] != ctx
println("clear fault at t = ", integ.t)
integ.ps[p.u] = ctx
#offer the initial value of algebraic variables for the reinitialization
integ.u[integ.differential_vars.==false] = u_temp_record[1]
end
end
fault_function = [(t==1.0) => (affect1!, [], [device_list[:fault].u=>:u], [device_list[:fault].u], 1.0),
(t==1.05) => (affect2!, [], [device_list[:fault].u=>:u], [device_list[:fault].u], 0.0)]
# -------set the initial guessvalues of models--------
function set_ini_syn2(; ra, xd1)
pg0 = 1.0
qg0 = 0.0
vm0 = 1.0
va0 = 0.0
V = vm0 .* exp.(va0 .* 1im)
S = pg0 - qg0 .* 1im
I = S ./ conj.(V)
E = V + (ra + xd1 .* 1im) .* I
delta = imag(log.(E ./ abs.(E) + 0im))
delta0 = delta
omega0 = 1.0
# d- and q-axis voltages and currents
vdq = V .* 1im .* exp.(-delta .* 1im)
idq = I .* 1im .* exp.(-delta .* 1im)
vd = real(vdq)
vq = imag(vdq)
Id = real(idq)
Iq = imag(idq)
# mechanical torques/powers
tm0 = (vq + ra .* Iq) .* Iq + (vd + ra .* Id) .* Id
vf0 = vq + ra .* Iq + xd1 .* Id
return delta0, omega0, tm0, vf0, pg0, qg0
end
u0_guess = Dict(zip([device_list[:syn].delta, device_list[:syn].omega, device_list[:syn].tm, device_list[:syn].vf, device_list[:syn].p, device_list[:syn].q], set_ini_syn2(ra = 0.01, xd1 = 0.1)))
# -------simplify the system--------
test_system_init = ODESystem(eqs, t,[],[]; systems = collect(values(merge(device_list, Bus_Dict))), name = :test_system_init, discrete_events = fault_function)
test_system_init_simplify = structural_simplify(test_system_init, fully_determined = true)
test_system_xy0 = SteadyStateProblem(test_system_init_simplify, u0_guess; jac = true, sparse = true)
sol = DifferentialEquations.solve(test_system_xy0)
xy0_sol_dict = Dict{Symbolics.Num, Any}()
for var in unknowns(test_system_xy0.f.sys)
xy0_sol_dict[var] = sol[var]
end
for var in observed(test_system_xy0.f.sys)
xy0_sol_dict[var.lhs] = sol[var.lhs]
end
defaults(test_system_init_simplify)[device_list[:syn].time_flag] = 1
# -------format the system to solve--------
prob = ODEProblem(test_system_init_simplify, xy0_sol_dict, (0,20); fully_determined = true, jac=true,sparse=true)
# sol = solve(prob, Rodas4(), tstops = [1.0,1.05])
sol = solve(prob, dtmax = 0.01, tstops = [1.0,1.05])
plot(sol)
plot(sol.t,sol[device_list[:syn].delta])
plot(sol.t,sol[device_list[:syn].omega])
plot(sol.t,sol[device_list[:zipload].bus.vm])But this way cannot work in the later version, because the way of initialisation has changed. But I do not know why I can not run my code after I modify that like the top side of this issue. When I run the above codes, the output of Pkg.status() |
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If nobody answers me, I would like to report that as a bug issue and close this one. This question is making me feel crazy. |
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There's just a lot of extra things in here so it will take some time to narrow it down before we can give a reasonable response. Is everything in that script actually needed to reproduce the issue? The plotting stuff for example seems unnecessary. If you can simplify the issue you'll get a quicker response, otherwise it will have to wait until I have the time to simplify the issue. |
Thank you so much! Your response gives me the confidence to solve it. |
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Yes it will definitely help, since someone has to simplify it. If I have to do it then I'll need to wait until I have a good chunk of time open, but if it's simplified I can pretty say what's going on. My guess from a quick look is that it's the initialization things being fixed in #2922 |
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I am trying to simplify the cases above as follows: using ModelingToolkit, DifferentialEquations, Plots
using ModelingToolkit: t_nounits as t, D_nounits as D_t
# --------system models --------
@connector AcBus begin
@variables begin
vm(t), [guess = 1.0]
va(t), [guess = 0.0]
pin(t), [connect = Flow, guess = 0.0]
qin(t), [connect = Flow, guess = 0.0]
end
end
@mtkmodel Sys_component begin
@components begin
bus = AcBus()
end
@variables begin
delta(t), [guess = 0.1]
omega(t), [guess = 1.0]
tm(t),[guess = 1.0]
p(t),[guess = 1.0]
q(t),[guess = 0.0]
end
@parameters begin
fn
H
Damp
xd1
gl
va0
end
@equations begin
p ~ bus.vm * sin(delta - bus.va) * 1.05 / xd1
q ~ bus.vm * cos(delta - bus.va) * 1.05 / xd1 - bus.vm^2/ xd1
D_t(delta) ~ 2 * π * fn * (omega - 1)
D_t(omega) ~ (tm - p - Damp * (omega - 1))/(2 * H)
D_t(tm) ~ 0
bus.pin ~ -p + gl * bus.vm ^2
bus.qin ~ -q
end
end
@mtkmodel Fault_component begin
@parameters begin
u = 0,[description="fault status"]
yf
end
@components begin
bus = AcBus()
end
@equations begin
bus.pin ~ u * yf * bus.vm^2
bus.qin ~ 0
end
end
# -------colection of instances of models--------
Bus_Dict = Dict{Symbol,ODESystem}(Symbol(1)=>AcBus(;name = Symbol("Bus 1")))
device_list::Dict{Symbol,ODESystem} = Dict(
:syn => Sys_component(;name = :syn, fn = 50.0, H = 1.0, Damp = 0.8, xd1 = 0.1, gl = 1.0, va0 = 0.0),
:fault => Fault_component(;name = :fault, yf = 1.0)
)
# -------connection of models--------
eqs = [ connect(Bus_Dict[Symbol(1)], device_list[:syn].bus),
connect(Bus_Dict[Symbol(1)], device_list[:fault].bus)]
# -------initialization of models--------
ini_eqs = [device_list[:syn].omega ~ 1,
device_list[:syn].tm - device_list[:syn].p ~ 0,
device_list[:syn].bus.va ~ device_list[:syn].va0]
# -------Apply and clear fault in the models--------
u_temp_record = Dict{Int,Vector{Float64}}()
function affect1!(integ, u, p, ctx)
if integ.ps[p.u] != ctx
println("apply fault at t = ", integ.t)
integ.ps[p.u] = ctx
u_temp_record[1] = copy(integ.u[integ.differential_vars.==false])
end
end
function affect2!(integ, u, p, ctx)
if integ.ps[p.u] != ctx
println("clear fault at t = ", integ.t)
integ.ps[p.u] = ctx
#offer the initial value of algebraic variables for the reinitialization
integ.u[integ.differential_vars.==false] = u_temp_record[1]
end
end
fault_function = [(t==1.0) => (affect1!, [], [device_list[:fault].u=>:u], [device_list[:fault].u], 1.0),
(t==1.01) => (affect2!, [], [device_list[:fault].u=>:u], [device_list[:fault].u], 0.0)]
# -------simplify the system--------
test_system_init = ODESystem(eqs, t,[],[]; systems = collect(values(merge(device_list, Bus_Dict))), name = :test_system_init, discrete_events = fault_function)
test_system_init_simplify = structural_simplify(test_system_init, fully_determined = true)
# -------format the system to solve--------
prob = ODEProblem(test_system_init_simplify,[], (0,20),[]; initialization_eqs = ini_eqs, fully_determined = true, jac=true,sparse=true)
# sol = solve(prob, Rodas4()) # retcode:success without discrete events
sol = solve(prob, tstops = [1.0,1.01]) # ERROR: UndefRefError: access to undefined reference
# sol = solve(prob, Rodas4(), tstops = [1.0,1.01]) # retcoe: UnstableThe output of Pkg.status() This code can also reproduce the issue above, but it is not simple enough. |
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When I am trying to narrow it down further, I face some other problems: using ModelingToolkit, DifferentialEquations, Plots
using ModelingToolkit: t_nounits as t, D_nounits as D_t
# --------system models --------
@mtkmodel Sys_component begin
@variables begin
delta(t), [guess = 0.1]
omega(t), [guess = 1.0]
tm(t), [guess = 1.0]
p(t), [guess = 1.0]
q(t), [guess = 0.0]
bus_vm(t), [guess = 1.0]
bus_va(t), [guess = 0.0]
end
@parameters begin
fn
H
Damp
xd1
gl
va0
u = 0,[description="fault status"]
yf
end
@equations begin
p ~ bus_vm * sin(delta - bus_va) * 1.05 / xd1
q ~ bus_vm * cos(delta - bus_va) * 1.05 / xd1 - bus_vm^2/ xd1
D_t(delta) ~ 2 * π * fn * (omega - 1)
D_t(omega) ~ (tm - p - Damp * (omega - 1))/(2 * H)
D_t(tm) ~ 0
0 ~ -p + gl * bus_vm ^2 + u * yf * bus_vm^2
0 ~ -q
end
@discrete_events begin
(t == 1.00) => [u ~ 1]
(t == 1.01) => [u ~ 0]
end
end
# -------simplify the system--------
sys = Sys_component(;name = :sys, fn = 50.0, H = 1.0, Damp = 0.8, xd1 = 0.1, gl = 1.0, va0 = 0.0, yf = 10.0)
test_system_init_simplify = structural_simplify(sys, fully_determined = true)
# -------initialization of models--------
ini_eqs = [sys.omega ~ 1,
sys.tm - sys.p ~ 0,
sys.bus_va ~ sys.va0]
# -------format the system to solve--------
prob = ODEProblem(test_system_init_simplify,[], (0,20),[]; initialization_eqs = ini_eqs, fully_determined = true, jac=true,sparse=true)
# sol = solve(prob, Rodas4())
sol = solve(prob, tstops = [1.0,1.01])
# sol = solve(prob, Rodas4(), tstops = [1.0,1.01])After simplifying the system, it shows error in building ODEProblem step: But there are 7 variables and 7 equations in total, why? |
I just check, this problem has been almost fixed in the latest version. Although I still don't know the reason of my last question, which indicates "The system is unbalanced", I will close this question. |
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I think this relates to my previous issues: #3043, and has some relationship to SciML/OrdinaryDiffEq.jl#2441.
I am stuck with this problem for a long time, no matter I use the latest version 9.41.0 or the older version of the ModelingToolkit.
What should I do? Should I modify my codes? Or this is a bug?
Environment (please complete the following information):
What I mean is that solving the problem with discrete event by default solver:
The output:
if solving the problem with discrete event by Rodas4() solver:
The output:
The text was updated successfully, but these errors were encountered: