  In engineering, it is a common desire to couple existing simulation tools
together into one big system by passing information from subsystems as
parameters into the subsystems under influence. As executed at fixed time
points, this data exchange gives the global method a strong explicit component.
Globally, such an explicit cosimulation schemes exchange time step can be seen
as a step of an one-step method which is explicit in some solution components.
Exploiting this structure, we give a convergence proof for such schemes. As
flows of conserved quantities are passed across subsystem boundaries, it is not
ensured that systemwide balances are fulfilled: the system is not solved as one
single equation system. These balance errors can accumulate and make simulation
results inaccurate. Use of higher-order extrapolation in exchanged data can
reduce this problem but cannot solve it. The remaining balance error has been
handled in past work by recontributing it to the input signal in next coupling
time step, a technique labeled balance correction methods. Convergence for that
method is proven. Further, a proof for the lack of stability of such methods is
given for cosimulation schemes with and without balance correction.
