我正在尝试构建一个继电器，但我总是收到一个对我来说没有任何意义的错误。
该错误表示缺少地面对象或未连接组件，
但我找不到任何丢失的东西。
我尝试以不同的方式构建继电器，但总是出现相同的错误......
我测试继电器的课程：
model test
Relay relay annotation (Placement(transformation(extent={{-20,4},{0,24}})));
ConstantVoltage constantVoltage annotation (Placement(transformation(
extent={{-10,-10},{10,10}},
rotation=-90,
origin={-74,10})));
ConstantVoltage constantVoltage1 annotation (Placement(transformation(
extent={{-10,-10},{10,10}},
rotation=-90,
origin={52,12})));
Modelica.Electrical.Analog.Basic.Ground ground
annotation (Placement(transformation(extent={{-42,-30},{-22,-10}})));
equation
connect(relay.n1, constantVoltage.n) annotation (Line(
points={{-20,9},{-46,9},{-46,0},{-74,0}},
color={0,0,255},
smooth=Smooth.None));
connect(constantVoltage.p, relay.p1) annotation (Line(
points={{-74,20},{-48,20},{-48,19},{-20,19}},
color={0,0,255},
smooth=Smooth.None));
connect(relay.n1, ground.p) annotation (Line(
points={{-20,9},{-26,9},{-26,-10},{-32,-10}},
color={0,0,255},
smooth=Smooth.None));
connect(relay.p2, constantVoltage1.p) annotation (Line(
points={{0,19},{26,19},{26,22},{52,22}},
color={0,0,255},
smooth=Smooth.None));
connect(constantVoltage1.n, relay.n2) annotation (Line(
points={{52,2},{26,2},{26,9},{0,9}},
color={0,0,255},
smooth=Smooth.None));
connect(ground.p, relay.n2) annotation (Line(
points={{-32,-10},{-16,-10},{-16,9},{0,9}},
color={0,0,255},
smooth=Smooth.None));
annotation (Diagram(coordinateSystem(preserveAspectRatio=false, extent={{-100,
-100},{100,100}}), graphics));
end test;
继电器类：很简单，我只看v1，如果电压为正，继电器应该让电流通过。
model Relay
extends Modelica.Electrical.Analog.Interfaces.TwoPort;
Boolean off;
equation
off = v1 < 0;
v2 = if off then 0 else v2;
i2 = if off then 0 else i2;
annotation (Diagram(coordinateSystem(preserveAspectRatio=false, extent={{-100,
-100},{100,100}}), graphics));
end Relay;
错误日志：
Check of MTS.test:
The model has the same number of unknowns and equations: 27
The problem is structurally singular.
It has 27 scalar unknowns and 27 scalar equations.
The Real part has 26 unknowns and 26 equations.
The Integer part has 0 unknowns and 0 equations.
The Boolean part has 1 unknowns and 1 equations.
The String part has 0 unknowns and 0 equations.
Attempting to further localize singularity.
Singularity of MTS.test is at the top level.
The model MTS.test is structurally singular.
The problem is structurally singular for the element type Real.
The number of scalar Real unknown elements are 26.
The number of scalar Real equation elements are 26.
The model includes the following hints:
An electrical current cannot be uniquely calculated.
The reason could be that
- a ground object is missing (Modelica.Electrical.Analog.Basic.Ground)
to define the zero potential of the electrical circuit, or
- a connector of an electrical component is not connected.
The problem has no elements of type Integer.
The problem is structurally regular for the element type Boolean.
The number of scalar Boolean elements are 1.
The problem has no elements of type String.
ERROR: 2 errors were found
WARNING: 2 warnings were issued