JPH04175972A - Circuit simulation device - Google Patents

Abstract

PURPOSE:To analyze an electric system and a mechanism system at the same time by representing characteristics of respective elements of the mechanism system as differential equations and solving them in combination with differential equations representing the electric system. CONSTITUTION:When the differential equations representing the characteristics of the respective elements of the mechanism system are linear, the differential equations can be represented in the form of state equations and characteristics of an electric circuit are also represented in the form of state equations, so those two features are utilized and the device is therefore provided with a part which converts the characteristics of the respective elements of the mechanism system described as the state equations to a form that a computer can analyze and a part which combines the state equations after the conversion with a conventional circuit simulation device. Then the equations representing both the mechanism system and electric system are solved at the same time. Consequently, a precise circuit analysis including the mechanism system can be taken.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention expresses the characteristics of each element of a mechanical system using differential equations,
This invention relates to a circuit simulation device that can simultaneously analyze an electrical system and a mechanical system by solving differential equations that express the electrical system.

BACKGROUND OF THE INVENTION In recent years, circuit simulation devices have been widely used to design control circuits for mechanical systems.

A conventional circuit simulation device will be explained below.

In conventional circuit simulation devices, the current characteristics of each element of an electrical system are expressed by the voltage between the terminals of each element, and Kirchhock's current law is applied to each node of the input circuit network to create an equation that characterizes the circuit. By deriving and solving this equation, the electrical characteristics of the circuit are simulated.

Problems to be Solved by the Invention However, the above-mentioned conventional circuit simulation devices can only analyze the elements that make up the electrical system.
It had the disadvantage that circuits including mechanical systems such as motor control could not be analyzed.

The present invention solves the above-mentioned conventional problems, and aims to provide a circuit simulation device that can perform precise circuit analysis including mechanical systems such as motors.

Means for Solving the Problems To achieve this object, the circuit simulation device of the present invention expresses the characteristics of each element of a mechanical system by a differential equation, and if the differential equation is linear, the differential equation is expressed as a state. This section focuses on two points: that it can be expressed in the form of an equation, and that the characteristics of an electric circuit can also be expressed in the form of an equation of state, and converts the characteristics of each element of the mechanical system described by the equation of state into a form that can be analyzed by a computer. and a part that connects the transformed state equation with a conventional circuit simulation device.

Function: This configuration allows equations representing both the mechanical system and the electrical system to be solved at the same time, making it possible to perform precise circuit analysis including the mechanical system.

Embodiments Hereinafter, embodiments of the present invention will be described based on its application to the constant speed control circuit for a DC motor shown in FIG.

In FIG. 1, the rotational speed ω of a motor 1 is detected by a DC voltage V proportional to the rotational speed ω generated in a tachogenerator 2 directly connected to the shaft of the motor.

It is done by The difference between the set voltage v2 and vl generated by the variable resistor 3 is amplified by the operational amplifier 4. Constant speed control of the motor is performed by feeding back the amplified result to the motor 1 through a voltage control circuit composed of bipolar transistors 5, 6, and 7. When a DC motor is modeled as shown in FIG. 2, the armature voltage V3 is represented by the sum of a voltage drop due to the resistance R of the armature winding, a voltage drop due to the inductance L, and a back electromotive force proportional to the motor speed. That is, if the armature current is i, then V3=Ri +L-! l! −i +klω
It is expressed as d. Furthermore, since the motor torque N is proportional to the armature current i, N=2i. Furthermore, if the moment of inertia of the motor and load is I, and the coefficient of viscous friction is D, then N=
There is a relationship of I↓ω+Dω.

t The characteristics of a DC motor are expressed by three equations.

If armature voltage V 3 + armature current i7 rotation speed ω is used as a state variable, the characteristics of a DC motor can be expressed by a state equation. It can be analyzed together with each element. In this example, it is possible to directly analyze how the rotational speed ω of the motor follows the time change in the set voltage v2 caused by the variable resistor 3, so the accuracy is improved by 10% compared to the conventional circuit simulation device. becomes.

As described in detail, the present invention has the advantage that mechanical systems such as motors can be handled at the same time in circuit analysis, resulting in more accurate analysis results than conventional circuit simulation devices.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing a constant speed control circuit for a DC motor.
Figure 2 is a circuit diagram modeling a DC motor. 1...Motor, 2...Tachogenerator, 3...Variable resistor, 5, 6.7...
・Bipolar transistors that make up the voltage control circuit. Name of agent: Patent attorney Haruaki Koebi and two others Figure 1 Figure 2

Claims (1)

[Claims] A means for converting the characteristics of each element of a mechanical system described by an equation of state into a form that can be analyzed by a computer, and a means for expressing the current characteristics of each element of an electrical system by the voltage between the terminals of each element, A circuit simulation device comprising means for applying Kirchhock's current law to each node, deriving an equation characterizing the circuit, and simulating the electrical characteristics of the circuit by solving this equation.