Tdk-Lambda Corporation

The University Of Electro-Communications

Tdk-Lameda Corporation

Kabushiki Kaisha Campuscreate

Tatsuyoshi Kajikawa

Eiji Takegami

Kazushi Nakano

Kazushi Watanabe

Kouji Higuchi

Satoshi Tomioka

There is provided a digital controller which can reduce a variation in output voltage as compared to the conventional digital controller at the time of abrupt changes in load and in input of a power amplifier. The digital controller is built in the power amplifier for supplying an output voltage vto a load and is equipped with a manipulated variable calculating unit which detects the output voltage vto calculate a manipulated variable &#x3be;and a signal generating unit which converts the manipulated variable &#x3be;into a signal for making the power amplifier operate. A feedforward function from an equivalent disturbance qy caused by the variation in the load is replaced by a feedback function from the output voltage vand the manipulated variable &#x3be;, thereby allowing a transfer characteristic from the disturbance qy to the output voltage vto result in a quadratic differential characteristic. Consequently, the variation in output voltage can be reduced as compared to the conventional controller at the time of the abrupt changes in the load and in the input of the power amplifier.

Digital controller for controlling output voltage under large variations in load and supply voltage

There is provided a digital controller which can generate no oscillation even if sensing a load side and enables control of supplying a desired voltage to the load. In an power amplifier which supplies an output voltage vto the load connected via a load connecting line, a load voltage vand the output voltage vare periodically sampled to calculate a manipulating variable &#x3be;from the output voltage v, the load voltage vand an arbitrary target value r. Based on the manipulating variable &#x3be;calculated, a control signal is output to the power amplifier. As a result, when connecting an LC filter with a load deviceof the power amplifier intended for a control target and besides the load connecting line is long, a robust digital controller without generating oscillation even if sensing the load side is performed can be realized.

Digital controller

A robust digital controller is equipped with a high degree of approximation and is able to incorporate a novel two-degree-of-freedom robust digital control system without substantially considering the magnitude of the control inputs and there is provided its designing device. A control compensating means is configured as an integral type control system in which a discrete transfer function W(z) between a target value r and a controlled variable y is approximated to a higher-approximate quadratic approximate model transfer function W(z) and an arithmetic processing can be performed within the digital controller based on the model transfer function W(z). Further, the designing device automatically calculates parameters constituting the control system. Consequently, a robust digital controller can be easily realized that is equipped with a high degree of approximation as compared with a conventional approximate digital control system for realizing a first-order model and is robust against output noises.

Robust digital controller and its designing device

Growing community of inventors

Chofu, Japan

Tatsuyoshi Kajikawa