| 摘要 |
PURPOSE:To control the variation of a large phase angle with a relatively simple circuit configuration of the thyristor phase control system by superimposing variable DC voltage with an input AC and alterning the arc pulse phase of an SCR. CONSTITUTION:A DC voltage controller DCT rectifies an AC voltage to vary the DC output voltage to alter it by the DC voltage variation component across a load. When a DC voltage having, for example, 1/2 of maximum voltage Eac is superimposed with the AC voltaye, it becomes Edc=-Eac/2, resulting that a position for crossing 0V is diplaced at 30 deg.. When the Edc becomes large toward negative near the Eac, it can generate a panel in displaced phase in the vicinity of approx. 90 deg., and when the Edc becomes high toward positive in the vinicity of the Eac, it can control in the range of 270 deg.-360 deg.. In this manner the arc pulse phase angle of controlling the SCR can be largely varied with a relatively simple configuration of superimposing the variable DC voltage with the input AC voltage. |
