PUMP UNIT AND CONTROL METHOD FOR PUMP UNIT

PROBLEM TO BE SOLVED: To provide a pump unit capable of suppressing pressure reduction when decreasing the number of pumps, and a control method for the pump unit.SOLUTION: The pump unit comprises multiple pumps and a control part. Based on a discharge pressure and a target pressure value of the multiple pumps, the control part controls operation and stop of the multiple pumps and controls a rotational speed of a motor of any pressure control target pump among the multiple pumps. The control part performs increase processing for operating the stopped pumps when a predetermined increase condition is satisfied, and decrease processing for decelerating and stopping any pump being operated when a predetermined decrease condition is satisfied. During the decrease processing, a target pressure value before decrease is maintained after the decrease processing is started, and when a predetermined decrease ending condition is satisfied, the target pressure value is switched to a lower value than that before the decrease.SELECTED DRAWING: Figure 3 【課題】減台時の圧力低下を抑えることが可能なポンプユニット及びポンプユニットの制御方法を提供する。【解決手段】本発明の一形態にかかるポンプユニットは、複数のポンプと、複数の前記ポンプの吐出圧力と目標圧力値に基づいて前記複数の前記ポンプの運転及び停止と、複数の前記ポンプのうちいずれかの圧力制御対象ポンプのモータの回転数と、を制御し、所定の増台条件を満たす場合に停止中の前記ポンプを運転させる増台処理と、所定の減台条件を満たす場合に運転中のいずれかの前記ポンプを減速して停止させる減台処理と、を行い、前記減台処理において、前記減台処理の開始後は減台前の目標圧力値を維持し、所定の減台終了条件を満たすと前記目標圧力値を減台前よりも低い値に切替える、制御部と、を備える。【選択図】図３