PRESSURE-COMPENSATION HYDRAULIC PUMP, ROTATION SPEED CONTROL SYSTEM AND CONTROL METHOD, AND ENGINEERING MACHINERY

A pressure-compensation controlled hydraulic pump, comprising an electric proportional pressure compensator (14), a hydraulic pump (11), a hydraulic control reversing valve (12) and a servo cylinder (13); the electric proportional pressure compensator (14) can be electrically connected to a controller (15), a first hydraulic control port (121) of the hydraulic control reversing valve (12) is connected to an internal oil drain path (23), and is connected to an internal output oil path (22) by means of a hydraulic control oil inlet path (24) provided with a first throttle valve (16), a second hydraulic control port (122) is connected to the internal output oil path (22), and the pressure difference between an opening pressure of the electric proportional pressure compensator (14) and an oil outlet pressure of the hydraulic pump (11) can drive the hydraulic control reversing valve to perform reversing, and selectively enable a piston chamber of the servo cylinder (13) to be in communication with the internal output oil path (22) or the internal oil drain path (23). Further disclosed are a rotation speed control method, a rotation speed control system and a construction machinery. The hydraulic pump can stabilize the output flow rate of the hydraulic pump at a demand value.