Electric power steering system of new energy vehicle and control method of electric control unit thereof

Abstract

The invention discloses an electric power steering system of a new energy vehicle and a control method of an electric control unit thereof. The electric control unit comprises an input circuit which is used for connecting with a sensor part, an MCU and an output circuit which is used for connecting with an actuator part, wherein both ends of the MCU are connected with the input circuit and the output circuit; the control method adopts an improved PI algorithm; integral separation and dead zone processing are carried out, and the smooth and steady follow of power torque under the condition of low cost of hardware is realized by the current closed-loop control of the variable parameter PID based on vehicle speed grouping; the duty ratio nonlinear compensation technique is adopted in the mode of limited bipolar pulse width modulation; the duty ratio is corrected by the current in the limited bipolar mode. When the current is across a dead zone, namely when the target current is changed from positive to negative or from negative to positive, and when the power is from zero to existence, the duty ratio is directly arranged near the target current value to be accurately adjusted by the current closed-loop feedback, and the current of the motor can reach the target value.

Description

technical field [0001] The invention belongs to the field of automobile electric power steering systems, and in particular relates to a new energy automobile electric power steering system and a control method for an electronic control unit thereof. Background technique [0002] At present, electric power steering system widely used in electric electronic control steering system, referred to as EPS (Electrical Power Steering System), is a power steering system that directly relies on the motor to provide auxiliary torque. The third-generation steering system belongs to the mechatronics system. The system directly provides steering assistance by the electric power booster, eliminating the need for power steering oil pumps, hoses, hydraulic oil, conveyor belts and pulleys installed on the engine that are necessary for hydraulic power steering systems, which not only saves energy, but also protects the environment. In addition, it also has the characteristics of simple adjustm...

AI Technical Summary

Problems solved by technology

Most new energy vehicles have not yet installed EPS, and a few new energy vehicles that have installed EPS have poor steering control and return. It is generally difficult to turn when driving at low speeds, and there are problems with unstable steering and fluttering when driving at high speeds. , work is still very unstable

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