A method and system for EPS controller bus current estimation

Abstract

A method and system for estimating bus current of an EPS controller wherein the inventive system comprises a FOC control module, Motor Rotor Position Detection Module, ADC Sampling Module and Motor, Bus Current Calculation Module, the input end of the rotor position detection module of the motor detects the position of the rotor in the motor through the rotor position sensor, An output terminal ofthe motor rotor position detection module is connected with a first input terminal of the FOC control module, The FOC control module drives the motor to rotate through the motor drive circuit, the ADC sampling module detects the phase current of the motor three-phase winding through the current detection circuit, and the bus current calculation module obtains the key conditions of the current calculation by using the phase current collected in real time by the ADC and the FOC intermediate control variable, and calculates the current. The system and the method of the invention utilize the original detection circuit and cooperate with a part of MCU resources to realize, and can estimate the bus current on the basis of not increasing the hardware cost, and the estimation process is simple and convenient.

Description

technical field [0001] The invention relates to an electric power steering system, in particular to a method and system for estimating bus current of an EPS controller. Background technique [0002] Electric power steering system (EPS) is a power steering system that directly relies on the motor to provide auxiliary torque. It is mainly composed of key elements such as sensor assist motor, motor deceleration mechanism, controller, and control strategy. Among them, motor control is the most important control part in EPS control, which determines the basic performance and reliability of EPS. The brushless permanent magnet synchronous motor has the characteristics of low noise, small torque fluctuation, high efficiency, and long life. Therefore, the ECU (Electronic Control Unit) based on the design of the brushless motor has become the development direction of EPS. [0003] In FOC control (field oriented control system, also known as vector control system), SPVWM is used for m...

AI Technical Summary

Problems solved by technology

At present, the phase current of the motor can be collected and calculated more accurately, and the motor control bus current can also be collected. Due to the irregular current waveform, a large number of acquisition instruments are required for collection, and the cost is relatively high. However, for the bus current of the control loop , there is no effective calculation method, the actual current waveform is irregular, and signals of different frequencies are superimposed, see image 3 ;If it is implemented by ADC sampling, the sampling point cannot be accurately selected, and with the change of the modulation wave form, the sampling point is also changing, which is difficult to realize; if it is estimated by phase current, it is not only difficult to realize because the efficiency of the motor is different at different speeds And the estimation is inaccurate, and the real-time performance is poor

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