A Seamless Transition Scheme of Position Sensorless Control in Industrial Permanent Magnet Motor Drives With Output Filter and Transformer for Oil Pump Applications
Jingbo Liu, T.A. Nondahl, Jingya Dai, Semyon Royak, P. Schmidt
Abstract
This article proposes a position sensorless control scheme for the induction and permanent magnetic low-voltage (LV) motor drives with an output filter and transformer for an electric submersible pump (ESP) and progressive cavity pump (PCP). The proposed sensorless strategy covers the full-speed range for ESP drives. An open velocity loop, current regulated sensorless controller is utilized to drive induction and permanent magnet motors (PMMs) during starting and at low speeds. A field-oriented controller (FOC) that utilizes an estimated rotor position based upon motor back electromotive force (EMF) is utilized to drive the motor at higher speeds. A seamless transition between controllers for the two operational modes, i.e., low-speed control and high-speed control, is proposed in this article. With velocity mode control over the full-speed range and mode control hysteresis, a smooth transition between open loop and EMF-based observer control can be achieved. The sensorless control scheme presented in this article has been implemented in a commercial drive for an ESP (deep well) application.