Estimation of the Mechanical Position of Reciprocating Compressor for Silent Stoppage

Abstract

This paper proposes the solution for decreasing of the reciprocating compressor noise and vibrations, which happens at stoppage. These vibrations and resulting noise are caused by the gas pressure in the cylinder, which impacts the compressor's piston and can reverse the motor at stoppage. To avoid this situation the motor must be stopped, when the gas is not pressurized, i.e., at the desired mechanical position, however motor is not equipped with a mechanical position sensor as the control system utilizes an electrical speed and position estimator. As a rule, it is impossible to estimate the mechanical position using an electrical position, however it has been noticed that at low speeds a detrimental feature of reciprocating compressorsvarying load torque can help identify the mechanical position. Load torque impacts the quadrature current, making it oscillate at the mechanical frequency of the motor, so this mechanical frequency and position can be estimated using a Phased Locked Loop (PLL) algorithm, applied to the quadrature current.

Fast Square Root Calculation without Division for High Performance Control Systems of Power Electronics

“…Therefore, this method is recommended for usage in high performance control systems of power electronics. The authors of this paper successfully used this algorithm in the control software of electrical drives [8] - [16] and put it into mass production.…”

“…Therefore, time saving implementation of square root calculation can significantly decrease the load to processor and make execution of larger amount of code possible. The authors of this work were faced with the above mentioned problem, whilst developing new motor drives with enhanced functionality [16], [17]. The basic software was taken from mass productive (MP) motor drives described in [18], [19], which had successfully been produced several years prior.…”

Design of Constraints for Seeking Maximum Torque per Ampere Techniques in an Interior Permanent Magnet Synchronous Motor Control

“…The experimental sample of the inverter was extended with an RS-232 communication interface used for the connection with the computer in order to send commands and monitor the internal data. The IPMSM control system implemented for verification of the proposed algorithm, was taken from a commercial motor drive discussed in [46] (Figure 13). It performs a sensorless control of IPM motors, using a back-EMF based speed and position estimation technique discussed in [47].…”

Recommendations and Typical Errors in Design of Power Converter PCBs With Shunt Sensors

“…the voltage drop corresponding to the current varying from zero to the rated value is 0~0.5 V [23]. The digitalization of this low-voltage signal with a built-in ADCs of microcontrollers, which are typically 10-or 12-bit, results in high discretization errors, therefore the signals from the shunts are typically preamplified and only after that, are sent to the ADC [24]. As a result, the PCB contains circuits with low-voltage analog signals, which are sensitive to external disturbances.…”