apfiff09 marine vacon • 16924- 67.8.4 Stabilization settings7.8.4.1 Torque stabiliserThe torque stabiliser is basically a first order high-pass filter for the estimated torque [𝑇]. Theoutput of the filter is a frequency correction term 𝑑𝑓 added to the output frequency reference. Thepurpose of the torque stabiliser is to stabilise the possible oscillations in the estimated torque. Thecontroller gain is changing linearly between the zero and field weakening point frequencies. Thezero and field weakening point gains can be controlled independently with gains. The stabiliseroperates at frequencies above 3 Hz.The discrete implementation of the filter is:1000𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝 𝑑𝑓𝑘 = 1000𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝 𝐺(𝑇𝑘 − 𝑇𝑘−1) + 𝑑𝑓𝑘−1 = 𝐺𝑓(𝑇𝑘 − 𝑇𝑘−1) + 𝑑𝑓𝑘−1Where 𝐺𝑓 is the total gain of the filter. The gain and the corner frequency of the filter is controlled bythe following parametersP2.8.7.1 Torque stabiliser damping ID1413If a PMS motor is used in open loop control mode it is recommended to use value 980instead of 800.This parameter defines the corner frequency of the high-pass filter. The time constant ofthe filter is calculated as𝑇𝑐 = 𝑇𝑠𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝1000 − 𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝 = 1𝑚𝑠 𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝1000 − 𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝It follows that the corner frequency of the filter is obtained from𝜔𝑐 = 1𝑇𝑐𝑟𝑎𝑑/𝑠For example, if Torque stabilizer damping = 600, it follows that 𝑇𝑐c = 1.5 ms and 𝜔𝑐 = 667rad/s.P2.8.7.2 Torque stabiliser GainID1412These parameters define together with the Torque Stabiliser Damping the actual gain ofthe filter. Torque Stabiliser Gain is the gain at the zero frequency. Torque stabiliser Gainin FWP is the gain at the field-weakening frequency. The gain changes linearly with thefrequency between these two points so that the gain is𝐺 = TorqStabGainFWP + TorqStabGain − ffFWPTorqStabGain, if f < fFWP𝐺 = TorqStabGainFWP, if f ≥ fFWPThe final gain is obtained by considering the value of Torque Stabiliser Damping and thescaling in which 256 means the gain 1. So, the final and the actual gain of the filter isobtained from𝐺𝑓 = 1000 ∗ 𝐺256 ∗ 𝑇𝑜𝑟𝑞𝑆𝑡𝑎𝑏𝐷𝑎𝑚𝑝
