| Electric traction drive system is the most important part of metro vehicles. In this paper, issuses such as voltage decoupling problem in vector control, implementation of flux observer, anti-slip/anti-slide control technology and pure electric brake control strategy are given close analysis. Then simulations, ground tests and on-site experiments are carried out to verify the theoretical result.Rotor field-oriented control strategy, based on dynamic model of asynchronous motor, has been widely used and at present, voltage source inverter accounts for most of those applications. In order to achieve better control performance, combining SV PWM control technology, this thesis proposes a voltage feedforward decoupling control strategy.Because of its integral part, voltage-model flux observer would result in integral saturation which would seriously affect its performance. In order to address this problem, this theis proposes an improved voltage-model flux observer. This improved flux observer replaces integral part with high-pass filter in series with low-pass filter. In addition, strategies for real-time phase and amplitude compensation are also proposed to enhance the observer’s performance.It is known that a first-orde disturbance obsercer can detect adhesion coefficient under current road condition. On this basis, this thesis devises a stable first-order disturbance observer to detect adhesion coefficient and its derivatives under current road condtion and proposes an anti-slip/anti-slide control strategy based on PI regulator and tourque tuning function to achieve optimized adhesion utilization.At present, most urban rail transit vehicles adopt electro-pneumatice barke. However, electro-pneumatic brake would lead to worse riding comfort and some other problems. This thesis proposes a pure electric brake control strategy for metro vehicles and makes some improvement to current speed measurement method so as.to prevent the train from reversing. |
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