Estudo e implementação de estrategia para minimização de sobretensões produzidas por inversores PWM em sistemas de acionamento de motores eletricos com cabos longos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The analysis of long distance induction motor driving systems is performed. This kind of system, usuaIly driven by a voltage source inverter, has been employed by Petrobras for oi! exploitation in deepwater. Due to the excessive cable length, undesirable effects such as overvoltages and overcurrents are recorded at the motor and the inverter, respectively. Passive filters are commonly used in order to overcome those effects. An alternative strategy based on the correct choice of the inverter switching frequency, set in a pulse width modulation, is proposed. The strategy raise interesting from fact ofnot demanding for additional elements. The switching frequency is set even in the running system and can be estimated through the digital processing of the signal current sampled at the inverter terminaIs. A mathematical toei caIled natural frequency technique is employed to estimate the electrical parameters of the cable, in such a way that system frequency response can be outlined. An assessment of the critical frequencies related to overvoltages is possible from the frequency response. A high power system was simulated taking into account the skin effect in the cable conductors and a low power prototype was built in a laboratory. The closing results aIlow the application of the same strategy to industrial plants, since enough long cables are employed. Systems demanding for a voltage step-up transformer are also covered in the work.

ASSUNTO(S)

acionamento eletrico maquinas eletricas processamento de sinais cabos submarinos eletronica industrial

ACESSO AO ARTIGO

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