| Electric power is the most convenient, cleanest; the most widely used energy, and however the power quality problems existed in power grid are seriously restricting the use of electrical equipments. Voltage sags have become the most severe power quality problems. In order to tackle it some positive and effective measures should be taken. Sensitive power equipments are deeply influenced by voltage sags, and those equipments usually accompanied with rectifier equipments. Based on this characteristic, a new method based on storage equipments was presented this paper, by controlling the charge and discharge circuit of bi-directional dc-converter to compensate the DC bus voltage of sensitive power equipments, in order to achieve the inhibition of voltage sags. Super capacitor is a kind of electrical energy storage equipment. With high power density, high energy density and facilitate to enlarge energy storage capacity therefore the super capacitor is considered the most promising energy storage technology to inhibit the voltage sags. In this paper the topology of bi-directional DC/DC was introduced. Complete the Parts selection of main circuit and the optimization design of super capacitor array, based on the research of super capacitor mathematical modeling. Analyzed the PWM control mode of bi-directional DC/DC, independent PWM control method was determined in this paper. And the super capacitor charging-discharging control method was proposed. The physical also experiment demonstrated that this control strategy was able to support the load DC bus voltage and maintain the voltage in its work scope, and effectively inhibit the voltage sags. |
PDF Full Text Request