Rubber-tired gantry crane (RTG)
Solution: Mainstream variable frequency drive solution for rubber-tired gantry crane (RTG), main equipment in container pier field bridge of the port is common DC bus drive way. CHV190 provides this mainstream RTG drive solution, namely apart from being as a motor of drive and hoisting mechanisms, the hoisting inverter provides DC power supply for DC bus of inverters of big and small carts. This common DC bus drive way has the following features:
- In case of drive for several motors, they can exchange energy with DC bus circuit. When several drive units connected to the common DC bus are working in a power generation state, and the energy it feeds back to DC bus circuit can be utilized by other drive units in electric operating state.
- In case big regenerated power energy occurs, if all the inverters stop simultaneously, regenerated energy produced by braking can be dissipated in the brake resistors set in a concentrated way.
- Compared with drive way of single inverter, it has smaller installation size. Elements at AC side, such as fuse, air switch, contactor or line reactor can be adopted for once in a concentrated way. Number of brake cells and brake resistors that are configured will be reduced.
RTG drive solution: Close-loop vector control way is adopted for hoisting mechanism, open-loop vector control way is adopted for small cart, and close-loop vector control way driven by two inverters respectively is adopted for left and right door legs for deviation correction. Hoisting mechanism and small-cart mechanism do not work simultaneously, so in selecting brake cell and brake resistor, consideration needs only to be taken in accordance with maximum braking energy by the hoisting mechanism and small-cart mechanism.
- It is highly safe, reliable contracting brake and contact control procedures ensure RTG to operate safely and reliably.
- The function of light load for speed rise improves hoisting efficiency of RTG.
- Integrating special-purpose function of several kinds of cranes, it simplifies design and improves on-site debugging efficiency.
- Mainstream common bus drive solution for RTG is not only of high performance versus price ratio, but it further improves capability and efficiency of RTG.