| 摘要 |
A DC-AC converter in a half bridge configuration is used for operation with high pressure discharge lamps as well as low pressure discharge lamps. The converter consists in two switches (T 1 -T 2 ) serially connected through a first series of diodes (D 1 , D 2 ) and a second series of diodes (D 3 ,D 4 ) to which at their middle points (N 1 , N 2 ) a first and a second lamp load (L 1 ,L 2 ,LA 1 ,LA 2 ) are connected. Furthermore, the second terminals of the lamp loads are connected to the middle point of a series of capacitors (C 3 ,C 4 ) which are also connected to the terminals (Ki,K 2 ) of the supply voltage source. The converter includes also four diodes (D 5 ,D 6 ,D 7 ,D 8 ) which shunt the switches (T 1 ,T 2 ) and their respective series of diodes (D 1 ,D 2 ,D 3 ,D 4 ). The switches (T 1 ,T 2 ) are controlled by a controller (CC) which renders alternatively conductive at low frequency the two switches (Ti,T 2 ). In the first operating state, the first switch (T 1 ) is rendered conductive and non-conductive at a high-frequency while the second switch (T 2 ) is maintained in a non-conductive state, in the second operating state the second switch (T 2 ) is rendered conductive and non-conductive at high-frequency while the first switch (T 1 ) is maintained in a non-conductive state. The series of two capacitors (C 3 ,C 4 ) can be replaced by a series of two switches (T 3 ,T 4 ) in order to obtain a full bridge configuration of the converter. The particular configuration of the network and its operating mode allow to drive the lamp loads in such a way that the difference in power consumed by the lamps is comparatively small.
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