| 摘要 |
<p>A method and apparatus for converting a direct current into an alternating current is disclosed. The load is connected between a first and a second load nodes and a source is connected between a first and a second source nodes. The method involves producing a positive and negative half cycle of alternating current through the load. The positive half cycle is produced by causing a first and a second switching control signals to effect a plurality of sub-cycles each comprising a first time period during which the first and second switching signals are asserted and a second time period during which the first and second switching signals are not asserted. During each first time period of each sub-cycle, direct current flows from the first source node then through a first switch that conducts current from the first source node to a first intermediate node in response to the first switching signal, then through a first inductor connected between the first intermediate node and the first load node, then through the load, then through a second inductance connected between the second load node and a second intermediate node, and then through a second switch that conducts current from the second intermediate node to the second source node in response to the second switching signal. During each second time period of each sub-cycle, a first shunt control signal is asserted to cause current to flow through a first unidirectional shunt from the second intermediate node to the first intermediate node, then through the first inductor, then through the load node and then through the second inductor back to the second intermediate node. The negative half cycle is produced by causing a third and a fourth switching control signals to effect a plurality of sub-cycles each comprising a third time period during which the third and fourth switching signals are asserted and a fourth time period during which the third and fourth switching signals are not asserted. During the third time period in each sub-cycle, direct current flows from the first source node, then through a third switch that conducts current from the first source node to a third intermediate node in response to the third switching signal, then through a third inductor connected between the third intermediate node and the second load node, then through the load, then through a fourth inductance connected between the first load node and a fourth intermediate node, and then through a fourth switch that conducts current from the fourth intermediate node to the second source node in response to the fourth switching signal. During each fourth time period of each sub-cycle, a second shunt control signal is asserted to cause current to flow through a second unidirectional shunt from the fourth intermediate node to the third intermediate node, then through the third inductor, then through the load, then through the fourth inductor back to the fourth intermediate load node.</p> |
