Parallel interleaving operated bidirectional DC-DC converter and method and apparatus for controlling the same
The present disclosure relates to a new bidirectional low voltage DC-DC converter (LDC), that is, a DC-DC converter capable of satisfying a safety level required for an eco-friendly vehicle and an autonomous vehicle and improving power conversion performance, and a method and an apparatus for controlling the same. The LDC proposed in the present disclosure is a new concept bidirectional LDC in which a plurality of converters having the same power circuit topology are subjected to a parallel interleaving operation so as to enable both a buck operation and a boost operation, satisfy a high safety level, and improve power conversion performance. To this end, a plurality of bidirectional active-clamp flyback converters (for example, two or more bidirectional active-clamp flyback converters) are connected in parallel and are interleaved and controlled by a controller (for example, a microcomputer).
1. A parallel interleaving operated bidirectional DC-DC converter which is a low voltage DC-DC converter (LDC) as a direct current power supply device for a vehicle, the converter comprising
two or more bidirectional DC-DC converters connected in parallel between a first battery and a second battery, a discharge voltage of the first battery being relatively higher than that of the second battery,
each of the bidirectional DC-DC converters connected in parallel includes:
a first current sensor configured to detect a current of a high voltage stage of each of the bidirectional DC-DC converters during the buck mode operation; and
a second current sensor configured to detect a current of a low voltage stage of each of the bidirectional DC-DC converters during a bidirectional operation,
wherein, among the bidirectional DC-DC converters, an interleaving operation is performed on switching of a power semiconductor included in one bidirectional DC-DC converter with respect to switching of power semiconductors included in other bidirectional DC-DC converters to perform a buck mode operation or a boost mode operation.
2. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , wherein the one bidirectional DC-DC converter is a bidirectional active-clamp flyback converter.
3. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , wherein an interleaving control of the bidirectional DC-DC converters connected in parallel is performed by a microcomputer.
4. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , wherein each of the bidirectional DC-DC converters connected in parallel includes:
a high voltage stage protection fuse configured to, when the one bidirectional DC-DC converter fails, separate the one bidirectional DC-DC converter from the other bidirectional DC-DC converters; and
a low voltage stage protection fuse configured to, when the one bidirectional DC-DC converter fails, separate the one bidirectional DC-DC converter from the other bidirectional DC-DC converters.
5. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , wherein each of the bidirectional DC-DC converters includes a low voltage stage protection power semiconductor which, when a low voltage stage of the one bidirectional DC-DC converter fails, is turned off to protect a circuit of the low voltage stage and separates the failed bidirectional DC-DC converter from the other bidirectional DC-DC converters.
6. A method of controlling two or more parallel interleaving operated bidirectional DC-DC converters which are connected in parallel between a first battery and a second battery, a discharge voltage of the first battery being relatively higher than that of the second battery, the method comprising
performing an interleaving operation on switching of a power semiconductor included in one bidirectional DC-DC converter with respect to switching of power semiconductors included in other bidirectional DC-DC converters among the bidirectional DC-DC converters to perform a buck mode operation or a boost mode operation,
wherein each of the bidirectional DC-DC converters connected in parallel includes:
a first current sensor configured to detect a current of a high voltage stage of each of the bidirectional DC-DC converters during the buck mode operation; and
a second current sensor configured to detect a current of a low voltage stage of each of the bidirectional DC-DC converters during a bidirectional operation.
7. The method of claim 6 , wherein an interleaving control of the bidirectional DC-DC converters connected in parallel is performed by a microprogram.
8. The method of claim 6 , further comprising, when the one bidirectional DC-DC converter of the bidirectional DC-DC converters connected in parallel fails, separating the one bidirectional DC-DC converter from the other bidirectional DC-DC converters.
9. The method of claim 6 , further comprising checking whether any bidirectional DC-DC converter of the bidirectional DC-DC converters connected in parallel fails using detected current and voltage values of each of the bidirectional DC-DC converters.
10. The method of claim 6 , further comprising:
detecting whether a low voltage stage of any one of the bidirectional DC-DC converters fails to protect a circuit of a high voltage stage thereof; and
separating the failed bidirectional DC-DC converter from other bidirectional DC-DC converters among the bidirectional DC-DC converters.
11. An apparatus for controlling two or more parallel interleaving operated bidirectional DC-DC converters which are connected in parallel between a first battery and a second battery, a discharge voltage of the first battery being relatively higher than that of the second battery, the apparatus comprising
a microcomputer configured to perform an interleaving operation on switching of a power semiconductor included in one bidirectional DC-DC converter with respect to switching of power semiconductors included in other bidirectional DC-DC converters among the bidirectional DC-DC converters to perform a buck mode operation or a boost mode operation,
each of the bidirectional DC-DC converters connected in parallel includes:
a first current sensor configured to detect a current of a high voltage stage of each of the bidirectional DC-DC converters during the buck mode operation; and
a second current sensor configured to detect a current of a low voltage stage of each of the bidirectional DC-DC converters during a bidirectional operation.
12. The apparatus of claim 11 , wherein the microcomputer includes a microprogram for an interleaving control of the bidirectional DC-DC converters connected in parallel.
13. The apparatus of claim 11 , wherein the microcomputer is further configured to, when the one bidirectional DC-DC converter of the bidirectional DC-DC converters connected in parallel fails, separate the failed bidirectional DC-DC converter from the other bidirectional DC-DC converters.
14. The apparatus of claim 11 , wherein the microcomputer is further configured to check whether any one of the bidirectional DC-DC converters fails by receiving detected current and voltage values of each of the bidirectional DC-DC converters.
15. The apparatus of claim 11 , wherein the microcomputer is further configured to detect whether a low voltage stage of any one of the bidirectional DC-DC converters fails to protect a circuit of a high voltage stage thereof and separate the failed bidirectional DC-DC converter from other bidirectional DC-DC converters among the bidirectional DC-DC converters.
16. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , wherein the two or more bidirectional DC-DC converters have the same power circuit topology.
17. The parallel interleaving operated bidirectional DC-DC converter of claim 1 , comprising not more than three bidirectional DC-DC converters.