Digital control of switched boundary mode interleaved power converter
A circuit arrangement, a signal processor, and a method of interleaved switched boundary mode power conversion are disclosed. The circuit arrangement comprises at least an input for receiving an input voltage from a power supply; an output to provide an output voltage to a load; a first interleaved circuit comprising a first energy storage device and a first controllable switching device; one or more secondary interleaved circuits, each comprising a secondary energy storage device, and a secondary controllable switching device; and a signal processor, connected to the controllable switching devices. The signal processor comprises a first switching cycle controller, configured for cycled zero-current switching operation of the first controllable switching device; and one or more secondary switching cycle controllers, configured for cycled zero-current switching operation of the secondary controllable switching devices. The signal processor is configured to control, in a given switching cycle, an on-time period of each of the secondary controllable switching devices to correspond to an on-time period of the first controllable switching device. The signal processor is further configured to control phases between the on-time periods of the first and the one or more secondary switching controllers, so that the on-time periods are distributed over the given switching cycle to reduce an overall current ripple at the input.
1. A circuit arrangement for interleaved switched boundary mode power conversion, comprising at least: an input for receiving an input voltage from a power supply; an output to provide an output voltage to a load; a first interleaved circuit comprising: a first energy storage device; and a first controllable switching device; one or more secondary interleaved circuits, each comprising: a secondary energy storage device; and a secondary controllable switching device; said circuit arrangement further comprising a signal processor, connected to the first controllable switching device and the secondary controllable switching device; the signal processor comprising a first switching cycle controller, configured for cycled zero-current switching operation of the first controllable switching device; and one or more secondary switching cycle controllers, configured for cycled zero-current switching operation of the secondary controllable switching device, wherein the signal processor is configured to control, in a given switching cycle, an on-time period of the secondary controllable switching device to correspond to an on-time period of the first controllable switching device; and wherein the signal processor is further configured to control the phase of the on- time period of at least one secondary controllable switching device with respect to the first controllable switching device to correspond to (n−1)/N*360, where N is a total number of interleaved circuits and n is an index number of a respective secondary interleaved circuit of the secondary controllable switching device.
2. The circuit arrangement of claim 1 , wherein the signal processor during zero-current switching is configured to control the first and secondary switching devices at least at one zero-current point of an associated energy storage device.
3. The circuit arrangement of claim 2 , wherein the signal processor is configured to control the first and secondary switching devices from an off-state to an on-state at the at least one zero-current point.
4. The circuit arrangement of claim 1 , wherein the signal processor is configured to control the on-time periods to correspond to each other in every switching cycle.
5. The circuit arrangement of claim 1 , wherein the signal processor is configured to control the phases between the on-time periods of the first and the secondary switching device in every switching cycle.
6. The circuit arrangement of claim 1 , wherein each of the first and one or more secondary switching cycle controllers is configured for PWM operation of an associated controllable switching device.
7. The circuit arrangement of claim 1 , wherein the signal processor comprises a delay module, configured so that at least one switching point is delayed for a predetermined delay time.
8. The circuit arrangement of claim 1 , wherein each of the first and the one or more secondary interleaved circuits comprises an energy storage current sensor, connected with the signal processor to determine at least one zero-current point of an associated energy storage device.
9. The circuit arrangement of claim 1 , wherein the signal processor is configured to determine the on-time period of the first controllable switching device from one or more of the input voltage, the output voltage, and a reference output voltage.
10. The circuit arrangement of claim 1 , wherein the signal processor is configured to determine a switching cycle period of the first interleaved circuit from a previous switching cycle of the first interleaved circuit.
11. The circuit arrangement of claim 1 , wherein
the first switching cycle controller is configured for PWM operation, wherein the first controllable switching device is set to an on-state at a zero-current point of the first energy storage device; and wherein
the one or more secondary switching cycle controllers are configured for PWM operation with a phase of
(
n
-
1
)
N
*
360
,
where N is the total number of interleaved circuits and n is an index number of the respective secondary switching cycle controller.
12. The circuit arrangement of claim 1 , wherein
the first switching cycle controller is configured for PWM operation, wherein the first controllable switching device is set to an on-state at a zero-current point of the first energy storage device; wherein two subsequent zero-current points define a switching cycle period of the first interleaved circuit; and wherein
the signal processor comprises a PWM module, configured to trigger an intermediate PWM cycle upon an on-state transition of the first controllable switching device and to conduct a phase state transition at half of the switching cycle period of the first interleaved circuit; and wherein
one of the secondary switching cycle controllers is configured for PWM operation, wherein an associated controllable switching device is set to an on-state upon the phase state transition of the intermediate PWM cycle.
13. The circuit arrangement of claim 1 , wherein the signal processor is further configured to receive input voltage and output voltage information and to determine at least one zero-current point from the input voltage and output voltage information.
14. The circuit arrangement of claim 1 , wherein the signal processor further comprises a limiter, configured to provide maximum on-time information to a PWM module.
15. The circuit arrangement of claim 1 , wherein the circuit arrangement is a boost converter.
16. The circuit arrangement of claim 1 , further comprising a rectifier circuit to rectify an AC input voltage.
17. A signal processor for use in a circuit arrangement for interleaved switched boundary mode power conversion with at least a first controllable switching device and one or more secondary controllable switching devices; said signal processor being connectable to the first and one or more secondary controllable switching devices and being configured for zero-current switching of the switching devices; wherein the signal processor comprises at least; a first switching cycle controller, configured for cycled zero-current switching operation of the first controllable switching device; and one or more secondary switching cycle controllers, configured for cycled zero-current switching operation of the secondary controllable switching devices, wherein the signal processor is configured to control, in a given switching cycle, an on-time period of each of the secondary controllable switching devices to correspond to an on-time period of the first controllable switching device; and wherein the signal processor is further configured to control the phase of the on-time period of at least one secondary controllable switching device with respect to the first controllable switching device to correspond to (n−1)/N*360, where N is a total number of interleaved circuits and n is an index number of a respective secondary interleaved circuit of the secondary controllable switching device.
18. A method of interleaved switched boundary mode power conversion with a circuit comprising an input for receiving an input voltage from a power supply; an output to provide an output voltage to a load; a first controllable switching device; and one or more secondary controllable switching devices; wherein in a given switching cycle, an on-time period of each of the secondary controllable switching devices is controlled to correspond to an on-time period of the first controllable switching device; and wherein a phase of the on-time period of at least one secondary controllable switching device with respect to the first controllable switching device is controlled to correspond to (n−1)/N*360, where N is a total number of interleaved circuits and n is an index number of a respective secondary interleaved circuit of the secondary controllable switching device.
19. A non-transitory machine-readable medium including contents that are configured to cause a signal processor to conduct the method of claim 18 .