Zero voltage switching operation of a minimum current trajectory for a DC-to-DC converter

Patent metadata

Field	Value
Publication number	US-9595873-B2
Application number	US-201514728890-A
Country	US
Kind code	B2
Filing date	Jun 2, 2015
Priority date	Jun 2, 2014
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

An apparatus for zero voltage switching is disclosed. A system and method also perform the functions of the apparatus. The apparatus includes an MCT region module that defines a minimum current trajectory (“MCT”) for operation between a maximum positive power output to a maximum negative power output of a bidirectional DC-to-DC converter. The converter includes a dual active bridge series resonant converter. The MCT defines a boundary between a zero voltage switching (“ZVS”) region and a hard switching region. The apparatus includes an offset module that defines an offset to the MCT, the offset in the ZVS region, and an MCT control module that adjust switching of switches of the converter to maintain operation of the converter in the ZVS region between the maximum positive power output to a maximum negative power output along a trajectory defined by the MCT and the offset.

First claim

What is claimed is:

1. An apparatus comprising:
an MCT region module that defines a minimum current trajectory (“MCT”) for operation between a maximum positive power output to a maximum negative power output of a bidirectional direct current (“DC”) to DC converter, the converter comprising a dual active bridge series resonant converter (“DABSRC”), the MCT defining a boundary between a zero voltage switching (“ZVS”) region and a hard switching region;
an offset module that defines an offset to the MCT, the offset in the ZVS region; and
an MCT control module that adjust switching of switches of the converter to maintain operation of the converter in the ZVS region between the maximum positive power output to a maximum negative power output along a trajectory defined by the MCT and the offset.

2. The apparatus of claim 1 , wherein the MCT control module further comprises one or more phase shift modulators that control switching of the switches of the converter by controlling a plurality of angles between switching legs of the converter, each switching leg comprising two switches connected in series between positive and negative connections to the switching leg.

3. The apparatus of claim 2 , wherein the MCT control module adjusts an angle φ AB , and angle φ DC , and an angle φ AD , wherein:
angle φ AB comprises a phase angle between a voltage at a midpoint between switches of a first switching leg of the converter, ν A , and a voltage at a midpoint between the switches of a second switching leg of the converter, ν B , the first and second switching legs comprising a full bridge switching network on a primary side of the converter;
angle φ DC comprises a phase angle between a voltage at a midpoint between switches of a third switching leg of the converter, ν D , and a voltage at a midpoint between switches of a fourth switching leg of the converter, ν C , the third and fourth switching legs comprising a full bridge switching network on a secondary side of the converter; and
angle φA D comprises a phase angle between the voltage ν A and the voltage ν D .

4. The apparatus of claim 3 , wherein the MCT is defined as

min

v
φ

⁢

(

I
RMS

⁡

(

v
φ

)

)

⁢

:

⁢

⁢

{

P
OUT

⁡

(

v
φ

)

=

P
OUT

-

P
OUT
MAX

≤

P
OUT

≤

+

P
OUT
MAX

which when solved for solved for P OUT ε[−P OUT MAX , P OUT MAX ], yields a parameterized curve v φ,MCT (P OUT ) in a control space comprising the MCT,
where:
P OUT is output power of the converter;
P OUT MAX is maximum positive output power of the converter;
−P OUT MAX is a maximum negative output power of the converter;
I RMS (v φ ) is current in a tank, the tank comprising converter components connected between the midpoints of the switching legs;
v φ is an operating vector v φ =(φ AD , φ AB , φ DC ).

5. The apparatus of claim 4 , wherein the MCT changes based on a conversion ratio defined by:

M
≡

1
n

·

V
out

V
g

where
n is a turns ratio of a transformer of the converter, wherein n=1 for a converter topology without a transformer;
V out is output voltage of the converter; and
V g is input voltage of the converter,
and wherein when M<1, the MCT involves the modulation of both angles φ AD and φ AB , when M>1 both angles φ AD and φ DC are modulated, and when M=1, angle |φ AD |≦90° controls active power flow of the converter, while φ AB =φ DC =180°.

6. The apparatus of claim 1 , wherein the offset comprises a fixed offset from the MCT in the ZVS region.

7. The apparatus of claim 1 , wherein the offset comprises a variable offset from the MCT in the ZVS region, wherein the offset decreases as output power increases.

8. The apparatus of claim 1 , wherein the MCT control module comprises a feed forward control loop and further comprising a constant current module that limits output current to a positive output current setpoint in a range between a minimum output voltage and output power of the converter reaching a positive power setpoint, wherein the constant current module comprises a current feedback control loop that limits output current to below the positive output current setpoint.

9. The apparatus of claim 8 , further comprising:
a voltage regulation module that controls output voltage of the converter to an output voltage setpoint over an output current range between an operating condition where output power of the converter reaches a positive power setpoint and output power of the converter reaches a negative power setpoint;
a positive power regulation module that controls output power of the converter to the positive power setpoint over a positive constant power range between the output voltage of the converter being at the output voltage setpoint and output current of the converter being at a positive output curre

Assignees

• Univ Utah State
• Raytheon Co
• Regents Of The Univ Of Colorado

Inventors

• Zane Regan A
• Seltzer Daniel
• Maksimovic Dragan
• Jacobson Boris
• Desrosiers Donald

Classifications

• H02M1/4241

  using a resonant converter · CPC title

• H02M3/1584

  with a plurality of power processing stages connected in parallel · CPC title

• H02M3/33592

  having a synchronous rectifier circuit or a synchronous freewheeling circuit at the secondary side of an isolation transformer · CPC title

• H02M7/5387

  in a bridge configuration · CPC title

• H02M3/285

  Single converters with a plurality of output stages connected in parallel (parallel operation of a plurality of converters in DC distribution networks H02J1/10) · CPC title