US 6,370,050 B1 · Isolated and soft-switched power converter

Abstract

An isolated and soft-switched power converter is used for DC/DC and DC/DC/AC power conversion. The power converter includes two resonant tank circuits coupled back-to-back through an isolation transformer. Each resonant tank circuit includes a pair of resonant capacitors connected in series as a resonant leg, a pair of tank capacitors connected in series as a tank leg, and a pair of switching devices with anti-parallel clamping diodes coupled in series as resonant switches and clamping devices for the resonant leg. The power converter is well suited for DC/DC and DC/DC/AC power conversion applications in which high-voltage isolation, DC to DC voltage boost, bidirectional power flow, and a minimal number of conventional switching components are important design objectives. For example, the power converter is especially well suited to electric vehicle applications and load-side electric generation and storage systems, and other applications in which these objectives are important. The power converter may be used for many different applications, including electric vehicles, hybrid combustion/electric vehicles, fuel-cell powered vehicles with low-voltage starting, remote power sources utilizing low-voltage DC power sources, such as photovoltaics and others, electric power backup systems, and load-side electric storage and generation systems.

Claims31

Dependent claims

An isolated and soft-switched power converter comprising:

an isolation transformer;
primary and secondary resonant tank circuits coupled back-to-back through the isolation transformer;
each resonant tank circuit comprising a pair of resonant capacitances present in series as a resonant leg, a pair of voltage sources connected in series as a tank leg, and a pair of switching devices coupled in series as resonant switches and voltage clamping devices for the resonant leg wherein each of the resonant leg, tank leg, and pair of switching devices and voltage clamping devices are connected in parallel to each other;
and
a switching controller operable for,
gating off the switching devices to cause a resonant voltage to resonant in each resonant leg, the resonant voltage repeatedly obtaining zero-voltage periods for soft-switching a device powered by the converter, and
gating on the switching devices during zero-current, zero-voltage conditions for soft-switching the switching devices of each resonant tank circuit.

4 more elements

An isolated and soft-switched power converter, comprising:

an isolation transformer including a primary input node, a primary output node, a secondary input node, and a secondary output node;
a primary resonant tank circuit comprising,
a primary top rail,
a primary center rail,
a primary bottom rail,
a first primary resonant capacitance present between the primary top rail and the primary center rail,
a second primary resonant capacitance present between the primary center rail and the primary bottom rail,
a first primary resonant switch connected between the primary top rail and the primary center rail,
a second primary resonant switch connected between the primary center rail and the primary bottom rail,
a first primary clamping diode connected between the primary high-voltage rail and the primary center rail,
a second primary clamping diode connected between the primary center rail and the primary bottom rail,
a first primary tank capacitor connected between the primary top rail and a primary tap node,
a second primary tank capacitor connected between the primary tap node and the primary bottom rail,
the primary center rail being connected to the primary input node of the isolation transformer, and
the primary tap node being connected to the primary output node of the isolation transformer;
and
a secondary resonant tank circuit comprising,
a secondary top rail,
a secondary center rail,
a secondary bottom rail,
a first secondary resonant capacitance present between the secondary top rail and the secondary center rail,
a second secondary resonant capacitance present between the secondary center rail and the secondary bottom rail,
a first secondary clamping diode connected between the secondary top rail and the secondary center rail,
a first secondary tank capacitor connected between the secondary top rail and a secondary tap node,
a second secondary tank capacitor connected between the secondary tap node and the secondary bottom rail,
the secondary center rail being connected to the secondary input node of the isolation transformer, and
the secondary tap node being connected to the secondary output node of the isolation transformer.

24 more elements

An isolated and soft-switched power converter, comprising:

an isolation transformer including a primary input node, a primary output node, a secondary input node, and a secondary output node;
a primary resonant tank circuit comprising,
a primary top rail,
a primary center rail,
a primary bottom rail,
a first primary resonant capacitance present between the primary top rail and the primary center rail,
a second primary resonant capacitance present between the primary center rail and the primary bottom rail,
a first primary resonant switch connected between the primary top rail and the primary center rail,
a second primary resonant switch connected between the primary center rail and the primary bottom rail,
a first primary clamping diode connected between the primary top rail and the primary center rail,
a second primary clamping diode connected between the primary center rail and the primary top rail,
a first primary tank capacitor connected between the primary top rail and a primary bottom node,
a second primary tank capacitor connected between the primary tap node and the primary bottom rail,
the primary center rail being connected to the primary input node of the isolation transformer,
the primary tap node being connected to the primary output node of the isolation transformer,
a primary bottom-rail terminal connected to the primary bottom rail for connection to a low-potential terminal of a DC voltage source;
a primary center-rail terminal for connection to a high-potential terminal of the DC voltage source, and
an inductor connected in series between the primary center-rail terminal and the primary center rail;
a secondary resonant tank circuit comprising,
a secondary top rail,
a secondary center rail,
a secondary bottom rail,
a first secondary resonant capacitance present between the secondary top rail and the secondary center rail,
a second secondary resonant capacitance present between the secondary center rail and the secondary bottom rail,
a first secondary clamping diode connected between the secondary top rail and the secondary center rail,
a second secondary clamping diode connected between the secondary center rail and the secondary bottom rail,
a first secondary resonant switch connected between the secondary top rail and the secondary center rail,
a second secondary resonant switch connected between the secondary center rail and the secondary bottom rail,
a first secondary tank capacitor connected between the secondary top rail and a secondary tap node,
a second secondary tank capacitor connected between the secondary tap node and the secondary bottom rail,
the secondary center rail being connected to the secondary input node of the isolation transformer, and
the secondary tap node being connected to the secondary output node of the isolation transformer;
and
a switching controller operable for gating the first and second primary switches to cause
a primary resonant voltage to resonate between the first primary resonant capacitance and the second primary resonant capacitance,
a secondary resonant voltage to resonate between the first secondary resonant capacitance and the second secondary resonant capacitance, and
the secondary resonant voltage repeatedly obtaining zero-voltage intervals for soft-switching a device connected between the secondary center rail and the secondary bottom rail.

34 more elements

Dependencies are inferred from the claim text.

Isolated and soft-switched power converter

Life of this patent

Isolated and soft-switched power converter

Life of this patent

Abstract

Claims31