Energy storage and hold-up method and apparatus for high density power conversion

• US 20050254272A1
• Filed: 04/19/2005
• Published: 11/17/2005
• Est. Priority Date: 02/24/2004
• Status: Active Grant

• Current Assignee: Vicor Corporation
• Original Assignee: VLT Incorporated (Vicor Corporation)
• Inventors: Vinciarelli, Patrizio
• Granted Patent: US 7,408,795 B2
• Time in Patent Office: Days
• US Class Current: 363/65
• CPC Class Codes: H02M 1/0074 Plural converter units whose inputs are connected in series
• CPC Class Codes: H02M 1/0077 Plural converter units whose outputs are connected in series
• CPC Class Codes: H02M 1/0096 Means for increasing hold-up time, i.e. the duration of time that a converter's output will remain within regulated limits following a loss of input power
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/1584 with a plurality of power processing stages connected in parallel
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer

Abstract

A method and apparatus for adaptively configuring an array of voltage transformation modules is disclosed. The aggregate voltage transformation ratio of the adaptive array is adjusted to digitally regulate the output voltage for a wide range of input voltages. An integrated adaptive array having a plurality of input cells, a plurality of output cells, or a plurality of both is also disclosed. The input and output cells may be adaptively configured to provide an adjustable transformer turns ratio for the adaptive array or in the case of an integrated VTM, an adjustable voltage transformation ratio for the integrated VTM. A controller is used to configure the cells and provide digital regulation of the output. A converter having input cells configured as a complementary pair, which are switched out of phase, reduces common mode current and noise. Series connected input cells are used for reducing primary switch voltage ratings in a converter and enabling increased operating frequency or efficiency. An off-line auto-ranging power supply topology is disclosed. An auto-ranging converter module (“ACM”) includes 2 or more input cells magnetically coupled to an output cell providing auto-ranging, isolation, and voltage transformation. The ACM converts a rectified line voltage to a low DC bus voltage. The topology allows regulation and power factor correction to be provided at a low voltage increasing energy density and efficiency and reducing cost. A fully integrated PCM may also include a hold-up circuit, a DC input, and a power regulator with or without power factor correction. A PCM with PFC may combine the hold-up and smoothing capacitors for further increases in power density.

Claims

114. A method of converting power from a source at a source voltage for delivery to a load at a load voltage, where the source voltage may vary between a high line voltage and a low line voltage in a normal operating range, comprising:

providing DC-DC voltage transformation and isolation in a first power conversion stage, the first stage having a CA input for receiving power from the source and a CA output;

providing power regulation in a second power conversion stage having a PR input for receiving power from the CA output of the first stage, regulation circuitry, and a PR output for delivering power to the load;

the regulation circuitry being adapted to maintain the load voltage within a regulation range while the PR input voltage remains within a normal operating range;

providing a hold-up circuit having a charge path and a discharge path for connection to a hold-up capacitance, the discharge path providing a low impedance connection between the hold-up capacitance and the PR input for supplying power to the power regulator, the charge path providing a charge current to charge the hold-up capacitance;

configuring the hold-up circuit to charge the hold-up capacitance when a first predetermined condition is satisfied and to provide power to the PR input when a second predetermined condition is satisfied.

115. The method of claim 114 wherein the providing DC-DC voltage transformation and isolation further comprises providing an integrated adaptive converter array having a first input cell and a second input cell, each input cell having a respective number, P_x, of turns, an output cell having a respective number, S_x, of turns, magnetic coupling between the turns to form a transformer common to the first and second input cells and the output cell;

and further comprising;

configuring the input cells in a parallel connection for operation at the low line voltage and in a series connection for operation at the high line voltage.

116. The method of claim 114 wherein the providing DC-DC voltage transformation and isolation further comprises:

providing an array of two or more VTMs, each VTM having an input, an output, and a substantially fixed voltage transformation ratio, K=V_out/V_in, over the normal operating range, where V_in is the voltage across the respective VTM input and V_out is the voltage across the respective VTM output, and providing isolation between its input and its output; and

configuring the inputs of the VTMs in a parallel connection for operation at the low line voltage and in a series connection for operation at the high line voltage.

117. The method of claim 114, 115, or 116 further comprising providing circuitry for performing the method in a self-contained assembly having terminals for connecting to the CA input, the PR output, and the hold-up circuit, for installation as a unit, and providing the hold-up capacitor as a component external to the assembly.

118. The method of claim 114 further comprising providing control circuitry adapted to detect the first and second predetermined conditions and to configure the hold-up circuit.

119. The method of claim 118 wherein the control circuitry is adapted to detect an error signal from the regulation circuitry and the second predetermined condition comprises the error signal being outside a predetermined range.

120. The method of claim 118 wherein the second predetermined condition comprises the source voltage being below a first predetermined level and the hold-up capacitor being charged above a second predetermined level.

121. The method of claim 114 further comprising providing a DC input for receiving power from an external DC source directly coupled to the second power conversion stage.

122. The method of claim 121 wherein the DC input is connected to the PR input via the discharge path.

123. The method of claim 121 wherein the DC input is connected to the PR input via switch circuitry capable of blocking current flow in both directions when OFF and conducting current in both directions when ON;

and further comprising turning the switch circuitry ON to connect the external DC source to the PR input.

124. The method of claim 118 wherein the hold-up circuit comprises switch circuitry capable of blocking current flow in both directions when OFF and conducting current in both directions when ON;

and further comprising controlling the switch circuitry to provide the charge path and the discharge path.

125. The method of claim 118 further comprising providing a switch in the discharge path for connecting the hold-up capacitance to the PR input when the switch is ON.

126. The method of claim 125 wherein the hold-up circuit comprises a current limiting element in the charge path.

127. The method of claim 118, 122, or 125 further comprising providing power factor correction in the power regulator and providing a smoothing capacitance at the PR output.

128. The method of claim 127 further comprising providing a boost circuit having an output connected to charge the hold-up capacitance.

129. The method of claim 128 wherein the boost circuit comprises an input connected to the PR output.

130. The method of claim 127 further comprising providing circuitry to switch a single capacitance between a first configuration and a second configuration wherein the capacitance is connected to the PR output as the smoothing capacitance in the first configuration and is connected to the hold-up circuit as the hold-up capacitance in the second configuration.

131. A method of converting power from an AC source for delivery to a system including a load, the method comprising:

providing a power converter module (“

PCM”

) having input terminals for receiving power from the source, output terminals for delivering power to a load at a regulated DC voltage, and power conversion circuitry, the PCM being a self-contained assembly adapted to be installed as a unit;

the power conversion circuitry comprising DC-DC voltage transformation (“

VT”

) circuitry and power regulation (“

PR”

) circuitry,

the VT circuitry having an input connected to the input terminals and an output for delivering power to the PR circuitry and providing voltage transformation and isolation;

the PR circuitry having an output connected to the output terminals and providing output regulation;

providing a capacitive energy storage component for the isolated side of the power conversion circuitry, the capacitive energy storage component being external to the PCM.

132. The method of claim 131 wherein the VT circuitry further comprises an integrated adaptive converter array having a first input cell and a second input cell, each input cell having a respective number, P_x, of turns, an output cell having a respective number, S_x, of turns, magnetic coupling between the turns to form a transformer common to the first and second input cells and the output cell;

and control circuitry for configuring the input cells in a parallel connection for operation at a low line voltage and in a series connection for operation at a high line voltage.

133. The method of claim 131 wherein the VT circuitry further comprises an array of two or more VTMs, each VTM having an input, an output, and a substantially fixed voltage transformation ratio, K=V_out/V_in, over the normal operating range, where V_in is the voltage across the respective VTM input and V_out is the voltage across the respective VTM output, and providing isolation between its input and its output;

and control circuitry for configuring the VTMs in a parallel connection for operation at a low line voltage and in a series connection for operation at a high line voltage.

134. The method of claim 131 wherein the PR circuitry further comprises a buck-boost converter with PFC circuitry.

135. The method of claim 131 wherein the power conversion circuitry further comprises a hold-up switch connected between a hold-up terminal and the PR input and a smoothing switch connected between the hold-up terminal and the PR output;

and wherein the PR circuitry further comprises power factor correction circuitry, the PCM requiring a single external capacitive energy storage component connected to the hold-up terminal.

136. The method of claim 131 wherein the power conversion circuitry further comprises a hold-up switch connected between a hold-up terminal and the PR input and the capacitive energy storage component is connected to the hold-up terminal to provide power to the PR input.

137. The method of claim 131 wherein the PR circuitry further comprises power factor correction circuitry, and the external capacitive energy storage component is connected to PR output as a smoothing capacitor.