Bi-directional inverter-charger

• US 8,816,641 B2
• Filed: 03/23/2012
• Issued: 08/26/2014
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Davide Andrea, Robert D. Emmerich
• Original Assignee: Davide Andrea, Robert D. Emmerich
• Inventors: Andrea, Davide, Emmerich, Robert D.
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): GRANT, ROBERT J
• Application Number:
  US13/428,252
• Publication Number:
  US 20120176090A1
• Time in Patent Office: 886 Days
• Field of Search: 320/128
• US Class Current: 320/128
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 7/797 using semiconductor devices only

Abstract

A bi-directional inverter-charger including a bridge rectifier and DC-to-DC conversion components. The inverter-charger may be connected between an alternating current source, e.g., an AC line, and a direct current source, e.g., a battery pack. The DC-to-DC conversion components may include boost and buck circuits that are switchably configured between a charge mode and an inverter mode such that common components are used in both charge and inverter configurations. In the charge configuration, a full wave rectified signal from the H-bridge is up converted by the boost circuit, and the buck circuit controls charge current to the direct current source. In the inverter configuration, the boost circuit up converts the direct current voltage source, and the buck circuit controls the current and its form to the bridge circuit so that the bridge circuit may be Connected directly with the AC source.

Claims

1. An inverter charger for providing a bi-directional energy flow between an alternating current source and a direct current chargeable voltage source, the inverter charger comprising:

an H-bridge rectifier inverter circuit coupled with an alternating current voltage source;

a direct current voltage to direct current voltage converter (DC-to-DC converter) comprising a boost circuit and a buck circuit, coupled between the H-bridge rectifier inverter circuit and a direct current chargeable voltage source having a direct current voltage, the DC-to-DC converter switchable between a charge configuration and an inverter configuration;

the charge configuration including the boost circuit operably coupled with the H-bridge rectifier inverter circuit, the H-bridge rectifier inverter circuit providing a full wave rectified output signal to the boost circuit, the boost circuit configured to up convert the full wave rectified output signal, the charge configuration further including the buck circuit operably coupled with the boost circuit, the buck circuit configured to provide a regulated charge current to the direct current chargeable voltage source;

the inverter configuration including the boost circuit operably coupled with the direct current chargeable voltage source, the boost circuit configured to up convert the direct current voltage of the direct current chargeable voltage source, and the buck circuit configured to provide a full wave rectified signal wave form to the H-bridge rectifier inverter circuit, the H-bridge rectifier inverter circuit configured to tie an alternating current voltage waveform to the alternating current voltage source; and

a plurality of switches configured to switch the DC-to-DC converter between the charge configuration and the inverter configuration by;

connecting an input of the boost circuit to the H-bridge rectifier circuit and an output of the buck circuit to the direct current chargeable voltage source in the charge configuration; and

connecting the input of the boost circuit to the direct current chargeable voltage source and the output of the buck circuit to the H-bridge rectifier circuit in the inverter configuration.

2. The inverter charger of claim 1 wherein the plurality of switches comprise a plurality of relays.

3. The inverter charger of claim 1 wherein the H-bridge rectifier inverter circuit comprises four sets of three parallel connected power MOSFETS connected in a full wave H-bridge configuration, with each MOSFET operating synchronously with the alternating current voltage source wave form to produce a full wave rectified output of the alternating current voltage source.

4. The inverter charger of claim 1 further comprising control signals to the MOSFETS, wherein the control signals provide a dead band where all MOSFETS are off for a period of time around a zero crossing point of the alternating current voltage source.

5. The inverter charger of claim 1 wherein:

the inverter charger further comprises a negative rail;

the boost circuit comprises a first inductor and a first diode coupled in series, and a first capacitor connected with the first inductor, the boost circuit further comprising a first switch connected between the first inductor and first diode, and the negative rail, the first switch in parallel with the first capacitor, the first switch receiving a first control signal to up convert the full wave rectified output signal when the inverter charger is in the charge configuration or to up convert the direct current voltage of the direct current chargeable voltage source when the inverter charger is in the inverter configuration.

6. The inverter charger of claim 5 further comprising:

a DC Link capacitor in parallel with the boost circuit; and

a boost circuit controller comprising a limiter circuit including a first comparator that generates a first output value as function of whether a boost circuit current output exceeds a maximum boost circuit current threshold and a second comparator that generates a second output value as a function of whether the up converted full wave rectified signal at the DC link capacitor exceeds a maximum boost circuit voltage threshold, wherein the limiter circuit causes the control signal to turn off the boost circuit switch when the first output value and/or the second output values indicates that the maximum boost circuit current and/or maximum boost circuit voltage is met.

7. The inverter charge of claim 1 wherein:

the inverter charger further comprises a negative rail;

the buck circuit comprises a second switch in series with a second inductor, and a second diode connected between the second switch and the second inductor and the negative rail;

the second switch receiving a second control signal for generating a specified charge current output of the buck circuit in the charge configuration; and

the second switch receiving a third control signal for generating a rectified sine wave input current to the bridge in the inverter configuration.

8. The inverter charger of claim 7 wherein the third control signal includes a dead band.