Bi-directional inverter-charger

• US 8,143,856 B2
• Filed: 09/11/2009
• Issued: 03/27/2012
• Est. Priority Date: 09/11/2008
• Status: Active Grant

• Current Assignee: Eetrex Incorporation
• Original Assignee: Betrex Corporation
• Inventors: Andrea, Davide, Emmerich, Robert D.
• Primary Examiner(s): RAMADAN, RAMY O
• Application Number:
  US12/558,458
• Publication Number:
  US 20100231173A1
• Time in Patent Office: 928 Days
• Field of Search: 320/109
• 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, the H-bridge rectifier 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;

a direct current voltage to direct current voltage converter (DC-to-DC converter) coupled between the H-bridge 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 a boost circuit operably coupled with the H-bridge, the H-bridge rectifier 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 a 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; and

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, the H-bridge configured to tie an alternating current voltage waveform to the alternating current voltage source.

2. The inverter charger of claim 1 further comprising a plurality of relays configured to switch the DC-to-DC converter between the charge configuration and the inverter configuration.

3. 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 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.

6. The inverter charger of claim 5 wherein the third control signal includes a dead band.

7. The inverter charger of claim 5 further comprising a controller configured to compare the output current of the buck circuit with a rectified line current reference voltage to provide the third control signal.

8. The inverter charger of claim 1 further comprising a controller configured to provide a control signal to the buck circuit in the inverter configuration to shut off the full wave rectified signal wave form to the H-bridge when the alternating current source current approaches zero.

9. The inverter charger of claim 8 wherein the controller includes a comparator configured to compare the alternating current voltage to a threshold value substantially similar to a zero crossing value of the line voltage, the comparator providing a control signal to the buck circuit to shut off the full wave rectified signal wave form to the H-bridge when the alternating current voltage sources meets the threshold value.

4. 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) coupled between the H-bridge 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 a boost circuit operably coupled with the H-bridge, the H-bridge rectifier 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 a 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, the H-bridge configured to tie an alternating current voltage waveform to the alternating current voltage source;

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; and

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.

10. A vehicle-to-grid inverter charger apparatus for a vehicle comprising:

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

a direct current voltage to direct current voltage converter (DC-to-DC converter) coupled between the H-Bridge circuit and a direct current chargeable voltage source having a direct current voltage, the DC-to-DC converter comprising a boost circuit and a buck circuit;

a switch arrangement coupled between the direct current chargeable voltage source and the DC-to-DC converter and between the DC-to-DC converter and the H-bridge rectifier circuit, the switch arrangement configured to arrange the boost circuit and the buck circuit to provide a charge current to the direct current chargeable voltage source and configured to arrange the boost circuit and the buck circuit to provide a source current to the H-bridge inverter circuit for vehicle-to-grid operation; and

a controller in communication with the DC-to-DC converter, the controller configured to synchronize a DC-to-DC converter output to the H-bridge during vehicle-to-grid operation such that a DC-to-DC output current waveform to the H-bridge provides an H-bridge output waveform that matches a waveform of the alternating current voltage source.

11. The vehicle-to-grid inverter charger apparatus of claim 10 wherein the controller configured to compare the DC-to-DC output current waveform to the H-bridge with a full wave rectified current reference to control a pulse width modulated control signal to a gate of the buck circuit.

12. The vehicle-to-grid inverter charger apparatus of claim 11 wherein the controller is configured to send a control signal to the DC-to-DC converter to shut off the output current to the H-bridge if the alternating current source voltage approaches zero.

13. The vehicle-to-grid inverter charger of claim 12 wherein:

the controller compares an alternating current reference source voltage to the source current to the H-bridge to provide the control signal to the DC-to-DC converter to shut off the output current to the H-bridge.