On-board charger for vehicle battery and method of charging and using vehicle battery
An electric vehicle that includes an on-board charger for a battery of an electric vehicle. The electric vehicle includes an AC machine and an inverter drive for the AC machine. The on-board charger includes an integrated active filter rectifier coupled to a DC/DC converter. The integrated active filter rectifier is configured to use at least one phase inductor of the AC machine and at least one leg of the inverter drive to perform power factor correction. The on-board charger is a non-isolated converter that renders both operations of traction and charging from both single-phase and three-phase grids. Moreover, the on-board charger performs fast AC charging without generating shaft torque during charging.
1 . An onboard charger for charging a battery of an electric vehicle, comprising:
a DC/DC converter;
an integrated active filter rectifier coupled to produce a DC signal to the DC/DC converter;
wherein the integrated active filter rectifier is coupled to use at least one phase inductor (La, Lb, Lc) of an AC machine of the electric vehicle and at least one leg of an inverter drive to perform power factor correction; and
wherein the integrated active filter rectifier includes a pair of active power switches for each phase (a, b, c) of a three-phase mains power supply, and each of the pairs of active power switches are coupled together at a common point, the common point being coupled to one of:
a neutral terminal of the AC machine; or
one of the phases (La, Lb, Lc) of the AC machine.
2 . The on-board charger of claim 1 , wherein the integrated active filter rectifier includes at least one pair of diodes for each phase of a three-phase mains power supply.
3 . The on-board charger of claim 2 , wherein the integrated active filter rectifier includes an active power switch in parallel with each of the diodes.
4 . The on-board charger of claim 3 , wherein each active power switch comprises a MOSFET device, and the diodes are provided by intrinsic body diodes of the MOSFET devices.
5 . The on-board charger of claim 3 , wherein the DC/DC converter is a bidirectional device.
6 . The on-board charger according to claim 1 , further comprising a first capacitor (C 1 ) connected across an input of the DC/DC converter, wherein the first capacitor is coupled to support commutation of switches of the inverter drive.
7 . The on-board charger of claim 6 , wherein the on-board charger is so configured that a second capacitor having a greater capacitance than the first capacitor is connected in parallel with the first capacitor while the AC machine is in propulsion mode.
8 . The on-board charger according to claim 1 , wherein the DC/DC converter is configurable to provide an internal path for current to flow from an output stage of the DC/DC converter to the AC machine in propulsion mode.
9 . The on-board charger according to claim 1 , wherein a switching device is provided to enable the DC/DC converter to be bypassed while the AC machine is propelling the electric vehicle but not when the on-board charger is providing charging current to the battery of the electric vehicle.
10 . The on-board charger according to claim 1 , wherein a second capacitor is coupled across the output of the DC/DC converter, and the DC/DC converter to supply energy from the second capacitor to the output of the first stage of the on-board charger during charging.
11 . The on-board charger of on claim 1 , wherein the on-board charger is coupled to support charging from a single-phase AC power supply by using the integrated active filter rectifier as a bridgeless totem-pole power factor correction rectifier.
12 . The on-board charger of claim 11 , wherein the on-board charger includes a control arrangement to modulate at least one leg of the bridge at high frequency to generate a sinusoidal current through a corresponding phase inductor of the AC machine.
13 . The on-board charger of claim 1 , wherein the on-board charger is coupled to support charging from a DC power supply by using the integrated active filter rectifier as a DC/DC converter.
14 . The on-board charger of claim 13 , wherein the on-board charger includes a control arrangement to modulate at least one leg of the bridge at high frequency to control a direct current through a corresponding phase inductor of the AC machine.
15 . A method of charging a battery of an electric vehicle that includes an AC machine, an inverter drive for the AC machine, and an on-board charger, the method comprising:
coupling an input of an integrated active filter rectifier to a single-phase or three-phase AC power supply network or a DC power supply;
feeding a DC/DC converter with an output of the integrated active filter rectifier;
supplying an output of the DC/DC converter to a battery of the electric vehicle;
wherein the integrated active filter rectifier is configured to use at least one phase inductor of the AC machine and at least one leg of the inverter drive to perform power factor correction; and
coupling a second capacitor across the output of the DC/DC converter, and the DC/DC converter to supply energy from the second capacitor to the output of the first stage of the on-board charger during charging.
16 . A method of using a battery of an electric vehicle as a power source for powering external loads, the electric vehicle including an AC machine, an inverter drive for the AC machine, and an on-board charger, the on-board charger including:
an integrated active filter rectifier coupled to a DC/DC converter;
wherein the integrated active filter rectifier is configured to use at least one phase inductor (La, Lb, Lc) of the AC machine and at least one leg of the inverter drive to perform power factor correction;
the method comprising:
coupling an input of the integrated active filter rectifier to a single-phase or three-phase AC load or a DC load;
feeding an output of the integrated active filter rectifier from an input of the DC/DC converter; and
supplying an output of the DC/DC converter from the battery of the electric vehicle; and
coupling a second capacitor having a greater capacitance than the first capacitor in parallel with the first capacitor while the AC machine is in propulsion mode.
17 . An electric vehicle, comprising:
an AC machine to propel the electric vehicle;
a battery for storing charge for use by the AC machine;
an inverter drive for converting stored charge to an AC voltage for the AC machine; and
an onboard charger for charging the battery from a power source, the on-board charger further comprising:
a DC/DC converter;
an integrated active filter rectifier coupled to the DC/DC converter; and
wherein the integrated active filter rectifier is configured to use at least one phase inductor (La, Lb, Lc) of the AC machine and at least one leg of the inverter drive to perform power factor correction; and
wherein the integrated active filter rectifier includes a pair of active power switches for each phase (a, b, c) of a three-phase mains power supply, and each of the pairs of active power switches are coupled together at a common point, the common point being coupled to one of:
a neutral terminal of the AC machine; or
one of the phases (La, Lb, Lc) of the AC machine.
18 . An onboard charger for charging a battery of an electric vehicle, comprising:
a DC/DC converter;
an integrated active filter rectifier coupled to produce a DC signal to the DC/DC converter;
wherein the integrated active filter rectifier is coupled to use at least one phase inductor (La, Lb, Lc) of an AC machine of the electric vehicle and at least one leg of an inverter drive to perform power factor correction; and
wherein the on-board charger is configured to selective couple a second capacitor having a greater capacitance than the first capacitor in parallel with the first capacitor while the AC machine is in propulsion mode.