Active ripple energy storage circuit implementation using the inverter system controller and electric machine
An automotive power system has circuitry, including a capacitor, inductor, and switch in series, connected such that a terminal of the switch is directly connected with only one phase leg of an inverter system controller between an electric machine and the inverter system controller and a terminal of the capacitor is referenced to a negative terminal of a traction battery. The switch is closed while the traction battery is being charged with energy from an AC grid, and open while the traction battery is not being charged.
1 . A vehicle comprising:
a traction battery;
an electric machine;
an inverter system controller connected between the traction battery and electric machine;
circuitry, including a capacitor, inductor, and switch in series, connected such that a terminal of the switch is directly connected with only one phase leg of the inverter system controller between the electric machine and inverter system controller and a terminal of the capacitor is referenced to a negative terminal of the traction battery; and
a controller programmed to close the switch while the traction battery is being charged with energy from an AC grid, and to open the switch while the traction battery is not being charged.
2 . The vehicle of claim 1 , wherein the electric machine includes Y-connected windings.
3 . The vehicle of claim 2 , wherein the controller is further programmed to activate switches of the only one phase leg to control current generated by the inverter system controller while the traction battery is being charged.
4 . The vehicle of claim 2 , wherein the controller is further programmed to operate the inverter system controller to generate AC current that is synchronized with a voltage of the AC grid.
5 . The automotive power system of claim 2 further comprising other circuitry configured to transfer power from the AC grid to the traction battery, wherein the controller is further programmed to operate the inverter system controller to generate AC current that is synchronized with AC current generated by the other circuitry.
6 . The automotive power system of claim 5 , wherein the other circuitry defines a battery current control module.
7 . The automotive power system of claim 2 , wherein the controller is further programmed to operate the inverter system controller to generate current that has an average value of zero.
8 . The automotive power system of claim 1 , wherein the electric machine includes delta-connected windings.
9 . The automotive power system of claim 8 , wherein the controller is further programmed to operate the inverter system controller to create zero voltage across one of the delta-connected windings such that two of the delta-connected windings are in parallel.
10 . A method comprising:
responsive to a command to charge a traction battery with energy from an AC grid, closing a switch of circuitry including a capacitor and inductor connected in series with the switch such that a terminal of the switch is directly connected with an electric machine and a terminal of the capacitor is referenced to a negative terminal of the traction battery that connects an inverter system controller between the traction battery and electric machine; and
operating the inverter system controller to create zero voltage across one winding of the electric machine such that two windings of the electric machine are in parallel.
11 . The method of claim 10 further comprising, responsive to a command to discontinue charge of the traction battery, opening the switch.
12 . The method of claim 10 further comprising operating the inverter system controller to generate AC current that has an average value of zero.