Power converter with dark start precharge circuit
The present disclosure provides a bidirectional power converter comprising dark start precharge circuit capable of receiving low-voltage DC power and boosting it to the target voltage specified by charge data of a BMS associated with an EV battery. Dark start precharge circuit allows to further establish a power connection with the EV and draw DC power from the EV battery to supply power to electrical loads of a household in absence of AC power at the AC power mains.
1 . A bidirectional power converter for converting AC power to DC charging power for an electric vehicle (EV) and for converting DC power from the EV to AC power, the bidirectional power converter comprising:
at least one bidirectional AC-to-DC power conversion module having an AC port connectable to mains power supply in a grid-tie or island mode and at least one DC port connectable to at least one EV cable connection;
a dark start precharge circuit for delivering DC voltage derived from an auxiliary battery to said at least one DC port in the absence of AC power at said AC port; and
a power conversion controller having an interface for receiving charge data from a battery management system (BMS) associated with an electric power storage battery of said EV, said power conversion controller operatively connected to said at least one bidirectional AC-to-DC power conversion module for:
(1) when said AC power is available at said AC port, controlling said at least one bidirectional AC-to-DC power conversion module to deliver to said DC port at least one voltage according to said charge data received from said BMS so as to establish a DC power connection to said EV and then begin charging or discharging said electric power storage battery of said EV; and
(2) when said AC power is not available at said AC port, controlling said dark start precharge circuit to deliver to said DC port at said at least one voltage corresponding to said charge data at said at least one DC port to establish a DC power connection to said EV and, in response to detecting that the DC power connection to said EV is established, stopping said dark start precharge circuit from delivering said DC voltage derived from the auxiliary battery, and controlling said at least one bidirectional AC-to-DC power conversion module to convert DC power from said EV to AC power.
2 . The power converter as defined in claim 1 , wherein said at least one bidirectional AC-to-DC power conversion module further comprises a DC-to-DC power conversion stage.
3 . The power converter as defined in claim 2 , wherein said DC-to-DC power conversion stage comprises galvanic isolation.
4 . The power converter as defined in claim 1 , wherein said dark start precharge circuit comprises a low-voltage input DC port for receiving a low-voltage DC power from said auxiliary battery.
5 . The power converter as defined in claim 1 , wherein dark start precharge circuit comprises a step-up DC-to-DC power conversion stage for stepping up said low-voltage DC power received from said auxiliary battery to match a target voltage corresponding to said charge data.
6 . The power converter as defined in claim 2 , wherein said dark start precharge circuit comprises a low-voltage input DC port for receiving a low-voltage DC power from said auxiliary battery, said low-voltage input DC port being connectable to said step-up DC-to-DC power conversion stage for boost and delivery to said at least one DC port.
7 . The power converter as defined in claim 2 , wherein said DC-to-DC power conversion stage comprises a first DC side connectable to said AC-to-DC power conversion stage and a second DC side comprising said at least one DC port further connectable to said EV connection, and wherein a DC side of the AC-to-DC power conversion stage further comprises a connection to DC link and bus capacitors, said DC link and bus capacitors connectable to said first side of said DC-to-DC power conversion stage.
8 . The power converter as defined in claim 7 , wherein said DC power provided by said step-up DC-to-DC power conversion stage is used to charge said DC link and bus capacitors allowing to provide said target voltage at said DC port of said at least one bidirectional AC-to-DC power conversion module.
9 . The power converter as defined in claim 1 , wherein said at least one DC port of said bidirectional AC-to-DC power conversion module further comprises a connection to an electromagnetic compatibility (EMC) filter, protection and precharge circuit.
10 . The power converter as defined in claim 9 , wherein said dark start precharge circuit is connectable to said EMC filter, protection and precharge circuit for filtering said DC power provided by said step-up DC-to-DC power conversion stage before providing said DC power to said EV.
11 . A method for delivering power between an electric power storage battery of an electric vehicle (EV) and at least one power conversion module of a power converter, the method comprising:
connecting an AC port of said at least one power conversion module to mains power supply, said mains power supply is in a grid-tie or island mode;
connecting at least one DC port of said at least one power conversion module to at least one EV cable connection;
connecting a dark start precharge circuit to at least one DC port of said power converter for delivering DC voltage delivered from an auxiliary battery to said at least one DC port;
receiving at an interface of a controller charge data from a battery management system (BMS) associated with said electric power storage battery of said EV, said controller operatively connected to said at least one power conversion module for, when said AC power is not available at said AC port, controlling said dark start precharge circuit to deliver to said at least one DC port at said at least one voltage corresponding to said charge data at said at least one DC port to establish a DC power connection to said EV and, in response to detecting that the DC power connection to said EV is established, stopping said dark start precharge circuit from delivering said DC voltage derived from the auxiliary battery, and controlling said at least one power conversion module to convert DC power from said EV to AC power.
12 . The method as defined in claim 11 , wherein controlling said dark start precharge circuit further comprises controlling a step-up DC-to-DC power conversion stage of said dark start precharge circuit using said controller for stepping up said DC power provided by said auxiliary battery, wherein the controller is a power conversion controller of the power converter.
13 . The method as defined in claim 11 , wherein said controlling said dark start precharge circuit further comprises controlling a DC-to-DC power conversion stage of said at least one power conversion module using said controller for stepping up said DC power derived from said auxiliary battery, said DC-to-DC power conversion stage is galvanically isolated and comprises a first DC side connectable to a DC side of said at least one power conversion module and a second DC side connectable to said at least one EV cable connection, and wherein the controller is a power conversion controller of the power converter.
14 . The method as defined in claim 11 , wherein said delivering said DC power at said target voltage corresponding to said charge data at said at least one DC port further comprises charging DC link and bus capacitors connected to said at least one DC port of said DC side of said at least one power conversion module using said step-up DC-to-DC power conversion stage of said dark start precharge circuit.
15 . The method as defined in claim 14 , further comprising providing said DC power stored in said DC link and bus capacitors to said DC-to-DC power conversion stage of said at least one power conversion module for further tunning allowing to achieve said target voltage corresponding to said charge data.
16 . The method as defined in claim 11 , further comprising providing said DC power to an electromagnetic compatibility (EMC) filter, protection and precharge circuit connected said at least one DC port of said at least one power conversion module.
17 . The method as defined in claim 11 , wherein said charge data issued by the BMS contains a charge voltage command, for establishing a connection between the EV and the power converter, and at least one charge current command, for transferring DC power between the EV and the power converter after the connection is established.
18 . An inverter for converting DC power from an electric vehicle (EV) to AC power, the inverter comprising:
at least one inverter module having an AC port connectable to mains power supply in a grid-tie or island mode and at least one DC port connectable to at least one EV cable connection;
a dark start precharge circuit for delivering DC voltage derived from an auxiliary battery to said at least one DC port; and
a controller having an interface for receiving charge data from a battery management system (BMS) associated with an electric power storage battery of said EV, said controller operatively connected to said at least one inverter module for, when said AC power is not available at said AC port, controlling said dark start precharge circuit to deliver to said DC port at said at least one voltage corresponding to said charge data at said at least one DC port to establish a DC power connection to said EV and, in response to detecting that the DC power connection to said EV is established, stopping said dark start precharge circuit from delivering said DC voltage derived from an auxiliary battery, and controlling said at least one inverter module to convert DC power from said EV to AC power.