Systems and methods for bulk capacitor pre-charge using silicon controlled rectifier for battery charger for electric vehicle
A system includes: a battery charger to convert AC power to DC power to charge a battery, wherein the battery charger includes: an upper switch to condition an input voltage and input current; a lower switch to condition the input voltage and the input current: an upper silicon controlled rectifier (SCR); a lower SCR; and a bulk capacitor.
1 . A system comprising:
a battery charger to convert alternating current (AC) power to direct current (DC) power to charge a battery, wherein the battery charger includes:
an upper switch to condition an input voltage and input current;
a lower switch to condition the input voltage and the input current;
an upper silicon controlled rectifier (SCR);
a lower SCR;
a bulk capacitor; and
one or more controllers, wherein the one or more controllers are configured to use a dynamic and adjustable pre-charge control algorithm to control the upper SCR and the lower SCR to pre-charge the bulk capacitor, wherein the one or more controllers are configured to determine a firing angle based on a threshold AC current, a voltage of the bulk capacitor, an inductance of a PFC converter, a capacitance of the bulk capacitor, a voltage of an input power, and a frequency of the input power to control the upper SCR and the lower SCR to pre-charge the bulk capacitor, and wherein the one or more controllers are configured to use the control algorithm in a continuous running configuration to determine the firing angle to ensure a calculation is completed in each AC half cycle before the upper SCR or the lower SCR is turned on.
2 . The system of claim 1 , wherein the one or more controllers are further configured to control the upper switch and the lower switch.
3 . The system of claim 1 , wherein the one or more controllers are further configured to determine the firing angle so that the firing angle is reduced as a voltage of the bulk capacitor increases.
4 . The system of claim 1 , wherein the one or more controllers are further configured to increase the threshold AC current at lower AC voltages.
5 . The system of claim 1 , wherein the upper switch, lower switch, upper SCR and lower SCR are a power factor correction (PFC) converter.
6 . The system of claim 1 , further comprising:
the battery configured to receive the DC power from the battery charger.
7 . A vehicle comprising the system of claim 6 .
8 . A system to pre-charge a bulk capacitor, the system comprising:
an upper silicon controlled rectifier (SCR) to switch an input power to a bulk capacitor;
a lower SCR to switch the input power to the bulk capacitor; and
one or more controllers, wherein the one or more controllers are configured to use a dynamic and adjustable pre-charge control algorithm to control the upper SCR and the lower SCR to pre-charge the bulk capacitor, wherein the one or more controllers are configured to determine a firing angle based on a threshold AC current, a voltage of the bulk capacitor, an inductance of a PFC converter, a capacitance of the bulk capacitor, a voltage of the input power, and a frequency of the input power to control the upper SCR and the lower SCR to pre-charge the bulk capacitor, and wherein the one or more controllers are configured to use the control algorithm in a continuous running configuration to determine the firing angle to ensure a calculation is completed in each AC half cycle before the upper SCR or the lower SCR is turned on.
9 . The system of claim 8 , wherein the upper SCR and lower SCR are in a power factor correction (PFC) converter.
10 . A method comprising:
receiving, by one or more controllers, one or more input variables including one or more of a threshold AC current, a voltage of a bulk capacitor, an inductance of a PFC converter, a capacitance of the bulk capacitor, a voltage of an input power, or a frequency of the input power; and
controlling, using a dynamic and adjustable pre-charge control algorithm, one or more silicon controlled rectifiers to pre-charge the bulk capacitor based on the one or more input variables, wherein the controlling the one or more silicon controlled rectifiers further comprises:
determining, using the control algorithm in a continuous running configuration, a firing angle based on the threshold AC current, the voltage of the bulk capacitor, the inductance of the PFC converter, the capacitance of the bulk capacitor, the voltage of the input power, and the frequency of the input power to ensure a calculation is performed in each AC half cycle before the one or more silicon controlled rectifiers are turned on, and
controlling the one or more silicon controlled rectifiers to pre-charge the bulk capacitor based on the determined firing angle.
11 . The method of claim 10 , wherein the controlling the one or more silicon controlled rectifiers further comprises:
changing the threshold AC current during the pre-charge of the bulk capacitor.