System and method for initiating operation of a fuel cell hybrid vehicle
View Patent ↗The present disclosure provides a method and system for powering a hybrid electric vehicle with a fuel cell, and in particular, efficiently initiating power generation in the fuel cell, the method and system comprising electrically connecting a battery to an ultracapacitor-based propulsion energy storage; using the battery to charge the propulsion energy storage to a predetermined voltage level for powering an air delivery compressor for a predetermined amount of time; disconnecting the battery from the propulsion energy storage; electrically connecting the propulsion energy storage to the air delivery compressor; operating the air delivery compressor using the charge on the propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and causing the fuel cell to generate electricity.
1. A method for starting up a fuel cell hybrid electric vehicle, the fuel cell hybrid electric vehicle having a battery, an air delivery compressor, an ultracapacitor-based propulsion energy storage, at least one DC-to-DC converter, and at least one electric propulsion motor, the method comprising:
electrically connecting the battery to the propulsion energy storage;
charging the propulsion energy storage with the battery to a predetermined level associated with powering an air delivery compressor;
disconnecting the battery from the propulsion energy storage;
electrically connecting the propulsion energy storage to the air delivery compressor;
operating the air delivery compressor using charge from the propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and
causing the fuel cell to generate electricity,
wherein, during the charging the propulsion energy storage, the predetermined level of propulsion energy storage charge comprises a predetermined voltage level associated with an amount of stored energy required to power the air delivery compressor for sufficient time to start up the fuel cell, and charging the propulsion energy storage comprises boosting the voltage of the battery to the predetermined voltage level and transmitting energy from the battery to the propulsion energy storage.
2. The method of claim 1 , wherein the causing the fuel cell to generate electricity comprises applying an electric load across the fuel cell such that supplied air and fuel are used by the fuel cell in approximately stoichiometric balance.
3. The method of claim 2 , further wherein applying the electric load across the fuel cell comprises supplying the electricity generated by the fuel cell to power vehicle accessories.
4. The method of claim 1 , further comprising determining an amount of charge on the propulsion energy storage prior to performing the step of electrically connecting the battery to the propulsion energy storage.
5. A method for starting up a fuel cell hybrid electric vehicle, the fuel cell hybrid electric vehicle having a battery, an air delivery compressor, an ultracapacitor-based propulsion energy storage, at least one DC-to-DC converter, and at least one electric propulsion motor, the method comprising:
electrically connecting the battery to the propulsion energy storage;
charging the propulsion energy storage with the battery to a predetermined level associated with powering an air delivery compressor;
disconnecting the battery from the propulsion energy storage;
electrically connecting the propulsion energy storage to the air delivery compressor;
operating the air delivery compressor using charge from the propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and
causing the fuel cell to generate electricity,
wherein the fuel cell hybrid electric vehicle also includes a DC bus configured to transfer propulsion power between the propulsion energy storage, the fuel cell, and the at least one electric propulsion motor; and,
wherein the operating the air delivery compressor using charge from the propulsion energy storage includes boosting voltage of the DC bus from a propulsion energy storage voltage to a bus voltage, transmitting power from the DC bus, bucking the bus voltage to a compressor voltage, and powering the air delivery compressor at the compressor voltage.
6. A method for starting up a fuel cell hybrid electric vehicle, the fuel cell hybrid electric vehicle having a battery, an air delivery compressor, an ultracapacitor-based propulsion energy storage, at least one DC-to-DC converter, and at least one electric propulsion motor, the method comprising:
electrically connecting the battery to the propulsion energy storage;
charging the propulsion energy storage with the battery to a predetermined level associated with powering an air delivery compressor;
disconnecting the battery from the propulsion energy storage;
electrically connecting the propulsion energy storage to the air delivery compressor;
operating the air delivery compressor using charge from the propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and
causing the fuel cell to generate electricity,
wherein the fuel cell hybrid electric vehicle also includes a DC bus configured to transfer propulsion power between the propulsion energy storage, the fuel cell, and the at least one electric propulsion motor, the fuel cell hybrid electric vehicle further including a DC-to-DC converter electrically in series between the fuel cell and the DC bus, and wherein the air delivery compressor is electrically in parallel with the fuel cell with reference to the DC-to-DC converter;
wherein the electrically connecting the propulsion energy storage to the air delivery compressor comprises electrically connecting the propulsion energy storage to the air delivery compressor via the DC bus and the DC-to-DC converter; and,
the method further comprising powering the air delivery compressor with the fuel cell in response to the causing the fuel cell to generate electricity.
7. A system controller installable in a fuel cell hybrid electric vehicle and comprising a computer readable medium having computer executable program code embodied thereon, the computer executable program code configured to cause the system controller to initiate power generation of a fuel cell when installed in the fuel cell hybrid electric vehicle by performing the steps of:
electrically connecting a start up battery to an ultracapacitor-based propulsion energy storage;
charging the ultracapacitor-based propulsion energy storage with the start up battery to a predetermined voltage level associated with powering an air delivery compressor for a predetermined amount of time;
disconnecting the start up battery from the ultracapacitor-based propulsion energy storage;
electrically connecting the ultracapacitor-based propulsion energy storage to the air delivery compressor;
operating the air delivery compressor using the charge on the ultracapacitor-based propulsion energy storage to provide a predetermined quantity of air to the fuel cell; and
causing the fuel cell to generate electricity,
using the electricity generated by the fuel cell including transmitting electricity across a shared high-voltage DC bus,
wherein the steps of charging the ultracapacitor-based propulsion energy storage, operating the air delivery compressor, and using the electricity generated by the fuel cell include transmitting electricity across the shared high-voltage DC bus, and
charging the propulsion energy storage comprises commanding a DC-to-DC converter to boost the voltage of the shared high-voltage DC bus from that of the start up battery to the predetermined voltage level, and transmitting energy from the shared high-voltage DC bus to the ultracapacitor-based propulsion energy storage.
8. The system controller of claim 7 , wherein further comprising powering the air delivery compressor with the fuel cell in response to the causing the fuel cell to generate electricity.