Hybrid Energy System

Abstract

A hybrid energy system is configured to carry a power load for a generator configured to output a first AC signal. The hybrid energy system includes a battery bank, a DC / DC converter, an AC / DC converter, and a DC / AC converter. The battery bank includes a plurality of batteries and outputs a first DC signal. The DC / DC converter, operating in a first mode, receives the first DC signal and converts it to a second DC signal, which is output to a DC bus. The AC / DC converter receives the first AC signal and converts it to a third DC signal. The second DC signal and the third DC signal are coupled together on the DC bus. The DC / AC converter receives the second DC signal from the DC bus and converts it to a plurality of second AC signals, which are output to an AC outlet interface.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 344,117, filed May 20, 2022, which is incorporated herein by reference in its entirety.

[0002] The present invention relates to battery systems, power generation and system control, and in particular to battery storage systems in combination with generators in mobile and stationary applications. [Background technology]

[0003] Generators are often powered by engines such as diesel engines and other engines that use a variety of fuels, such as propane, natural gas, gasoline, biodiesel, and hydrogen. While diesel engines are efficient drives for generators when properly loaded, they are prone to wet stacking when lightly loaded (i.e., when unburned diesel fuel enters the diesel exhaust system, creating an oily residue). Wet stacking occurs when a diesel engine is operating at a low percentage or rate of its capacity. For example, a diesel engine coupled to a generator is prone to wet stacking when the generator it is driving is unloaded or minimally loaded, and also when the generator is operating less efficiently (consuming more fuel per kWh produced compared to an optimally loaded generator). When a generator is operating at unloaded or minimally loaded conditions, the diesel engine is operating inefficiently, resulting in a risk of wet stacking because the diesel engine is not at the proper operating temperature, which allows unburned fuel to enter the diesel exhaust system. Diesel engines are most efficient when they are operating at a sufficient percentage or ratio of their full capacity. When diesel engines are operating under sufficient load, they can operate at their optimal operating temperature. Generators used to power electrical equipment typically experience fluctuating loads throughout their normal use intervals. To help prevent wet stacking of diesel engines coupled to generators, a dummy load or load bank can be applied to those generators. The load bank provides a sufficient load on the generator to prevent wet stacking of the generator's diesel engine. However, when the load on the generator is increased with the application of a load bank or actual load, the diesel generator, although burning cleaner, consumes significantly more fuel to meet the increased generator load. Summary of the Invention [Means for solving the problem]

[0004] An embodiment of the present invention provides a system for managing the operating environment of an engine-driven generator. Exemplary engines can be powered by various fuel sources, such as diesel, propane, natural gas, gasoline, biodiesel, and hydrogen. A hybrid energy system improves the efficiency of the engine-driven generator by running the generator at its optimal load and reducing the generator's runtime by storing unused power, or power the generator can produce in excess of what the load needs, in a battery. Using a hybrid energy system completely eliminates the problems of light loads and wet stacking in the engine / generator and allows the engine / generator to be powered down while the hybrid energy system's battery powers the load. Once the hybrid energy system's battery is sufficiently charged, the engine / generator can be shut down to reduce its runtime, and the battery can be used to run the load until the battery reaches a low charge threshold (by percentage or battery voltage). Once the battery charge reaches this low charge threshold, the engine / generator is turned back on to power the load. By having the engine / generator power the load, the battery can be recharged with the generator's available power output in excess of the load. The engine / generator may also be turned on when the required power load exceeds a load threshold for the generator and / or battery, thus allowing the hybrid energy system to minimize engine / generator run time, improve fuel consumption, and reduce emissions compared to a conventional engine / generator configured to power a load.

[0005] The hybrid energy system includes a battery bank including multiple batteries arranged in an electrical circuit to provide a desired voltage output. The hybrid energy system may include a DC / DC converter that regulates (steps up or down) the voltage output of the battery bank to a desired DC voltage applied to a DC bus. The hybrid energy system may include an AC / DC converter that receives AC voltage from a generator and converts it to a DC voltage applied to the DC bus. The hybrid energy system may include a DC / AC converter that converts DC voltage from the DC bus to an AC voltage applied to an AC outlet panel, and the DC / AC converter may include a filter and / or a transformer. The hybrid energy system may also include a DC bus interface coupled to the DC bus for supplying DC power to external loads and / or for supplying DC power from an external DC power source to the DC bus. The hybrid energy system supplies power to the loads while the engine / generator is powered down.

[0006] In another embodiment of the present invention, a hybrid energy system is configured to provide a load to a generator while the generator is charging the hybrid energy system, with the hybrid energy system further configured to supply power to the load so that the generator can be powered down. The hybrid energy system includes a battery bank including a plurality of batteries arranged in a configuration to output a first DC voltage at a desired voltage level. The hybrid energy system may include a DC / DC converter, an AC / DC converter, and a DC / AC converter. The DC / DC converter converts the first DC voltage from the battery bank to a second DC voltage applied to a DC bus. The AC / DC converter converts the first AC voltage from the generator to a third DC voltage applied to the DC bus. The second DC voltage and the third DC voltage have approximately the same target voltage level and are applied to a common DC bus. The DC / AC converter converts the DC voltage from the DC bus to a second AC voltage. The second AC voltage is applied to an AC outlet interface that provides various AC voltage levels using various step-up or step-down transformers to obtain the desired voltage at the AC outlet interface. The DC / DC converter provides a fourth DC voltage to the battery bank for charging the battery bank.

[0007] In a further embodiment of the present invention, an exemplary hybrid energy system is configured to carry a power load for a generator configured to output a first AC signal. The hybrid energy system includes a battery bank, a DC / DC converter, an AC / DC converter, and a DC / AC converter. The battery bank includes a plurality of batteries and outputs a first DC signal. The DC / DC converter, operating in a first mode, receives the first DC signal and converts it to a second DC signal, which is output to a DC bus. The AC / DC converter receives the first AC signal and converts it to a third DC signal, which has the same voltage level. The DC / AC converter receives the second DC signal from the DC bus and converts it to a second AC signal, which is output to an AC outlet interface.

[0008] In yet another embodiment of the present invention, an exemplary method for controlling a hybrid energy system carrying a power load for a generator includes outputting a first DC signal from a battery bank. The method includes receiving and converting the first DC signal to a second DC signal using a DC / DC converter and outputting the second DC signal to a DC bus. The first AC signal output by the generator is received by the AC / DC converter and converted to a third DC signal. The second DC signal and the third DC signal have the same voltage level. The method also includes receiving and converting the second DC signal from the DC bus to a second AC signal using the DC / AC converter. The second AC signal is output to an AC outlet interface.

[0009] In one aspect of the invention, the hybrid energy system is placed on the bed of a trailer or truck that also holds the engine / generator. In another aspect of the invention, the engine / generator and hybrid energy system are combined into an integrated body (i.e., an "all-in-one" body, rather than two separate bodies combined) that can be placed on the bed of a trailer or truck, or on some other surface.

[0010] In a further aspect of the invention, an external battery system is coupled to the DC bus via a DC bus interface, the external battery system configured to provide DC power to the DC bus and / or receive DC power from the DC bus via the DC bus interface.

[0011] In a further aspect of the invention, an external generator is coupled to the DC bus via a DC bus interface and / or to the AC bus via an AC bus interface, and is configured to provide AC power to the AC bus via the AC bus interface and / or to provide DC power to the DC bus via the DC bus interface.

[0012] In another aspect of the invention, an exemplary hybrid energy system is configured to maximize fuel usage during the majority of the time the generator is running (except during warm-up and cool-down modes) while charging the battery and powering the existing loads, allowing the generator to operate at optimal or full load (up to approximately 100%). This applies to both fixed-speed generators at a particular engine RPM, and variable-speed generators where the engine can run at higher speeds (providing more output power to the common DC bus) or lower speeds (providing less power but potentially improving fuel consumption). This allows the generator to generate more power than the battery can output from its DC / DC converter to offset the load. High loads on the AC outlet interface are sensed by the DC / AC converter, which causes the controller to run the variable-speed generator at higher rpm as needed to offset the demand.

[0013] In yet another aspect of the present invention, the DC / AC converter is configured to regulate an AC voltage output at the AC outlet interface, either up or down, to generate a regulated AC voltage having a regulated voltage level.

[0014] In a further aspect of the invention, the system is configured to simultaneously provide multiple AC signals at multiple voltage levels.

[0015] In another aspect of the invention, the battery bank and the external battery bank are independently controlled so that the battery bank and the external battery bank are charged and / or discharged at different rates to maximize cycle life, improve overall system efficiency, and improve operation.

[0016] In yet another aspect of the invention, the hybrid energy system is configured to work with any fuel type generator, such as propane, natural gas, gasoline, ethanol, biodiesel, or hydrogen.

[0017] In a further aspect of the present invention, the hybrid energy system is configured to interface with and function with a DC generator by replacing the AC / DC converter with a DC / DC converter. In this aspect, if the DC generator can output a DC voltage that matches the DC bus, a DC / DC converter is not required. In this configuration, there are only two converters (i.e., a DC / DC converter for the battery and a DC / AC converter to the AC outlet interface). The AC / DC converter has been replaced with the DC generator.

[0018] In another aspect of the invention, the controller is configured to control the recharging of the battery bank so that the generator operates at an optimum load and / or full load during operation, and the controller is configured to control the discharging of the battery bank so that the generator's operational run time is minimized.

[0019] In yet another aspect of the invention, the controller is configured to output a startup signal to the generator to initiate output of the first AC signal when the controller selects the second mode for the DC / DC converter. The controller is configured to control operation of the generator such that the generator warms up and cools down before shutting down. The controller controls operation of the generator such that the generator ramps up its power output and ramps down its power output.

[0020] In a further aspect of the invention, the hybrid energy system is paralleled with a second generator, the two generators being configured to utilize a common output bus such that the second generator may be utilized as a spinning reserve.

[0021] The exemplary system control and DC bus configuration allows for smooth transfer of power between the generator and the battery bank, and loss of one of the input sources (either the generator or the battery bank) does not result in an immediate loss of power.

[0022] These and other objects, advantages, aims and features of the present invention will become apparent from a review of the following specification in conjunction with the drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a block diagram illustrating an exemplary hybrid energy system and generator coupled to a DC bus through a converter in accordance with the present invention. FIG. [Figure 2] FIG. 1 is a perspective view of an exemplary hybrid energy system in side-by-side configuration with a generator, showing a DC bus access panel, in accordance with the present invention. [Figure 3] FIG. 3 is an opposite perspective view of the hybrid energy system and generator of FIG. 2, showing the AC outlet panel. [Figure 4] FIG. 3 is a perspective view of the hybrid energy system and generator of FIG. 2 showing an accessory outlet post, in accordance with the present invention. [Figure 5] 3 is a perspective view of the hybrid energy system and generator of FIG. 2 showing an electric vehicle cabled to an accessory outlet post for recharging, in accordance with the present invention. [Figure 6A] FIG. 3 is a perspective view of the hybrid energy system and generator of FIG. 2 showing a second hybrid energy system cabled to a DC bus access panel in accordance with the present invention. [Figure 6B] FIG. 3 is a perspective view of the hybrid energy system and generator of FIG. 2 showing a second generator (i.e., another identical generator) cabled to the DC bus access panel, providing the generator with redundancy or combined power by connecting the secondary generator to the generator's own hybrid energy system, in accordance with the present invention. [Figure 6C] 1 is a diagram of an exemplary solar panel array or assembly connected via a DC / DC converter for coupling to an exemplary hybrid energy system via a DC bus access panel in accordance with the present invention. [Figure 6D] FIG. 6D is a diagram of the hybrid energy system of FIG. 6C placed on a trailer and integrated with a solar panel array, in accordance with the present invention. [Figure 6E] 1A-1D are perspective views of various hybrid energy system and generator configurations in accordance with the present invention; [Figure 6F] FIG. 1 is a block diagram of a hybrid energy system and generator arranged together in a single housing for stationary operation in accordance with the present invention. [Figure 6G] FIG. 6F is a block diagram of the hybrid energy system and generator of FIG. 6E disposed on a trailer in accordance with the present invention. [Figure 6H] FIG. 1 is a block diagram of an exemplary hybrid energy system and generator arranged for stationary operation in accordance with the present invention. [Figure 7] FIG. 1 is a block diagram of an exemplary hybrid energy system and generator arranged in parallel with multiple hybrid energy systems in accordance with the present invention. [Figure 7A] FIG. 10 is a block diagram of an alternative hybrid energy system and generator arranged in parallel with multiple hybrid energy systems and associated generators in accordance with the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] With reference to the drawings and the illustrative embodiments depicted therein, a hybrid energy system provides for the elimination or reduction of load issues in engine-driven generators. Such engines can be powered by a variety of fuels, such as diesel, propane, natural gas, gasoline, biodiesel, and hydrogen. For example, the engine / generator can include an exemplary diesel-engine-driven generator, such as an EPA Tier 4F certified (as well as Stage 5 and above) or other similarly compliant diesel-engine-driven mobile generator. The hybrid energy system also provides for powering down the diesel-engine-driven generator while the hybrid energy system powers the load. The exemplary hybrid energy system can be either integrated with or side-by-side with a portable, prime-output skid-type generator or a trailer-mounted diesel generator and can provide selective AC and / or DC power output to power the load while the generator is powered down. Alternatively, the hybrid energy system can be designed for stationary and mobile applications. Alternatively, a hybrid energy system may provide additional power loads to associated generators when the actual load is below a threshold load value (unused power is used to recharge the hybrid energy system's battery bank). Most generators are more efficient at or near full load, where the generator can provide more kilowatts per amount of fuel consumed, than at light loads, where efficiency is reduced. Lightly loading certain generators, such as diesel generators, can cause engine and exhaust problems due to unburned fuel, resulting in additional generator maintenance and repairs. Powering the loads with a generator running at optimal or full load and utilizing some or all of the generator's remaining power to charge batteries that can be used to power the loads while the generator is off significantly improves generator efficiency and reduces overall fuel consumption, emissions, and operating time.The exemplary embodiments discussed herein relate to temporary or portable power generation and energy storage that can be transported from one location to another or may be permanently installed.

[0025] FIG. 1 illustrates a hybrid energy system 100 including an exemplary AC generator 120 and a battery bank 102. An exemplary AC / DC converter (active front end "AFE") 108 is electrically coupled to the AC generator 120, and a bidirectional DC / DC converter 104 is electrically coupled to the battery bank. A DC bus is configured to electrically couple the AC / DC converter 108 and the bidirectional DC / DC converter 104a. A DC / AC converter 110 and a DC bus interface 114 are electrically coupled to the DC bus 106. As shown in FIG. 1, an AC load 101a is coupled to the AC generator 120, and a second AC load 101b is coupled to AC outlets 116a-n of an AC outlet interface 112, which is electrically coupled to the DC / AC converter 110. FIG. 1 also shows external DC loads 115a-n and / or external DC power sources 117a-n coupled to the DC bus 106 via a DC bus interface 114 for connection to multiple energy trailers (e.g., external battery banks) or other DC devices.

[0026] As shown in Figure 1, hybrid energy system 100 is configured to receive power from AC generator 120, which is configured to output an AC voltage (e.g., three-phase 480 VAC). An AC / DC converter 108, electrically coupled to AC generator 120, is configured to convert the AC voltage output of the generator to a selected DC voltage that is applied to DC bus 106. In one aspect of this embodiment, AC / DC converter 108 is an exemplary active front-end (AFE) inverter, including power system magnetic components (filters) and associated hardware and software (see Figures 3-5) for converting AC signals to DC signals. The exemplary AC / DC converter 108 is fabricated using insulated gate bipolar transistor (IGBT) technology. In a further aspect of this embodiment, the AC / DC converter 108 (implemented as an active front-end inverter) is configured to reject harmonics and provide a unity (1.0) or near-unity power factor at the AC generator 120, ideally in the case where 100% of the current output from the AC generator 120 contributes real power to the load. In one aspect of this embodiment, the AC / DC converter 108 is configured to provide a power factor between 0.95 and 1.0. When the example AC / DC converter 108 achieves a unity or near-unity power factor, the current output of the AC generator 120 has a real power output that matches its apparent power output. Thus, the AC generator 120 meets the required load power output with a lower total current draw. This allows for the construction of a simpler and less expensive diesel generator due to the lower total current draw required. The example AC / DC converter 108 is an improvement over conventional engine-driven generators and AC / DC inverter assemblies that must deal with undesirable harmonics and low power factors fed back to the engine-driven generator.

[0027] The DC voltage output by AC / DC converter 108 is approximately the same voltage level (e.g., approximately 700 VDC) as the DC voltage output by bidirectional DC / DC converter 104. For example, in one exemplary embodiment, AC / DC converter 108 and bidirectional DC / DC converter 104 are both configured to output a DC voltage of approximately 700 VDC. That is, the DC voltages output by AC / DC converter 108 and DC / DC converter 104 are within ±10% of the desired voltage level. In other embodiments, the converters may be configured for different voltage outputs.

[0028] A battery bank 102 comprising multiple batteries 110a-n is configured to output a selected DC voltage (see FIG. 2B). In one exemplary embodiment, the battery bank 102 is configured to output a DC voltage (e.g., 250-400 VDC). Higher output DC voltages (up to the DC bus voltage) are possible by adding more batteries 110 and arranging the batteries in a series configuration. There is no predefined system limit in terms of kWh, as additional batteries can be connected in parallel without affecting the DC battery voltage, as long as the battery management system (BMS) is configured and can handle the parallel connection.

[0029] The battery bank 102 is coupled to a bidirectional DC / DC converter 104 configured to convert the DC voltage output by the battery bank 102 to a selected DC voltage applied to the DC bus 106. In one exemplary embodiment, the 250-400 VDC output from the battery bank 102 is stepped up to approximately 700 VDC by the bidirectional DC / DC converter 104. In one aspect of this embodiment, the bidirectional DC / DC converter 104 is an exemplary bidirectional DC-DC converter that includes power system magnetic components (filters) and associated hardware and software (see FIGS. 3-5) to convert the DC signal to a different DC signal having a different voltage level. The exemplary bidirectional DC / DC converter 104 is fabricated using insulated gate bipolar transistor (IGBT) technology. The bidirectional DC / DC converter 104 is configured as a dual-mode or bidirectional converter that can either discharge the battery bank 102 (while powering a load) or recharge the battery bank 102. In one aspect of this embodiment, the bidirectional DC / DC converter 104 is configured to automatically reverse from outputting DC voltage from the battery pack 102 and begin recharging the battery bank 102 when the battery bank output voltage / current drops below a threshold set point. The AC generator 120 is signaled to start either from a configurable state-of-charge reading of the battery bank 102 from the internal BMS or from predefined load limits. These are example programmable limits.

[0030] When operating in the second mode (or battery recharge mode), the bidirectional DC / DC converter 104 receives the approximately 700 VDC voltage output from the DC bus 106 and converts (steps down) it to a programmable charging voltage for the battery bank 102 (which varies based on the number of batteries in the battery bank 102). This DC voltage is received by the battery bank 102 during the recharge mode. As discussed herein, when operating in the recharge mode, the bidirectional DC / DC converter 104 enables the AC generator 120 to operate at optimal efficiency (at or near 100% power output). Recharging the battery bank 102 at or near full current output allows the AC generator 120 to operate most efficiently and maximize its fuel efficiency.

[0031] The DC / AC converter 110 is coupled to the DC bus 106 and configured to convert the DC voltage (e.g., approximately 700 VDC) of the DC bus 106 to an AC voltage applied to the AC outlet interface 112. In one aspect of this embodiment, the exemplary DC / AC converter 110 is a DC-to-AC output inverter and configured to simultaneously output multiple AC voltages, e.g., single-phase 120 V and 240 V, and three-phase 120 V / 208 V and 277 V / 480 V. Such voltage, phase, and frequency selections include those for use in Europe and Canada, as well as other applications requiring different voltages and frequencies that the DC / AC converter can output. The DC / AC converter 110 includes a transformer and associated hardware and software (see FIGS. 3-5) for converting the DC signal to multiple AC signals. The exemplary DC / AC converter 110 is fabricated using insulated gate bipolar transistor (IGBT) technology. The DC / AC converter 110 outputs various AC voltage levels to each of the AC outlets 116a-n of the AC outlet interface 112. Each of the exemplary AC voltage levels is supplied to one or more corresponding AC outlets 116a-n. For example, the AC outlet interface 112 may include only a single AC outlet 116c and 116d, each outputting 277 VAC or 480 VAC, while the AC outlet interface 112 may include two (or more) AC outlets 116a-b, each outputting 120 VAC. Each of these AC voltages output from the AC outlets 116a-n is received by an AC load 101b. As shown in FIG. 1, in addition to the AC load 101b coupled to the AC outlet 116 of the AC outlet interface 112, a separate AC load 101a is coupled to the AC generator 120. The AC load 101a and the AC / DC converter 108 are arranged in a circuit parallel to the AC generator 120. Although the exemplary load bank may be used to provide additional load to the AC generator 120, the AC loads 101a,b are considered to be "real" loads that require AC power.Load banks are described in detail in US patent application Ser. No. 17 / 668,579, which is incorporated herein by reference in its entirety.

[0032] 1 , the hybrid energy system 100 includes a DC bus interface 114. The DC bus interface 114 is configured to provide external access to the DC bus 106. As discussed herein, one or more external DC power sources 117a-n may be coupled to the DC bus 106 via the DC bus interface 114 to supply additional DC power to the DC bus 106. Alternatively, one or more external DC loads 115a-n may be coupled to the DC bus 106 via the DC bus interface 114 to receive DC power from the DC bus 106. The DC bus interface 114 may also include an exemplary bidirectional DC / DC converter 116 to convert a DC voltage on the DC bus 106 to a desired DC voltage output for the external DC loads 115a-n or to convert a DC voltage provided by the external DC power sources 117a-n to a desired DC voltage level applied to the DC bus 106.

[0033] As shown in FIG. 1 , bidirectional DC / DC converter 104 selectively converts the DC voltage of DC bus 106 to a desired DC voltage for recharging batteries 110a-n in battery bank 102. A controller 118 communicatively coupled to battery bank 102 and bidirectional DC / DC converter 104 controls the output of battery bank 102 and the operation of bidirectional DC / DC converter 104 (e.g., selectively recharging battery bank 102). Bidirectional DC / DC converter 104 responds to the voltage level of the DC bus, i.e., charges the battery when the DC bus voltage level exceeds a set value and discharges the battery when the DC bus voltage level falls below another set value. Controller 118 can dynamically change its set value to enable control of multiple energy sources (generators) or independent loads and sources of a battery system. The charge rate of the battery is dynamically controlled by controller 118 and DC / DC converter 104.

[0034] The controller 118 also controls the operation of the AC generator 120. For example, the controller 118 outputs a startup signal or a shutdown signal to the AC generator 120 to start and stop the AC generator 120, respectively. The controller 118 controls the operation of the AC generator 120 so that the AC generator 120 can be warmed up during startup and cooled down before shutdown. Such control during startup and shutdown by the controller 118 may include ramping up the power output of the AC generator 120 during startup and ramping down the power output of the AC generator 120 during shutdown. The controller 118 is also configured to control the recharging of the battery bank 102 when the AC generator 120 is running to operate optimally (i.e., optimal in terms of fuel efficiency and operating conditions) and / or at full load. The controller 118 may also be used to control the discharging of the battery bank 102 to minimize the operating run time of the AC generator 120. That is, by using power from the battery bank 102 (if sufficiently charged as discussed herein) to power the loads placed on the system, the AC generator 120 can be shut down to save fuel and run time.

[0035] As such, the AC generator 120 (controlled by the controller 118) and the hybrid energy system 100 may operate in various modes. For example, in a first mode of operation, the AC generator 120 outputs an AC voltage to power the AC load 101a, while the controller 118 selectively shuts down the AC / DC converter so that the AC generator 120 does not supply power to the DC bus 106. In the case of a DC generator, there is no AC / DC converter, so the DC generator is shut down and does not supply power to the DC bus 106. The AC generator 120 may be in the first mode of operation when it is supplying power to the AC load 101a that exceeds a power threshold for the maximum power output of the AC generator 120. In the first mode of operation, the AC generator 120 supplies power to the AC load 101a without providing power to the AC outlet interface 112 or providing “recharging” power to the battery bank 102. In a first mode of operation, when the battery bank 102 is fully charged, a DC voltage may be output by the battery bank 102 to power external DC loads 115a-n (via DC bus interface 114) and / or converted to an AC signal via the DC / AC converter 110 to power the AC load 101b via the AC outlet interface 112. The example AC generator 120 may be configured as a fixed-speed generator (at a selected engine RPM) or as a variable-speed generator where the engine may increase its RPM rate (which provides more output power to the DC bus 106). Such a configuration may allow the generator 120 to generate more power than the battery 102 can output from its DC / DC converter 104 to offset the load. A high load at the AC outlet interface 112 is detected by the DC / AC converter 110, which causes the controller 118 to run the variable-speed generator at a higher RPM as needed to offset the power demand.

[0036] In the second mode of operation, AC generator 120 outputs an AC voltage to AC / DC converter 108 to power AC load 101a and / or AC load 101b (via DC bus 106 and DC / AC converter 110). In the second mode of operation, controller 118 also disables bidirectional DC / DC converter 104 so that AC generator 120 does not provide "recharging" power to battery bank 102 due to the absence or insufficient amount of "unused" power. When "disabled," bidirectional DC / DC converter 104 is not "shut off," but simply does not charge or discharge battery bank 102.

[0037] In the third operating mode, the AC generator 120 outputs an AC voltage to the AC / DC converter 108 to power the AC load 101a and / or the AC load 101b (via the DC bus 106 and the DC / AC converter 110). In the third operating mode, the controller places the bidirectional DC / DC converter 104 in a recharge mode so that the bidirectional DC / DC converter 104 provides “recharge” power to recharge the battery bank 102. The selective recharging of the battery bank 102 is controlled by the controller 118. Whether the battery bank 102 is recharged depends on several factors monitored by the controller 118. For example, the controller 118 may cause the battery bank 102 to recharge when the charge level of the battery bank 102 is below a first charge threshold, while stopping the recharging of the battery bank 102 when the charge level of the battery bank 102 is above a second charge threshold. The controller 118 can also selectively recharge the battery bank 102 in response to the AC loads 101 a,b coupled to the AC generator 120 and / or the AC outlet interface 112, and in response to the external DC loads 115 a-n coupled to the DC bus interface 114.

[0038] As discussed herein, AC generator 120 may be used to selectively recharge battery bank 102 when the variable actual load (e.g., AC loads 101a, 101b, and DC loads 115a-n) is too small to prevent wet stacking, allowing AC generator 120 to operate under load conditions sufficient to prevent wet stacking (even when there is no or only minimal load coupled to AC generator 120). Wet stacking can occur when a diesel engine operates below its optimum operating temperature.

[0039] 2 illustrates an example hybrid energy system 100 disposed on a trailer 202 alongside an example AC generator 120. As shown in FIG. 2, the hybrid energy system 100 includes a DC bus interface 114 with a number of example power cords 602 running to example DC loads 115 or DC power sources 117 (see FIGS. 5 and 6A-6C).

[0040] FIG. 3 shows the opposite side of the hybrid energy system 100 and AC generator 120 of FIG. 2. As shown in FIG. 3, the hybrid energy system 100 includes an AC outlet interface 112 having a plurality of AC outlets 116. FIG. 3 also shows an exemplary programmable control panel 702 for interfacing with the hybrid energy system 100. For example, the control panel 702 allows for user interaction with the controller 118 of the hybrid energy system 100. The control panel 702 includes a programmable graphical user interface (e.g., a touch-sensitive panel) for inputting user feedback. The control panel 702 displays basic generator information and operational status that can be monitored and reported. The control panel 702 also displays basic battery and converter / inverter information from the hybrid energy system 100.

[0041] Figure 4 illustrates the hybrid energy system 100 and AC generator 120 of Figure 2 with the addition of an exemplary DC outlet box 802. As shown in Figure 4, the DC outlet box 802 is electrically coupled to the DC bus interface 114 via an exemplary cable 804.

[0042] FIG. 5 illustrates the example hybrid energy system 100 and AC generator 120 of FIG. 2 with the DC outlet box 802 of FIG. 4. FIG. 5 illustrates an example DC load 115a cabled to the DC outlet box 802 for recharging the onboard batteries. While FIG. 5 illustrates an example battery-powered forklift as the DC load, other industrial battery-powered equipment may be electrically coupled through the DC outlet box 802 for recharging. In one aspect of this embodiment, one or more DC loads 115 may be coupled to the DC outlet box 802. The DC outlet box 802 is configured to provide DC power for power supply and / or recharging. As shown in FIG. 6D, the example hybrid energy system 100 and AC generator 120 may be sized for the anticipated load needs.

[0043] In FIG. 6A, an exemplary external power source 117a is coupled to the DC bus interface 114. In one exemplary embodiment, the power source 117a shown in FIG. 6A is an exemplary external battery bank 117a. The external battery bank 117a may be similar to the battery bank 102, or may be of a different configuration or may use a different energy storage technology or battery chemistry. With reference to FIG. 7, the external power source 117a (of FIG. 6A) is replaced with a second hybrid energy system 100d or multiple hybrid energy systems 100d-100n. A controller 118 is configured to control the multiple hybrid energy systems (100, 100d-100n). The outputs of each of the multiple hybrid energy systems 100, 100d-100n are tied together using a common bus 702 communicatively coupled to the AC output interfaces of at least two or more of the hybrid energy systems 100, 100d-100n such that the multiple hybrid energy systems 100, 100d-100n may output both three-phase AC power and single-phase AC power in parallel. In FIG. 7A, an alternative configuration to FIG. 7, each of the hybrid energy systems 100d-100n is paired with an associated generator 120d-100n. The parallel configuration shown in FIG. 7A can provide increased flexibility, with multiple generators 120, 120d-120n selectively used to power loads or recharge the battery bank 102 in their own hybrid energy system 100 or in another parallel-configured hybrid energy system 100d-100n.

[0044] In FIG. 6B , an exemplary external power source 117b is coupled to the DC bus interface 114 via an external distribution box 1002 configured to provide a redundant interface for coupling loads to the generator 120 and the hybrid energy system 100. In one exemplary embodiment, the power source 117b shown in FIG. 6B is an external AC generator 117b. The external AC generator 117b may be similar to the AC generator 120, or may be of a different configuration or use a different AC generation technology. In one aspect of this embodiment, the external power source outputs a DC voltage via an AC / DC converter in the external AC generator 117b. The hybrid energy system 100 may also be paralleled with the external AC generator 117b. That is, the AC generator 120 and the external AC generator 117b may utilize a common output bus such that the external AC generator 117b may be utilized as a spinning reserve.

[0045] In a further aspect of the invention, the hybrid energy system is paralleled with a second generator, the two generators being configured to utilize a common output bus such that the second generator may be utilized as a spinning reserve.

[0046] In FIG. 6C, an exemplary external power source 117c is coupled to the DC bus interface 114. In one exemplary embodiment shown in FIG. 6C, the power source 117c is an exemplary solar panel array 117c. Other alternative renewable energy sources, such as wind turbines, fuel cell technology, and other energy sources, are also contemplated. The alternative power sources in FIGS. 6A-6H provide energy storage or power generation redundancy. An external power distribution box 1002 and a DC outlet box 802 provide redundant interfaces for coupling loads to the generator 120 and hybrid energy system 100. In FIG. 6D, an exemplary on-board solar panel 117c and solar inverter 150 are plugged into an AC outlet interface 112 that supplies power to the load and charges the battery 102 of the hybrid energy system 100 (via either of the DC / DC converters 104, 116 of the hybrid energy system 100) when the load falls below the output of the solar panel 117c.

[0047] As shown in Figures 6A-6H, multiple hybrid energy systems 100 may be coupled together to operate in parallel. The outputs of each of the multiple hybrid energy systems 100 are tied together using a common bus that is communicatively coupled to the AC output interfaces of two or more of the multiple hybrid energy systems 100 such that the multiple hybrid energy systems output both three-phase AC power and single-phase AC power in parallel. Also, as shown in Figures 6A-6H, the hybrid energy systems 100 and generators 120 may be configured in a variety of sizes and shapes. For example, the hybrid energy systems 100 and generators in Figures 6F-6H (and others shown in Figures 6A-6E) are not drawn to scale.

[0048] FIG. 6E shows three exemplary embodiments with variously sized hybrid energy systems 100a, 100b, and 100c and corresponding variously sized AC generators 120a, 120b, and 120c. As shown in FIG. 6D, the exemplary embodiments can be sized to fit the desired operating environment and AC and / or DC power load needs. In FIG. 6F, the hybrid energy system 100 and generator 120 are disposed within a single body 130. Such a configuration 130 may be placed on a trailer 202 (see FIG. 6G) or configured as a freestanding or stationary configuration (see FIG. 6F). Such a combined version (with separate housings for the hybrid energy system 100 and generator 120) may be deployed as a freestanding or stationary configuration (see FIG. 6H). The single body configuration 130 may be substituted for any of the embodiments in which the generator 120 and hybrid energy system 100 are disposed in separate housings. For example, the generators 120d-120n and hybrid energy systems 100d-100n of Figure 7A, which are shown as being disposed in separate housings, can be replaced with a combination generator / hybrid energy system disposed in a single body 130. In another exemplary embodiment, a combination single body 130 (each housing a generator 100 / hybrid energy system 120 configuration) can also be used with one or more generators 120 and hybrid energy systems 100 in separate housings.

[0049] A control panel 702 (see FIG. 3 ) displays the hybrid energy system voltage output and operating parameters, and in one aspect of the embodiments discussed herein, the output voltage and operating parameters may be selected from the control panel 702. The selected voltage may also be fine-tuned and adjusted up or down by up to 10% by a user via the control panel 702. For example, an exemplary user may request an output voltage of 210 VAC instead of 208 VAC. Such an adjustment may be necessary if an electrical device drawing power from the hybrid energy system 100 is remote from the hybrid energy system 100 and experiences a voltage drop as a result.

[0050] The control panel 702 also allows for control of the DC bus interface 114 and any peripherals attached to it (eg, electrical devices that couple to the DC bus interface 114 directly or through a DC outlet box 802).

[0051] Access to the DC bus 106 (via the DC bus interface 114) allows, for example, the connection of Level 3 DC electric vehicles or devices, or the fast charging of electric devices. Providing such DC voltage can be used for mobile or temporary energy delivery applications.

[0052] The exemplary hybrid energy system 100 and diesel generator 120 may be mounted as a utility in the bed of a pickup truck or towed on a trailer and used as a mobile vehicle charger for EVs or construction equipment, providing, for example, an exemplary 250 kilowatts or more of Level 3 DC charging. Exemplary electrical equipment uses include construction elevators, rechargeable construction equipment, welding equipment, pumps, job trailers, lifts and cranes, location events and / or filming, and telecommunications equipment such as base stations and microwave equipment where refueling is more difficult.

[0053] In an alternative embodiment, hybrid energy system 100 is configured to receive power from DC generator 122 (replacing AC generator 120 with DC generator 122) (see FIG. 1 ). AC / DC converter 108 is then replaced with a DC / DC converter (similar to DC / DC converter 104). This additional DC / DC converter is configured to receive the DC voltage output of the DC generator and convert it to the required voltage level for DC bus 106. Note that if DC generator 122 includes an alternator that matches the voltage level of DC bus 106, AC / DC converter 108 can be eliminated (replacing AC generator 120 with DC generator 122).

[0054] Thus, the exemplary embodiments discussed herein improve the efficiency of diesel generators by running them at optimal loads and reducing their runtime by storing unused generated power in batteries. When the battery bank of the hybrid energy system is fully charged, the generator can be shut down to reduce runtime, or the battery bank of the hybrid energy system can fully power the load until a charge threshold is reached. The generator is turned back on when the battery bank's charge level reaches a threshold, providing power to the load while any unused power is used to recharge the battery bank. The generator can also be turned on regardless of the battery bank's charge level when the load approaches either the generator's load capacity or the battery bank's load capacity. The hybrid energy system minimizes generator runtime, improves fuel consumption, and reduces emissions compared to a conventional generator configured to power a load. When using a variable-speed generator, the rpm can be increased as needed to provide more power when the output load is greater than the DC / DC converter's output.

[0055] Changes and modifications in the specifically described embodiments can be made without departing from the principles of the invention, which is intended to be limited only by the appended claims as interpreted in accordance with principles of patent law, including the doctrine of equivalents.

Claims

1. 1. A hybrid energy system configured to carry a power load for a generator configured to output a first AC signal, the hybrid energy system comprising: a battery bank including a plurality of batteries and configured to output a first DC signal; a DC / DC converter configured to receive and convert the first DC signal into a second DC signal when operating in a first mode, the second DC signal being output onto a DC bus; an AC / DC converter configured to receive the first AC signal from the generator and convert it to a third DC signal, the second DC signal and the third DC signal being tied together on the DC bus; a DC / AC converter configured to receive the second DC signal from the DC bus and convert it into a second AC signal, the second AC signal being output to an AC outlet interface; and A hybrid energy system.

2. 10. The hybrid energy system of claim 1, further comprising a controller configured to control the DC / DC converter, the controller operable to adjust a voltage level of the second DC signal.

3. 3. The hybrid energy system of claim 2, wherein the controller is configured to output a shutdown signal to the generator to cause the generator to stop outputting the first AC signal when the controller selects the first mode for the DC / DC converter.

4. 3. The hybrid energy system of claim 2, wherein the controller is operable to select a second mode for the DC / DC converter, and wherein the DC / DC converter, when operating in the second mode, is configured to receive and convert the second DC signal from the DC bus to a fourth DC signal, and wherein the fourth DC signal is output to the battery bank to recharge the battery bank, and wherein the first mode is a battery discharge mode and the second mode is a battery recharge mode.

5. 5. The hybrid energy system of claim 4, wherein the controller is configured to control the recharging of the battery bank such that the generator operates at an optimum load and / or full load when operational, and wherein the controller is configured to control the discharging of the battery bank such that operational run time of the generator is minimized.

6. 5. The hybrid energy system of claim 4, wherein the controller is configured to output a start-up signal to the generator to cause the generator to begin outputting the first AC signal when the controller selects the second mode for the DC / DC converter, the controller is configured to control the operation of the generator to warm up and cool down before shutting down, and the controller is configured to control the operation of the generator to ramp up a power output and ramp down a power output.

7. 10. The hybrid energy system of claim 1, further comprising: a DC bus interface configured to couple to the DC bus, the DC bus interface configured to electrically couple the electric device to the DC bus such that the DC bus outputs a fifth DC voltage to the electric device via the DC bus interface, the electric device being one or more of an electric vehicle charger, battery powered construction equipment, an electric appliance, and a household appliance device.

8. 8. The hybrid energy system of claim 7, wherein the DC bus interface is configured to electrically couple an external power source to the DC bus such that the external power source outputs a sixth DC voltage to the DC bus via the DC bus interface, the external power source comprising one or more of an external battery bank, a solar panel energy source, a wind generator, and a secondary (backup) generator.

9. 10. The hybrid energy system of claim 1, wherein the system is configured to simultaneously output multiple AC signals, the multiple AC signals including one or more of single-phase voltages of 120V and / or 240V, and three-phase voltages of 120V / 208V and / or 277V / 480V, the multiple AC signals including voltages and frequencies for use in Europe and Canada and other applications requiring different voltages and frequencies that the DC / AC converter can output.

10. 1. A method for controlling a hybrid energy system carrying a generator power load, the method comprising: outputting a first DC signal using a battery bank; receiving and converting the first DC signal to a second DC signal using a DC / DC converter and outputting the second DC signal to a DC bus; receiving and converting, with an AC / DC converter, a first AC signal output by the generator into a third DC signal, wherein the second DC signal and the third DC signal are coupled together on the DC bus; receiving the second DC signal from the DC bus and converting it into a second AC signal using a DC / AC converter, wherein the second AC signal is output to an AC outlet interface; A method comprising:

11. The method of claim 10 further comprising adjusting the DC / DC converter to adjust a voltage level of the second DC signal.

12. The method of claim 10 , further comprising adjusting the AC / DC converter to adjust the voltage level of the third DC signal.

13. The method of claim 10 , further comprising adjusting the DC / AC converter to adjust the voltage level of the second AC signal.

14. 11. The method of claim 10, further comprising operating the DC / DC converter in one of a plurality of modes, a first mode comprising the hybrid energy system outputting a shutdown signal to the generator to cease outputting the first AC signal.

15. 15. The method of claim 14, wherein a second mode includes the hybrid energy system receiving the second DC signal from the DC bus, converting it to a fourth DC signal, and outputting the fourth DC signal to the battery bank to recharge the battery bank, and the second mode further includes the hybrid energy system outputting a start-up signal to the generator to begin outputting the first AC signal, and the first mode is a battery discharge mode and the second mode is a battery recharge mode.

16. 11. The method of claim 10, further comprising electrically coupling an electric device to the DC bus via a DC bus interface electrically coupled to the DC bus, the DC bus outputting a fifth DC voltage to the electric device via the DC bus interface, the electric device being one or more of an electric vehicle charger, battery-powered construction equipment, an appliance, and a consumer electronics device.

17. 11. The method of claim 10, further comprising electrically coupling an external power source to the DC bus via the DC bus interface, the external power source outputting a sixth DC voltage to the DC bus via the DC bus interface, the external power source comprising one or more of an external battery bank, a solar panel energy source, a wind generator, and a secondary (backup) generator.

18. The method of claim 17 , wherein the external power source is used to recharge the battery bank via the DC bus.

19. 11. The method of claim 10, wherein the DC / AC converter simultaneously outputs multiple AC signals, the multiple AC signals including one or more of single-phase voltages of 120V and / or 240V, and three-phase voltages of 120V / 208V and / or 277V / 480V, the multiple AC signals including voltages and frequencies for use in Europe and Canada and other applications requiring different voltages and frequencies that the DC / AC converter can output.

20. 11. The method of claim 10, wherein the outputs of each of the plurality of hybrid energy systems are tied together using a common bus communicatively coupled to the AC output interfaces of two or more hybrid energy systems of the plurality of hybrid energy systems such that the plurality of hybrid energy systems output both three-phase AC and single-phase AC in parallel, the method further comprising paralleling the hybrid energy systems with a second generator, the two generators utilizing the common output bus such that the second generator is utilized as a spinning reserve.

21. 21. The method of claim 20, wherein the hybrid energy system continues to power the load at one or more simultaneous output voltages while the generator is powered down, and the generator is available for service or maintenance while the hybrid energy system is powering the load.

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