FIELD

The disclosure herein relates to an electrically powered accessory configured to be used with at least one of a vehicle, trailer and a transport container. More particularly, the disclosure herein relates to optimized power management to control charge and discharge of a rechargeable energy storage used for powering the electrically powered accessory.

BACKGROUND

A transport climate control system is generally used to control environmental condition(s) (e.g., temperature, humidity, air quality, and the like) within a climate controlled space of a transport unit (e.g., a truck, a container (such as a container on a flat car, an intermodal container, etc.), a box car, a semi-tractor, a bus, or other similar transport unit). The transport climate control system can include, for example, a transport refrigeration system (TRS) and/or a heating, ventilation and air conditioning (HVAC) system. The TRS can control environmental condition(s) within the climate controlled space to maintain cargo (e.g., produce, frozen foods, pharmaceuticals, etc.). The HVAC system can control environmental conditions(s) within the climate controlled space to provide passenger comfort for passengers travelling in the transport unit. In some transport units, the transport climate control system can be installed externally (e.g., on a rooftop of the transport unit, on a front wall of the transport unit, etc.).

In some embodiments, the transport climate control system can be a multi-zone transport climate control system (MTCS). The MTCS can be used to separately and independently control environmental condition(s) within each of the multiple zones of the climate controlled space. The MTCS can include a host unit, and one or more remote units that may be provided in different locations of the transport unit for separate climate control within each of the zones. In some instances, the MTCS can have two or more remote units without a host unit.

SUMMARY

The embodiments disclosed herein relate to an electrically powered accessory configured to be used with at least one of a vehicle, trailer and a transport container. More particularly, the embodiments disclosed herein relate to optimized power management to control charge and discharge of a rechargeable energy storage device used for powering the electrically powered accessory.

In particular, the embodiments described herein can integrate charging and discharging of a transport climate control rechargeable energy storage in a single circuit. Generally, the rechargeable energy storage has a lower voltage than a Direct Current (“DC”) link voltage (either powered from a generator/alternator controlled regeneration or an external power source (e.g., a utility power source, a commercial charging station, etc.) controlled by a front end converter). The embodiments described herein can provide an optimized DC/DC converter between the rechargeable energy storage and the DC link that is configured to boost voltage and limit current in a discharge mode of the rechargeable energy storage and buck voltage in a charging mode.

The embodiments described herein can also provide an optimized power converter that can alternatively operate in a charge mode and a discharge mode using a single DC/DC converter circuit based on a status of the transport climate control system and available power source options. In particular, a controller can provide pulse width modulation (PWM) control of switches of the single DC/DC converter circuit to provide only a voltage boost (step-up) in one direction of the single DC/DC converter circuit and only a voltage buck (step-down) in an opposite direction of the single DC/DC converter circuit. Accordingly, a rechargeable energy storage connected to the single optimized DC/DC converter circuit can be used more flexibility as the rechargeable energy storage voltage can be matched to the DC link regardless of the voltage at the DC link. That is, the embodiments described herein can allow for a universal rechargeable energy storage that can operate at multiple voltage levels via the optimized power converter. During the charging mode, the controller can modify (e.g., buck) the voltage level of a power source using PWM control to match an operating/state of charge voltage level of the rechargeable energy storage. During the discharge mode, the controller can modify (e.g., boost) the voltage level of the rechargeable energy storage using PWM control to match the voltage level at the DC link.

In one embodiment, an optimized power converter for use in a transport electrical system that provides power to a transport climate control system is provided. The optimized power converter includes an optimized DC/DC converter and an inverter/active rectifier. The optimized DC/DC converter is connected between a rechargeable energy storage of the transport electrical system that provides DC power and the inverter/active rectifier. The optimized DC/DC converter is configured to only boost a voltage level when current is directed from the rechargeable energy storage to the inverter/active rectifier and is configured to only buck a voltage level when current is directed from the inverter/active rectifier to the rechargeable energy storage. The inverter/active rectifier is connected to the optimized DC/DC converter. The optimized power converter is configured to operate in a charging mode and a discharge mode. When the optimized power converter is operating in the charging mode, the inverter/active rectifier is configured to convert three phase Alternating Current (“AC”) power into DC power, and the optimized power converter is configured to buck the DC power to a voltage level that is acceptable for charging the rechargeable energy storage. When the optimized power converter is operating in the discharge mode, the optimized DC/DC converter is configured to boost voltage from the rechargeable energy storage, and the inverter/active rectifier is configured to convert boosted DC power into three phase AC power for powering one or more AC loads of the transport climate control system.

In another embodiment, a transport electrical system for powering a transport climate control system is provided. The transport electrical system includes a transport climate control load network and an optimized power converter. The transport climate control load network includes a plurality of transport climate control loads that use power to operate the transport climate control system. The optimized power converter provides power to one or more transport climate control loads of the transport climate control load network. The optimized power converter includes an optimized DC/DC converter and an inverter/active rectifier. The optimized DC/DC converter is connected between a rechargeable energy storage of the transport electrical system that provides DC power and an inverter/active rectifier. The optimized DC/DC converter is configured to only boost a voltage level when current is directed from the rechargeable energy storage to the inverter/active rectifier and is configured to only buck a voltage level when current is directed from the inverter/active rectifier to the rechargeable energy storage. The inverter/active rectifier is connected to the optimized DC/DC converter. The optimized power converter is configured to operate in a charging mode and a discharge mode. When the optimized power converter is operating in the charging mode, the inverter/active rectifier is configured to convert three phase AC power into DC power, and the optimized power converter is configured to buck the DC power to a voltage level that is acceptable for charging the rechargeable energy storage. When the optimized power converter is operating in the discharge mode, the optimized DC/DC converter is configured to boost voltage from the rechargeable energy storage, and the inverter/active rectifier is configured to convert boosted DC power into three phase AC power for powering the one or more transport climate control loads.

In yet another embodiment, an optimized power converter for use in a transport electrical system that provides power to an electrically powered accessory is provided. The optimized power converter includes an optimized DC/DC converter and an inverter/active rectifier. The optimized DC/DC converter is connected between a rechargeable energy storage of the transport electrical system that provides DC power and the inverter/active rectifier. The optimized DC/DC converter is configured to only boost a voltage level when current is directed from the rechargeable energy storage to the inverter/active rectifier and is configured to only buck a voltage level when current is directed from the inverter/active rectifier to the rechargeable energy storage. The inverter/active rectifier is connected to the optimized DC/DC converter. The optimized power converter is configured to operate in a charging mode and a discharge mode. When the optimized power converter is operating in the charging mode, the inverter/active rectifier is configured to convert three phase AC power into DC power, and the optimized power converter is configured to buck the DC power to a voltage level that is acceptable for charging the rechargeable energy storage. When the optimized power converter is operating in the discharge mode, the optimized DC/DC converter is configured to boost voltage from the rechargeable energy storage, and the inverter/active rectifier is configured to convert boosted DC power into three phase AC power for powering one or more AC loads of the electrically powered accessory.

In a further embodiment, a transport electrical system for powering an electrically powered accessory is provided. The transport electrical system includes an electrically powered accessory load network and an optimized power converter. The electrically powered accessory load network includes a plurality of electrically powered accessory loads that use power to operate the electrically powered accessory. The optimized power converter provides power to one or more electrically powered accessory loads of the electrically powered accessory load network. The optimized power converter includes an optimized DC/DC converter and an inverter/active rectifier. The optimized DC/DC converter is connected between a rechargeable energy storage of the transport electrical system that provides DC power and an inverter/active rectifier. The optimized DC/DC converter is configured to only boost a voltage level when current is directed from the rechargeable energy storage to the inverter/active rectifier and is configured to only buck a voltage level when current is directed from the inverter/active rectifier to the rechargeable energy storage. The inverter/active rectifier is connected to the optimized DC/DC converter. The optimized power converter is configured to operate in a charging mode and a discharge mode. When the optimized power converter is operating in the charging mode, the inverter/active rectifier is configured to convert three phase AC power into DC power, and the optimized power converter is configured to buck the DC power to a voltage level that is acceptable for charging the rechargeable energy storage. When the optimized power converter is operating in the discharge mode, the optimized DC/DC converter is configured to boost voltage from the rechargeable energy storage, and the inverter/active rectifier is configured to convert boosted DC power into three phase AC power for powering the one or more electrically powered accessory loads.

Other features and aspects will become apparent by consideration of the following detailed description and accompanying drawings.

