DC-to-DC converter with variable set-point control

A DC-to-DC converter may be disposed in a vehicle for converting a high voltage from a power source to a low voltage. The DC-to-DC converter may include a primary converter, a secondary converter, and a DC-to-DC module. The DC-to-DC module may control the operation of the secondary converter based on a set-point threshold and a power output of the primary converter, where the set-point threshold may be variably set.

FIELD

The present disclosure relates to a DC-to-DC converter, and more particularly, a dual board converter having variable set-point control for a vehicle.

BACKGROUND

Vehicles, such as electric vehicles and/or hybrid vehicles, include a buck type DC-to-DC converter for converting high voltage from a battery to a low voltage. Such DC-to-DC converters provide electrical power to various electrical driven components in the vehicle.

As customer demand for increased electrical features increases, so does the electrical load placed on a vehicle system. Consequently, the DC-to-DC converter is required to support the vehicle system by outputting the necessary voltage and/or current for powering the electrical components. The typical DC-to-DC converter may simply output the voltage and/or current while the efficiency of the DC-to-DC converter and the vehicle system may only be a result. As an electrical system, the efficiency of vehicle is critical to the performance and fuel economy of the vehicle.

SUMMARY

A DC-to-DC converter for a vehicle may include a primary converter and a secondary converter. The primary converter and the secondary converter are electrically coupled to a power source of the vehicle, and both convert a first voltage from the power source to a second voltage lower than the first voltage.

The DC-to-DC converter may also include a DC-to-DC module that controls the operation of the secondary converter based on a set-point threshold and a power output of the primary converter. For example, the DC-to-DC module may activate the secondary converter when the power output of the primary converter is greater than or equal to the set-point threshold and deactivate the secondary converter when the power output of the primary converter is less than the set-point threshold.

The set-point threshold may be variably set. For example, in a feature of the disclosure, the DC-to-DC module may set the set-point threshold based on a desired set-point threshold transmitted by a device external of the vehicle.

In another feature of the disclosure, the set-point threshold may be adjusted based on an operation parameter of the primary converter and a correlation table.

In yet another feature of the disclosure, the set-point threshold may be adjusted based on performance history of the vehicle, the operation parameter, and/or the correlation table.

DETAILED DESCRIPTION

The present disclosure will now be described more fully with reference to the accompanying drawings.

With reference toFIG. 1, a vehicle system10is now presented. The vehicle system10may be for a hybrid vehicle and/or electric vehicle. The vehicle system10may include multiple control modules for controlling various components or devices in a vehicle. For example, the vehicle system10may include a navigation module12, an audio-visual module14, a passenger seat module16, a climate control module18, and a lighting module20.

The navigation module12may provide information regarding a location of the vehicle from a GPS receiver. The navigation module12may provide such information to the audio-visual module14via a communication network22. The communication network22may be a car area network (CAN), a local interconnect network (LIN), or other suitable vehicle communication networks.

The passenger seat module16may control a driver seat and a front passenger seat. For example, vehicle seats may be equipped with a heating element28and power seat electronics30. The heating element28may be embedded in the fabric of the seat for heating the seat. The power seat electronics30controls the position of the seat. For example, the power seat electronics30can adjusts the fore-and-aft position, seat height, lumbar position, and/or seat depth. The passenger seat module16may receive a signal from seat control switches which may activate the heated seat feature and/or adjusts the position of the seat. Based on the signal received, the passenger seat module16controls the heating element28and/or the power seat electronics30.

The climate control module18controls the heat, ventilation, air-conditioning system (HVAC) of the vehicle. Various gauges may be used to adjust the environment in the passenger cabin. Based on the settings of the gauges, the climate control module18controls various components of the HVAC system. For example, the climate control module18may control a defroster32and a blower fan34.

The lighting module20controls the exterior lighting of the vehicle. The lighting module20may turn on headlamps36and/or fog lamps38. The lighting module20may automatically turn on exterior lights based on information from photosensors. The lighting module20may also control the exterior lights based on the settings of light gauges disposed in the passenger cabin.

The vehicle system10also includes a vehicle control module37. The vehicle control module37monitors the various sub-systems within the vehicle system10. Specifically, the vehicle control module37communicates with the other modules of the vehicle system10via the communication network22. For example, the audio-visual module14may notify the vehicle control module37of the activation of the display24and the speaker system26. Similarly, the climate control module18may notify the vehicle control module37of the performance of the HVAC system and the activation of its various components.

In addition to communicating with modules of the vehicle system10via the communication network22, the vehicle control module37may communicate with devices external of the vehicle such as a communication tool39via the vehicle network. The communication tool39may be connectable and disconnectable to and from the communication network22. The communication tool39transmits and receives information from the vehicle control module37via the communication network22. It is readily understood that an external device such as the communication tool39may communicate with other modules disposed in the vehicle and is not limited to the vehicle control module37.

The various components disposed within the vehicle may require electrical power in order to operate. With reference toFIG. 2, an example of an electrical system of the vehicle is presented. A battery44provides high voltage power to the vehicle. The battery44may power one or more electric motors (not shown). The electric motors may convert the electrical power from the battery44to mechanical power to move the vehicle.

The battery44may also be used to power components within the vehicle (vehicle components). More particularly, voltage from the battery44is distributed to the vehicle components via the DCDC converter42and a power distribution board (PDB)46. The DCDC converter42converts the high voltage (HV) from the battery44to low voltage (LV). The low voltage is then supplied to the PDB46.

The PDB46distributes the low voltage to other vehicle components. For example, as shown inFIG. 2, the PDB46is electrically coupled to a 12V battery48, the speaker system26, the display24, the headlamps36, the fog lamps38, the blower fan34, the defroster32, the heating element28, and the power seat electronics30. The PDB46may be coupled to other power distribution boards and/or other vehicle components which may not be shown. For example, the PDB46may be electrically coupled to another power distribution board that powers electrical components of the HVAC system. Accordingly, the blower fan34and the defroster32may receive electrical power from the PDB46by way of the other power distribution board. While certain modules and components are depicted inFIGS. 1 and 2, it will be appreciated by one skilled in the art, that other modules and components may also be included in the vehicle system10.

With reference toFIG. 3, an example of the DCDC converter42is presented. The DCDC converter42includes two DC-to-DC buck type converters. Specifically, the DCDC converter42includes a primary DCDC converter50and secondary DCDC converter52. The primary DCDC converter50may be known as a master DCDC converter, and the secondary DCDC converter52may be known as a slave DCDC converter. For the sake of brevity, the primary DCDC converter50is referred to as the primary converter50and the secondary DCDC converter52is referred to as the secondary converter52in the following.

As DC-to-DC buck type converters, the primary converter50and the secondary converter52may be provided as an electric circuit disposed on a board. The primary converter50and the secondary converter52may be disposed together within, for example, one housing. Alternatively, the primary converter50and the secondary converter52may be disposed in separate housings.

In the example embodiment ofFIG. 3, the primary converter50and the secondary converter52are both electrically coupled to the battery44and the PDB46. As the DCDC converter42, the primary converter50and the secondary converter52are electrically coupled to the battery44, via a high voltage insular cable54A,54B. The high voltage insular cable54A may couple a negative terminal of the battery44to a negative terminal of the DCDC converter42and the high voltage insular cable54B may couple a positive terminal of the battery44to a positive terminal of the DCDC converter42. The primary converter50and the secondary converter52are electrically coupled to the PDB46by way of a low voltage insular cable56.

With reference toFIG. 4, an example of the DCDC module40is now presented. The DCDC module40includes a primary module58(i.e., master module) and a secondary module60(i.e., slave module). The primary module58is part of the primary converter50, and the secondary module60is part of the secondary converter52. The primary module58may be programmed to identify its converter as the “primary”, and the secondary module60may be programmed to identify its converter as the “secondary”.

The primary module58includes a processor62A, a current sensor64A, a temperature sensor66A, and a voltage sensor68A. Similarly, the secondary module60includes a processor62B, a current sensor64B, a temperature sensor66B, and a voltage sensor68B. The processor62A of the primary module58is communicably coupled to the processor62B of the secondary module60. Accordingly, the primary module58and the secondary module60may exchange, for example, data operation instructions and other switchable information.

In the following description, components of the primary module58may be referenced with “primary” and components of the secondary module60may be referenced with “secondary”. For example, the processor62A may be referred to as the primary processor62A, and the processor62B may be referred to as the secondary processor62B.

The primary current sensor64A detects the amount of current being outputted by the primary converter50and communicates such information to the primary processor62A. The primary temperature sensor66A detects the temperature of the primary converter50and communicates such information to the primary processor62A. The primary voltage sensor68A detects the amount of voltage being outputted by the primary converter50and communicates such information to the primary processor62A.

The secondary current sensor64B, the secondary temperature sensor66B, and the secondary voltage sensor68B function in a similar manner as the primary current sensor64A, the primary temperature sensor66A and the primary voltage sensor68A, respectively. The secondary current sensor64B, the secondary temperature sensor66B, and the secondary voltage sensor68B communicate the information detected to the secondary processor62B.

The primary module58may also include a memory70. The memory70is communicatively coupled to the primary processor62A. The memory70may store, for example, processes to be performed by the primary processor62A. The memory70is a non-transitory computer readable medium.

The DCDC module40may also include an input/output interface72. The primary module58may communicate with the communication network22via the I/O interface72. In the example embodiment, the primary module58is communicatively coupled to the I/O interface72. Alternatively, the secondary module60may also be communicatively coupled to the I/O interface72.

In the example embodiment, the primary converter50and the secondary converter52perform in a similar manner. More particularly, when in operation, both the primary converter50and the secondary converter52convert a high voltage from the battery44to a lower voltage.

As the primary, the primary converter50is the lead converter for continuously supplying low voltage to the PDB46. The primary module58monitors the performance of the primary converter50. Specifically, the primary module58monitors the amount of voltage and/or current being outputted by the primary converter50.

As the number of components that receive power from the PDB46increases, the load placed on the primary converter50also increases. To meet the electrical demands of the vehicle system10, the secondary converter52is utilized to supplement the primary converter50. More particularly, the secondary converter52is turned on when a power output of the primary converter50reaches a set-point threshold.

The power output of the primary converter50may be gauged by the amount of current and/or the amount of voltage the primary converter50is producing. The power output of the primary converter50is compared with the set-point threshold to determine whether the secondary converter52is to be activated/deactivated. For example, when the primary converter50outputs a current and/or a voltage above the set-point threshold, the primary module58may send a signal to the secondary module60. The secondary module60may then turn on the secondary converter52which begins to convert high voltage to low voltage. Accordingly, during high electric loads, the vehicle system10utilizes both the primary converter50and the secondary converter52.

As the primary converter50and the secondary converter52are in operation, the load placed on the DCDC converter42may begin to decrease. For example, vehicle components may be turned off and, therefore, no longer require power from the PDB46. Accordingly, the primary module58may turn off the secondary converter52. For example, when the current and/or voltage level outputted by the primary converter50is below the set-point threshold, the primary processor62A transmits a signal to the secondary processor62B to turn off the secondary converter52. The primary converter50continues to provide power while the secondary converter52is in the off state.

The set-point threshold interchanges the DCDC converter42between a single DCDC converter (i.e., primary converter50) and a dual DCDC converter (primary converter50and secondary converter52). The set-point threshold may be a variable set-point. More particularly, the set-point threshold may be determined based on the efficiency of the DCDC converter42and the vehicle system10.

In the example embodiment, the set-point threshold may be determined by the original equipment manufacturer (OEM) of the vehicle. The OEM may set the set-point threshold based on the efficiency and standards of the vehicle system10. For example, after extensive testing, the OEM may determine at which current and/or voltage output level the DCDC converter42should switch from a single DCDC converter to a dual DCDC converter.

The OEM may set the set-point threshold via the communication tool39. The communication tool39may communicate the set-point threshold (i.e., a desired set-point threshold) to the vehicle control module37. The vehicle control module37transmits the set-point threshold to the DCDC module40via the communication network22. For example, the primary processor62B of the DCDC module40receives the set-point threshold and stores the set-point threshold in the memory70. Once set, the DCDC module40utilizes the set-point threshold provided by the communication tool37for switching between the single DCDC converter and the dual DCDC converter. Accordingly, the OEM is able to set the set-point threshold based on the optimum efficiency of their vehicle system10.

Once set, the set-point threshold is permanently fixed and may not change. As an alternative to the fixed set-point threshold determined by the OEM, the set-point threshold may be adjustable. For example, the primary module58may adjust the set-point threshold based on an operation parameter of the primary converter50.

Using a predefined correlation table80, the primary module58may adjust the set-point threshold based on the operation parameter of the primary converter50. With reference toFIG. 5, an example of the correlation table80is presented. The correlation table80may be stored in the memory70. The correlation table80identifies a set-point threshold (“Set-Point” inFIG. 5) for specific temperature, voltage, and current ranges. As the temperature, current, and/or voltage of the primary converter50varies, the set-point threshold may be adjusted.

In the example embodiment, the primary module58may adjust the set-point threshold when any one of the operation parameters fluctuates. For example, if the temperature of the primary converter50changes from a value between the range T1-T2to a value between the range T3-T4, the primary module58may adjust the set-point threshold to SP2. Accordingly, the set-point threshold may be adjusted per the change in temperature even if the voltage and the current of the primary converter50do not change. Alternatively, the primary module58may change the set-point threshold when, for example, two more of the operation parameters change. As such, it would be appreciated by one skilled in the art that the set-point threshold may be adjusted based on one or more operation parameters.

Furthermore, in the example embodiment, the set-point threshold is adjusted based on the temperature, the voltage, and/or current. Alternatively, the set-point threshold may be adjusted based on the voltage, and/or current, or only the voltage. In other words, the operation parameter used to adjust the set-point threshold may include one or more characteristics and is not limited to temperature, voltage, and current as described herein.

Furthermore, the operation parameter may be determined by a predefined algorithm that utilizes information detected by a sensor to determine the operation parameter. For example, the algorithm may weigh the temperature, the current, and/or voltage detected by the sensors64A,66A, and68A to determine an overall operation parameter. A correlation table may then associate various levels of the overall operation parameter with a given set-point threshold.

By adjusting the set-point threshold, the DCDC converter42functions at optimal level. More particularly, as the load on the DCDC converter42fluctuates, the operation parameter also fluctuates. The DCDC module40adjusts the set-point threshold to meet the performance requirements of the vehicle system10while optimizing the efficiency of the DCDC converter42.

To further optimize the efficiency of the DCDC converter42, the DCDC module40may be a smart module by learning an operation pattern of vehicle system10. For example, the DCDC module40may collect and store information regarding the performance of the DCDC converter42and the components of the vehicle system10.

The DCDC module40via the primary module58may receive and/or request information regarding which vehicle components are receiving power from, for example, the vehicle control module37. The DCDC module40may build a performance history of the vehicle system10. For example, when the primary module58adjusts the set-point threshold, the primary module58may store the temperature, the voltage, and the current of the primary converter50. In addition, the primary module58may also store information regarding the vehicle components that are receiving power and a time stamp indicating the time at which such information was stored. The primary module58may also store additional information, such as the temperature, the voltage, and the current of the secondary converter52, whether the DCDC converter42is performing as single DCDC converter or a dual DCDC converter, and other suitable information.

As part of the DCDC module40, the primary module58may store such information in the memory70. The primary module58may store such information at the time the set-point threshold is adjusted. Alternatively, the primary module58may also store such information periodically or as the information changes.

In the example embodiment, the primary module58, as part of the DCDC module40, is referenced for adjusting the set-point threshold and storing performance history of the vehicle. Alternatively, the DCDC module40may include a system module separate from the primary module58and the secondary module60. The system module may adjust and store information. It would be appreciated by one skilled in the art that the DCDC module40may be configured in various suitable ways for collecting information, and is not limited to the example described herein.

Using the predefined correlation table80as an initial set point and the information stored in the memory70, the DCDC module40may detect a pattern between the vehicle components being used and the set-point threshold for a particular point in time. The DCDC module40may then adjust the set-point threshold based on the pattern detected. For example, at certain times during the day, the vehicle system10may be utilizing more vehicle components than at other times. For instance, in the morning a user may heat the seats and turn on the defroster and blower fans to warm the vehicle during the winter months. Whereas, in the afternoon, a user may not heat the seats and/or turn on the defroster and blower fan.

Accordingly, the DCDC module40may adjust the set-point threshold to a suitable level to meet expected performance requirement of the vehicle system10. More particularly, the set-point threshold is set to a suitable level based on the performance history of the vehicle. Thus, the pattern learned by the DCDC module40, may alter the set-point threshold to further optimize the efficiency of the system.

With reference toFIG. 6, a flow chart of an example method100for switching the DCDC converter42between the single converter and the dual converter is now presented. At102the DCDC module40receives power output information from the sensors disposed at the primary converter50. For example, the DCDC module40may receive a voltage and/or the current being outputted by the primary converter50from the voltage sensor68A and/or current sensor64A.

The DCDC module40may then determine whether the power output of the primary converter50is greater than or equal to the set-point threshold at104. If the power output is not greater than or equal to the set-point threshold, the control returns to102. If the power output is determined as greater than or equal to the set-point threshold, the DCDC module40activates the secondary converter52at106. For example, the primary module58may transmit a signal to the secondary module60which in response, turns on the secondary converter52.

At108, the DCDC module40receives the power output of the primary converter50. At110, the DCDC module40determines whether the power output is less than the set-point threshold. If the power output is not less than the set-point threshold, the control returns to108. If the power output is less than the set-point threshold, the DCDC module40deactivates the secondary converter52at112. For example, the primary module58may transmit a signal to the secondary module60which in response turns off the secondary converter52. After the deactivation of the secondary converter52at112, the DCDC module40returns to the beginning of the process and continues to monitor the power output of the primary converter50.

With reference toFIG. 7, a flow chart of an example method200for adjusting the set-point threshold based on the operation parameter of the primary converter50is now presented. The DCDC module40may perform the method200and the method100at the same time. At202the DCDC module40receives information regarding the operation parameter of the primary converter50from the sensors. For example, the DCDC module40may receive information from the current sensor64A, temperature sensor66A, and/or voltage sensor68A, as the operation parameter.

If the values received are not outside their respective range for the current set-point threshold, the DCDC module40returns to202. When one of the values is outside its range for the current set-point threshold, the DCDC module40adjusts the set-point threshold based on the operation parameter and the correlation table at208. Accordingly, the DCDC module40changes the set-point threshold based on the performance of the primary converter50. After208, the DCDC module40returns to202.

With reference toFIG. 8, the flow chart of an example method300for adjusting the set-point threshold based on a performance history of the vehicle system10is now presented. The DCDC module40may perform the method100and the method300at the same time. At302the DCDC module40receives the operation parameter of the primary converter50. Furthermore, the DCDC module40at304receives vehicle system information from the vehicle control module37. For example, the DCDC module40may receive information regarding vehicle components within the vehicle system10which are receiving power from the PDB46as the vehicle system information.

The DCDC module40determines whether the inputs received correspond with the performance history of the DCDC converter42at306. For example, the DCDC module40may determine whether the performance history stored in the memory70matches the inputs provided from the primary converter50and the vehicle control module37.

When the inputs received do not correspond with the performance history, the DCDC module40continues to308. On the other hand, when the inputs received correspond with the performance history, the DCDC module40continues to310.

At307, the DCDC module40compares the operation parameter with the correlation table, and, at308, determines whether the operation parameter is outside the range for the current set-point threshold per the correlation table. If the operation parameter is not outside the range for the current set-point threshold, the DCDC module40returns to302. On the other hand, if the operation parameter is outside the range for the current set-point threshold, the DCDC module40adjusts the set-point threshold based on the operation parameter received and the correlation table at312.

At310, the DCDC module40determines whether the set-point threshold from the performance history is different from the current set-point threshold. If the set-point threshold from the performance history is not different from the current set-point threshold, the DCDC module40returns to302. On the other hand, if the set-point threshold from the performance history is different from the current set-point threshold, the DCDC module40at314adjusts the set-point threshold based on the performance history. In other words, the DCDC module40may adjust the set-point threshold to the one provided in the performance history.

From either312or314, the DCDC module40stores the input received and the set-point threshold at316. The DCDC module40returns to the beginning of the process at302.