DE102014101478B4 - METHOD OF CONTROLLING A COMPRESSOR OF A HEAT PUMP SYSTEM FOR THERMAL STORAGE AND SUCH A HEAT PUMP SYSTEM - Google Patents

Abstract

A method for controlling a compressor (108) of a heat pump system (100) for thermal storage in a vehicle (101) which has a passenger compartment (102), wherein the heat pump system (100) for thermal storage has a refrigeration circuit (103) which is connected via a first heat exchanger (106) in thermal communication with a first coolant circuit (104) and via a second heat exchanger (107) in thermal communication with a second coolant circuit (105), the compressor (108) being arranged in the refrigeration circuit (103) and a compressor motor (109) and a motor controller, wherein the compressor motor (109) is a brushless DC electric motor having a coefficient of performance, and is a three-phase system in which, in an unmodified state, each phase is offset by a set angle and a having a defined frequency, the method comprising: by at least one system control When (131) a measurement of at least one parameter is received; an operating mode of the heat pump system (100) for thermal storage is determined by the at least one system controller (131) on the basis of the measurement of the at least one parameter; andthe compressor motor (109) is operated by the motor controller in the unmodified state or a modified state based on the operating mode of the heat pump system (100) for thermal storage, wherein operating the compressor motor (109) in the modified state reduces the coefficient of performance of the compressor motor comprises by displacing at least one of the phases of the compressor motor (109) from the set angle and / or changing the defined frequency of at least one of the phases of the compressor motor (109); wherein the operating mode is a heating mode or a cooling mode; andwherein the compressor motor (109) is operated in the unmodified state when the thermal storage heat pump system (100) is in the cooling mode and operated in the modified state when the thermal storage heat pump system (100) is in the heating mode is located.

Description

TECHNICAL AREA

The present invention relates to a method for controlling a compressor of a heat pump system for thermal storage in a vehicle, such as a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) and such a heat pump system.

BACKGROUND

From the U.S. 5,549,153 A For example, a device for cooling drive components and heating a passenger compartment of an electric vehicle with a drive motor fed by a battery has become known which comprises a first coolant circuit which is coupled to a second coolant circuit via an intermediate heat exchanger. A first heat exchanger acting as a cooler and a second heat exchanger acting as a radiator are provided in the second coolant circuit. The heat exchangers arranged in the second coolant circuit are each provided with a controllable bypass. A control unit records several temperature states as well as signals derived from the battery control unit and processes them in order to actuate appropriate actuating and drive means for the flow of the cooling medium.

Regarding the further state of the art, please refer to the publications at this point DE 100 13 510 A1 and EP 1 739 822 A1 referenced.

An electric vehicle, such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or the like generally has an electric motor that can drive the vehicle alone in an electric vehicle (EV) or charge-depleting driving mode. The vehicle may also have an internal combustion engine (ICE) that serves as the primary propulsion system of the vehicle in a range extending mode or operates in conjunction with the electric motor in a hybrid or charge sustaining mode.

The electric motor generally receives electrical power from an electrical power source, such as an energy storage system (ESS). The ESS may include a battery pack or other rechargeable energy storage device capable of storing large amounts of thermal energy. The ESS can store the thermal energy when the vehicle is connected to an external power source, such as an electrical power grid, for charging. In colder ambient temperatures, the charge depletes faster due to various factors.

The ESS can be used in conjunction with a thermal management system, such as a heat pump system, thereby forming a thermal storage heat pump system to transfer the stored thermal energy to another medium for other purposes, such as heating a passenger compartment of the vehicle.

The heat pump system (and therefore the heat pump system for thermal storage) comprises a compressor that compresses refrigerant, which serves as a heat transfer medium for the heat pump system. The compressor motor requires a certain amount of electrical energy, which in turn is converted into electrical heat to be used to compress the refrigerant. The electrical power that is required depends on the coefficient of performance (COP) of the compressor motor. As the COP increases, the compressor motor uses less electrical power.

The invention is based on the object of specifying a realization with which a heat pump system for thermal storage can be operated as efficiently as possible.

SUMMARY

This object is achieved with a method with the features of claim 1 and with a heat pump system with the features of claim 3.

The at least one parameter can be an ambient air temperature. When the ambient air temperature is at or below a switching temperature, the heat pump system can operate in the heating mode for thermal storage. When the ambient air temperature is above the switching temperature, the heat pump system can operate in the cooling mode for thermal storage. The compressor motor is operated in the unmodified state when the thermal storage heat pump system is in the cooling mode and operated in the modified state when the thermal storage heat pump system is in the heating mode.

The above features and advantages, as well as other features and advantages of the present invention, will become readily apparent from the following detailed description of some of the best modes and other modes for carrying out the invention included solely in the appended hereto Claims defined is readily apparent in connection with the accompanying drawings.

Figure list

• 1 Figure 13 is a schematic diagram of a thermal storage heat pump system that includes a compressor with a compressor motor;
• 2 FIG. 13 is a schematic diagram of the compressor motor of FIG 1 ;
• 3 Figure 3 is a schematic flow diagram of a method for controlling the compressor;
• 4th FIG. 13 is a schematic flow diagram illustrating one step of the method of FIG 3 shows;
• 5 Fig. 13 is a graph showing a relationship between the coefficient of performance (COP) of the compressor motor and the ambient air temperature; and
• 6th Fig. 13 is a graph showing a relationship between the electric heat generated by the compressor motor and the ambient temperature.

DETAILED DESCRIPTION

The following description and figures relate to exemplary embodiments and are merely exemplary in nature and are not intended to limit the invention, its application, or uses. In the figures, some components are shown with standardized or basic symbols. These symbols are representative and illustrative only and are in no way limiting of any specific configuration shown, combinations between the various configurations shown, or limitative of the claims. All component descriptions are open ended and any examples of components are not exhaustive.

Referring to the drawings, wherein like reference numbers correspond to like or similar components wherever possible in the different figures, is a heat pump system 100 for thermal storage for use in a vehicle 101 , which includes, but is not limited to, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or the like, in 1 shown. The vehicle 101 can be selectively operated in a range extension mode, a hybrid or charge sustaining mode, and an electric vehicle (EV) or charge depletion driving mode. An internal combustion engine (ICE) works in a mode that extends the range 128 as described below as the exclusive propulsion system for the vehicle 101 . The vehicle works in a hybrid mode 101 using both electric power from an electric motor (not shown) and power from the internal combustion engine 128 . In the EV driving mode, the vehicle operates 101 only with electricity.

The heat pump system 100 for thermal storage generally has a cooling circuit 103 in thermal connection with a first coolant circuit 104 and a second coolant circuit 105 via a first heat exchanger 106 or a second heat exchanger 107 on. The refrigeration cycle 103 , the first coolant circuit 104 and the second coolant circuit 105 are configured to circulate a refrigerant, a first coolant, and a second coolant, respectively. The first heat exchanger 106 may be a coolant-to-liquid cooler heat exchanger that can function as a heat pump evaporator to remove heat from the first coolant in the first coolant circuit 104 on the refrigerant in the refrigeration cycle 103 to dissipate. The second heat exchanger 107 can also be a refrigerant-to-liquid heat exchanger that can function as a heat pump condenser to remove heat from the refrigerant in the refrigeration cycle 103 on the second coolant in the second coolant circuit 105 to dissipate.

The refrigeration cycle 103 has a compressor 108 on, the downstream of the first heat exchanger 106 and upstream of the second heat exchanger 107 is arranged. The compressor 108 may be configured to compress the refrigerant. The compressor 108 is powered by a compressor motor 109 which can be a brushless direct current (DC) electric motor, as shown in the schematic diagram in FIG 2 is shown.

Now referring to 2 takes the compressor motor 109 generally a DC input signal from a power source 110 on. An inverter 111 converts the direct current signal to an alternating current (AC) signal to the compressor motor 109 to drive. The compressor motor 109 is generally a three-phase system, and as such has three motor windings 112 around a rotor 113 to record the AC signal. While the motor windings 112 are shown in a star (Y) configuration, it should be understood that they can be in a delta (Δ) configuration as well. In an unmodified state of the compressor motor 109 , in which the compressor motor 109 is most efficient, each phase is offset by a specified angle equal to one third of a period, or 120 degrees. In addition, phase works with a defined frequency. As with procedures 200 is explained below, can do this and other properties of the compressor motor 109 modified to reduce its coefficient of performance (COP), that is, to make it less efficient.

The compressor motor 109 also has a motor controller 114 configured to operate the compressor motor 109 including, but not limited to, the speed and position of the rotor 113 of the compressor motor 109 to control the frequency and the offset of the three phases, commutation and the like.

Referring back to 1 shows the refrigeration cycle 103 also a first device 115 for thermal expansion, a second device 116 for thermal expansion and a third heat exchanger 117 on. The third heat exchanger 117 can be a heat exchanger from ambient to refrigerant that can function as a cabin evaporator. It can be configured to absorb heat from the air flowing over it to the passenger compartment 102 to cool and dehumidify and to transfer the heat to the refrigerant flowing through. The refrigerant can then be sent to the compressor 108 and then to the second heat exchanger 107 where the heat in the refrigerant can be absorbed by the second coolant, as explained above.

The first device 115 for thermal expansion and the second device 116 for thermal expansion, downstream of the second heat exchanger 107 be arranged and configured such that the refrigerant for distribution to the first heat exchanger 106 or the third heat exchanger 117 to cool and expand. The first device 115 for thermal expansion and the second device 116 thermal expansion valves can be thermostatic valves or thermal expansion valves and can be either electronically or mechanically operated.

The refrigeration cycle 103 can also have a fourth heat exchanger 118 exhibit. The fourth heat exchanger 118 can be a heat exchanger from refrigerant to ambient and can act as a condenser for an air conditioning (A / C) system (not shown) in the vehicle 101 function.

The refrigeration cycle 103 may further include a plurality of flow control valves 119 , 120 , 121 and 122 exhibit. The flow control valves 119 , 120 , 121 and 122 can be configured to control the flow to the various components in the refrigeration cycle 103 to control. It should be noted that the flow control valves 119 , 120 , 121 and 122 may be any valve capable of restricting the flow of refrigerant in a particular line and may, but are not limited to, two position open / closed valves or, alternatively, modulating valves.

The first coolant circuit 104 has a device 123 for thermal storage and a first coolant pump 124 on. The device 123 thermal storage can be any medium, device, machine, or the like that is capable of generating and storing thermal energy. For example, the device 123 be an energy storage system (ESS) for thermal storage, which has at least one battery or a battery pack.

The first coolant pump 124 that may have a variable speed may be configured to flow the first coolant through the device 123 for thermal storage to circulate so that the first coolant heat by the device 123 for thermal storage is generated, or absorbing heat in the device 123 for thermal storage can deposit. The first coolant pump 124 may further be configured such that the first coolant through the first heat exchanger 106 to circulate so that heat can be transferred from the first coolant to the refrigerant, as explained above. While the first coolant pump 124 downstream of the device 123 for thermal storage, it should be noted that it is upstream of the device 123 can be arranged for thermal storage.

The first coolant circuit 104 can also be a heater 125 exhibit. The stoker 125 may be configured such that the first coolant is in the first coolant circuit 104 to heat that to the device 123 for thermal storage flows where the heat can be deposited and stored. The stoker 125 may, but is not limited to, a resistance heater.

The second coolant circuit 105 includes a heater core 126 and a second coolant pump 127 . The second coolant pump 127 that may have a variable speed may be configured to flow the second coolant through the heater core 126 to circulate. The heater core 126 in turn, may be configured to receive the second coolant to remove air passing over it and into the passenger compartment 102 flows to heat. As explained above, the second coolant can remove heat from the device 123 for thermal storage via the first heat exchanger 106 and / or from the ambient air via the third heat exchanger 117 take up. While the second coolant pump 127 downstream of the heater core 126 It should be understood that it is upstream of the heater core 126 can be arranged.

The second coolant circuit 105 can also be the internal combustion engine 128 as mentioned above. The internal combustion engine 128 can have heat in itself from an operation. The heat can be present in the second coolant when it is through the internal combustion engine 128 flows, whereby the internal combustion engine 128 is cooled.

The second coolant circuit 105 can also be a bypass valve 129 and a bypass line 130 exhibit. The bypass valve 129 is configured to selectively deliver the second coolant to the internal combustion engine 128 to steer in order to cool this when the vehicle is moving 101 is in a range-extending mode or hybrid mode, or to the bypass line 130 to steer when the vehicle is moving 101 is in the EV driving mode. While the bypass valve 129 in 1 is shown as a three-way valve with two positions, it should be noted that the bypass valve 129 can be any three-way valve configured to selectively direct flow to the internal combustion engine 128 and / or the bypass line 129 to steer. In an alternative embodiment, which is not shown, instead of a three-way valve, two separate flow control valves, one in each case on the bypass line 130 and the second coolant circuit 105 downstream of the extraction for the bypass line 130 be provided.

The heat pump system 100 at least one system controller can also be used for thermal storage 131 have, which is electrically connected to the heat pump system 100 can be connected to thermal storage to control its operation. In particular, the system controller 131 with various devices of the heat pump system 100 for thermal storage and their operation with the motor controller 114 control based on at least one parameter including, but not limited to, ambient air temperature, as in the method 200 is described below.

The system controller 131 can also be configured to communicate with and receive information from other auxiliary devices, including, but not limited to, a temperature sensor 132 and an input module 133 as described below. The system controller 131 may process the information received from these auxiliary devices to determine the mode of operation in which the heat pump system 100 works for thermal storage, and to operate the devices accordingly. As explained below, the heat pump system 100 work in a heating mode or a cooling mode for thermal storage. The system controller 131 can also be configured to include any other devices in the heat pump system 100 for thermal storage as well as any other subsystems in the vehicle 101 to control.

The temperature sensor 132 is generally any device configured to measure ambient air temperature. The temperature sensor 132 can be configured to send data, such as the measurement of the temperature of the ambient air, to the system controller 131 for storage and / or processing. The temperature sensor 132 can be outside the system controller 131 as in 1 is shown and can transmit the data over a wired or wireless connection. In another embodiment, not shown, the temperature sensor can be located within the system controller 131 are located. In yet another embodiment, not shown, the system controller 131 be configured to receive such data as the temperature of the ambient air from a remote source (not shown) via the Internet or other communication network.

The input module 133 Any device configured to provide an input, such as a set temperature or heat supply for the passenger compartment 102 , or other data from a user of the heat pump system 100 for thermal storage. The input module 133 can also be configured to send such data to the controller 131 transferred to. The input module 133 may, but is not limited to, an on-board computer in the vehicle 101 be.

As explained above, the heat pump system can 100 work in a heating mode or a cooling mode for thermal storage. In the heating mode, the refrigerant can be in the refrigeration cycle 103 used to transfer heat to the second coolant in the second coolant circuit 105 via the second heat exchanger 107 transfer to the passenger compartment 102 over the heater core 126 to heat as explained above. Conversely, in the cooling mode, the refrigerant can be used to remove heat from the ambient air via the third heat exchanger 117 to absorb to the passenger compartment 102 to cool. The heat pump system 100 for thermal storage can selectively switch between the two modes based on a parameter such as ambient air temperature.

In each mode, the refrigerant is in the refrigeration cycle 103 used to transfer heat, and thus the compressor will work 108 and the compressor motor 109 to compress the refrigerant. The compressor motor 109 requires a certain amount of electrical power to operate Power coming from the power source 110 is recorded. When the refrigerant is compressed, the compressor motor converts 109 converts the electrical power into electrical heat, which can then be transferred to the refrigerant.

In the heating mode, the electrical power is that for the compressor motor 109 is necessary, and thus the electrical heat generated by the compressor motor 109 generated equal to the total thermal load required to the passenger compartment 102 to heat divided by the COP of the compressor motor 109 . All thermal load that is required can be taken from the system controller 131 based on a desired temperature or heat supply for the passenger compartment 102 can be determined as from the input module 133 is recorded. The remaining thermal load that is not provided by the electrical heat generated by the compressor motor 109 can be generated by the device 123 for thermal storage.

Now referring to that 5 and 6th is the effect of the modification of the COP, as indicated by the y-axis 302 in 5 is shown on the electrical heat that is generated and represented by the y-axis 312 in FIG 6th is shown when switching between the heating and cooling modes indicated by the sections 308 or. 310 are shown in the 5 and 6th shown. The x-axis 304 in the 5 and 6th represents the ambient air temperature. As explained above, the compressor motor 109 be made less efficient by modifying its characteristics to reduce its COP. Generally there is the compressor motor 109 in the cooling mode in its unmodified state. However, by reducing the COP in the heating mode, the electric heat that is generated increases with the fixed total thermal load that is required. Thus, the amount of thermal load exerted by the device 123 for thermal storage, decrease. This in turn can reduce the need for heating 125 operate to those in the device 123 provide stored heat for thermal storage.

Now referring to 3 is a procedure 200 to control the heat pump system 100 for thermal storage, especially of the compressor 108 and the compressor motor 109 shown.

The procedure 200 starts at step 202 where the system controller 131 takes a measurement of at least one parameter. The at least one parameter can be, but is not limited to, an ambient air temperature. As explained above, the measurement of the temperature of the ambient air from the temperature sensor 132 taken and sent to the system controller 131 be transmitted.

After step 202 drives the procedure 200 with step 204 away. At step 204 the system controller determines 131 the operating mode of the heat pump system 100 for thermal storage based on the measurement of the at least one parameter. As explained above, the heat pump system can 100 work in either a heating mode or a cooling mode for thermal storage.

If the measurement of the at least one parameter fulfills a certain condition, the heat pump system works 100 for thermal storage in the particular mode associated with this condition. For example, as shown in the diagrams of the 5 and 6th is shown when the ambient air temperature (x-axis 304 ) at or below a switching temperature 306 lies, the heat pump system 100 for thermal storage in the heating mode (section 308 ) work. Conversely, if the ambient air temperature is above the switching temperature 306 lies, the heat pump system 100 for thermal storage in the cooling mode (section 310 ) work. The switchover temperature can be set in the system controller 131 saved and can be adjustable.

After step 204 drives the procedure 200 with step 206 away. At step 206 operates the compressor controller 114 the compressor motor 109 either in an unmodified state or a modified state depending on the operating mode. As explained above, when the thermal storage heat pump system is in the cooling mode, the compressor controller operates 114 the compressor motor 109 in the unmodified or most efficient state. When the heat pump system 100 is in the heating mode for thermal storage, the compressor controller operates 114 the compressor motor 109 in the modified state in which its COP is decreased. This can involve several sub-steps, as in 4th is shown.

Referring to 4th can at partial step 206a the compressor controller 114 at least one of the three phases of the compressor motor 109 offset from the specified angle. For example, the compressor controller 114 offset one of the phases by 30 degrees. At partial step 206b can the compressor controller 114 change the defined frequency of at least one of the three phases. As explained above, each phase operates at a fixed frequency. Changing at least one of these can reduce the COP. It should be noted that step 204 one of the substeps 206a and 206b may have that can be performed in any order. It should also be noted that step 206 may include several sub-steps in which the compressor motor 109 can be changed in other ways, such as an internal motor restriction, mechanical losses within the compressor motor 109 (or frictional losses), mechanical braking, and the like to reduce the COP.

Claims (5)

A method for controlling a compressor (108) of a heat pump system (100) for thermal storage in a vehicle (101) which has a passenger compartment (102), wherein the heat pump system (100) for thermal storage has a refrigeration circuit (103) which is connected via a first heat exchanger (106) in thermal communication with a first coolant circuit (104) and via a second heat exchanger (107) in thermal communication with a second coolant circuit (105), the compressor (108) being arranged in the refrigeration circuit (103) and a compressor motor (109) and a motor controller, wherein the compressor motor (109) is a brushless DC electric motor having a coefficient of performance, and is a three-phase system in which, in an unmodified state, each phase is offset by a set angle and a having a defined frequency, the method comprising: a measurement of at least one parameter is received from at least one system controller (131); the at least one system controller (131) determines an operating mode of the heat pump system (100) for thermal storage on the basis of the measurement of the at least one parameter; and the compressor motor (109) is operated by the motor controller in the unmodified state or a modified state based on the operating mode of the heat pump system (100) for thermal storage, the operating of the compressor motor (109) in the modified state reducing the coefficient of performance of the compressor motor comprises by displacing at least one of the phases of the compressor motor (109) from the set angle and / or changing the defined frequency of at least one of the phases of the compressor motor (109); wherein the operating mode is a heating mode or a cooling mode; and wherein the compressor motor (109) is operated in the unmodified state when the thermal storage heat pump system (100) is in the cooling mode and operated in the modified state when the thermal storage heat pump system (100) is in the heating mode is located. Procedure according to Claim 1 , wherein the at least one parameter is an ambient air temperature. Heat pump system (100) for thermal storage of a vehicle (101) having a passenger compartment (102), the system (100) comprising: a first coolant circuit (104) configured to circulate a first coolant; a second coolant circuit (105) configured to circulate a second coolant; a refrigeration circuit (103) configured to circulate a refrigerant, the refrigeration circuit (103) in thermal communication with the first coolant circuit (104) via a first heat exchanger (106) and in thermal communication via a second heat exchanger (107) with the second coolant circuit (105); a compressor (108) arranged in the refrigeration cycle (103), the compressor (108) being configured to compress the refrigerant, and having a compressor motor (109) and a motor controller configured to operate the compressor motor ( 109) selectively operate in an unmodified state or a modified state, wherein the compressor motor (109) is a brushless DC electric motor having a coefficient of performance, and is a three-phase system in which, in the unmodified state, each phase by a fixed one Is angularly offset and has a defined frequency; and at least one system controller (131) configured to selectively operate the heat pump system (100) for thermal storage in a heating mode or a cooling mode based on a measurement of at least one parameter; wherein the compressor motor (109) is operated in the unmodified state when the heat pump system (100) for thermal storage is in the cooling mode, and operated in the modified state when the heat pump system (100) for thermal storage is in the heating mode, wherein operating the compressor motor (109) in the modified state comprises reducing the coefficient of performance of the compressor motor (109) by offsetting at least one of the phases of the compressor motor (109) from the set angle and / or the defined frequency of at least one of the phases of the Compressor motor (109) is changed. Heat pump system for thermal storage according to Claim 3 , wherein the at least one parameter is an ambient air temperature. Heat pump system for thermal storage according to Claim 3 wherein the coefficient of performance when the thermal storage heat pump system (100) is in the heating mode is less than the coefficient of performance when the thermal storage heat pump system (100) is in the cooling mode.

Images