System and method for temperature estimation of inverter ac power bus

Abstract

The invention relates to a system and method for temperature estimation of an inverter AC power bus. A system for controlling operation of a vehicle having a power inverter module includes an alternating current (AC) power bus coupled to the power inverter module. The AC power bus has a plurality of bus bars for conducting an AC current having multiple phases. The AC power bus is coupled to a stator in an electric motor configured to generate torque to propel the vehicle. The controller is adapted to determine an estimated temperature for the multi-phase AC power bus based on a plurality of factors. The plurality of factors include an oil flow rate of engine oil and a coolant flow rate of inverter coolant in direct or indirect thermal contact with the plurality of bus bars, respectively. The controller is adapted to control operation of the vehicle based in part on the highest one of the estimated temperatures of the multiple phases.

Description

Technical Field

[0001] The present disclosure generally relates to a system for controlling operation of a vehicle having a power inverter module. More specifically, the present disclosure relates to determining an estimated temperature of an alternating current (AC) power bus coupled to the power inverter module. Background Art

[0002] Hybrid and electric vehicles typically include an AC electric motor driven by a direct current (DC) power source, such as a rechargeable battery. The stator windings of the electric motor may be coupled to a power inverter that converts the DC power into AC power for driving the electric motor. The electric motor is used to power the drive system of the hybrid and electric vehicle. The AC power bus and its related components may have thermal limitations for certain operating conditions of the drive system. However, the drive system may not have physical sensors on the AC power bus and its related components to monitor temperature. Summary of the invention

[0003] A system for controlling the operation of a vehicle having a power inverter module is disclosed herein. The system includes an alternating current (AC) power bus coupled to a power inverter module. The AC power bus has a plurality of bus bars for conducting AC current having multiple phases. An electric motor is configured to generate torque to propel a vehicle. The AC power bus is coupled to a stator in the electric motor. Inverter coolant and motor oil are in direct or indirect thermal contact with the plurality of bus bars, respectively. The system includes a controller adapted to determine an estimated temperature of the AC power bus for each phase in the multiphase based on a plurality of factors, the controller having a processor and a tangible non-transitory memory on which instructions are recorded. The plurality of factors include an oil flow rate of the motor oil and a coolant flow rate of the inverter coolant. The controller is adapted to control the operation of the vehicle based in part on the highest of the estimated temperatures of the multiphases (e.g., in a system having three phases, the highest estimated temperature among the three phases).

[0004] In some embodiments, a common mode choke is in thermal communication with the plurality of bus bars. The plurality of factors may include an estimated choke heat of the common mode choke, the estimated choke heat being based in part on a switching frequency, a modulation index, and a PWM type of the power inverter module. The estimated choke heat (Q) of each phase of the plurality of phases choke ) can be obtained as: Here Q base is a calibrable value for the basic heat loss, f sw is the switching frequency, K fsw is a calibratable scalar value of the switching frequency, and K MI ,,KPWM Accordingly there are corresponding calibratable values ​​based on the modulation index and the PWM type.

[0005] Controlling operation of the vehicle may include determining an inverter capability of the power inverter module based in part on the estimated temperature, and de-rating the torque based in part on the inverter capability. The vehicle may include an auxiliary inverter, and controlling operation of the vehicle may include load sharing with the auxiliary inverter based in part on the inverter capability.

[0006] In some embodiments, determining the estimated temperature of the AC power bus may include initializing to a starting temperature for each of the plurality of phases. The starting temperature may be based in part on a cutout temperature of the AC power bus when the vehicle is shut down, an elapsed time between the vehicle shut down and the vehicle restart, a calibratable time constant of the AC power bus, and an expected cooling temperature of the AC power bus.

[0007] In some embodiments, the starting temperature (T ACBB ) is obtained as: Here T KeyOff is the cut-out temperature of the AC power bus when the vehicle is turned off, t inactv is the time elapsed between the vehicle shut down and the vehicle restart, τ is the calibratable time constant of the AC power bus, and T Clnt is the expected cooling temperature of the AC power bus.

[0008] The plurality of factors may include respective resistances of the plurality of bus bars based on respective calibratable nominal resistances (R 25C ), the starting temperature (T ACBB ) and the temperature coefficient of copper.

[0009] In some embodiments, the plurality of factors include respective heat flows between the AC power bus and a reference component of each of the plurality of phases, the respective heat flows (Q ref ) is obtained as: Q ref =[T ref -T ACBB ]*K ref Here T ref represents the corresponding temperature of the reference component, T ACBB represents the corresponding temperatures of the plurality of bus bars, and K ref The reference components may include a stator, a power inverter module, an engine oil, and an inverter coolant.

[0010] In some embodiments, the plurality of factors include respective electrical losses of the plurality of bus bars, the respective electrical losses (P loss ) is based in part on the speed of the electric motor in RPM (N Mtr ), and a calibrable speed threshold (N Thrs ) for determining whether the electric motor is in stall operation. The corresponding electrical loss may be based on the root mean square current (I RMS ) and each phase current (I abc ).

[0011] A method for operating a vehicle is disclosed herein, the vehicle having a power inverter module, an electric motor configured to generate torque, and a controller having a processor and a tangible non-transitory memory. The method includes coupling an alternating current (AC) power bus to the power inverter module, the AC power bus having a plurality of bus bars for conducting AC current having multiple phases. The AC power bus is coupled to a stator in the electric motor. The method includes positioning the plurality of bus bars in thermal contact with an inverter coolant and an engine oil, respectively. The method includes determining an estimated temperature of the AC power bus for each of the multiple phases of the AC current based on a plurality of factors, the plurality of factors including an oil flow rate of the engine oil and a coolant flow rate of the inverter coolant. Controlling the operation of the vehicle may be based in part on the highest of the estimated temperatures of the multiple phases.

[0012] The present invention also includes the following technical solutions:

[0013] Solution 1. A system for controlling operation of a vehicle having a power inverter module, comprising:

[0014] an alternating current (AC) power bus coupled to the power inverter module, the AC power bus having a plurality of bus bars for conducting AC current having multiple phases;

[0015] an electric motor configured to generate torque to propel the vehicle, the AC power bus being coupled to a stator in the electric motor;

[0016] inverter coolant and oil in direct or indirect thermal contact with the plurality of bus bars, respectively;

[0017] a controller adapted to determine an estimated temperature of the AC power bus for each of the plurality of phases based on a plurality of factors, the controller having a processor and a tangible, non-transitory memory having instructions recorded thereon;

[0018] wherein the plurality of factors include an oil flow rate of the engine oil and a coolant flow rate of the inverter coolant; and

[0019] Wherein the controller is adapted to control operation of the vehicle based in part on a highest one of the estimated temperatures of the plurality of phases.

[0020] Solution 2. The system according to Solution 1 further includes:

[0021] a common mode choke in thermal communication with the plurality of bus bars; and

[0022] Wherein the plurality of factors include an estimated choke heat of the common mode choke, the estimated choke heat being based in part on a switching frequency, a modulation index, and a PWM type of the power inverter module.

[0023] Solution 3. The system according to solution 2:

[0024] Wherein, the estimated choke heat (Q choke ) can be obtained as: as well as

[0025] Among them, Q base is a calibrable value for the basic heat loss, f sw is the switching frequency, K fsw is a calibratable scalar value of the switching frequency, and K MI , K PWM Accordingly there are corresponding calibratable values ​​based on the modulation index and the PWM type.

[0026] Embodiment 4. The system of embodiment 1, wherein controlling operation of the vehicle comprises determining an inverter capability of the power inverter module based in part on the estimated temperature, and de-rating the torque based in part on the inverter capability.

[0027] Option 5. The system of Option 4, wherein the vehicle includes an auxiliary inverter, and controlling operation of the vehicle includes load sharing with the auxiliary inverter based in part on the inverter capability.

[0028] Solution 6. The system according to solution 1:

[0029] wherein determining the estimated temperature of the AC power bus comprises initializing to a starting temperature of each of the plurality of phases; and

[0030] The starting temperature is based in part on a cutout temperature of the AC power bus when the vehicle is shut down, an elapsed time between vehicle shut down and vehicle restart, a calibratable time constant of the AC power bus, and an expected cooling temperature of the AC power bus.

[0031] Solution 7. The system according to solution 6:

[0032] Wherein, the estimated initial temperature (T ACBB ) is obtained as: as well as

[0033] Among them, T KeyOff is the cut-out temperature of the AC power bus when the vehicle is turned off, t inactv is the time elapsed between the vehicle shut down and the vehicle restart, τ is the calibratable time constant of the AC power bus, and T Clnt is the expected cooling temperature of the AC power bus.

[0034] Embodiment 8. The system of embodiment 1, wherein the plurality of factors include respective resistances of the plurality of bus bars, the respective resistances being based on respective calibratable nominal resistances (R 25C ), the estimated temperature (T ACBB ) and the temperature coefficient of copper.

[0035] Solution 9. The system according to solution 1:

[0036] The multiple factors include a corresponding heat flow between the AC power bus and a reference component of each of the multiple phases, the corresponding heat flow (Q ref ) is obtained as: Q ref =[T ref -T ACBB ]*K ref ;as well as

[0037] Among them, T ref represents the corresponding temperature of the reference component, T ACBB represents the corresponding temperatures of the plurality of bus bars, and K ref denotes the corresponding thermal conductivity of the reference component.

[0038] Embodiment 10. The system of embodiment 9, wherein the reference components include the stator, the power inverter module, the engine oil, the inverter coolant, and a common mode choke in thermal communication with the plurality of bus bars.

[0039] Solution 11. The system according to Solution 1, wherein the plurality of factors include respective electrical losses of the plurality of bus bars, the respective electrical losses (P loss ) is based in part on the speed of the electric motor in RPM (N Mtr ), and a calibrable speed threshold (N Thrs ) for determining whether the electric motor is in stall operation.

[0040] Embodiment 12. The system of embodiment 11, wherein the corresponding electrical loss is based on the root mean square current (I RMS ) and each phase current (I abc ).

[0041] Embodiment 13. A method of operating a vehicle having a power inverter module, an electric motor configured to generate torque, and a controller having a processor and a tangible non-transitory memory, the method comprising:

[0042] coupling an alternating current (AC) power bus to the power inverter module, the AC power bus having a plurality of bus bars for conducting AC current having multiple phases;

[0043] coupling the AC power bus to a stator in the electric motor;

[0044] positioning the plurality of bus bars in thermal contact with the inverter coolant and the engine oil, respectively;

[0045] determining an estimated temperature of the AC power bus for each of the plurality of phases of the AC current based on a plurality of factors, the plurality of factors including an oil flow rate of the engine oil and a coolant flow rate of the inverter coolant; and

[0046] Operation of the vehicle is controlled based in part on a highest one of the estimated temperatures of the plurality of phases.

[0047] Solution 14. The method according to Solution 13 further includes:

[0048] An inverter capability is determined based in part on the temperature estimate, wherein controlling operation of the vehicle includes de-rating the torque based in part on the inverter capability.

[0049] Solution 15. The method according to Solution 13 further includes:

[0050] An auxiliary source is incorporated into the vehicle for selectively providing an auxiliary torque contribution to propel the vehicle, wherein controlling operation of the vehicle includes load sharing with the auxiliary source.

[0051] Solution 16. The method according to Solution 13 further includes:

[0052] coupling a common mode choke for thermal communication with the plurality of bus bars, the plurality of factors including an estimated choke heat of the common mode choke; and

[0053] The estimated choke heating is obtained based in part on a PWM type, a switching frequency, and a modulation index of the power inverter module.

[0054] Solution 17. The method according to Solution 16 further includes:

[0055] Determine the estimated choke heat (Q) for each phase in the multi-phase choke ) can be obtained as: Among them, Q base is a calibrable value for the basic heat loss, f sw is the switching frequency, K fsw is a calibratable scalar value of the switching frequency, and K MI , K PWM Accordingly there are corresponding calibratable values ​​based on the modulation index and the PWM type.

[0056] Solution 18. The method according to Solution 13 further comprises:

[0057] determining the estimated temperature of the AC power bus based on a starting temperature of each of the plurality of phases; and

[0058] The starting temperature is determined based in part on a cutout temperature of the AC power bus when the vehicle is shut down, an elapsed time between the vehicle shut down and the vehicle restart, a calibratable time constant of the AC power bus, and an expected cooling temperature of the AC power bus.

[0059] Solution 19. The method according to Solution 13, further comprising:

[0060] The respective electrical losses of the plurality of bus bars are combined into the plurality of factors, the respective electrical losses (P loss ) is based in part on the speed of the electric motor in RPM (N Mtr ), and a calibrable speed threshold (N Thrs ) for determining whether the electric motor is in stall operation.

[0061] Solution 20. A motor vehicle, comprising:

[0062] Rechargeable Energy Storage Systems (RESS);

[0063] a power inverter module adapted to receive a DC voltage from the RESS;

[0064] an alternating current (AC) power bus coupled to the power inverter module, the AC power bus having a plurality of bus bars for conducting AC current having multiple phases;

[0065] an electric motor configured to generate torque to propel the vehicle, the AC power bus being coupled to a stator in the electric motor;

[0066] inverter coolant and oil in direct or indirect thermal contact with the plurality of bus bars, respectively;

[0067] a controller adapted to determine an estimated temperature of the AC power bus for each of the plurality of phases of the AC current based on a plurality of factors, the controller having a processor and a tangible, non-transitory memory having instructions recorded thereon;

[0068] wherein the plurality of factors include an oil flow rate of the engine oil and a coolant flow rate of the inverter coolant; and

[0069] Wherein the controller is adapted to control operation of the vehicle based in part on a highest one of the estimated temperatures of the plurality of phases.

[0070] The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 is a schematic diagram of a system for a vehicle having a power inverter, an electric motor, and a controller;

[0072] Figure 2 It can be Figure 1 A flowchart of a method performed by a controller;

[0073] Figure 3 yes Figure 2 A flow chart of a portion of a method;

[0074] Figure 4 It can be Figure 1 A flowchart of another method performed by a controller; and

[0075] Figure 5 yes Figure 1 Schematic diagram of an exemplary architecture that may be adopted by a system.

[0076] Representative embodiments of the present disclosure are shown in the accompanying drawings by way of non-limiting examples and are described in more detail below. However, it should be understood that the novel aspects of the present disclosure are not limited to the specific forms shown in the drawings listed above. On the contrary, the present disclosure will cover modifications, equivalents, combinations, sub-combinations, permutations, groupings, and alternatives that fall within the scope of the present disclosure as, for example, covered by the appended claims. DETAILED DESCRIPTION

[0077] Referring to the drawings, wherein like reference numerals refer to like parts, Figure 1 A system 10 having an AC power bus 12 is schematically illustrated. The AC power bus 12 is composed of a plurality of bus bars, such as a first bus bar 14, a second bus bar 16, and a third bus bar 18. The AC power bus 12 may be part of a vehicle 20, which may include, but is not limited to, a passenger car, a sport utility vehicle, a light truck, a heavy vehicle, a minivan, a bus, a transport vehicle, a bicycle, a mobile robot, an agricultural implement (e.g., a tractor), sports-related equipment (e.g., a golf cart), a boat, an airplane, a train, or another mobile platform. The vehicle 20 may be fully electric or partially electric. It is to be understood that the vehicle 20 may take many different forms and have additional components.

[0078] The AC power bus 12 acts as a junction for receiving and transmitting electrical power and heat. Figure 1 The receipt and transmission of electrical power and heat through the AC power bus 12 is illustrated by a plurality of bidirectional arrows. Arrows A, B, C, D, E, F (shown in shading) represent AC power and heat flow. Arrows G, H, I, J, K, L, M, N, P represent heat flow.

[0079] refer to Figure 1 , the system 10 includes a power inverter module (PIM) 22, a rechargeable energy storage system (RESS) 24, an electric motor (EM) 26, and a transmission 28. For example, in response to a pulse width modulated signal, the power inverter module 22 receives a DC voltage from the rechargeable energy storage system 24 (e.g., a high-voltage battery) or returns a DC voltage to the rechargeable energy storage system 24 (e.g., a high-voltage battery), and is operable to invert the DC voltage to an AC voltage as needed, and vice versa. Arrows A, B, and C show the bidirectional flow of electrical power and heat between the power inverter module 22 and the AC power bus 12 (respectively the first bus bar 14, the second bus bar 16, and the third bus bar 18).

[0080] The AC voltage is transmitted to the stator 25 of the electric motor 26 via the AC power bus 12. The AC power bus 12 is connected to each phase winding of the electric motor 26. Arrows D, E, and F show the bidirectional flow of electric power and heat between the electric motor 26 and the AC power bus 12 (respectively the first bus bar 14, the second bus bar 16, and the third bus bar 18). The energized electric motor 26 delivers mechanical power or torque to the input member of the transmission 28, and the output torque is transmitted to the output member of the transmission 28, and is ultimately transmitted to the drive wheels 30 via one or more drive shafts (not shown).

[0081] The AC power bus 12 and its associated components, such as sensors, insulators, and seals, may present thermal limitations for many operating conditions of the electric drive system. The temperature of the AC power bus 12 depends on many factors, including internal heating losses due to the electrical power transmitted through the AC power bus 12, electrical resistance, and external heat transmitted to or from associated matching or nearby components (e.g., fluid for cooling). Due to the complexity and number of sources, obtaining the temperature of each component is not a trivial matter.

[0082] The system 10 enables temperature estimation of the AC power bus 12 over a wide range of applications and operating conditions. Figure 1 The system 10 includes a controller 50 having at least one processor 52 and at least one memory 54 (or non-transitory tangible computer-readable medium) on which instructions for operating the method 100 of the system 10 may be recorded, the method 100 being described below and in Figure 2-3 The memory 54 may store a controller-executable instruction set, and the processor 52 may execute the controller-executable instruction set stored in the memory 54 .

[0083] refer to Figure 1 A common-mode choke 32 (hereinafter referred to as "choke") may be associated with the AC power bus 12. The choke 32 is adapted to filter common-mode currents and may act as a heat source. The choke 32 is in thermal communication with each component of the AC power bus 12, as indicated by arrows G, H, and I. The controller 50 is adapted to selectively execute a choke heat estimator 200 for determining an estimated temperature of the choke heat, which choke heat estimator 200 is described below with reference to FIG. Figure 4 describe.

[0084] The AC power bus 12 also interacts with the PIM coolant 34 as indicated by arrows J, K, L, and with the engine oil 36 as indicated by arrows M, N, P. Figure 1The vehicle 20 may include one or more auxiliary inverters 40 and an auxiliary torque source 42 (eg, an internal combustion engine) configured to selectively provide an auxiliary torque contribution to propel the vehicle 20 via, for example, the wheels 30 .

[0085] By estimating the temperature of the AC power bus 12, the system enables potential derating and load sharing, for example, thermally balancing loads between different inverters (e.g., auxiliary inverter 40) in a multi-drive application and / or employing auxiliary torque source 42. This allows for increased vehicle capability as loads can be transferred to a propulsion system with less risk of derating in order to maintain vehicle speed under high AC current conditions. Specifically, this feature can be used to support heavy use conditions with high and / or continuous AC current, such as towing, repeated wide-open throttle acceleration, and using torque from the traction motor to hold the vehicle 20 on a hill.

[0086] Reference now Figure 2 , shows an exemplary flow chart of method 100. Method 100 may be implemented as stored in Figure 1 The controller 50 and can be Figure 1 The computer readable code or instructions executed by the controller 50 portion of the method 100 need not be applied in the specific order described herein and can be executed dynamically. In addition, it is understood that certain steps can be eliminated.

[0087] According to block 110, the method 100 includes receiving input data, such as motor speed, oil flow rate, phase current, and temperature of surrounding components. The input data includes the following reference Figure 4 The estimated choke heating generated by the described choke heating estimator 200. For a particular AC power bus design, this input data may be obtained through physical sensors, finite element analysis, numerical simulation, and other methods available to those skilled in the art.

[0088] Proceeding to block 115, the controller 50 is adapted to determine if a fault is present in the motor current. If so (block 115=yes), the method 100 proceeds to block 120 where the estimator state is set to disabled, the phase temperature is 0°C and the AC busbar losses are set to zero.

[0089] If not (block 115=No), the method 100 proceeds to block 125, where the controller 50 is adapted to determine whether the reference temperatures available to the surrounding components (e.g., the stator 25 of the electric motor 26, the power inverter module 22, the oil 36, and the PIM coolant 34) are acceptable. These temperatures may be obtained by sensors or estimated by other means. If the reference temperatures are not acceptable (block 125=No), the method 100 proceeds to block 130, where the controller 50 is adapted to set a predetermined degradation temperature and set the estimated state to "degraded".

[0090] If the reference temperatures are acceptable (block 125=yes), the method 100 proceeds to block 140, where the controller 50 is adapted to update these temperatures and set the estimator state to "available". From block 140, proceeding to block 145, the controller 50 is adapted to determine whether the delay timer started at the beginning of the cycle (when the vehicle 20 is started) is greater than or equal to a calibrated delay threshold. In one example, the calibrated delay threshold is set to approximately 2 seconds.

[0091] If not (block 145 =No), the method 100 proceeds to block 150 where the controller 50 is adapted to initialize the AC bus temperature to a starting temperature (T ACBB ), which can be calculated per phase based on the following: the temperature of the AC power bus 12 when the vehicle 20 is turned off (T KeyOff ), how much time has passed between the vehicle being turned off and restarted (t inactv ), a calibratable time constant (τ) of the AC power bus 12, and a reference temperature (T Clnt In one example, the starting temperature (T ACBB ) is obtained as:

[0092] If so (block 145=yes), method 100 proceeds to block 160, which includes sub-blocks 161 through 167, where Figure 3 Now refer to Figure 3 According to sub-block 161, the controller 50 is adapted to calculate the busbar resistance per phase based on the estimated busbar temperature. The temperature-scaled electrical resistance (R elec ) can be based on the calibrated nominal resistance (R 25C ), estimated temperature (T ACBB ) and the temperature coefficient of copper This calculation is performed separately for each of the three phases, because for each phase R of the bus 25C Possible changes: Relec =[R 25C* (1+K CU *(T ACBB -25))].

[0093] Proceed to Figure 3 At sub-block 162, the controller 50 is adapted to determine whether the motor speed is less than or equal to a threshold. If so (sub-block 162 = yes), the method 100 proceeds to sub-block 163, where the controller 50 is adapted to calculate the busbar electrical losses per phase based on the phase currents of the stall (doing stall).

[0094] If not (sub-block 162 = No), the method 100 proceeds to sub-block 164 where the controller 50 is adapted to calculate the per-phase busbar electrical losses. The electrical losses (P loss ) or heat loss may be based in part on the speed (N) of the electric motor 26 in RPM. Mtr ) and a calibratable speed threshold (N) for determining whether the electric motor 26 is in a stall state. Thrs ) is used to calculate each phase. If the phase current (I abc ) is used with a corresponding resistor for each phase (ie, power loss for phase A = Ia*Ia*Ra, and power loss for phase B = Ib*Ib*Rb). loss ) is shared with sub-blocks 162 and 163. loss ) can be obtained as:

[0095]

[0096] Proceeding from sub-block 164 and sub-block 163 to sub-block 165, the controller 50 is adapted to obtain conductivity data, including the per-phase thermal conductivity between the AC power bus 12 and the oil 36. The per-phase thermal conductivity (K Oil_ACBB ) is a function of the oil flow rate and can be determined using a lookup table, e.g., K Oil_ACBB (dV)=LUT(dV), where dV is the flow rate.

[0097] Go to Figure 3 In sub-block 166, the controller 50 may be adapted to calculate the per-phase heat flow between the AC power bus 12 and each reference component (e.g., the stator 25 of the electric motor 26, the power inverter module 22, the oil 36, and the PIM coolant 34) based on the thermal conductivity. The per-phase heat flow may be expressed as:

[0098] Q ref =[T ref -T ACBB ]*K ref

[0099] Here Q ref and T ref represents the corresponding heat flow and temperature of each reference component, T ACBB is the temperature of the AC busbar, and K ref represents the thermal conductivity. The total per-phase heat flow between the AC busbars, self-heating, and other components is expressed as the sum of the calculated heats:

[0100] Q Total =Q Loss +Q Choke +Q PIM +Q stator +Q oil +Q Coolant

[0101] Finally, according to sub-block 167, the temperature of the AC power bus 12 for each phase may be determined based on the total heat flow, the busbar temperature at the previous time instance, the calibratable mCp (mass*specific heat) of the busbar, and the time step N as follows:

[0102]

[0103]

[0104] Return to reference Figure 2 , the method 100 proceeds from block 160 to block 170, wherein the controller 50 is adapted to store the cut-off AC bus temperature and other data, including the maximum value of the estimated temperatures of the three phases. The maximum of the estimated temperatures from the three phases is set as the estimated temperature of the AC power bus 12. Proceeding to block 180, the operation of the vehicle 20 is controlled (via the system 10) based on the estimated temperature. The estimated temperature is used in the evaluation and load sharing algorithms, such as by Figure 5 Controlling the operation of the vehicle 20 includes optimally balancing thermal loads between various components based on the estimated temperature of the AC power bus 12 (from block 170 ), such as re-ratioing torque to one or more auxiliary inverters 40 or to generate torque through the auxiliary torque source 42 .

[0105] Figure 5 An exemplary architecture 300 that may be employed by the system 10 is shown in FIG. It is to be understood that other types of topologies or arrangements may be employed. The choke thermal estimator or module 200 receives as input the following parameters: switching frequency, modulation index, and PWM type. Figure 5, the choke heat estimator 200 calculates the choke heat per phase and transmits it to the temperature estimator 310. The temperature estimator 310 also receives as input the phase, dq axis current, external temperature, oil flow rate, and motor speed. The temperature estimator 310 and the choke heat estimator 200 employ both measured variables as well as estimates and can be optimized with considerations of accuracy versus complexity. The temperature estimator 310 can accommodate an unlimited number of external heat sources and / or heat sinks with individually calibrated thermal resistances.

[0106] refer to Figure 1 , the temperature estimator 310 generates an estimated AC bus temperature, which is sent as an output along with the estimator state to the inverter capability module 320. The inverter capability module 320 calculates the inverter capability based on the estimated AC bus temperature. The output of the inverter capability module 320 is sent to the de-rating module 330, which is adapted to derate the motor torque based on the inverter capability and the temperature limit.

[0107] As described above, the temperature output of the temperature estimator 310 may be used by a supervisory control having information about the temperature limits of the AC power bus 12 to shift torque demands from inverters approaching their temperature limits to inverters not approaching their temperature limits. Figure 5 The output of the temperature estimator 310 may also be transmitted to a monitoring controller 340, which is adapted to assess the probability that the system 10 has reached its thermal limit. Based on this, the monitoring controller 340 may re-prioritize strategies to prevent system power de-rating due to temperature, for example, by reallocating torque to other drive systems in the vehicle 20.

[0108] Reference now Figure 4 , shows an exemplary flow chart of a choke heat estimator 200, referred to herein as module 200. Module 200 may be implemented as a memory stored in Figure 1 The controller 50 and can be Figure 1 The computer readable code or instructions executed by the controller 50 portion of the module 200 need not be applied in the specific order described herein and can be executed dynamically. It is understood that certain steps can be eliminated.

[0109] At Figure 4Beginning at block 202 of , the controller 50 is adapted to determine whether the system 10 includes a common mode choke 32. If not (block 202=No), the module 200 proceeds to block 204, where the controller 50 is adapted to set the estimated choke thermal to zero. If so (block 202=Yes), the module 200 proceeds to block 206, where the controller 50 is adapted to retrieve input data, including PWM type, switching, frequency, and modulation index. Proceeding to block 208, the controller 50 is adapted to determine whether the power stage is open or shorted.

[0110] If the power stage is open or shorted (block 208=yes), the module 200 proceeds to block 210, where the controller 50 is adapted to set the estimated choke heat to zero. If the power stage is not open or shorted (block 212=yes), the module 200 proceeds to block 212, where the controller 50 is adapted to determine the AC choke heat per phase based on the PWM type, switching frequency, and modulation index. In one embodiment, the estimated choke heat (Q choke ) is obtained as:

[0111]

[0112] Here Q base is a calibrable value for the basic heat loss, f sw is the switching frequency, K fsw is a calibrable scalar value for the switching frequency, and K MI , K PWM Correspondingly, it is a corresponding calibrable value based on the modulation index (MI) and PWM. MI , K PWM It can be obtained as follows:

[0113]

[0114]

[0115] Here K SVPWM is a calibrable scalar determined by the PWM type. MI is the calibrated y-intercept of the piecewise linear slope, X MI is a calibrable MI threshold of a piecewise linear function, and K MI is a predetermined scalar value. Proceeding to block 214, it is estimated that the choke heat is transferred to Figure 5 , and the module 200 ends.

[0116] refer to Figure 1, the vehicle 20 may include a mobile application 56 embedded in a smart device (e.g., a smart phone) that can be plugged into the vehicle 20 or otherwise linked to the vehicle 20. The mobile application 56 can be used to perform portions of the above-described method 100. Circuits and components of a mobile application ("app") available to those skilled in the art can be employed.

[0117] In one embodiment, Figure 1 The controller 50 is embedded in the vehicle 20. In another embodiment, the controller 50 may be hosted or based on a remotely located cloud computing service 60. The cloud computing service 60 may include one or more remote servers hosted on the Internet to store, manage, and process data. The cloud computing service 60 may be at least partially managed by personnel at various locations.

[0118] The system 10 may use a wireless network 62 for communication between components. The wireless network 62 may be a short-range network or a long-range network. The wireless network 62 may be a communication bus, which may be in the form of a serial controller area network (CAN-BUS). The wireless network 62 may be a serial communication bus in the form of a local area network. The local area network may include, but is not limited to, a controller area network (CAN), a controller area network with a flexible data rate (CAN-FD), Ethernet, Bluetooth, WIFI, and other data forms. The wireless network 62 may be a wireless local area network (LAN) that uses a wireless distribution method to link multiple devices, a wireless metropolitan area network (MAN) that connects several wireless LANs, or a wireless wide area network (WAN) that covers a large area such as a neighboring town. Other types of network technologies or communication protocols available to those skilled in the art may also be used.

[0119] In summary, the system 10 allows for operational control based on temperature feedback on the AC power bus 12. Excessive loading is minimized because the controller 50 is adapted to derate power and / or employ load sharing through the system 10. Specifically, this feature can improve traction capabilities in electric truck vehicles.

[0120] As used herein, the terms "dynamic" and "dynamically" describe a step or process that is performed in real time and is characterized by monitoring or otherwise determining the state of a parameter and regularly or periodically updating the state of the parameter during execution of a routine or between execution iterations of a routine.

[0121] Figure 1 The controller 50 may be an integral part of other controllers of the vehicle 20 or a separate module operatively connected to other controllers of the vehicle 20 . Figure 1The controller 50 includes a computer-readable medium (also referred to as a processor-readable medium), which includes a non-temporary (e.g., tangible) medium that participates in providing data (e.g., instructions) that can be read by a computer (e.g., by a processor of a computer). Such media can take a variety of forms, including but not limited to non-volatile media and volatile media. For example, non-volatile media may include optical or magnetic disks and other persistent memories. For example, volatile media may include dynamic random access memory (DRAM), which may constitute a main memory. Such instructions may be transmitted through one or more transmission media, including coaxial cables, copper wires, and optical fibers, including wires such as: the wires include a system bus coupled to a processor of a computer. For example, some forms of computer-readable media include floppy disks, floppy disks, hard disks, tapes, other magnetic media, CD-ROMs, DVDs, other optical media, physical media, RAMs, PROMs, EPROMs, FLASH-EEPROMs, other memory chips or cassettes, or other media that can be read by a computer.

[0122] The lookup tables, databases, data repositories, or other data stores described herein may include various mechanisms for storing, accessing, and retrieving various data, including hierarchical databases, a set of files in a file storage system, an application database in a proprietary format, a relational database energy management system (RDBMS), and the like. Each such data store may be included in a computing device that employs a computer operating system such as one of those mentioned above, and may be accessed via a network in one or more of a variety of ways. The file system may be accessed from the computer operating system and may include files stored in various formats. In addition to languages ​​for creating, storing, editing, and executing stored programs, such as the PL / SQL language mentioned above, the RDBMS may also employ structured query language (SQL).

[0123] The flowcharts shown in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of the systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, segment, or portion of a code, which includes one or more executable instructions for implementing a specified logical function. It will also be noted that each block in the block diagram and / or flowchart illustration, as well as the combination of blocks in the block diagram and / or flowchart illustration, may be implemented by a system based on special purpose hardware that performs a specific function or action, or a combination of special purpose hardware and computer instructions. These computer program instructions may also be stored in a computer-readable medium, which may direct a controller or other programmable data processing device to operate in a specific manner so that the instructions stored in the computer-readable medium produce an article of manufacture including instructions for implementing the functions / actions specified in the flowchart and / or block diagram blocks.

[0124] The numerical values ​​of parameters (e.g., quantities or conditions) in this specification, including the attached claims, should be understood as being modified by the term "approximately" in each corresponding instance, regardless of whether "approximately" actually appears before the numerical value. "Approximately" means that the numerical value allows some slight imprecision (approximate the accuracy of the numerical value by some method; approximately or reasonably close to the numerical value; almost). If the imprecision provided by "approximately" is not understood in this ordinary sense in the art, "approximately" as used herein at least represents the changes that may arise from the ordinary methods of measuring and using these parameters. In addition, the disclosure of the range includes the disclosure of each value and the range further divided within the entire range. Each value within the range and the endpoints of the range are disclosed as separate embodiments herein.

[0125] The detailed description and the figures or drawings are support and description of the present disclosure, but the scope of the present disclosure is limited only by the claims. Although some best modes and other embodiments for implementing the claimed disclosure have been described in detail, there are various alternative designs and embodiments for practicing the disclosure defined in the appended claims. In addition, the embodiments shown in the drawings or the features of the various embodiments mentioned in this specification are not necessarily to be understood as embodiments independent of each other. On the contrary, it is possible that each feature described in an example of an embodiment may be combined with one or more other desired features from other embodiments, resulting in other embodiments that are not described in words or with reference to the drawings. Therefore, such other embodiments fall within the framework of the scope of the appended claims.

Claims

1. A system for controlling operation of a vehicle having a power inverter module, comprising: an alternating current (AC) power bus coupled to the power inverter module, the AC power bus having a plurality of bus bars for conducting AC current having multiple phases; an electric motor configured to generate torque to propel the vehicle, the AC power bus being coupled to a stator in the electric motor; inverter coolant and oil in direct or indirect thermal contact with the plurality of bus bars, respectively; a controller adapted to determine an estimated temperature of the AC power bus for each of the plurality of phases based on a plurality of factors, the controller having a processor and a tangible, non-transitory memory having instructions recorded thereon; wherein the plurality of factors include an oil flow rate of the engine oil and a coolant flow rate of the inverter coolant; and Wherein the controller is adapted to control operation of the vehicle based in part on a highest one of the estimated temperatures of the plurality of phases.

2. The system according to claim 1, further comprising: a common mode choke in thermal communication with the plurality of bus bars; as well as Wherein the plurality of factors include an estimated choke heat of the common mode choke, the estimated choke heat being based in part on a switching frequency, a modulation index, and a PWM type of the power inverter module.

3. The system according to claim 2: in, The estimated choke heat (Q choke ) can be obtained as: as well as Among them, Q base is a calibrable value for the basic heat loss, f sw is the switching frequency, K fsw is a calibratable scalar value of the switching frequency, and K MI , K PWM Accordingly there are corresponding calibratable values ​​based on the modulation index and the PWM type.

4. The system according to claim 1, wherein: Controlling operation of the vehicle includes determining an inverter capability of the power inverter module based in part on the estimated temperature, and de-rating the torque based in part on the inverter capability.

5. The system according to claim 4, wherein: The vehicle includes an auxiliary inverter, and controlling operation of the vehicle includes load sharing with the auxiliary inverter based in part on the inverter capability.

6. The system according to claim 1: in, Determining the estimated temperature of the AC power bus includes initializing to a starting temperature of each of the plurality of phases; and The starting temperature is based in part on a cutout temperature of the AC power bus when the vehicle is shut down, an elapsed time between vehicle shut down and vehicle restart, a calibratable time constant of the AC power bus, and an expected cooling temperature of the AC power bus.

7. The system according to claim 6: in, The estimated starting temperature (T ACBB ) is obtained as: as well as Among them, T KeyOff is the cut-out temperature of the AC power bus when the vehicle is turned off, t inactv is the time elapsed between the vehicle shut down and the vehicle restart, τ is the calibratable time constant of the AC power bus, and T Clnt is the expected cooling temperature of the AC power bus.

8. The system according to claim 1, wherein: The plurality of factors include respective resistances of the plurality of bus bars, the respective resistances being based on respective calibratable nominal resistances (R 25C ), the estimated temperature (T ACBB ) and the temperature coefficient of copper.

9. The system according to claim 1: in, The plurality of factors include respective heat flows between the AC power bus and a reference component for each of the plurality of phases, the respective heat flows (Q ref ) is obtained as: Q ref =[T ref -T ACBB ]*K ref ;as well as Among them, T ref represents the corresponding temperature of the reference component, T ACBB represents the corresponding temperatures of the plurality of bus bars, and K ref denotes the corresponding thermal conductivity of the reference component.

10. The system according to claim 9, wherein: The reference components include the stator, the power inverter module, the engine oil, the inverter coolant, and a common mode choke in thermal communication with the plurality of bus bars.

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