Method and apparatus for transferring electrical energy between a pair of series connected batteries

Abstract

The present application relates to a method and apparatus for transferring electrical energy between a pair of series connected batteries. In particular, a method and apparatus for transferring electrical energy between a pair of series connected batteries coupled between positive and negative DC bus bars of a power inverter operatively connected to a plurality of stator phase windings of a stator winding of a motor can include coupling a midpoint of the pair of series connected batteries to the stator winding of the motor, and controlling the power inverter to operate the power inverter and the stator winding as a switched mode power converter to charge at least one of the stator phase windings from one of the pair of series connected batteries and to discharge the at least one stator phase winding to the other of the pair of series connected batteries.

Description

Technical Field

[0001] This subject matter disclosure relates to electric vehicle charging. More specifically, this subject matter disclosure relates to recharging electric vehicles having a reconfigurable rechargeable energy storage system. Background Technology

[0002] Individual capacity, state of charge, depth of discharge, state of health, and voltage of battery packs, modules, and cells within a rechargeable energy storage system may be inequivalent. Differences in chemistry and design capacity can occur even between matched battery packs, modules, and cells with equivalent lifespan due to factors such as load imbalance, differences in short- or long-term discharge histories, temperature gradients, and high-voltage bus wiring. These differences may manifest before, during, or after a recharge cycle, posing challenges to the recharging and reconfiguration of modular rechargeable energy storage systems. Summary of the Invention

[0003] In one exemplary embodiment, a method for transferring electrical energy between a pair of series-connected batteries connected between positive and negative DC rails of a power inverter operatively connected to a plurality of stator phase windings of a motor stator winding may include connecting the midpoint of the pair of series-connected batteries to the stator windings of the motor, and controlling the power inverter to operate the power inverter and the stator windings as a switch-mode power converter to charge at least one of the stator phase windings from one of the pair of series-connected batteries and discharge the at least one stator phase winding to the other of the pair of series-connected batteries.

[0004] In addition to one or more features described herein, the method can be performed periodically during a DC fast charging cycle.

[0005] In addition to one or more features described herein, the method can be executed when a DC fast charging cycle is completed.

[0006] In addition to one or more features described herein, connecting the midpoint of the pair of series-connected batteries to the stator winding of the motor may include closing a switch between the midpoint of the pair of series-connected batteries and the neutral terminal of the stator phase winding.

[0007] In addition to one or more features described herein, connecting the midpoint of the pair of series-connected batteries to the stator windings of the motor includes closing a switch between the midpoint of the pair of series-connected batteries and a corresponding phase terminal of one of the stator phase windings.

[0008] In addition to one or more features described herein, controlling the power inverter to operate the power inverter and stator windings as a switch-mode power converter may include synchronous pulse width modulation control of the power inverter.

[0009] In addition to one or more features described herein, controlling the power inverter to operate the power inverter and stator windings as a switch-mode power converter may include interleave pulse width modulation control of the power inverter.

[0010] In addition to one or more features described herein, controlling the power inverter to operate the power inverter and stator windings as a switch-mode power converter may include synchronous pulse width modulation control of the power inverter.

[0011] In addition to one or more features described herein, controlling the power inverter to operate the power inverter and stator windings as a switch-mode power converter may include interleaved pulse width modulation control of the power inverter.

[0012] In another exemplary embodiment, an apparatus for shuttle charging between a pair of batteries may include a pair of batteries configured in series, a motor including stator windings having a plurality of stator phase windings generally connected at a neutral terminal and having corresponding phase terminals, a power inverter having a plurality of phase legs connected between positive and negative DC buses connected to the two ends of the pair of batteries configured in series, and each phase leg including a corresponding upper and lower solid-state switch, wherein a corresponding phase pole is connected at its corresponding phase terminal to a corresponding stator phase winding, a switch between the midpoint node of the pair of batteries configured in series and the stator windings, and a controller that operates the switch to close to connect the midpoint node of the pair of batteries configured in series to at least one of the plurality of stator phase windings, and controls the conduction of the phase legs of the power inverter to operate the power inverter and the stator windings as a switch-mode power converter operation, the switch-mode power converter including at least one stator phase winding and one of the upper and lower solid-state switches of at least one phase leg.

[0013] In addition to one or more features described herein, the switch between the midpoint node of a pair of batteries in series configuration and the stator windings may include the switch between the midpoint node of a pair of batteries in series configuration and the corresponding phase terminal of one of the stator phase windings.

[0014] In addition to one or more features described herein, the switch between the midpoint node of a pair of batteries in series configuration and the stator windings may include the switch between the midpoint node of a pair of batteries in series configuration and the neutral terminals of a plurality of stator phase windings.

[0015] In addition to one or more features described herein, controlling the conduction of a phase foot of the power inverter may include controlling the conduction of a corresponding solid-state switch on at least one phase foot to operate the power inverter and stator windings as a switch-mode power converter, wherein energy is transferred from one of a pair of batteries between the midpoint node and the positive DC bus to the other of a pair of batteries between the midpoint node and the negative DC bus.

[0016] In addition to one or more features described herein, controlling the conduction of phase pins of the power inverter may include controlling the interleaved conduction of corresponding solid-state switches on at least two phase pins to operate the power inverter and stator windings as a switch-mode power converter, wherein energy is transferred from one of a pair of batteries between the midpoint node and the positive DC bus to the other of a pair of batteries between the midpoint node and the negative DC bus.

[0017] In addition to one or more features described herein, controlling the conduction of phase feet of the power inverter may include controlling the synchronous conduction of corresponding solid-state switches on at least two phase feet to operate the power inverter and stator windings as a switch-mode power converter, wherein energy is transferred from one of a pair of batteries between the midpoint node and the positive DC bus to the other of a pair of batteries between the midpoint node and the negative DC bus.

[0018] In addition to one or more features described herein, controlling the conduction of a phase foot of the power inverter may include controlling the conduction of a corresponding lower solid-state switch of at least one phase foot to operate the power inverter and stator windings as a switch-mode power converter, wherein energy is transferred from one of a pair of batteries between the midpoint node and the negative DC bus to the other of a pair of batteries between the midpoint node and the positive DC bus.

[0019] In addition to one or more features described herein, controlling the conduction of phase pins of the power inverter may include controlling the interleaved conduction of corresponding solid-state switches of at least two phase pins to operate the power inverter and stator windings as a switch-mode power converter, wherein energy is transferred from one of a pair of batteries between the midpoint node and the negative DC bus to the other of a pair of batteries between the midpoint node and the positive DC bus.

[0020] In addition to one or more features described herein, controlling the conduction of phase feet of the power inverter may include controlling the synchronous conduction of corresponding lower solid-state switches of at least two phase feet to operate the power inverter and stator windings as switch-mode power converter operations, wherein energy is transferred from one of a pair of batteries between the midpoint node and the negative DC bus to the other of a pair of batteries between the midpoint node and the positive DC bus.

[0021] In yet another exemplary embodiment, the electric vehicle may include an electric propulsion system comprising a rechargeable energy storage system, a multiphase motor having stator windings, and a traction power inverter module. The stator windings have a plurality of stator phase windings. The traction power inverter module includes a motor controller and a power inverter. The rechargeable energy storage system includes a pair of similar or dissimilar batteries connected in series. The power inverter has a plurality of phase pins connected between positive and negative DC buses connected to the two ends of the pair of batteries connected in series, and each phase... The foot includes corresponding upper and lower solid-state switches, with corresponding phase poles connected to a corresponding stator phase winding at their respective phase terminals, a switch between the midpoint node of a series-connected battery and the stator winding, and a motor controller operating the switch to close to connect the midpoint node of a series-connected pair of batteries to at least one stator phase winding, and controlling the conduction of the phase foot of the power inverter to operate the power inverter and stator winding as a switch-mode power converter, the switch-mode power converter including at least one stator phase winding and at least one upper and lower solid-state switch of the phase foot.

[0022] In addition to one or more features described herein, a motor controller that controls the conduction of phase legs of a power inverter to operate the power inverter and stator windings as a switch-mode power converter may include interleaved pulse width modulation control.

[0023] The above-described features and advantages, as well as other features and advantages, of this disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. Attached Figure Description

[0024] Other features, advantages, and details appear only by way of example in the following detailed description, which is illustrated in the accompanying drawings:

[0025] Figure 1 An electric propulsion system on a vehicle according to one or more embodiments is shown;

[0026] Figure 2 An electric propulsion system and control system on a vehicle according to one or more embodiments are shown;

[0027] Figure 3A , 3B The images and text in 3C illustrate various configurations of an exemplary reconfigurable rechargeable energy storage system according to this disclosure;

[0028] Figure 4A and 4B An embodiment of a charging shuttle device according to the present disclosure is shown;

[0029] Figure 5A and 5BAn embodiment of a charging shuttle device according to the present disclosure is shown;

[0030] Figure 6A and 6B An embodiment of a charging shuttle device according to the present disclosure is shown;

[0031] Figure 7A and 7B An embodiment of a charging shuttle device according to the present disclosure is shown; and

[0032] Figure 8 Flowchart routines for multiple tasks related to recharging and charging shuttle of a rechargeable energy storage system according to one or more embodiments are shown. Detailed Implementation

[0033] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or use. Throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0034] Figure 1 An embodiment of an electric propulsion system 101 on a vehicle 100 is illustrated schematically. Vehicles and vehicles are understood to refer to any means of transportation, including but not limited to motorcycles, automobiles, trucks, buses, excavators, earthmoving equipment, construction and agricultural equipment, rail vehicles such as trains and trams, and water vehicles such as ships and small boats. The electric propulsion system 101 may include various control components, electrical systems, and electromechanical systems, including, for example, a rechargeable energy storage system (RESS) 104 and an electric drive unit (EDU) 102. The electric propulsion system 101 can be used in a power system to generate propulsive torque, respectively, as an alternative to or in combination with an internal combustion engine in various electric vehicle (EV) applications and hybrid electric vehicle (HEV) applications.

[0035] EDU 102 can have varying degrees of complexity, components, and integration. An exemplary highly integrated EDU 102 may include, for example, an AC motor (motor) 120 and a traction power inverter module (TPIM) 106, which includes a motor controller 105 and a power inverter 110. Motor 120 may include a stator and a rotor, with the rotor connected to a motor output shaft 125 and a position sensor 182, such as a variable reluctance resolver or encoder. Position sensor 182 may be directly connected to motor controller 105 in a signaling manner and is used to monitor the angular position (θe) of the rotor of motor 120. Motor controller 105 uses the angular position (θe) of the rotor of motor 120 to control the operation of inverter module 110, which controls motor 120.

[0036] Motor output shaft 125 can transmit torque between motor 120 and transmission system components (not shown), such as a reduction gear set and a differential gear set, as well as a final drive with one or more axle outputs. The final drive can simply include a reduction gear and a driveshaft output coupled to a differential gear set. If separated from the final drive or differential gear set, one or more shafts can be coupled to the final drive or differential gear set. Axles can be coupled to wheels for transmitting traction between the wheels and the road surface. Alternative arrangements of the transmission system components will be recognized by those skilled in the art. Propulsion torque request or command 136 (T cmd The information can be provided to the motor controller 105 by the vehicle controller 103.

[0037] Motor controller 105 may include one or more control modules. As used herein, control module, module, control, controller, control unit, electronic control unit, processor, and similar terms refer to any one or more application-specific integrated circuits (ASICs), electronic circuits, central processing units (preferably microprocessors), and associated memory and storage devices (read-only memory (ROM), random access memory (RAM), electrically programmable read-only memory (EPROM), hard disk drives, etc.) or various combinations thereof, or microcontrollers executing one or more software or firmware programs or routines, combinational logic circuits, input / output circuits and devices (I / O), as well as appropriate signal conditioning and buffering circuitry, high-speed clocks, analog-to-digital (A / D) and digital-to-analog (D / A) circuitry, and other components providing said functionality. Control modules may include various communication interfaces, including point-to-point or discrete lines and wired or wireless interfaces to networks, including wide area networks and local area networks, as well as factory and service-related networks including over-the-air (OTA) software updates. The functionality of the control modules described in this disclosure can be performed in a distributed control architecture among several networked control modules. Software, firmware, programs, instructions, routines, code, algorithms, and similar terms refer to any set of executable instructions for a controller, including calibration, data structures, and lookup tables. A control module may have a set of control routines executed to provide the aforementioned functions. These routines, for example, are executed by a central processing unit and are operable to monitor inputs from sensing devices and other networked control modules, and to execute control and diagnostic routines to control actuator operation. Programs may be executed periodically during ongoing engine and vehicle operation. Alternatively, routines may be executed on demand in response to events, software calls, or via user interface input or requests.

[0038] In one embodiment, RESS 104 may include one or more electrochemical battery packs 112, such as high-capacity, high-voltage (HV) rechargeable lithium-ion battery packs for supplying power to the vehicle via an HV DC bus 108. RESS 104 may also include a battery manager module 114. RESS 104 may include one or more battery packs, allowing for configuration flexibility and adaptability to application requirements. Battery packs may consist of multiple battery pack modules, allowing for configuration flexibility and adaptability to application requirements. Battery pack modules may consist of multiple battery cells, allowing for configuration flexibility and adaptability to application requirements. For example, in vehicle use, RESS 104 may be modular, allowing the number and arrangement of battery packs, battery pack modules, and battery cells to vary to suit specific vehicle platform energy density or range targets, market demands, intended use, cost targets, packaging constraints, etc. Battery packs, battery pack modules, and battery cells can be configured differently and selectively depending on the desired propulsion architecture and charging capabilities. It should be understood that RESS 104 can be reconfigured at any level of integration, including battery packs, battery pack modules, and battery cells.

[0039] Motor 120 may be a multiphase AC motor that receives multiphase AC power via a multiphase motor control power bus (AC bus) 111 connected to power inverter 110. In one embodiment, motor 120 is a three-phase motor, and power inverter 110 is a three-phase inverter. Power inverter 110 may include multiple solid-state switches. Power inverter 110 is connected from RESS 104 to DC power (DC input voltage (V)) via HV DC bus 108. dc For example, at 400 volts. Motor controller 105 is coupled to power inverter 110 to control it. Power inverter 110 is electrically connected via AC bus 111 to the stator phase windings of the three-phase stator windings of motor 120, monitoring current on two or three phase leads. Power inverter 110 may be configured with suitable control circuitry, including pairs of power transistors (e.g., IGBTs) for converting the high-voltage DC voltage on HV DC bus 108 into a high-voltage three-phase AC voltage (Voltage per 100 volts) on AC bus 111. abc ), and the high-voltage three-phase AC voltage (V) on AC bus 111 abc The voltage is converted into a high-voltage DC voltage on the HV DC bus 108. The power inverter 110 can employ any suitable pulse width modulation (PWM) control, such as sinusoidal pulse width modulation (SPWM) or space vector pulse width modulation (SVPWM), to generate a switching vector signal (S... abc) 109, thereby converting the DC power stored in the battery pack 112 from RESS 104 into AC power to drive the motor 120 to generate torque. Similarly, inverter 110 can convert the mechanical power delivered to the motor 120 into DC electrical power to generate electrical energy that can be stored in the battery pack 112 of RESS 104, including as part of a regenerative braking control strategy. Power inverter 110 can be configured to receive switching vector signals (S) from motor controller 105. abc ) 109, and controls the inverter state to provide motor drive and regenerative functions. Switch vector signal (S abc ) 109 can also be referred to as the conduction command here.

[0040] Control of the power inverter 110 may include high-frequency switching of a solid-state switch based on PWM control. Many design and application considerations and limitations determine the inverter switching frequency and PWM control. Inverter control for AC motor applications may include a fixed switching frequency, such as approximately 10-12 kHz, and PWM control to minimize switching losses of the IGBTs or other power switches of the power inverter 110.

[0041] See also Figure 2 The electric propulsion system 101 on vehicle 100 may include a control system 208, which includes one or more electronic control units (ECUs), such as vehicle controller 103, battery manager module 114, and motor controller 105. Control system 208 may be responsible for performing functions related to monitoring, controlling, and diagnosing the electric propulsion system 101 based on multiple inputs, including RESS charging control or supervision. Vehicle controller 103 may include one or more ECUs and may be responsible for supervising, interpreting various user and environmental inputs, arbitrating information, and issuing and receiving control commands and requests from various other ECUs, including battery manager module 114 and motor controller 105, as shown in communication lines 242, 246, and 248. The battery manager module 114 can receive multiple inputs 240 related to RESS 104, including, for example, voltage, current, and temperature of battery cells, modules, battery packs, and RESS levels for various module and battery pack configurations, and can determine the state of charge (SOC), depth of discharge (DOD), state of health (SOH), and other metrics of battery cells, modules, battery packs, and RESS levels for various module and battery pack configurations. The battery manager module 114 can primarily be responsible for the charging and discharging control, monitoring, and diagnostics of RESS 104. The motor controller 105 can receive various inputs 252 for monitoring, controlling, and diagnostics of the motor 120 and power inverter 110, including phase current I from corresponding current sensors 260, 261, and 263. a Ib and I c The rotor position information comes from position sensor 182. Motor controller 105 can control motor 120 by issuing turn-on commands 254 to inverter solid-state switches S1205, S2237, S3215, S4207, S5235, and S6217. Each turn-on command is issued to each switch S1-S6 in the form of a PWM signal from motor controller 105. Any suitable solid-state device can be used as switches S1-S6, including, for example, solid-state relays and transistors such as Si IGBTs, Si MOSFETs, SiC MOSFETs, GaN HEMTs, SiC JFETs, diamond, gallium oxide, and other power switching devices based on wide bandgap (WBG) semiconductors. Each switch S1-S6 may also have an associated anti-parallel diode, either as a discrete component or integrated with each switch S1-S6. According to one embodiment, the battery manager module 114 may be responsible for monitoring and diagnostics of the RESS 104, including discharge and charge control during propulsion operations and power transmission from and to external power sources.

[0042] Power inverter 110 includes a positive DC bus 218, a negative DC bus 222, and a plurality of phase pins therebetween. The phase pins in an exemplary three-phase power inverter 110 include switches S1 and S4 (phase pin A) connected at node 227 (phase A), switches S3 and S6 (phase pin B) connected at node 228 (phase B), and switches S5 and S2 (phase pin C) connected at node 229 (phase C). Switches S1 205, S3 215, and S5 235 can be referred to as upper solid-state switches because they are connected to the positive DC bus 218. Switches S2 237, S4 207, and S6 217 can be referred to as lower solid-state switches because they are connected to the negative DC bus 222. Phase A (node ​​227) is connected via line 250 to phase winding L of the stator winding 123 of motor 120. A Phase B (node ​​228) is connected via line 251 to phase winding L of stator winding 123 of motor 120. B And the phase pole C (node ​​229) is connected via line 253 to the phase winding L of the stator winding 123 of the motor 120. C All phase windings L A L B and L C All are connected at the common neutral point N of stator windings 123. The phase winding L opposite to the common neutral point N... A L B and L CThe terminals can be referred to as phase terminals. Each line 250, 251, and 253 can have associated current sensors 260, 261, and 263, respectively, for sensing phase current. HV DC bus 108 ( Figure 1 The high-current disconnect units SW1 and SW2 can be selectively connected to the positive DC bus 218 and the negative DC bus 222 via corresponding high-current disconnect switches. SW1 is controllable to connect and disconnect the positive DC bus 218 and the positive terminal of RESS 104 via the HV DC bus 108. Similarly, SW2 is controllable to connect and disconnect the negative DC bus 222 and the negative terminal of RESS 104 via the HV DC bus 108. SW1 and SW2 may be referred to herein as DC contactors 216 and 212 to distinguish them from the solid-state switches S1-S6 of the power inverter 110, and may be electromechanical relays or solid-state switches.

[0043] The embodiments described herein are in applications at the battery pack level, where a battery pack is understood to include one or more battery pack modules, which may include one or more battery cells. However, these embodiments are described by way of non-limiting example. The subject matter of this disclosure can be implemented at any level of integration, including battery packs, battery modules, and battery cells. Therefore, the term "battery" can refer to a battery pack, a battery pack module, or a battery cell, or a combination or grouping thereof.

[0044] refer to Figures 3A-3C An exemplary RESS 104 is shown in various configurations. RESS 104 may include a pair of battery packs P1 and P2. Battery packs P1 and P2 may have equivalent nominal voltages, such as 400 volts. Battery packs P1 and P2 may also have equivalent nominal capacities. Controllable switches SWP1, SWP2, and SWS can provide various configurations for battery packs P1 and P2 of RESS 104. For example, with SWP1 and SWP2 closed and SWS open, battery packs P1 and P2 can be configured in parallel (…). Figure 3B ), used for the 400-volt RESS 104 voltage during propulsion (V RESS With SWP1 and SWP2 disconnected and SWS closed, battery packs P1 and P2 can be configured in series during DC fast charging (DCFC). Figure 3C For 800V RESS 104 voltage (V) RESS When switch SWS is closed, connecting battery packs P1 and P2 in series, the midpoint node 310 is established between the negative terminal of battery pack P1 and the positive terminal of battery pack P2. When SWP1, SWP2, and SWS are open, battery packs P1 and P2 may be isolated from each other. Figure 3A The RESS 104 can also be controlled via a switch (e.g., described herein and...). Figure 2 SW1 and SW2 shown are selectively connected to the HV DC bus 108 and the charging port. Some or all of these controllable switches and other switches may be integrated into one or more controllable battery disconnection units (BDUs) (not shown), or may be distributed differently in components or subsystems such as RESS 104. Control of such switches may be from one or more control modules, including, for example, the vehicle controller 103 and the battery manager module 114.

[0045] When RESS 104 is configured with battery packs P1 and P2 connected in series, DCFC can be performed. Figure 3C However, the capacity, SOC, DOD, SOH, and voltage of individual battery packs may not be equivalent. This can occur even with matched battery packs P1 and P2 that are equivalent in age, chemistry, and design capacity due to factors such as load imbalance, differences in short- or long-term discharge history, temperature gradients, and HV bus wiring. Battery pack equivalence issues can be anticipated when battery packs are known to have capacity mismatches, which may occur when some battery packs, modules, or cells are replaced during use, or if the RESS 104 is configured with battery packs, modules, or cells with mixed chemistry. Therefore, during DCFC charging of battery packs P1 and P2 in series, one battery pack may reach its charging capacity (SOC=100%) before the other and may be a limiting factor for continuing DCFC. This may lead to charging termination to prevent the battery pack from being overcharged at 100% SOC. Thus, one battery pack may be charged to 100% SOC and 400 volts, while the other may be charged to less than 100% SOC and less than 400 volts. Therefore, the total capacity of RESS 104 may be compromised, and an undesirable voltage difference may exist between battery packs P1 and P2. When battery packs P1 and P2 are reconfigured to be connected in parallel, the voltage difference between the battery packs may result in a large inrush current from the battery pack with the higher voltage to the battery pack with the lower voltage, as well as arcing of switches SWP1 and SWP2.

[0046] To address these issues, a charging shuttle scheme is used to achieve battery pack balancing, ensuring voltage equivalence between battery packs P1 and P2 before parallel reconfiguration. Furthermore, battery pack balancing is performed while battery packs P1 and P2 remain in a series configuration. Additionally, battery pack balancing may be continuously invoked throughout the entire DCFC process or after DCFC termination. Further references are available. Figure 4A , 4BPower inverters 110 and stator windings 123, 5A, 5B, 6A, 6B, 7A, and 7B, provide the power components of a switch-mode power converter for shuttle charging between battery packs P1 and P2. A switch SWM is connected between the midpoint node 310 and the stator winding 123. Figure 4A An embodiment is shown in which the switch SWM is located between the midpoint node 310 and the neutral point N of the stator winding 123. Figure 5A , 6A Embodiments 7A and 7A illustrate an example in which the switch SWM is located at the midpoint node 310 and the phase winding L of the stator winding 123. A L B or L C Between one of the phase terminals. It should be understood that, for clarity, Figure 4A , 5A The power inverter 110 in 6A and 7A is shown in a simplified form, including solid-state switches S1-S6. Figure 4B , 5B 6B and 7B are respectively corresponding to Figure 4A , 5A Simplified equivalent circuit diagrams for 6A and 7A are provided. The motor controller 105 can be controlled by the turn-on command 254 of the inverter solid-state switches S1-S6, as further described herein. In operation, through controlled operation of various combinations of switches SWM and inverter solid-state switches S1-S6, the phase winding L of stator winding 123... A L B and L C In various configurations, it is used to store energy from one of the battery packs P1 and P2 and release the stored energy to the other of the battery packs P1 and P2, thereby shuttling charging and balancing the battery packs P1 and P2.

[0047] Special Reference Figure 4A and 4B The embodiments shown and the corresponding Table 1 herein should be understood to indicate that various equivalent inductances (L) can be established by combining closed SWM switches and closed inverter solid-state switches S1-S6. EQ Inverter solid-state switches S1, S3, and S5 are designated as upper switches because they are connected to the positive DC bus 218 and the corresponding phases A, B, and C, as well as the phase winding L of the stator winding 123. A L B and L C Between. Inverter solid-state switches S4, S6, and S2 are designated as lower switches because they are connected to the negative DC bus 222 and the corresponding phases A, B, and C, as well as the phase winding L of stator winding 123. A L B and L CBetween. As the SWM switch closes to connect the midpoint node 310 to the common neutral point N of the stator winding 123, as Figure 4A As shown, the upper and lower switches of inverter 110 can be controlled in a predetermined combination to achieve various equivalent inductances L. EQ And charging shuttle targets. Table 1 here corresponds to... Figure 4A and 4B The upper switches S1, S3, and S5 can be designated as SU, while the lower switches S4, S6, and S2 can be designated as SL. Various combinations of the upper switches S1, S3, and S5 can be designated as the SU state, and various combinations of the lower switches S4, S6, and S2 can be designated as the SL state. Figure 4B In Table 1, where 0 represents an open switch and 1 represents a closed switch, it can be understood that closing any one or more of the upper switches S1, S3, and S5 will establish a connection through the battery pack P1 and the corresponding equivalent inductance L. EQ The current path. Similarly, closing any one or more of the lower switches S4, S6, and S2 will establish a current path through the battery pack P2 and the corresponding equivalent inductance L. EQ The current path. When only one of the upper switches S1, S3, or S5 is closed (SU state I, II, or III), L EQ Mainly related to the phase winding L corresponding to the phase poles A, B, or C connected to the closed upper switch S1, S3, or S5. A L B or L C The inductance is related. Similarly, when only one of the lower switches S4, S6, or S2 is closed (SL state I, II, or III), L EQ Mainly related to the phase winding L corresponding to the phase poles A, B, or C connected to the closed upper switch S1, S3, or S5. A L B or L C The inductance is related. When two of the upper switches S1, S3, and S5 are closed (SU state IV, V, or VI), L EQ Mainly related to the L of the corresponding two phase poles of A, B, and C of the two closed upper switches connected to S1, S3, and S5. A L B and L C The parallel combined inductance of the two-phase windings is related. Similarly, when the two lower switches S4, S6, and S2 are closed (SL state IV, V, or VI), L EQ Mainly related to the L of the corresponding two phase poles of A, B, and C of the two closed lower switches connected to S4, S6, and S2. A L B and L CThe parallel combined inductance of the two-phase windings is related. When all upper switches S1, S3, and S5 are closed (SU state VII), L EQ Mainly related to all phase windings L A L B and L C The parallel combination of inductors is related. Similarly, when all lower switches S4, S6, and S2 are closed (SL state VII), L EQ Mainly related to all phase windings L A L B and L C The parallel combination of inductors is related. Table 1 only shows the on state of SU and SL, but it should be understood that the off state of SU corresponds to all upper switches S1, S3 and S5 being off, and the off state of SL corresponds to all lower switches S4, S6 and S2 being off.

[0048]

[0049] For details, please refer to the following: Figure 5A and 5B As illustrated in the embodiments and the corresponding Table 2 herein, it should be understood that various equivalent inductances (L) can be established through combinations of closed SWM switches and closed inverter solid-state switches S1-S6. EQ Inverter solid-state switches S1, S3, and S5 are designated as upper switches because they are connected to the positive DC bus 218 and the corresponding phases A, B, and C, as well as the phase winding L of the stator winding 123. A L B and L C Between. Inverter solid-state switches S4, S6, and S2 are designated as lower switches because they are connected to the negative DC bus 222 and the corresponding phases A, B, and C, as well as the phase winding L of stator winding 123. A L B and L C Between. As switch SWM closes to connect midpoint node 310 to phase A and phase L of stator winding 123. A Phase terminals, such as Figure 5A As shown, the upper and lower switches of inverter 110 can be controlled in a predetermined combination to achieve various equivalent inductances L. EQ And charging shuttle targets. Table 2 here corresponds to... Figure 5B The upper switches S1, S3, and S5 can be designated as SU, while the lower switches S4, S6, and S2 can be designated as SL. Various combinations of the upper switches S1, S3, and S5 can be designated as the SU state, and various combinations of the lower switches S4, S6, and S2 can be designated as the SL state. Figure 5BIn Table 2, 0 represents an open switch and 1 represents a closed switch. This can be understood as phase pin A (PL) A The upper and lower switches S1 and S4 remain open, and the closing of one or both of the upper switches S3 and S5 will establish a connection through the battery pack P1 and the corresponding equivalent inductance L. EQ The current path. Similarly, closing one or both of the lower switches S6 and S2 will establish a current path through the battery pack P2 and the corresponding equivalent inductance L. EQ The current path. When only one of the upper switches S3 or S5 is closed (SU state I or II), L EQ Mainly related to phase winding L A and the phase winding L corresponding to the phase pole B or C connected to the closed upper switch S3 or S5 C or L B One of the series-connected inductors is related. Similarly, when only one of the lower switches S6 or S2 is closed (SL state I or II), L EQ Mainly related to phase winding L A and the phase winding L corresponding to the phase pole B or C connected to the closed lower switch S6 or S2. C or L B One of the series-connected inductors is related. When both upper switches S3 and S5 are closed (SU state III), L EQ Mainly related to phase winding L A Same two-phase winding L B and L C The parallel combination of inductors is related to the series combination of inductors. Similarly, when both lower switches S6 and S2 are closed (SL state III), L EQ Mainly related to phase winding L A Same two-phase winding L B and L C The parallel combination inductance is related to the series combination inductance. Table 2 only shows the on state of SU and SL, but it should be understood that the off state of SU corresponds to all upper switches S1, S3 and S5 being open, and the off state of SL corresponds to all lower switches S4, S6 and S2 being open.

[0050]

[0051] For details, please refer to the following: Figure 6A and 6B The embodiments shown and the corresponding Table 3 herein should be understood to indicate that various equivalent inductances (L) can be established by combining closed SWM switches and closed inverter solid-state switches S1-S6. EQInverter solid-state switches S1, S3, and S5 are designated as upper switches because they are connected to the positive DC bus 218 and the corresponding phases A, B, and C, as well as the phase winding L of the stator winding 123. A L B and L C Between. Inverter solid-state switches S4, S6, and S2 are designated as lower switches because they are connected to the negative DC bus 222 and the corresponding phases A, B, and C, as well as the phase winding L of stator winding 123. A L B and L C Between. As switch SWM closes to connect midpoint node 310 to phase B and phase winding L of stator winding 123. B Phase terminals, such as Figure 6A As shown, the upper and lower switches of inverter 110 can be controlled in a predetermined combination to achieve various equivalent inductances L. EQ And charging shuttle targets. Table 3 here corresponds to... Figure 6B The upper switches S1, S3, and S5 can be designated as SU, while the lower switches S4, S6, and S2 can be designated as SL. Various combinations of the upper switches S1, S3, and S5 can be designated as the SU state, and various combinations of the lower switches S4, S6, and S2 can be designated as the SL state. Figure 6B In Table 3, 0 represents an open switch and 1 represents a closed switch. This can be understood as phase pin B (PL) B The upper and lower switches S3 and S6 remain open, and the closing of one or both of the upper switches S1 and S5 will establish a connection through the battery pack P1 and the corresponding equivalent inductance L. EQ The current path. Similarly, closing one or both of the lower switches S4 and S2 will establish a current path through the battery pack P2 and the corresponding equivalent inductance L. EQ The current path. When only one of the upper switches S1 or S5 is closed (SU state I or II), L EQ Mainly related to phase winding L B and the phase winding L corresponding to the phase pole A or C connected to the closed upper switch S1 or S5 A or L C One of the series-connected inductors is related. Similarly, when only one of the lower switches S4 or S2 is closed (SL state I or II), L EQ Mainly related to phase winding L B and the phase winding L corresponding to the phase pole A or C connected to the closed lower switch S4 or S2 A or L C One of the series-connected inductors is related. When both upper switches S1 and S5 are closed (SU state III), L EQ Mainly related to phase winding LB Same two-phase winding L A and L C The parallel combination of inductors is related to the series combination of inductors. Similarly, when both lower switches S4 and S2 are closed (SL state III), L EQ Mainly related to phase winding L B Same two-phase winding L A and L C The parallel combination inductance is related to the series combination inductance. Table 1 only shows the on state of SU and SL, but it should be understood that the off state of SU corresponds to all upper switches S1, S3 and S5 being open, and the off state of SL corresponds to all lower switches S4, S6 and S2 being open.

[0052]

[0053] For details, please refer to the following: Figure 7A and 7B As illustrated in the embodiments and the corresponding Table 4 herein, it should be understood that various equivalent inductances (L) can be established through combinations of closed SWM switches and closed inverter solid-state switches S1-S6. EQ Inverter solid-state switches S1, S3, and S5 are designated as upper switches because they are connected to the positive DC bus 218 and the corresponding phases A, B, and C, as well as the phase winding L of the stator winding 123. A L B and L C Between. Inverter solid-state switches S4, S6, and S2 are designated as lower switches because they are connected to the negative DC bus 222 and the corresponding phases A, B, and C, as well as the phase winding L of stator winding 123. A L B and L C Between. As switch SWM closes to connect midpoint node 310 to phase pole C and phase winding L of stator winding 123. C Phase terminals, such as Figure 7A As shown, the upper and lower switches of inverter 110 can be controlled in a predetermined combination to achieve various equivalent inductances L. EQ And charging shuttle targets. Table 4 here corresponds to... Figure 7B The upper switches S1, S3, and S5 can be designated as SU, while the lower switches S4, S6, and S2 can be designated as SL. Various combinations of the upper switches S1, S3, and S5 can be designated as the SU state, and various combinations of the lower switches S4, S6, and S2 can be designated as the SL state. Figure 7B In Table 4, 0 represents an open switch and 1 represents a closed switch. This can be understood as the phase pin C (PL) CThe upper and lower switches S5 and S2 remain open, and the closing of one or both of the upper switches S1 and S3 will establish a connection through the battery pack P1 and the corresponding equivalent inductance L. EQ The current path. Similarly, closing one or both of the lower switches S4 and S6 will establish a current path through the battery pack P2 and the corresponding equivalent inductance L. EQ The current path. When only one of the upper switches S1 or S3 is closed (SU state I or II), L EQ Mainly related to phase winding L C and the phase winding L corresponding to the phase pole A or B connected to the closed upper switch S1 or S3 A or L B One of the series-connected inductors is related. Similarly, when only one of the lower switches S4 or S6 is closed (SL state I or II), L EQ Mainly related to phase winding L C and the phase winding L corresponding to the phase pole A or B connected to the closed lower switch S4 or S6 A or L B One of the series-connected inductors is related. When both upper switches S1 and S3 are closed (SU state III), L EQ Mainly related to phase winding L C Same two-phase winding L A and L B The parallel combination of inductors is related to the series combination of inductors. Similarly, when both lower switches S4 and S6 are closed (SL state III), L EQ Mainly related to phase winding L C Same two-phase winding L A and L B The parallel combination inductance is related to the series combination inductance. Table 1 only shows the on state of SU and SL, but it should be understood that the off state of SU corresponds to all upper switches S1, S3 and S5 being open, and the off state of SL corresponds to all lower switches S4, S6 and S2 being open.

[0054]

[0055] In operation, each embodiment can effectively transfer charge from one of battery packs P1 and P2 to the other, thereby balancing battery packs P1 and P2 according to the goal of balancing SOC or balancing voltage. Shuttle charging from battery pack P1 to battery pack P2 may include closing switch SWM, followed by an on command issued by inverter solid-state switches S1-S6 to achieve a closed SU state, which closes battery pack P1 and the corresponding equivalent inductance L. EQ The circuit between them, thus giving L EQCharging or energizing. Then, before establishing the complementary SL state, an open SU ​​state is established by a conduction command within a finite dodge time to prevent short circuit between the positive DC bus 218 and the negative DC bus 222. The short dodge time can be considered as part of the duration of the closed SU state. Through the anti-parallel diode associated with the lower switch of the complementary SL state, the L... EQ The current can continue during the stagnation period until a turn-on command is issued to establish a complementary closed SL state, which closes the battery pack P2 and the corresponding equivalent inductance L. EQ The circuit between them, thus making L EQ Discharge and store in L EQ The energy is transferred from the P1 to the P2 battery pack. Then, a subsequent SU state is established to begin another L state. EQ Before a charging event begins another energy storage and release cycle through stator winding 123, a finite slack state is established by a turn-on command within a short period to prevent a short circuit between the positive DC bus 218 and the negative DC bus 222. This short slack time can be considered part of the duration of the closed SL state. The operation described above uses a lower switch as the discharge L. EQ The synchronous rectifier in the middle. However, it should be understood that the discharge L EQ This can be achieved solely through an anti-parallel diode associated with the lower switch. It should be understood that shuttle charging from battery pack P2 to battery pack P1 can be similarly achieved by closing the SL state, which closes battery pack P2 and the corresponding equivalent inductance L. EQ The circuit between them, thus affecting the equivalent inductance L EQ Charging then establishes a complementary closed SU state, which closes the battery pack P1 and the corresponding equivalent inductance L. EQ The circuit between them, thereby storing the L EQ The energy is transferred to battery pack P1.

[0056] PWM control can be used to control the frequency and the corresponding switching cycle (T) according to a predetermined frequency. s The PWM control uses a duty cycle (D) to control the on-time of the SU (i.e., the SU is in the closed state). In this example of shuttle charging from battery pack P1 to battery pack P2, the duty cycle (D) of the PWM control corresponds to the on-time of the SU (i.e., the SU is in the closed state), T. s The remaining part (i.e., (1-D)T) s This corresponds to the SU disconnection time (i.e., the SU disconnection state). This is achieved through period T. sBy changing the duty cycle D, the output voltage of battery pack P2 can be controlled, and the switch-mode power converter can be controlled to be in continuous conduction mode (CCM) or discontinuous conduction mode (DCM). Table 5 here shows the relative sequence of PWM control described herein. In Table 5, the dwell time can be labeled DT.

[0057]

[0058] In one embodiment, reference Figure 4A and 4B And as shown in Table 1, the SU state can be state VII, where the upper switch is turned on synchronously or simultaneously via a synchronous turn-on command. In one embodiment, the SL state is state VII, where the upper switch is turned on synchronously or simultaneously. This PWM control of the power inverter can be referred to herein as synchronous pulse width modulation control. Advantageously, the available SU states and complementary SL states include states I, II, and III, where the L of each state... EQ Essentially equivalent to other states (i.e., L) A = L B = L C Furthermore, their states are completely independent and do not share a common upper or lower switch closure. Therefore, any two or all three states I, II, and III can be alternated or interleaved via phase-shift PWM turn-on commands. This interleaving operation can reduce ripple current through stator windings 123 and through battery packs P1 and P2. This PWM control of the power inverter can be referred to here as interleaved pulse width modulation control.

[0059] In one embodiment, reference Figure 5A and 5B And as shown in Table 2, the SU state can be state III, where the upper switches are turned on synchronously or simultaneously via a synchronous turn-on command. In one embodiment, the SL state is state VII, where the upper switches S3 and S5 are turned on synchronously or simultaneously. This PWM control of the power inverter can be referred to herein as synchronous pulse width modulation control. Advantageously, the available SU states and complementary SL states include states I and II, where the L of each state... EQ Essentially equivalent to other states (i.e., L) A + L B = L A + L C Furthermore, their states are completely independent and do not share a common upper or lower switch closure. Therefore, each of states I and II can be alternated or interleaved via phase-shift PWM turn-on commands. This interleaving operation can reduce ripple current through stator windings 123 and through battery packs P1 and P2. Figure 6A , Figure 6Band Table 3 and Figure 7A , Figure 7B The embodiments in Table 4 are similar. Figure 4A , Figure 4B As in the embodiments in Table 1, the corresponding SU state can be state III, in which the upper switch is turned on synchronously or simultaneously by a synchronous turn-on command, and the corresponding SL state can be state III, in which the lower switch is turned on synchronously or simultaneously by a synchronous turn-on command, and states I and II can be interleaved by a phase-shift PWM turn-on command.

[0060] Figure 8 An exemplary method for balancing a pair of battery packs in an electric vehicle 100 by controlling a system as described herein is illustrated. Figure 8 This represents multiple tasks in flowchart routine 800, which can be performed at least partially by control system 208, which includes one or more ECUs, for example, combined with... Figure 1 and Figure 2 The vehicle controller 103, motor controller 105, and battery manager module 114 are described. Figure 8At least some of the tasks can be implemented using computer-readable code or instruction sets stored in the non-volatile memory of one or more ECUs. In this example, vehicle 100 may have a RESS 104 comprising a pair of 400-volt battery packs P1 and P2, which may be configured in series at 800 volts for propulsion and DCFC, or in parallel at 400 volts for propulsion and in series at 800 volts for DCFC. Starting at 803, the vehicle operator may bring vehicle 100 into the charging bay of an adjacent 800-volt DCFC charging station and control vehicle 100 to stop. A diagnostic check may be performed at 809 to check for failed faults before proceeding further. A failed fault will cause the routine to exit at 810. Faults checked at 809 may include, for example, isolation faults related to proper isolation of the vehicle's high-voltage system and any low-voltage systems of the vehicle. In the absence of a failed fault, routine 800 continues to 811. At 811, routine 800 can verify the appropriate charging port connection, including verifying the handshake and communication between vehicle 100 and the charging station via the charging port connection. Until the charging port connection is verified at 811, the routine continues diagnostic checks at 809, as described above. While the charging port connection is being verified at 811, routine 800 continues to 813, where, if necessary, control system 208 configures battery packs P1 and P2 in series. This task may not be necessary if RESS 104 is configured with series-connected battery packs P1 and P2 for propulsion. Next, at 815, the appropriate pre-charge voltage level of the link or large-capacity capacitor on vehicle 100 or at the charging station can be checked and pre-charged if necessary. At 816, DCFC charging can be performed according to vehicle charging control, which includes RESS requirements established based on monitored RESS 104 indicators including SOC, DOD, SOH, etc. Routine 800 continues to 817, where, during the ongoing DCFC charging cycle, it can be periodically determined whether to perform battery pack balancing. For example, a capacity mismatch between battery packs P1 and P2 may cause one of them to reach a charging acceptance limit, such as reaching a DCFC SOC target (e.g., 80%) before the total RESS capacity reaches a target or the charging voltage limit is reached. In this case, it may be advantageous at 818 to pause charging during the DCFC charging cycle and perform a balancing routine for battery packs P1 and P2. The balancing of battery packs P1 and P2 at 818 is performed according to a suitable hardware and control configuration as described in detail herein. As part of the balancing routine at 818, additional diagnostics related to the power inverter 110 and motor 120 (e.g., short circuit, open circuit, current, voltage, and temperature limits, etc.) can be performed, and the balancing routine can be exited when a failure is detected.After balancing battery packs P1 and P2 at 818 (or exiting due to a failure), routine 800 returns to 819, where it is determined whether DCFC is complete. Various RESS metrics, including SOC, DOD, SOH, and others, can indicate that the DCFC charging target or limit (e.g., total RESS SOC) has been reached, indicating the termination of the DCFC charging cycle. If DCFC charging is not complete, routine 800 returns to 816 to continue the DCFC charging cycle. When DCFC charging is complete, the routine continues to 821, where it is determined whether battery pack balancing should be performed. For example, after the DCFC charging cycle is determined to be complete at 819, at 818, battery packs P1 and P2 can undergo final balancing to obtain individual battery pack voltages whose differences will not cause arcing and damage to the switching contactors (e.g., SWP1 and SWP2) when the battery packs are reconfigured in parallel. When DCFC charging is complete (819) and battery packs P1 and P2 do not require further balancing (821), routine 800 continues to 822, where control system 208 can configure battery packs P1 and P2 in parallel if needed. This task may not be necessary if RESS 104 is configured with series-connected battery packs P1 and P2 for propulsion. After any reconfiguration at 822, routine 800 ends at 823.

[0061] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the terms “comprising” and / or “including” as used in this specification specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0062] Whether explicitly stated or not, all numerical values ​​herein are assumed to be modified by the term "about". For the purposes of this disclosure, a range may be expressed as from "about" one particular value to "about" another particular value. The term "about" generally refers to a range of numerical values ​​that a person skilled in the art would consider equivalent to the stated value, having the same function or result, or generally reasonably within manufacturing tolerances of the stated value. Similarly, the numerical values ​​set forth herein are by way of non-limiting examples and may be nominal values; it should be understood that actual values ​​may differ from nominal values ​​depending on environment, design and manufacturing tolerances, age, and other factors.

[0063] Unless explicitly described as “direct,” when the relationship between the first and second elements is described in the above disclosure, the relationship may be a direct relationship in which there are no other intervening elements between the first and second elements, but it may also be an indirect relationship in which there are one or more intervening elements (spatial or functional) between the first and second elements.

[0064] Without altering the principles of this disclosure, one or more steps in the method may be performed in a different order (or simultaneously). Furthermore, while each embodiment is described above as having certain features, any one or more of those features described with respect to any embodiment of this disclosure may be implemented in and / or combined with features of any other embodiment, even if such combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and substitutions of one or more embodiments for each other remain within the scope of this disclosure.

[0065] While the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and equivalents can replace its elements without departing from its scope. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A method for transferring electrical energy between a pair of series-connected batteries, the pair of series-connected batteries being connected between positive and negative DC buses of a power inverter operatively connected to a plurality of stator phase windings of a motor, the method comprising: Connect the midpoint of the pair of series-connected batteries to the stator winding of the motor; and The power inverter is controlled to operate as a switch-mode power converter, using both the power inverter and the stator windings, to charge at least one of the stator phase windings from one of the pair of series-connected batteries, and to discharge at least one of the stator phase windings to the other of the pair of series-connected batteries. Connecting the midpoint of the pair of series-connected batteries to the stator winding of the motor includes closing a switch between the midpoint of the pair of series-connected batteries and a corresponding phase terminal of one of the stator phase windings. The power inverter is controlled to operate as a switch-mode power converter, including interleaved pulse width modulation control of the power inverter and the stator winding.

2. The method of claim 1, wherein the method is performed periodically during a DC fast charging cycle.

3. The method of claim 1, wherein the method is performed when a DC fast charging cycle is completed.

4. A device for shuttling charging between a pair of batteries, comprising: The pair of batteries are connected in series; A motor, comprising a stator winding having a plurality of stator phase windings commonly connected at a neutral terminal and having respective phase terminals; A power inverter having multiple phase pins connected between positive and negative DC buses connected to the two ends of a pair of batteries configured in series, and each phase pin including corresponding upper and lower solid-state switches, wherein the corresponding phase pole is connected to the corresponding phase terminal of a corresponding stator phase winding. A switch between the midpoint of the series-connected pair of batteries and the stator windings, wherein the switch between the midpoint of the series-connected pair of batteries and the stator windings includes a switch between the midpoint of the series-connected pair of batteries and a corresponding phase terminal of one of the stator phase windings; and Controller: The operating switch is closed to connect the midpoint of a pair of batteries configured in series to at least one of the multiple stator phase windings; and The power inverter controls the conduction of a phase pin to operate the power inverter and stator winding as a switch-mode power converter, which includes at least one stator phase winding and one of the upper and lower solid-state switches of at least one phase pin. The power converter controls the conduction of phase pins of the power inverter to operate the power inverter and stator windings in switch mode. The power converter includes interleaved pulse width modulation control of the power inverter.

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