Rechargeable energy storage system heating

Abstract

A rechargeable energy storage system is heated. A system includes a rechargeable energy storage system, a quasi-resonant circuit, and a controller. The rechargeable energy storage system has a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor. The battery temperature sensor is operable to generate a battery temperature signal representative of a storage system temperature within the rechargeable energy storage system. The quasi-resonant circuit is coupled between the positive terminal and the negative terminal and is operable to draw an alternating current signal through the internal impedance of the rechargeable energy storage system in response to a resonance control signal. The controller is coupled to the quasi-resonant circuit and is operable to sense the storage system temperature within the rechargeable energy storage system via the battery temperature signal and generate the resonance control signal to heat the rechargeable energy storage system in response to the battery temperature signal.

Description

[0001] introduction

[0002] This disclosure relates to systems and methods for heating rechargeable energy storage systems.

[0003] If the heat generated for preheating the vehicle's battery pack is inefficient and / or slow (i.e., in cold environments), the result can be reduced driving range and degraded performance. Positive temperature coefficient heaters have size and warranty limitations. Furthermore, the DC fast charging performance of the battery pack is poor at low temperatures.

[0004] Therefore, those skilled in the art continue to conduct research and development in the field of rechargeable energy storage systems for heated vehicles. Summary of the Invention

[0005] This document provides a system. The system includes a rechargeable energy storage system, a quasi-resonant circuit, and a controller. The rechargeable energy storage system has a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor. The battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system. The quasi-resonant circuit is coupled between the positive and negative terminals and is operable to draw an AC signal through the internal impedance of the rechargeable energy storage system in response to a resonant control signal. The controller is coupled to the quasi-resonant circuit and is operable to: sense the storage system temperature within the rechargeable energy storage system via the battery temperature signal, and generate a resonant control signal in response to the battery temperature signal to heat the rechargeable energy storage system.

[0006] In one or more embodiments of the system, the quasi-resonant circuit includes: a half-bridge power module having a center node; an inductor coupled to the center node; and a resonant capacitor coupled in parallel with the half-bridge power module.

[0007] In one or more embodiments, the system includes a current sensor operable to generate a measured current signal representing an alternating current signal. The controller is further operable to generate a resonant control signal in response to the measured current signal.

[0008] In one or more embodiments of the system, the current sensor is connected in series with the inductor.

[0009] In one or more embodiments of the system, the half-bridge power module has an AC output terminal, and a current sensor is located at the AC output terminal.

[0010] In one or more embodiments of the system, the current sensor is a current mirror connected in series with the half-bridge power module.

[0011] In one or more embodiments of the system, the current sensor is a battery current sensor within a rechargeable energy storage system.

[0012] In one or more embodiments of the system, the rechargeable energy storage system includes a pair of DC fast charging terminals through which the rechargeable energy storage system is rechargeable. An inductor is directly connected to one of the terminals of the pair of DC fast charging terminals. A switch is arranged between the quasi-resonant circuit and the positive terminal of the rechargeable energy storage system and is controlled by a resonant control signal to alternately connect and isolate the quasi-resonant circuit from the rechargeable energy storage system.

[0013] In one or more embodiments of the system, the controller is further operable to generate a pulse-width modulated signal in response to a measured current signal. The half-bridge power module has a first transistor with a first gate and a second transistor with a second gate. The second gate receives the pulse-width modulated signal.

[0014] In one or more embodiments of the system, the switching frequency of the quasi-resonant circuit is tuned to achieve zero-current switching in the second transistor.

[0015] In one or more embodiments of the system, the switching frequency of the quasi-resonant circuit is tuned to achieve a set peak current through the half-bridge power module.

[0016] In one or more embodiments of the system, the quasi-resonant circuit further includes a resonant switch connected in series with an inductor and controlled by a resonant control signal to alternately connect and isolate the quasi-resonant circuit from the rechargeable energy storage system.

[0017] In one or more embodiments, the system includes a traction inverter coupled to the positive and negative terminals of a rechargeable energy storage system. The traction inverter provides a filter capacitor between the positive and negative terminals. When the quasi-resonant circuit is operational, the filter capacitor is coupled in parallel with the resonant capacitor.

[0018] In one or more embodiments of the system, the quasi-resonant circuit is operational while the rechargeable energy storage system is charging.

[0019] In one or more embodiments of the system, a rechargeable energy storage system, a quasi-resonant circuit, and a controller are arranged in the vehicle. The quasi-resonant circuit is operable when the vehicle is in motion.

[0020] In one or more embodiments of the system, the controller is further operable to dither the resonant control signal.

[0021] In one or more embodiments of the system, the rechargeable energy storage system has a charging state and a plurality of battery relays. The controller is further operable to generate a resonant control signal in response to the charging state and one or more of the temperatures of the plurality of battery relays.

[0022] In one or more embodiments of the system, the quasi-resonant circuit is directly connected to the positive and negative terminals of the rechargeable energy storage system. The resonance control signal is transmitted directly from the controller to the quasi-resonant circuit.

[0023] This document provides a method for heating a rechargeable energy storage system. The method includes: generating a battery temperature signal representing the storage system temperature within the rechargeable energy storage system using a battery temperature sensor, wherein the rechargeable energy storage system has internal impedance; receiving the battery temperature signal at a controller; generating a resonant control signal in the controller in response to the battery temperature signal; and, in response to the resonant control signal, drawing an AC signal from the rechargeable energy storage system through the internal impedance using a quasi-resonant circuit to heat the rechargeable energy storage system.

[0024] This document provides a vehicle. The vehicle includes a rechargeable energy storage system, a traction inverter, a quasi-resonant circuit, and a controller. The rechargeable energy storage system has a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor. The battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system. The traction inverter is coupled to the positive and negative terminals of the rechargeable energy storage system. The quasi-resonant circuit is coupled between the positive and negative terminals and is operable to draw an AC signal through the internal impedance of the rechargeable energy storage system in response to a resonant control signal. The controller is coupled to the quasi-resonant circuit and is operable to: sense the storage system temperature within the rechargeable energy storage system via the battery temperature signal, and generate a resonant control signal in response to the battery temperature signal to heat the rechargeable energy storage system.

[0025] This application provides the following technical solution:

[0026] 1. A system comprising:

[0027] A rechargeable energy storage system having a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor, wherein the battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system.

[0028] A quasi-resonant circuit coupled between the positive and negative terminals, operable to draw AC signals through the internal impedance of a rechargeable energy storage system in response to a resonant control signal; and

[0029] The controller, coupled to the quasi-resonant circuit, is operable to:

[0030] The temperature of the storage system within the rechargeable energy storage system is sensed via battery temperature signals; and

[0031] A resonant control signal is generated in response to the battery temperature signal to heat the rechargeable energy storage system.

[0032] 2. The system according to technical solution 1, wherein the quasi-resonant circuit includes:

[0033] A half-bridge power module with a central node;

[0034] Inductor, which is coupled to the central node; and

[0035] A resonant capacitor is coupled in parallel with the half-bridge power module.

[0036] 3. The system according to technical solution 2 further includes:

[0037] A current sensor operable to generate a measured current signal representing an alternating current signal, wherein:

[0038] The controller is further operable to generate a resonant control signal in response to the measured current signal.

[0039] 4. The system according to technical solution 3, wherein:

[0040] The current sensor is connected in series with the inductor.

[0041] 5. The system according to technical solution 3, wherein:

[0042] The half-bridge power module has an AC output terminal; and

[0043] The current sensor is located at the AC output terminal.

[0044] 6. The system according to technical solution 3, wherein:

[0045] The current sensor is a current mirror connected in series with the half-bridge power module.

[0046] 7. The system according to technical solution 3, wherein:

[0047] A current sensor is a battery current sensor within a rechargeable energy storage system.

[0048] 8. The system according to technical solution 3, wherein:

[0049] The rechargeable energy storage system includes a pair of DC fast charging terminals through which the rechargeable energy storage system can be recharged;

[0050] The inductor is directly connected to one of the terminals of the pair of DC fast charging terminals; and

[0051] A switch, positioned between the quasi-resonant circuit and the positive terminal of the rechargeable energy storage system and controlled by a resonant control signal, alternately connects and isolates the quasi-resonant circuit from the rechargeable energy storage system.

[0052] 9. The system according to technical solution 3, wherein:

[0053] The controller is further operable to generate a pulse width modulated signal in response to a measured current signal;

[0054] The half-bridge power module has a first transistor with a first gate and a second transistor with a second gate; and

[0055] The second gate receives the pulse width modulation signal.

[0056] 10. The system according to technical solution 9, wherein:

[0057] The switching frequency of the quasi-resonant circuit is tuned to achieve zero-current switching in the second transistor.

[0058] 11. The system according to technical solution 2, wherein:

[0059] The switching frequency of the quasi-resonant circuit is tuned to achieve the set peak current through the half-bridge power module.

[0060] 12. The system according to technical solution 2, wherein the quasi-resonant circuit further comprises:

[0061] A resonant switch, connected in series with an inductor and controlled by a resonant control signal, alternately connects and isolates a quasi-resonant circuit from a rechargeable energy storage system.

[0062] 13. The system according to technical solution 2 further includes:

[0063] A traction inverter, coupled to the positive and negative terminals of a rechargeable energy storage system, wherein:

[0064] The traction inverter provides a filter capacitor between the positive and negative terminals; and

[0065] When the quasi-resonant circuit is operational, the filter capacitor is coupled in parallel with the resonant capacitor.

[0066] 14. The system according to technical solution 1, wherein

[0067] The quasi-resonant circuit is operational when the rechargeable energy storage system is charging.

[0068] 15. The system according to technical solution 1, wherein:

[0069] A rechargeable energy storage system, a quasi-resonant circuit, and a controller are arranged in the vehicle; and

[0070] The quasi-resonant circuit is operable when the vehicle is in motion.

[0071] 16. The system according to technical solution 1, wherein the controller is further operable to jitter the resonant control signal.

[0072] 17. The system according to technical solution 1, wherein:

[0073] The rechargeable energy storage system has a charging state and multiple battery relays; and

[0074] The controller is further operable to generate a resonant control signal in response to the state of charging and one or more of the temperatures of multiple battery relays.

[0075] 18. The system according to technical solution 1, wherein:

[0076] The quasi-resonant circuit is directly connected to the positive and negative terminals of the rechargeable energy storage system; and

[0077] The resonant control signal is transmitted directly from the controller to the quasi-resonant circuit.

[0078] 19. A method for heating a rechargeable energy storage system, comprising:

[0079] A battery temperature signal representing the temperature of the storage system within a rechargeable energy storage system is generated using a battery temperature sensor, wherein the rechargeable energy storage system has internal impedance;

[0080] Receive battery temperature signal at the controller;

[0081] In response to the battery temperature signal, a resonant control signal is generated in the controller; and

[0082] In response to a resonant control signal, a quasi-resonant circuit is used to draw an AC signal from the rechargeable energy storage system through its internal impedance to heat the rechargeable energy storage system.

[0083] 20. A vehicle comprising:

[0084] A rechargeable energy storage system having a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor, wherein the battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system.

[0085] A traction inverter coupled to the positive and negative terminals of a rechargeable energy storage system;

[0086] A quasi-resonant circuit coupled between the positive and negative terminals, operable to draw AC signals through the internal impedance of a rechargeable energy storage system in response to a resonant control signal; and

[0087] The controller, coupled to the quasi-resonant circuit, is operable to:

[0088] The temperature of the storage system within the rechargeable energy storage system is sensed via battery temperature signals; and

[0089] A resonant control signal is generated in response to the battery temperature signal to heat the rechargeable energy storage system.

[0090] The foregoing features and advantages, as well as other features and advantages, of this disclosure will become readily apparent when taken in conjunction with the accompanying drawings, based on the following detailed description of the best mode for carrying out this disclosure. Attached Figure Description

[0091] Figure 1 This is a schematic diagram illustrating the environment of a system according to one or more exemplary embodiments.

[0092] Figure 2 This is a schematic diagram of an electronic configuration for heating a rechargeable energy storage system according to one or more exemplary embodiments.

[0093] Figure 3 This is a schematic diagram of another electronic configuration according to one or more exemplary embodiments.

[0094] Figure 4 This is a schematic diagram illustrating yet another electronic configuration according to one or more exemplary embodiments.

[0095] Figure 5 This is a flowchart of a method for operating a controller according to one or more exemplary embodiments. Detailed Implementation

[0096] Embodiments of this disclosure provide a system and / or method suitable for heating a rechargeable energy storage system used in a vehicle. The system includes a rechargeable energy storage system (RESS), a quasi-resonant circuit (QRC), and a controller. A battery temperature sensor within the rechargeable energy storage system generates a battery temperature signal representing the storage system temperature within the rechargeable energy storage system. The quasi-resonant circuit draws an alternating current (AC) signal through the internal impedance of the rechargeable energy storage system in response to a resonant control signal. The AC signal heats the rechargeable energy storage system when the vehicle is stationary and when the vehicle is moving. The controller senses the storage system temperature within the rechargeable energy storage system via the battery temperature signal and generates a resonant control signal in response to the battery temperature signal to control the heating. The system / method can be configured with a separate QRC, DC fast charging (DCFC) equipment, a permanently powered QRC, and can use a capacitor in a traction converter connected in parallel with the QRC. In various embodiments, the QRC can be encapsulated within a battery disconnect unit (BDU).

[0097] refer to Figure 1 The illustrated system 90 is shown as a schematic diagram of the environment of the illustrated system 90 according to one or more exemplary embodiments. The system 90 typically includes a vehicle 100 having a rechargeable energy storage system 102 (or battery pack), an optional battery disconnect unit 104, a quasi-resonant circuit 106 (QRC), a traction inverter 108, a controller 110, an optional DC fast charging (DCFC) interface circuit 112, and an optional DCFC socket 114.

[0098] Vehicle 100 may include, but is not limited to, moving objects such as passenger cars, trucks, autonomous vehicles, electric vehicles, hybrid vehicles, motorcycles, ships, agricultural vehicles, trains, and / or aircraft. In some embodiments, vehicle 100 may include stationary objects such as billboards, kiosks, and / or marquees. Other types of vehicle 100 may be implemented to meet the design criteria of specific applications.

[0099] RESS102 is a high-voltage battery pack operable to store electrical energy. RESS102 is typically operable to receive power from DCFC interface circuitry 112 (or a similar power source) and supply power to traction inverter 108 via battery disconnect unit 104. RESS102 may include multiple battery modules electrically connected in series and / or parallel. In various embodiments, RESS102 can provide a DC (direct current) potential of approximately 400 to 1000 volts. Other battery voltages can be implemented to meet the design specifications of specific applications.

[0100] Battery disconnect unit (BDU) 104 connects RESS 102 directly to traction inverter 108. Battery disconnect unit 104 is operable to provide multiple switches or relays (not shown) for connecting and disconnecting RESS 102 from traction inverter 108.

[0101] The QRC is a self-starting quasi-resonant circuit that operates to draw an AC signal through the internal impedance within RESS102. The AC signal through the internal impedance generates heat, which warms RESS102. Heating can be performed while RESS102 is being charged, discharged, and / or not in use.

[0102] The traction inverter 108 is a 3-phase DC-to-AC traction inverter. The traction inverter 108 is operable to convert DC power received from RESS 102 into 3-phase AC power for motor power supply.

[0103] Controller 110 implements the battery controller, inverter controller, QRC controller, and DCFC interface circuit controller. Controller 110 is typically operable to control the charging and discharging of RESS 102.

[0104] Optional DCFC interface circuitry 112 implements relays and diodes for connecting and disconnecting RESS 102 from the DCFC socket. The relays in DCFC interface circuitry 112 are controlled by controller 110. In various embodiments, DCFC interface circuitry 112 is operable to connect RESS 102 to two parallel battery packs for simultaneous charging of both packs.

[0105] Optional DCFC socket 112 is a high-voltage DC charging socket. In various embodiments, DCFC socket 112 may comply with the Society of Automotive Engineers (SAE) international standard J1772 / CCS (Combined Charging System), the International Electrotechnical Commission (IEC) standard 61851, and / or the IEC 62196-3 standard. Vehicle 100 may achieve DC Level 1 and / or DC Level 2 charging capabilities. Other standards may be implemented to meet the design requirements of specific applications.

[0106] refer to Figure 2 The diagram illustrates example implementations of various electronic configurations for RESS heating according to one or more exemplary embodiments. A standalone configuration typically includes an RESS 102, a quasi-resonant circuit 106, a traction inverter 108, a controller 110, and at least one current sensor 140-146. A DC fast charging (DCFC) interface circuit 112 is included to implement a "DCFC-enabled" configuration.

[0107] RESS102 includes terminals 116a-116b, DCFC terminals 118a-118b, a battery 120, switches (or battery relays) 122a-122c, a pre-charge resistor 124, an internal impedance 126, and a battery temperature sensor 128. Terminals 116a and 118a can be positive terminals. Terminals 116b and 118b can be negative terminals. Switches 122b and 122c controllably connect RESS102 to a traction inverter 108. Switch 122a controllably bypasses the open switch 122b to pre-charge RESS102 through the pre-charge resistor 124. In various embodiments, the internal impedance 126 can be a parasitic impedance used when heating RESS102. In some embodiments, the internal impedance 126 can be an intentional impedance in a bus built into RESS102. In other embodiments, the internal impedance 126 may represent the total ohmic internal resistance of each battery cell. The battery temperature sensor 128 is operable to generate a battery temperature signal 129 representing the storage system temperature within the rechargeable energy storage system 102. The battery temperature signal 129 is transmitted to the controller 110.

[0108] QRC 106 includes a resonant switch 130, a high-current, high-frequency AC inductor 132 (or simply "inductor"), a half-bridge power module 134, and a DC capacitor 136 (or simply "resonant capacitor") with high ripple current capability. The half-bridge power module 134 includes an upper transistor and a lower transistor connected at a center node 138, and a pair of diodes connected in parallel with each corresponding transistor. When the vehicle 100 is in the off state and / or charging, additional DC and AC current is drawn from RESS 102. In a permanently powered configuration, the resonant switch 130 is not present.

[0109] Resonant switch 130 is connected in series with inductor 132. Inductor 132 is coupled to the center node 138 of half-bridge power module 134. When resonant switch 130 is in the open state, QRC 106 does not draw current from RESS 102 and does not generate heat. When resonant switch 130 is in the closed state and the half-bridge switch is properly controlled, QRC 106 generates an AC signal 150, which generates heat in the internal impedance 126 of RESS 102. Inductor 132, half-bridge power module 134, and resonant capacitor 136 form a self-stabilizing resonance circuit that generates AC signal 150. Resonant switch 130 and inductor 132 are used to isolate QRC 106 from the remaining high-voltage buses between RESS 102 and traction inverter 108.

[0110] Current sensors 140-146 generate measured current signals 148 by measuring the current at various points in the system. The measured current signals 148 are transmitted to controller 110. Controller 110 uses the measured current signals 148 to define the pulse parameters of QRC 106.

[0111] A battery current sensor 140 can be integrated into RESS 102. A first current sensor 142 can be integrated in series with inductor 132 into QRC 106. A second current sensor 144 is located at AC output terminal 152 of half-bridge power module 134. A third current sensor 146 is located on the underside of half-bridge power module 134. In some embodiments, the third current sensor 146 includes a current sensor power MOSFET (e.g., a current mirror) to directly measure the switching current.

[0112] The DCFC interface circuit 112 includes a pair of battery relays 160-162 and a power diode 164. The battery relays 160-162 are controlled by the controller 110 to couple to the DCFC socket (…). Figure 1 Connect and disconnect RESS102 from the charging station when needed.

[0113] refer to Figure 3 The diagram illustrates an example implementation of another electronic configuration according to one or more exemplary embodiments. The electronic configuration illustrates a permanently powered DCFC interface circuit 112 configuration. The permanently powered configuration typically includes a RESS 102, a quasi-resonant circuit 106a, a traction inverter 108, a controller 110, and an optional DCFC interface circuit 112.

[0114] QRC 106a is a variant of QRC 106 that does not have the resonant switch 130, such as Figure 2 As shown in the diagram. Therefore, QRC 106a remains continuously connected to the high-voltage direct current (HVDC) bus, but becomes operable after the control half-bridge switches. In an alternative embodiment, QRC 106a can be replaced by QRC 106, where the resonant switch 130 is normally closed, and the controller 110 does not command the resonant switch 130 to open.

[0115] refer to Figure 4 The illustrated electronic configuration is a schematic diagram of an example implementation of another electronic configuration according to one or more exemplary embodiments. The illustrated electronic configuration uses a filter capacitor within a traction inverter 108 and a QRC 106. The filter capacitor configuration includes a RESS 102, a BDU 104, a QRC 106a, a traction inverter 108, a controller 110, and an optional DCFC interface circuit 112.

[0116] BDU 104 includes a disconnect switch 170 that alternately connects and disconnects one side of QRC 106a with one of terminals 116a-116b (e.g., the positive terminal 116a as illustrated). The other side of QRC 106a is connected to another terminal 116a-116b (e.g., the negative terminal 116b as illustrated). Inductor 132 is connected to one of DCFC terminals 118a-118b (e.g., the positive DCFC terminal 118a as illustrated).

[0117] The traction inverter 108 includes a filter capacitor 172 coupled across terminals 116a-116b. When the disconnect switch 170 is closed, the filter capacitor 172 is electrically connected in parallel with the resonant capacitor 136, thus increasing the capacitance seen by the half-bridge power module 134. Therefore, QRC 106a can resonate at a frequency depending on the filter capacitor 172. In various embodiments, multiple traction inverters 108 may be included in the vehicle 100, and thus multiple filter capacitors 172 may be electrically connected in parallel when the disconnect switch 170 is closed.

[0118] refer to Figure 5 The diagram illustrates a flowchart of a method for example operation of a controller, according to one or more exemplary embodiments. Method 180 (or process) is implemented by controller 110. As shown, method 180 typically includes steps 182 to 202. The order of the steps is shown as a representative example. Other orderings of steps may be implemented to meet the standards of a particular application.

[0119] Method 180 begins in step 182. In decision step 184, controller 110 determines whether QRC 106 has been installed and initialized. If QRC 106 has not been installed and / or initialized, method 180 may return to start-up step 182. If QRC 106 has been installed and initialized, in step 186, controller 110 may check the battery state of charge (SOC), battery voltage, battery relay temperature, and battery temperature. In decision step 188, a check is performed to determine whether the vehicle battery temperature warrants that RESS 102 should be pre-regulated. If RESS 102 is sufficiently hot, decision step 188 returns to start-up step 182.

[0120] If decision step 188 determines that RESS 102 should be pre-regulated, another check is performed in step 190 on the battery temperature relative to the operating temperature. If the battery temperature exceeds the operating temperature, method 180 may terminate in step 202. Otherwise, controller 110 sets the current limit of QRC 106 in step 192 based on SOC, battery voltage, battery relay temperature, and / or battery temperature. In step 194, resonant switch 130 is closed to enable QRC 106. In step 196, controller 110 determines the PWM duty cycle of the pulse width modulation (PWM) signal applied to the lower transistor of the two transistors in the half-bridge power module. The PWM duty cycle is based on a priori lookup table of duty cycle and heating rate.

[0121] In step 198, AC heating of RESS102 is initiated, and a timer is started. The predetermined heating time (e.g., T) is calculated after AC heating has started in step 198. HC AC heating can be stopped in step 200. Afterward, method 180 can return to step 186 to recheck the battery SOC, battery voltage, and battery temperature. The loop around steps 186 to 200 returns to step 186 until, according to decision step 190, the battery temperature exceeds the operating temperature, and method 180 ends at step 202.

[0122] In various embodiments, the vehicle's electronics can provide a separate quasi-resonant circuit for generating an AC current signal through the high-voltage rechargeable energy storage system. The QRC includes a half-bridge power module, a high-current, high-frequency AC inductor, and a DC capacitor with high ripple current capability. A current sensor can be embedded within the inductor or at the AC output terminal of the half-bridge power module to measure the AC current through the inductor and the high-voltage battery. Alternatively, a SENSEFET (e.g., a current mirror) can be used on the underside of the half-bridge power module to directly measure the switching current.

[0123] The controller compares the current sensor signal with a reference value to generate a pulse-width modulated (PWM) signal, which is applied to the gate of the lower transistor of the half-bridge power module to initiate QRC operation. The switching frequency of the QRC is tuned to maximize the AC root-mean-square (RMS) current for a set peak current and / or achieve zero-current switching for the lower transistor. A resonant switch connected in series with an inductor isolates the QRC from the remaining high-voltage bus. In various embodiments, the input filter capacitors of one or more traction inverters may be shared by the QRC circuit to control the resonant frequency of the AC signal.

[0124] The QRC can be operational when the vehicle is charging, when the vehicle is in motion, and when the vehicle is in a power-off mode (e.g., off). The power devices within the QRC may share the same package as the traction inverter. As an example, the QRC power devices may be mounted on the same heatsink as the traction inverter.

[0125] The current sensor can be a battery current sensor, which provides the controller with the battery RMS current value to define the QRC pulse parameters. Frequency jitter is used to improve the noise-vibration-roughness (NVH) (e.g., audible noise) of the QRC circuit. Frequency jitter causes the AC signal frequency to spread across a frequency band, rather than being set at a single frequency. Furthermore, the RMS current of the QRC AC current signal may be limited depending on the battery SOC limit in the RESS and the temperature of the switches, inductors, resonant capacitors, and battery relays.

[0126] Implementations of the system / method provide an independent half-bridge architecture enabling AC heating during a variety of possible vehicle operating modes. The heating system can be implemented in vehicles without an electric oil pump while the vehicle is in motion, and in vehicles with a single motor drive unit. The heating system / method is compatible with 800V DC (Vdc) or 400Vdc DCFC, and with 400Vdc traction inverters.

[0127] AC heating utilizes the battery's internal resistance to "self-heat." This system / method is capable of heating the battery without implementing convection heating methods (e.g., without an external positive temperature coefficient (PTC) heater). Furthermore, this system / method is capable of heating the battery in every possible operating mode (e.g., when the vehicle is in motion, stationary, and / or during DCFC).

[0128] Embodiments of this disclosure generally provide a system including a rechargeable energy storage system, a quasi-resonant circuit, and a controller. The rechargeable energy storage system has a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor. The battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system. The quasi-resonant circuit is coupled between the positive and negative terminals of the rechargeable energy storage system. The quasi-resonant circuit is operable to draw an AC signal through the internal impedance of the rechargeable energy storage system in response to a resonant control signal. The controller is coupled to the quasi-resonant circuit and the rechargeable energy storage system. The controller is operable to sense the storage system temperature within the rechargeable energy storage system via the battery temperature signal and to generate a resonant control signal in response to the battery temperature signal to heat the rechargeable energy storage system.

[0129] The numerical values ​​of parameters (e.g., parameters of quantity or condition) in this specification (including the appended claims) are to be understood to be modified in every instance by the term "about," regardless of whether "about" actually precedes the numerical value. "About" indicates that the numerical value allows for some slight imprecision (numerically close to exact; approximately or fairly close to the value; nearly). If the imprecision provided by "about" is not otherwise understood in this ordinary sense in the art, then "about," as used herein, at least indicates the variation that may arise from common methods of measuring and using such parameters. Furthermore, the disclosure of ranges includes values ​​throughout the range and disclosures of further subdivided ranges. Each value within the range and the endpoints of the range are thus disclosed as separate embodiments.

[0130] While the best mode for carrying out this disclosure has been described in detail, those skilled in the art will recognize various alternative designs and embodiments for implementing this disclosure within the scope of the appended claims.

Claims

1. A system comprising: A rechargeable energy storage system having a positive terminal, a negative terminal, an internal impedance, and a battery temperature sensor, wherein the battery temperature sensor is operable to generate a battery temperature signal representing the storage system temperature within the rechargeable energy storage system. A quasi-resonant circuit coupled between the positive and negative terminals, and operable to draw AC signals through the internal impedance of a rechargeable energy storage system in response to a resonant control signal; as well as The controller, coupled to the quasi-resonant circuit, is operable to: The temperature of the storage system within the rechargeable energy storage system is sensed via battery temperature signals. as well as A resonant control signal is generated in response to the battery temperature signal to heat the rechargeable energy storage system.

2. The system according to claim 1, wherein the quasi-resonant circuit comprises: A half-bridge power module with a central node; An inductor coupled to a central node; as well as A resonant capacitor is coupled in parallel with the half-bridge power module.

3. The system according to claim 2, further comprising: A current sensor operable to generate a measured current signal representing an alternating current signal, wherein: The controller is further operable to generate a resonant control signal in response to the measured current signal.

4. The system according to claim 3, wherein: The current sensor is connected in series with the inductor.

5. The system according to claim 3, wherein: The half-bridge power module has an AC output terminal; and The current sensor is located at the AC output terminal.

6. The system according to claim 3, wherein: The current sensor is a current mirror connected in series with the half-bridge power module.

7. The system according to claim 3, wherein: A current sensor is a battery current sensor within a rechargeable energy storage system.

8. The system according to claim 3, wherein: The rechargeable energy storage system includes a pair of DC fast charging terminals through which the rechargeable energy storage system can be recharged; The inductor is directly connected to one of the terminals of the pair of DC fast charging terminals; as well as A switch, positioned between the quasi-resonant circuit and the positive terminal of the rechargeable energy storage system and controlled by a resonant control signal, alternately connects and isolates the quasi-resonant circuit from the rechargeable energy storage system.

9. The system according to claim 3, wherein: The controller is further operable to generate a pulse width modulated signal in response to a measured current signal; The half-bridge power module has a first transistor with a first gate and a second transistor with a second gate; and The second gate receives the pulse width modulation signal.

10. A method for heating a rechargeable energy storage system, comprising: A battery temperature signal representing the temperature of the storage system within a rechargeable energy storage system is generated using a battery temperature sensor, wherein the rechargeable energy storage system has internal impedance; Receive battery temperature signal at the controller; A resonant control signal is generated in the controller in response to the battery temperature signal; as well as In response to a resonant control signal, a quasi-resonant circuit is used to draw an AC signal from the rechargeable energy storage system through its internal impedance to heat the rechargeable energy storage system.

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