System and method for raising battery temperature using motor drive system

Abstract

The present application relates to a system and method for raising a battery temperature using a motor driving system, the system for raising a battery temperature comprising: an inverter including a plurality of branches, each branch including a pair of switching devices connected in series with each other between both ends of a battery, the plurality of branches respectively corresponding to a plurality of phases; a motor including a plurality of windings respectively corresponding to the plurality of phases, one end of each winding of the plurality of windings being connected to a connection node between the pair of switching devices included in a corresponding branch, the other end of the plurality of windings being connected to each other; and a controller configured to select two phases among the plurality of phases, and alternately control on / off states of the switching devices included in two branches in the inverter corresponding to the selected two phases at a predetermined switching frequency, to generate alternating current (AC) supplied to the battery.

Description

Technical Field

[0001] This invention relates to a system and method for raising the temperature of a battery used in a motor drive system of a vehicle. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not constitute prior art.

[0003] Generally, an environmentally friendly vehicle powered by electricity includes a battery for storing electrical energy, an inverter for converting the electrical energy stored in the battery into alternating current (AC) with multiple phases, and an electric motor that uses the AC converted by the inverter to generate rotational kinetic energy.

[0004] In recent years, lithium-ion batteries have been primarily used in environmentally friendly vehicles. Lithium-ion batteries exhibit excellent performance due to their high energy density and good charge-discharge cycle life at room temperature. However, due to the properties of the electrolyte contained in lithium-ion batteries, they suffer from drawbacks such as reduced capacity, increased resistance, and decreased efficiency at low temperatures. In particular, when lithium-ion batteries are charged or overcharged at low temperatures, lithium ions irregularly deposit on the surface of the negative electrode, thus shortening the battery's lifespan. Because of this issue, lithium-ion batteries require a heating device that can rapidly raise the temperature from a low-temperature state to a high-efficiency state.

[0005] Conventionally, there is a method of installing a separate heater (e.g., a positive temperature coefficient (PTC) heater) inside the battery to directly heat the battery or to heat the coolant supplied to the battery and circulate the coolant. However, in conventional battery heating methods, the applicant has found that a separate heater needs to be installed inside the battery, which increases the additional cost and size of the battery.

[0006] As another conventional method for heating batteries, a method of generating heat in the battery electrically has been studied. In this method, the internal resistance of the battery is used to allow current to flow through it, and the heat generated is utilized by losses proportional to the amount of current flowing through it. The advantage of this method is that the current flows uniformly within the battery, resulting in uniform heat generation. However, the applicant found that this method requires a separate dedicated circuit to allow the current to flow through the battery, thus increasing the battery's size and cost. Furthermore, the dedicated circuit (which generates the current to raise the battery temperature and allows it to flow) introduces additional management points, complicating vehicle maintenance.

[0007] The information disclosed in the background section is merely for the purpose of enhancing the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0008] This invention provides a system for raising the temperature of a battery used in a motor drive system. The system includes: an inverter comprising multiple branches, each branch including a pair of switching devices connected in series between the two ends of the battery, the multiple branches corresponding to multiple phases; a motor including multiple windings corresponding to the multiple phases, one end of each winding connected to a connection node between the pair of switching devices included in the corresponding branch, the other ends of the multiple windings being interconnected; and a controller configured to select two of the multiple phases and generate alternating current (AC) supplied to the battery by alternately controlling the on / off state of the pair of switching devices included in each of the two branches of the inverter corresponding to the two selected phases at a preset switching frequency.

[0009] The controller can control the on / off state of a first pair of switching devices in a first branch corresponding to one of the two selected phases at the switching frequency, so that they are complementary, and control the on / off state of a second pair of switching devices in a second branch corresponding to the other two selected phases at the switching frequency, so that they are complementary, and the controller can control the on / off state of one of the switching devices in the first pair of switching devices connected to the positive terminal of the battery in the first branch and the on / off state of one of the switching devices in the second pair of switching devices connected to the positive terminal of the battery in the second branch, so that they are complementary.

[0010] The controller can shut off a third pair of switches included in a third branch corresponding to a phase other than the two selected phases.

[0011] The system may further include a rotor position sensor configured to detect the rotor angle of the motor, wherein the controller can select two phases from the plurality of phases based on the rotor angle.

[0012] The controller can select two phases that reduce the difference between the rotor angle and the angle of AC generated by controlling a pair of switching devices included in each branch corresponding to two of the plurality of phases, the angle of AC being indicated on the dq stationary coordinate system.

[0013] According to another aspect of the invention, a system for raising the temperature of a battery used in a motor drive system includes: an inverter including an a-phase branch, a b-phase branch, and a c-phase branch, each branch including a pair of switching devices connected in series between the two ends of the battery; a motor including an a-phase winding, a b-phase winding, and a c-phase winding, one end of the a-phase winding being connected to a connection node between a first pair of switching devices included in the a-phase branch, one end of the b-phase winding being connected to a connection node between a second pair of switching devices included in the b-phase branch, one end of the c-phase winding being connected to a connection node between a third pair of switching devices included in the c-phase branch, and the other ends of the a-phase winding, the b-phase winding, and the c-phase winding being interconnected; and a controller configured to select two branches of the a-phase branch, the b-phase branch, and the c-phase branch, and to generate AC supplied to the battery by alternately controlling the on / off state of a pair of switching devices included in the selected branch at a preset switching frequency.

[0014] The controller can control the on / off state of a pair of switching devices included in one branch of the selected branch at the switching frequency, so that they are complementary, and control the on / off state of a pair of switching devices included in the remaining branches of the selected branch at the switching frequency, so that they are complementary. The controller can also control the on / off state of one of the switching devices in a pair of switching devices connected to the positive terminal of the battery in each of the two selected branches, so that they are complementary.

[0015] The controller can shut off a pair of switching devices included in an unselected branch.

[0016] The system may further include a rotor position sensor configured to detect the rotor angle of the motor, wherein the controller can select two branches based on the rotor angle.

[0017] The controller can select two phase branches whose rotor angle is reduced by the difference between the AC generated by controlling the first and second pairs of switching devices included in each phase branch of phase a and phase b, the AC generated by controlling the second and third pairs of switching devices included in each phase branch of phase b and phase c, and the AC generated by controlling the third pair of switching devices and the first pair of switching devices included in each phase branch of phase c and phase a. The angle of AC is indicated on the dq stationary coordinate system.

[0018] When the rotor angle is 0° to 60° and 180° to 240°, the controller can select the c-phase branch and the a-phase branch, and can alternately control the on / off state of the third pair of switching devices and the first pair of switching devices included in each phase branch of the c-phase branch and the a-phase branch at a preset switching frequency, and can turn off the second pair of switching devices included in the b-phase branch to generate AC.

[0019] When the rotor angle is 60° to 120° and 240° to 300°, the controller can select the b-phase branch and the c-phase branch, and can alternately control the on / off state of the second pair of switching devices and the third pair of switching devices included in each phase branch of the b-phase branch and the c-phase branch at a preset switching frequency, and can turn off the first pair of switching devices included in the a-phase branch to generate AC.

[0020] When the rotor angle is 120° to 180° and 300° to 360°, the controller can select phase a branch and phase b branch, and can alternately control the on / off state of the first pair of switching devices and the second pair of switching devices included in each phase branch of phase a branch and phase b branch at a preset switching frequency, and can turn off the third pair of switching devices included in phase c branch to generate AC.

[0021] According to another aspect of the present invention, a method for raising battery temperature using the above system includes the following steps: determining the range to which the rotor angle belongs; determining a branch that remains in the off state according to the range to which the rotor angle belongs; and generating AC by alternately controlling the on / off state of a pair of switching devices included in two branches other than the branch that remains in the off state at a switching frequency.

[0022] When the rotor angle is between 0° and 60° and between 180° and 240°, the step of determining a branch to remain in the off state can be performed. The step of determining a branch to remain in the off state may include turning off the second pair of switching devices included in the b-phase branch, and the step of generating AC may include generating AC by alternately controlling the on / off states of the third pair of switching devices and the first pair of switching devices included in each phase branch of the c-phase branch and the a-phase branch at a preset switching frequency.

[0023] The steps for generating AC may include the following: controlling the on / off state of the third pair of switching devices included in the c-phase branch at the switching frequency so that they are complementary; controlling the on / off state of the first pair of switching devices included in the a-phase branch at the switching frequency so that they are complementary; and controlling the on / off state of one of the switching devices of the third pair of switching devices connected to the positive terminal of the battery in the c-phase branch and the on / off state of one of the switching devices of the first pair of switching devices connected to the positive terminal of the battery in the a-phase branch at the switching frequency so that they are complementary.

[0024] When the rotor angle is between 60° and 120° and between 240° and 300°, the step of determining a branch to remain in the off state can be performed. The step of determining a branch to remain in the off state may include turning off the first pair of switching devices included in the a-phase branch, and the step of generating AC may include generating AC by alternately controlling the on / off states of the second and third pairs of switching devices included in each phase branch of the b-phase and c-phase branches at a preset switching frequency.

[0025] The steps for generating AC may include the following: controlling the on / off state of the second pair of switching devices included in the b-phase branch at the switching frequency so that they are complementary; controlling the on / off state of the third pair of switching devices included in the c-phase branch at the switching frequency so that they are complementary; and controlling the on / off state of one of the switching devices of the second pair of switching devices connected to the positive terminal of the battery in the b-phase branch and the on / off state of one of the switching devices of the third pair of switching devices connected to the positive terminal of the battery in the c-phase branch at the switching frequency so that they are complementary.

[0026] When the rotor angle is between 120° and 180° and between 300° and 360°, the step of determining a branch to remain in the off state can be performed. The step of determining a branch to remain in the off state may include turning off the third pair of switching devices included in the c-phase branch, and the step of generating AC may include generating AC by alternately controlling the on / off states of the first pair of switching devices and the second pair of switching devices included in each phase branch of the a-phase branch and the b-phase branch at a preset switching frequency.

[0027] The steps for generating AC may include the following: controlling the on / off state of a first pair of switching devices included in the a-phase branch at the switching frequency so that they are complementary; controlling the on / off state of a second pair of switching devices included in the b-phase branch at the switching frequency so that they are complementary; and controlling the on / off state of one of the switching devices of the first pair of switching devices connected to the positive terminal of the battery in the a-phase branch and the on / off state of one of the switching devices of the second pair of switching devices connected to the positive terminal of the battery in the b-phase branch at the switching frequency so that they are complementary.

[0028] As will become clear from the description provided herein, many more areas of application will emerge. It should be understood that this specification and the specific examples are for illustrative purposes only and are not intended to limit the scope of the invention. Attached Figure Description

[0029] To better understand the invention, various embodiments of the invention, given by way of example, will be described with reference to the accompanying drawings, in which:

[0030] Figure 1 This is a circuit diagram of a system for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention.

[0031] Figure 2 This means that in Figure 1 Waveform diagram of the method for generating battery current in a motor drive system;

[0032] Figure 3 This means that in Figure 1 A vector diagram illustrating methods for reducing torque ripple in a motor drive system; and

[0033] Figure 4 Is it an increase? Figure 1 A flowchart of a method for controlling the temperature of batteries used in a motor drive system.

[0034] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Detailed Implementation

[0035] The following description is merely exemplary in nature and is not intended to limit the invention, its application, or its uses. It should be understood that throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0036] Hereinafter, a system for raising the temperature of a battery used in a motor drive system according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

[0037] Figure 1 This is a circuit diagram of a system for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention.

[0038] like Figure 1 As shown, a general-purpose system for driving the motor 30 may include a battery 10 and an inverter 20. The battery 10 is an energy storage device that stores electricity for driving the motor 30. The inverter 20 is used to convert the direct current (DC) stored in the battery 10 into alternating current (AC) with multiple phases and supply the converted AC to the motor 30. The inverter 20 may include multiple branches 21, 23, and 25 connected in parallel across the two ends of the battery 10. Each branch 21, 23, and 25 may have two switching devices (two of S1 to S6) connected in series. The connection node of the two switching devices can supply one phase of drive power to the motor 30. To drive the motor, pulse width modulation control can be performed on the switching devices S1 to S6 in the inverter 20 to supply the motor 30 with a current corresponding to a current reference corresponding to the torque of the motor 30, which will be obtained by driving the motor 30.

[0039] According to an embodiment of the present invention, a system for raising the temperature of a battery used in a motor drive system can control the states of the switching devices S1 to S6 of the inverter 20 to supply AC (pulsating current) to the battery 10, while using this universal motor drive system to suppress the torque generated by the motor 30.

[0040] Specifically, according to an embodiment of the present invention, a system for raising the temperature of a battery used in a motor drive system may include a battery 10, an inverter 20, a motor 30, and a controller 100; the inverter 20 has multiple branches 21, 23, and 25, each branch including a pair of switching devices S1 to S6, the pair of switching devices being connected in series at both ends of the battery 10; the motor 30 has multiple windings L1, L2, and L3, the multiple windings L1, L2, and L3 being respectively connected to the connection nodes of the switching devices included in the branches 21, 23, and 25 of the inverter 20; the controller 100 is used to control the state of the connected inverter 20 and the state of the switching devices included in two branches of the multiple branches of the inverter 20, and to generate AC to be supplied to the battery 10.

[0041] According to an embodiment of the invention, the controller 100 can turn off the switching device included in one of the branches 21, 23 and 25 in the inverter 20 and control the on / off state of the switching devices included in the other two branches to switch the polarity of the voltage applied to two of the multiple corresponding windings L1 to L3 included in the motor 30, so that AC can be supplied to the battery 10.

[0042] When using the heat generated by the internal resistance of battery 10 to raise the temperature of battery 10, the amount of heat generated and the heat generation efficiency need to be considered.

[0043] First, the amount of heat generated is directly proportional to the amount of current flowing through battery 10. That is, regardless of the direction, a large amount of heat can be generated when a large amount of current flows through the internal resistance of battery 10. With this in mind, the amount of heat in battery 10 can be increased by changing the charging or discharging of the DC supplied to battery 10 or the discharging of the DC output from battery 10.

[0044] Then, to improve efficiency, the battery 10 can be charged and discharged alternately, instead of only charging or discharging it. In this way, when the battery 10 is charged and discharged alternately, the energy consumed in the battery 10 is low, but the current flowing through the battery 10 is large, thus improving energy efficiency and significantly increasing heat generation. That is, when AC is supplied to the battery 10 instead of DC, the output current from and input current to the battery 10 can be repeatedly performed, thereby generating heat in the battery 10 with higher energy efficiency.

[0045] In this case, when the AC frequency is high enough, heat can be generated from battery 10, while suppressing lithium deposition and battery aging within battery 10.

[0046] With this in mind, according to various embodiments of the present invention, the switching devices S1 to S6 in the inverter 20 can be controlled to supply AC with a high frequency to the battery 10.

[0047] In order to supply AC to battery 10, it may be necessary to receive and store energy from battery 10, and then resupply the stored energy to battery 10. Here, according to various embodiments of the invention, the multiple corresponding windings L1 to L3 included in motor 30 can be used to store the required energy. That is, for windings L1 to L3 of motor 30, energy can be stored and discharged, and AC can be supplied to battery 10.

[0048] In order to supply high-frequency AC to the battery 10 using the inverter 20 and the motor 30, and in order to raise the temperature of the battery 10, as described above, it is necessary to provide battery current and suppress the generation of torque by the motor 30.

[0049] Figure 2 This is a waveform diagram illustrating a method for generating battery current in a motor drive system and method according to an embodiment of the present invention. Figure 3 This is a vector diagram illustrating a method for reducing torque ripple in a motor drive system and method according to an embodiment of the present invention.

[0050] Reference Figure 2 and Figure 3 The method for generating AC supplied to battery 10 and the method for suppressing the generation of torque in motor 30 during the generation of AC supplied to battery 10 will be described in more detail.

[0051] First, refer to Figure 1 and Figure 2In a system for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention, the controller 100 can control the on / off state of the switching devices included in two of the three branches included in the inverter 20, and can turn off the switching devices included in the remaining branch. Figure 2 An example is shown in which the controller 100 controls the on / off states of the switching devices S1, S2, S5 and S6 included in branches 21 and 25 of the a-phase winding L1 and the c-phase winding L3 of the motor 30, and turns off the switching devices S3 and S4 of the branch 23 connected to the b-phase winding L2.

[0052] exist Figure 2 In the interval 'D1' shown, the controller 100 can control the switching devices S1, S2, S5, and S6 to make the a-phase voltage Va applied to the a-phase winding L1 of the motor 30 a high level and the c-phase voltage Vc applied to the c-phase winding L3 a low level. That is, the controller 100 can turn on the switching device S1 of branch 21, turn off the switching device S2, turn off the switching device S5 of branch 25, and turn on the switching device S6.

[0053] Through this control, in interval D1, the a-phase winding L1 of motor 30 can be connected to the positive (+) terminal of battery 10, thus increasing the current Ias flowing through the a-phase winding L1 of motor 30 and decreasing the current Ics flowing through the c-phase winding L3. Here, the currents Ias and Ics of each phase can flow from inverter 20 to motor 30 in the positive (+) direction. Due to the electrical characteristics of the windings (inductors) used for energy storage, even if an electrical path is formed by switching devices, the currents Ias and Ics flowing through each winding can gradually increase or decrease. Therefore, the direction of the current flowing in the previous interval can be changed only after a predetermined time. Here, the windings L1, L2, and L3 of each phase of motor 30 can have one end connected to a pair of switching devices included in each branch 21, 23, and 25 of inverter 20, and the other end connected together to form a neutral point.

[0054] When interval 'D1' changes to interval 'D5' according to a preset switching frequency, controller 100 can control switching devices S1, S2, S5, and S6 to make the c-phase voltage Vc applied to the c-phase winding L3 of motor 30 high and the a-phase voltage Va applied to the a-phase winding L1 low. That is, controller 100 can turn off switching device S1 of branch 21 and turn on switching device S2, and can turn on switching device S5 of branch 25 and turn off switching device S6.

[0055] Through this control, in interval D5, the c-phase winding L3 of motor 30 can be connected to the positive (+) terminal of battery 10. Therefore, the current Ics flowing through the c-phase winding L3 of motor 30 can increase, and the current Ias flowing through the a-phase winding L1 can decrease. As described above, according to the characteristics of the inductor, even if the on / off state of the switching device is changed in interval D5, the amplitude of the current flowing in the previous interval D1 can gradually decrease while maintaining the current direction for a predetermined time, and the current direction can only change after the predetermined time has elapsed.

[0056] In other words, when the switching interval is changed, even if the connection state of the switching device is changed, the current flowing in the previous interval remains constant for a predetermined time. Therefore, battery 10 can enter a charging state where it receives current, and after a predetermined time, battery 10 can enter a discharging state where it outputs current, until the next switching device change. The current of the battery changed in this way is... Figure 2 In Chinese, it is represented as 'Ibat'. For example... Figure 2 As shown, the battery current Ibat can be an AC that pulsates with a half-cycle switching period (D1+D5), that is, the pulsation frequency is twice the switching frequency.

[0057] In summary, as described and defined above, the system for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention can be configured such that the on / off states of a pair of switching devices included in a branch connected to two windings corresponding to two of the plurality of phases are controlled to be complementary by a preset switching frequency; the on / off states of two switching devices connected to the positive terminal of the battery 10 in two branches connected to the two corresponding windings are controlled to be complementary by a preset switching frequency; and the switching devices connected to the branches corresponding to the remaining windings are turned off, thus generating AC and supplying AC to the battery 10.

[0058] According to an embodiment of the present invention, during the process of controlling the switching devices S1 to S6 to raise the temperature of the battery 10, it is necessary to suppress the generation of torque in the motor 30. As described above, in the method of not supplying current to one corresponding winding and supplying current to the other two corresponding windings, torque can be generated. Figure 3 The arrows 51, 52, and 53 shown represent the currents.

[0059] In other words, when all the switching devices of branch 23 corresponding to phase b are turned off to avoid using winding L2 corresponding to phase b and using windings L1 and L3 of motor 30 corresponding to phases a and c, a current as indicated by reference numeral '51' can be generated, with a value of 0 (perpendicular to the b-axis) corresponding to the b-axis. Similarly, when all the switching devices of branch 21 corresponding to phase a are turned off to avoid using winding L1 corresponding to phase a and using windings L2 and L3 of motor 30 corresponding to phases b and c, a current as indicated by reference numeral '52' can be generated, with a value of 0 (perpendicular to the a-axis) corresponding to the a-axis. Similarly, when all the switching devices of branch 25 corresponding to phase c are turned off to avoid using winding L3 corresponding to phase c and using windings L1 and L2 of motor 30 corresponding to phases a and b, a current as indicated by reference numeral '53' can be generated, with a value of 0 (perpendicular to the c-axis) corresponding to the c-axis. Here, the arrows indicated by reference numeral '51' can correspond to 30° and 210° with respect to the a-axis, the arrows indicated by reference numeral '52' can correspond to 90° and 270° with respect to the a-axis, and the arrows indicated by reference numeral '53' can correspond to 150° and 330° with respect to the a-axis.

[0060] In the case of a permanent magnet synchronous motor with salient polarity, the torque generated in the motor according to the motor current can be expressed by the following equation 1.

[0061] [Equation 1]

[0062]

[0063] In equation 1 above, T e It is the torque of the motor, λ f It is the electromotive force of the motor, L d and L q These are the d-axis and q-axis inductances of the motor, i d and i q These are the d-axis and q-axis currents supplied from the motor.

[0064] From Equation 1 above, it can be seen that when the q-axis current is 0 (i q When q = 0, the motor will not generate torque. In other words, when the AC generated in the motor does not point to the q-axis of the synchronous reference coordinate system and only exists on the d-axis, the motor will not generate torque.

[0065] Therefore, when the d-axis, corresponding to the axis connecting the n and s poles of the rotor of motor 30, is aligned with... Figure 3 When the arrows in the dq stationary coordinate system are aligned, that is, when the rotor angles correspond to 30°, 90°, 150°, 210°, 270°, and 330° (this is...) Figure 3When the angle of the arrow shown is 0, the torque of motor 30 can be 0.

[0066] The position of the rotor of the motor 30 can be arbitrarily determined. Therefore, according to the embodiment of the present invention, two phases can be selected to reduce the difference between the rotor angle detected by the rotor position sensor 40 included in the motor 30 and the angle corresponding to AC generated by the on / off control of the switching devices of the two corresponding branches. The on / off state of the switching devices of the two selected branches can be controlled, thereby reducing the generation of torque.

[0067] Reference Figure 3 When the rotor angle is 0° to 60° and 180° to 240°, the c-phase branch and a-phase branch corresponding to arrow 51 can be selected. The on / off state of the switching devices included in the c-phase branch and a-phase branch can be alternately controlled at a preset switching frequency. The switching devices included in the b-phase branch can be turned off to generate AC.

[0068] When the rotor angle is 60° to 120° and 240° to 300°, the b-phase branch and the c-phase branch can be selected. The on / off state of the switching devices included in the b-phase branch and the c-phase branch can be alternately controlled at a preset switching frequency. The switching devices included in the a-phase branch can be turned off to generate AC.

[0069] When the rotor angle is 120° to 180° and 300° to 360°, phase a branch and phase b branch can be selected. The on / off state of the switching devices included in phase a branch and phase b branch can be alternately controlled at a preset switching frequency. The switching devices included in phase c branch can be turned off to generate AC.

[0070] The present invention provides a method for raising battery temperature by using a system that utilizes the above-described motor drive system to raise battery temperature.

[0071] Figure 4 This is a flowchart of a method for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention.

[0072] Reference Figure 4A method for raising the temperature of a battery used in a motor drive system according to an embodiment of the present invention may include: receiving the rotor angle of the motor 30 detected by the rotor position sensor 40 via a controller 100 and determining the range to which the rotor angle belongs (S11); determining, based on the range to which the rotor angle belongs, a branch to be kept off (S21, S31, S41); and alternately controlling the on / off states of switching devices included in branches other than those kept off, to generate AC (S22, S32, S42). The above steps may be repeated until the battery temperature Tbat rises to a preset target temperature (S51).

[0073] In step S11, when the rotor angle is 0° to 60° and 180° to 240°, the controller 100 can turn off the switching devices S3 and S4 included in the b-phase branch 23 (S21), and can alternately control the on / off state of the switching devices S1, S2, S5 and S6 included in the c-phase branch 25 and the a-phase branch 21 at a preset switching frequency to generate AC (S22).

[0074] In step S22, the controller 100 can control the states of a pair of switching devices S5 and S6 included in the c-phase branch 25 at a preset switching frequency, making them complementary, and can also control the states of a pair of switching devices S1 and S2 included in the a-phase branch 21 at a preset switching frequency, making them complementary. The controller 100 can control the state of the switching device S5 in the c-phase branch 25 connected to the positive (+) terminal of the battery 10 and the state of the switching device S1 in the a-phase branch 21 connected to the positive terminal of the battery 10 at the switching frequency, making them complementary, thereby generating AC to be supplied to the battery 10.

[0075] In step S11, when the rotor angle is 60° to 120° and 240° to 300°, the controller 100 can turn off the switching devices S1 and S2 included in the a-phase branch 21 (S31), and can alternately control the on / off state of the switching devices S3, S4, S5 and S6 included in the b-phase branch 23 and the c-phase branch 25 at a preset switching frequency to generate AC (S32).

[0076] In step S32, the controller 100 can control the states of a pair of switching devices S3 and S4 included in the b-phase branch 23 at a switching frequency to make them complementary, and can also control the states of a pair of switching devices S5 and S6 included in the c-phase branch 25 at a switching frequency to make them complementary. Furthermore, the controller 100 can control the states of the switching device S3 in the b-phase branch 23 connected to the positive (+) terminal of the battery 10 and the switching device S5 in the c-phase branch 25 connected to the positive terminal of the battery 10 at a switching frequency to make them complementary, thereby generating AC power supplied to the battery 10.

[0077] In step S11, when the rotor angle is 120° to 180° and 300° to 360°, the controller 100 can turn off the switching devices S5 and S6 included in the c-phase branch 25 (S41), and can alternately control the on / off state of the switching devices S1, S2, S3 and S4 included in the a-phase branch 21 and the b-phase branch 23 at a preset switching frequency to generate AC (S42).

[0078] In step S42, the controller 100 can control the states of a pair of switching devices S1 and S2 included in phase a branch 21 at a switching frequency to make them complementary, and can control the states of a pair of switching devices S3 and S4 included in phase b branch 23 at a switching frequency to make them complementary. The controller 100 can control the state of the switching device S1 in phase a branch 21 connected to the positive (+) terminal of battery 10 and the state of the switching device S3 in phase b branch 23 connected to the positive terminal of battery 10 at a switching frequency to make them complementary, thereby generating AC supplied to battery 10.

[0079] As described above, the systems and methods for raising the temperature of batteries used in motor drive systems according to various embodiments of the present invention can supply AC to the battery using an inverter and motor connected to the battery and configured to drive environmentally friendly vehicles without having a separate heating device, thus effectively raising the battery temperature without additional cost.

[0080] In particular, when an inverter and a motor are used to generate AC in a system and method for raising the temperature of a battery used in a motor drive system, torque pulsation generated in the motor can be suppressed as much as possible, thereby providing vehicle stability.

[0081] Systems and methods for raising the temperature of batteries used in motor drive systems can supply AC to the batteries by utilizing an inverter and a motor configured to drive environmentally friendly vehicles without the need for separate heating devices such as heaters, thus effectively raising the battery temperature without additional cost.

[0082] Although the invention has been described in conjunction with exemplary embodiments that are now considered to be in practice, it should be understood that the invention is not limited to the disclosed embodiments, but rather, the invention is intended to cover various modifications and equivalents included within the spirit and scope of the invention.

Claims

1. A system for raising the temperature of a battery used in a motor drive system, the system comprising: An inverter comprising multiple branches, each branch including a pair of switching devices connected in series between the two ends of a battery, the multiple branches corresponding to multiple phases; An electric motor includes a plurality of windings corresponding to the plurality of phases, one end of each of the plurality of windings being connected to a connection node between a pair of switching devices included in a corresponding branch, and the other ends of the plurality of windings being interconnected. as well as The controller is configured to select two phases from the plurality of phases and generate alternating current supplied to the battery by alternately controlling the on / off states of a pair of switching devices included in each of two branches of the inverter corresponding to the two selected phases at a preset switching frequency. The controller controls the on / off state of a first pair of switching devices in a first branch corresponding to one of the two selected phases at the switching frequency, so that they are complementary; and controls the on / off state of a second pair of switching devices in a second branch corresponding to the remaining two selected phases at the switching frequency, so that they are complementary.

2. The system for raising the temperature of a battery used in a motor drive system according to claim 1, wherein, The controller controls the on / off state of one of the first pair of switching devices connected to the positive terminal of the battery in the first branch and the on / off state of one of the second pair of switching devices connected to the positive terminal of the battery in the second branch, so that they are complementary.

3. The system for raising the temperature of a battery used in a motor drive system according to claim 2, wherein, The controller shuts off the third pair of switching devices included in the third branch corresponding to the phases other than the two selected phases.

4. The system for raising the temperature of a battery used in a motor drive system according to claim 2, further comprising a rotor position sensor configured to detect the rotor angle of the motor. in, The controller selects two phases from the plurality of phases based on the rotor angle.

5. The system for raising the temperature of a battery used in a motor drive system according to claim 4, wherein, The controller selects two phases that reduce the difference between two angles: the rotor angle and the angle of alternating current generated by controlling a pair of switching devices included in each branch corresponding to two of the plurality of phases, the angle of alternating current being indicated on the dq stationary coordinate system.

6. A system for raising the temperature of a battery used in a motor drive system, the system comprising: An inverter comprising an a-phase branch, a b-phase branch, and a c-phase branch, each branch comprising a pair of switching devices connected in series between the two ends of a battery. An electric motor includes an a-phase winding, a b-phase winding, and a c-phase winding. One end of the a-phase winding is connected to a connection node between a first pair of switching devices included in the a-phase branch. One end of the b-phase winding is connected to a connection node between a second pair of switching devices included in the b-phase branch. One end of the c-phase winding is connected to a connection node between a third pair of switching devices included in the c-phase branch. The other ends of the a-phase winding, the b-phase winding, and the c-phase winding are interconnected. as well as The controller is configured to select two branches from phase a, phase b, and phase c, and generate AC power to the battery by alternately controlling the on / off state of a pair of switching devices included in the selected branch at a preset switching frequency. The controller controls the on / off state of a pair of switching devices included in one of the selected branches at the switching frequency, so that they have a complementary relationship; and controls the on / off state of a pair of switching devices included in the remaining branches of the selected branches at the switching frequency, so that they have a complementary relationship.

7. The system for raising the temperature of a battery used in a motor drive system according to claim 6, wherein, The controller controls the on / off state of one of the pair of switching devices connected to the positive terminal of the battery in each of the two selected branches, making them complementary.

8. The system for raising the temperature of a battery used in a motor drive system according to claim 6, wherein, The controller shuts off a pair of switching devices included in an unselected branch.

9. The system for raising the temperature of a battery used in a motor drive system according to claim 6, further comprising a rotor position sensor configured to detect the rotor angle of the motor. in, The controller selects two branches based on the rotor angle.

10. The system for raising the temperature of a battery used in a motor drive system according to claim 9, wherein, The controller selects two phase branches that reduce the difference between the following two angles: the rotor angle and the angle of the alternating current generated by controlling the first and second pairs of switching devices included in each phase branch of phase a and phase b, the alternating current generated by controlling the second and third pairs of switching devices included in each phase branch of phase b and phase c, and the alternating current generated by controlling the third pair of switching devices and the first pair of switching devices included in each phase branch of phase c and phase a. The angle of the alternating current is indicated on the dq stationary coordinate system.

11. The system for raising the temperature of a battery used in a motor drive system according to claim 9, wherein, When the rotor angle is 0° to 60° and 180° to 240°, the controller selects the c-phase branch and the a-phase branch, and alternately controls the on / off state of the third pair of switching devices and the first pair of switching devices included in each phase branch of the c-phase branch and the a-phase branch at a preset switching frequency, and turns off the second pair of switching devices included in the b-phase branch to generate alternating current.

12. The system for raising the temperature of a battery used in a motor drive system according to claim 9, wherein, When the rotor angle is 60° to 120° and 240° to 300°, the controller selects the b-phase branch and the c-phase branch, and alternately controls the on / off state of the second pair of switching devices and the third pair of switching devices included in each phase branch of the b-phase branch and the c-phase branch at a preset switching frequency, and turns off the first pair of switching devices included in the a-phase branch to generate alternating current.

13. The system for raising the temperature of a battery used in a motor drive system according to claim 9, wherein, When the rotor angle is 120° to 180° and 300° to 360°, the controller selects phase a branch and phase b branch, and alternately controls the on / off state of the first pair of switching devices and the second pair of switching devices included in each phase branch of phase a branch and phase b branch at a preset switching frequency, and turns off the third pair of switching devices included in phase c branch to generate alternating current.

14. A method for raising the temperature of a battery using the system of claim 9, the method comprising the following steps: Determine the range to which the rotor angle belongs; Determine a branch that remains in the off state based on the range to which the rotor angle belongs; Alternating current is generated by alternately controlling the on / off state of a pair of switching devices in two branches, excluding the branch that remains in the off state, at a switching frequency.

15. The method according to claim 14, wherein, When the rotor angle is 0° to 60° and 180° to 240°, the step of determining a branch that remains in the off state is performed; The step of determining a branch that remains in the off state includes the step of turning off the second pair of switching devices included in the b-phase branch; The steps of generating alternating current include alternating current by alternately controlling the on / off states of the third pair of switching devices and the first pair of switching devices included in each phase branch of the c-phase branch and the a-phase branch at a preset switching frequency.

16. The method according to claim 15, wherein, The steps to generate alternating current include the following: The switching frequency is used to control the on / off state of the third pair of switching devices included in the c-phase branch, so that they have a complementary relationship. The switching frequency is used to control the on / off state of the first pair of switching devices included in phase a branch, so that they have a complementary relationship. The switching frequency controls the on / off state of one of the switches in the third pair of switches connected to the positive terminal of the battery in the c-phase branch and the on / off state of one of the switches in the first pair of switches connected to the positive terminal of the battery in the a-phase branch, so that they are complementary.

17. The method according to claim 14, wherein, When the rotor angle is 60° to 120° and 240° to 300°, the step of determining a branch that remains in the off state is performed; The steps of determining a branch that remains in the off state include the step of turning off the first pair of switching devices included in the a-phase branch; The steps for generating alternating current include alternating current by alternately controlling the on / off states of a second pair of switching devices and a third pair of switching devices included in each phase branch of the b-phase branch and the c-phase branch at a preset switching frequency.

18. The method according to claim 17, wherein, The steps to generate alternating current include the following: The switching frequency is used to control the on / off state of the second pair of switching devices included in the b-phase branch, so that they have a complementary relationship. The switching frequency is used to control the on / off state of the third pair of switching devices included in the c-phase branch, so that they have a complementary relationship. The switching frequency controls the on / off state of one of the switches in the second pair of switches connected to the positive terminal of the battery in the b-phase branch and the on / off state of one of the switches in the third pair of switches connected to the positive terminal of the battery in the c-phase branch, so that they are complementary.

19. The method of claim 14, wherein, When the rotor angle is 120° to 180° and 300° to 360°, the step of determining a branch that remains in the off state is performed; The steps of determining a branch that remains in the off state include the step of turning off the third pair of switching devices included in the c-phase branch; The steps of generating alternating current include alternating current by alternately controlling the on / off states of a first pair of switching devices and a second pair of switching devices included in each phase branch of the a-phase branch and the b-phase branch at a preset switching frequency.

20. The method according to claim 19, wherein, The steps to generate alternating current include the following: The switching frequency is used to control the on / off state of the first pair of switching devices included in phase a branch, so that they have a complementary relationship. The switching frequency is used to control the on / off state of the second pair of switching devices included in the b-phase branch, so that they have a complementary relationship. The switching frequency controls the on / off state of one of the first pair of switching devices in the a-phase branch connected to the positive terminal of the battery and the on / off state of one of the second pair of switching devices in the b-phase branch connected to the positive terminal of the battery, so that they have a complementary relationship.

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