Motor controller, heat exchange system and current injection method
By outputting alternating current with DC bias to the direct or zero axis of the motor, iron consumption and permanent magnet loss of the excitation motor, the problem of low heating power of the motor heating power battery in the prior art is solved, and more efficient power battery heating is achieved.
Patent Information
- Application Number
- CN202510069481.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2020-11-24
- Publication Date
- 2025-05-23
AI Technical Summary
In the prior art, the heating power of the motor heating power battery is small, resulting in a slower heating speed.
A motor controller is adopted to increase the heating power of the motor by outputting alternating current with DC bias to the direct or zero axis of the motor, and excite the iron and permanent magnet losses of the motor.
It effectively improves the heating power of the motor, improves the heating speed of the power battery, and uses the uniform three-phase winding to generate heat, making full use of the heating ability of the winding.
Smart Images
Figure CN120034074A_ABST
Abstract
Description
[0001] This application is a divisional application. The application number of the original application is 202080019346.X, and the original application date is November 24, 2020. The entire contents of the original application are incorporated into this application by reference. Technical Field
[0002] The present application relates to the technical field of new energy vehicles, and in particular to a motor controller, a heat exchange system and a current injection method. Background Art
[0003] With the development of new energy technology, the application of new energy vehicles is becoming more and more popular, such as electric vehicles / electric vehicles / hybrid electric vehicles. In low temperature environments, the performance of the power battery of electric vehicles / electric vehicles decreases, so it is necessary to heat the power battery to improve the performance of the power battery.
[0004] In the prior art, one solution for heating the power battery is to pass current into the motor, use the end windings of the motor to generate heat, and then remove the heat generated by the heat exchange system to heat the power battery. Since this solution cannot stimulate the iron loss and permanent magnet loss of the motor, the heat generation power is small and the heating speed of the power battery is slow.
[0005] Therefore, the solutions provided by the prior art have the problems of low heating power and slow heating speed for the power battery. Summary of the invention
[0006] Embodiments of the present application provide a motor controller, a heat exchange system, and a current injection method for improving the efficiency of motor heating.
[0007] In a first aspect, an embodiment of the present application provides a motor controller. The motor controller includes a control device and an inverter circuit. The control device is used to control the inverter circuit to input an alternating current into the motor, wherein the alternating current has a DC bias and is used to heat the motor; the inverter circuit is used to output the alternating current to the direct axis or zero axis of the motor under the control of the control device.
[0008] The alternating current may be any one of a sine wave, a square wave, a triangle wave, a sawtooth wave and a trapezoidal wave, or may be other non-DC current with periodic changes.
[0009] With the motor controller provided in the first aspect, since no current is passed into the quadrature axis of the motor, the motor will not generate additional vibration and torque. Since the alternating current with a DC bias is passed into the direct axis or zero axis, compared with the prior art method of using only the end winding for heating, since the current passed into the motor contains an alternating component, the iron loss and permanent magnet loss of the motor can be effectively stimulated, the heating power of the motor can be increased, and thus the heating speed of the power battery can be increased.
[0010] In a possible design, the inverter circuit adopts a three-phase three-wire system, and the inverter circuit is specifically used to: under the control of the control device, output a first alternating current with a DC bias to the direct axis of the motor.
[0011] With the above solution, since no current is passed through the quadrature axis of the motor, the motor will not generate additional vibration and torque. Since the first alternating current with a DC bias passed through the direct axis contains an alternating component, it can effectively stimulate the iron loss and permanent magnet loss of the motor, increase the heating power of the motor, and thus increase the heating speed of the power battery.
[0012] In another possible design, the inverter circuit adopts a three-phase four-wire system, and the inverter circuit is specifically used to: under the control of the control device, output a second alternating current with a DC bias to the zero axis of the motor, or output a third alternating current with a DC bias to the direct axis of the motor.
[0013] With the above solution, since no current is passed through the quadrature axis of the motor, the motor will not generate additional vibration and torque. Since the second alternating current with a DC bias passed through the zero axis contains an alternating component, it can effectively stimulate the iron loss and permanent magnet loss of the motor, increase the heating power of the motor, and thus increase the heating speed of the power battery.
[0014] In addition, when a second alternating current with a DC bias is passed through the zero axis of the motor, the amplitude and phase of the three-phase current are the same, so the three-phase windings in the motor heat up evenly and at similar temperatures. There will not be a phenomenon where one phase winding reaches the temperature limit while the other two phase windings have lower temperatures. Therefore, the heating capacity of the winding can be more fully utilized.
[0015] Further, the inverter circuit is connected to the DC bus, the inverter circuit adopts a two-level topology, and the neutral point of the inverter circuit is connected to the positive pole of the DC bus through the first switch unit and the first inductor; or, the inverter circuit adopts a two-level topology, and the neutral point of the inverter circuit is connected to the negative pole of the DC bus through the second switch unit and the second inductor; or, the inverter circuit adopts a two-level topology, the neutral point of the inverter circuit is connected to the positive pole of the DC bus through the third switch unit and the third inductor, and the neutral point of the inverter circuit is connected to the negative pole of the DC bus through the fourth switch unit and the fourth inductor.
[0016] By adopting the above scheme, a star point loop (neutral line loop) can be provided for the current flowing through the neutral line of the three-wire or four-wire power supply.
[0017] In addition, if the inverter circuit adopts an open winding structure or a multi-level topology, there is no need to additionally connect the star point loop.
[0018] In a possible design, the alternating current does not contain negative values.
[0019] The meaning of no negative value is: at any moment, the alternating current is positive. The alternating current has no negative value, and the magnetic field generated by the winding coil is a pulsating magnetic field with only amplitude changes but no direction changes, and no demagnetization magnetic field will be generated, thereby reducing the risk of demagnetization during the motor heating process and reducing the electromagnetic vibration and noise caused by the positive and negative changes of the magnetic field in the same direction.
[0020] In a second aspect, an embodiment of the present application provides a heat exchange system, comprising a motor, a heat exchanger, a liquid pump, a power battery, and a motor controller provided in the first aspect and any possible design thereof; the motor, the heat exchanger, and the liquid pump are connected through a pipeline; the motor controller is used to output an alternating current to the direct axis or zero axis of the motor, the alternating current having a DC bias, and the alternating current is used to make the motor heat up; the liquid pump is used to drive the pipeline so that the heat generated by the motor is exchanged to the power battery through the heat exchanger.
[0021] In one possible design, the motor is an oil-cooled motor.
[0022] The specific functions and structures of the motor controller in the heat exchange system provided in the second aspect may refer to the relevant description of the motor controller provided in the first aspect.
[0023] In a third aspect, an embodiment of the present application provides a current injection method, which includes the following steps: a motor controller determines parameters of an alternating current output to the motor, wherein the alternating current has a DC bias and is used to heat the motor; the motor controller outputs the alternating current to the direct axis or zero axis of the motor.
[0024] Specifically, the parameters of the alternating current include the waveform, phase, amplitude, frequency, and DC bias value of the alternating current.
[0025] Since the alternating current output to the motor is to heat the motor and then heat the power battery, the motor controller can determine the parameters of the alternating current based on factors such as the temperature of the motor, the temperature of the power battery, the current limit and temperature limit of the three-phase winding of the motor, etc.
[0026] The current injection method provided in the third aspect can be regarded as the method executed by the motor controller provided in the first aspect, and the specific implementation method can refer to the relevant description in the motor controller provided in the first aspect.
[0027] In a fourth aspect, an embodiment of the present application further provides a powertrain, comprising a motor, a reducer, and a motor controller provided in the first aspect and any possible design thereof.
[0028] In a fifth aspect, an embodiment of the present application also provides a vehicle, comprising a power battery and the powertrain provided in the fourth aspect.
[0029] In addition, the technical effects brought about by any possible design method in the second aspect to the fifth aspect can refer to the technical effects brought about by different design methods in the first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 A schematic diagram of the structure of a heat exchange system provided in an embodiment of the present application;
[0031] Figure 2 A schematic diagram of the structure of a motor provided in an embodiment of the present application;
[0032] Figure 3 A schematic diagram of the structure of a motor controller provided in an embodiment of the present application;
[0033] Figure 4 A schematic diagram of an alternating current with a DC bias provided in an embodiment of the present application;
[0034] Figure 5 A schematic diagram of an alternating current with a small amount of negative value provided in an embodiment of the present application;
[0035] Figure 6 A schematic diagram of the structure of an inverter circuit using a three-phase three-wire system provided in an embodiment of the present application;
[0036] Figure 7 A schematic diagram of a three-phase current output to a motor provided in an embodiment of the present application;
[0037] Figure 8 A schematic diagram of the structure of an inverter circuit using a three-phase four-wire system provided in an embodiment of the present application;
[0038] Fig. 9 A schematic diagram of another three-phase current output to a motor provided in an embodiment of the present application;
[0039] Fig.10 A schematic diagram of the structure of a star point loop provided in an embodiment of the present application;
[0040] Fig.11 A schematic diagram of the structure of an inverter circuit provided in an embodiment of the present application;
[0041] Fig.12A schematic diagram of the structure of an inverter circuit of a three-level topology provided in an embodiment of the present application;
[0042] Fig.13 A schematic diagram of the structure of another heat exchange system provided in an embodiment of the present application;
[0043] Fig.14 A schematic diagram of a flow chart of a current injection method provided in an embodiment of the present application;
[0044] Fig.15 A schematic diagram of the structure of a powertrain provided in an embodiment of the present application;
[0045] Fig.16 A schematic diagram of the structure of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION
[0046] Below, the application scenarios of the embodiments of the present application are first introduced.
[0047] The present application embodiment can be applied Figure 1 The heat exchange system shown in the figure can be a heat exchange system in an electric vehicle.
[0048] Figure 1 The heat exchange system shown includes a power battery 101 , a motor controller 102 , a motor 103 , a heat exchanger 104 and a liquid pump 105 .
[0049] The power battery 101 is used to output direct current, and may be, for example, a storage battery, a lithium battery, a fuel cell, a supercapacitor, etc. The motor controller may also be referred to as a motor control unit (MCU), which includes a control device and an inverter circuit. The motor 103 may be a permanent magnet synchronous motor, an asynchronous motor, a reluctance motor, or an electrically excited motor, etc.
[0050] The power battery 101 is connected to the inverter circuit through a DC bus, and the inverter circuit is connected to the motor 103 through a three-phase line. The motor 103, the heat exchanger 104 and the liquid pump 105 are coupled through an oil cooling pipeline, and an insulating coolant flows in the oil cooling pipeline. The insulating coolant may include mineral insulating oil, synthetic insulating oil and vegetable oil, etc. The motor controller 102, the heat exchanger 104 and the power battery 101 are coupled through a water cooling pipeline, and the water inlet of the water cooling pipeline is arranged around the motor controller 102, and the water outlet is arranged around the power battery 101. In particular, the heat exchanger 104 can be arranged around the power battery 101 to facilitate heat exchange with the power battery 101. There is no insulation requirement for the coolant in the water cooling pipeline, for example, it can be water, alcohol, or a mixture of different types of antifreeze. For the sake of simplicity of description, the coolant flowing in the water cooling pipeline is described as water in the embodiment of the present application.
[0051] In the embodiment of the present application, the motor controller 102 injects current into the motor 103 to heat the motor 103, and the heat generated by the motor 103 is exchanged to the power battery 101 through the heat exchanger 104 to heat the power battery 101 and improve the performance of the power battery 101.
[0052] Specifically, the process of heating the power battery 101 may be as follows: the control device controls the inverter circuit to inject current into the motor 103, and the motor 103 generates heat; the liquid pump 105 pumps the insulating coolant between the motor 103 and the heat exchanger 104, so that the heat generated by the motor 103 is transferred to the heat exchanger 104 and the motor 103 is cooled; the heat generated by the motor 103 exchanges heat with the water in the water-cooled pipeline at the heat exchanger 104; the water in the water-cooled pipeline transfers the heat to the power battery 102 to heat the power battery 101.
[0053] In addition, in the embodiment of the present application, when the motor controller 102 works, the heat generated by the resistance heating in the motor controller 102 is also transferred to the power battery 101 through the water-cooled pipeline to heat the power battery 101.
[0054] In Figure 1 the shown heat exchange system, a possible structural schematic diagram of the motor 103 can be as Figure 2 shown. In Figure 2 the shown cross-sectional view, the motor 103 includes a housing, a rotor core, a stator and a rotating shaft. Windings ( Figure 2 not shown in Figure 2 ) are wound on the stator, that is, coils wound on the stator teeth of the motor, used to provide a path for the current input to the motor. The part of the rotating shaft of the motor extending out of the rotor core at both axial ends is called the end winding. The material of the winding is generally copper; permanent magnets ( Figure 2 not shown in
[0055] ) are installed on the rotor core to generate an excitation magnetic field. Among them, oil channels are left in the housing, the rotating shaft and the rotor core. When the liquid pump 105 drives the oil-cooled pipeline, the insulating coolant can flow in the oil channels of the motor 103, so as to more fully take away the heat generated by the motor 103 and fully cool the motor 103. Specifically, the insulating coolant can enter and exit the motor cavity from the motor housing, or enter and exit the motor cavity from both ends of the motor.
[0055] In addition, the insulating coolant flowing inside the motor 103 can also be used for lubricating motor components including bearings.
[0056] To make the embodiment of the present application easier to understand, some basic concepts involved in the embodiment of the present application are explained below.
[0057] 1. U / V / W three-phase coordinate axes
[0058] At present, the motor of electric vehicles is generally an AC motor, and the power battery is a DC source. Therefore, the DC output of the power battery is converted into three-phase AC power of the motor through an inverter circuit. The coordinate axes of the three-phase AC power are U axis, V axis and W axis. The three phases of AC power can also be called U phase, V phase and W phase respectively.
[0059] 2. Direct axis, quadrature axis, zero axis
[0060] In order to simplify motor analysis, the stationary three-phase coordinates are usually transformed into rotating dq coordinates. This transformation is called Park transformation.
[0061] In the dq coordinate system, the three coordinate axes are called the direct axis, the quadrature axis and the zero axis.
[0062] The direct axis, also known as the D axis or d-axis, is a time-varying DC coordinate axis obtained by Park transformation of the stationary U / V / W three-phase coordinate axes.
[0063] The quadrature axis, also known as the Q axis or q-axis, is a time-varying AC coordinate axis obtained by Park transformation of the stationary U / V / W three-phase coordinate axes.
[0064] The zero axis, also known as the 0 axis or 0-axis, is the coordinate axis perpendicular to the dq plane where the direct axis and the quadrature axis are located.
[0065] Specifically, the formula for the Parker transformation can be shown as follows:
[0066] Among them, θ is the angle between the d-axis and the U-axis; I_d is called the direct-axis current, which is mainly used to adjust the magnetic field; I_q is called the quadrature-axis current, which is mainly used to adjust the torque; I_0 is called the zero-sequence current; I_u, I_v, I_w are the currents on the U-axis, V-axis and W-axis respectively, that is, the three-phase current.
[0067] In the embodiment of the present application, current is output to the direct axis of the motor, that is, I_d is passed into the motor, and I_q and I_0 are controlled to be 0; current is output to the zero axis of the motor, that is, I_0 is passed into the motor, and I_d and I_q are controlled to be 0.
[0068] The above matrix is the expression of the three-phase current transformed into I_d, I_q, I_0. By performing an inverse transformation on the matrix, we can obtain the expression of the three-phase current transformed from I_d, I_q, I_0, which will not be repeated here.
[0069] Since the three-phase current is the current corresponding to the real winding in the motor, when outputting current to the direct axis of the motor, the motor controller needs to convert I_d into the three-phase current I_u, I_v, I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, I_w into the motor winding; when outputting current to the zero axis of the motor, the motor controller needs to convert I_0 into the three-phase current I_u, I_v, I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, I_w into the motor winding.
[0070] 3. Copper loss, rotor core loss, eddy current loss of permanent magnet
[0071] Copper loss, referred to as copper loss, refers to the loss caused by the flow of current in copper conductors.
[0072] The loss of the rotor core, referred to as iron loss, refers to the loss of the rotor core in the alternating magnetic field, including eddy current loss caused by induced eddy current and hysteresis loss caused by hysteresis effect. Similarly, the rotor shaft and stator will also generate eddy current loss and hysteresis loss in the alternating magnetic field.
[0073] The eddy current loss of permanent magnet, referred to as permanent magnet loss, refers to the eddy current generated by the permanent magnet in the alternating magnetic field, which in turn causes corresponding eddy current loss.
[0074] The embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.
[0075] It should be noted that, in the embodiments of the present application, a plurality refers to two or more. In addition, in the description of the present application, words such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.
[0076] The present application embodiment provides a motor controller, such as Figure 3 As shown, the motor controller 300 includes a control device 301 and an inverter circuit 302. The control device 301 is used to control the inverter circuit 302 to input an alternating current into the motor, the alternating current has a DC bias, and the alternating current is used to heat the motor; the inverter circuit 302 is used to output the alternating current to the direct axis or zero axis of the motor under the control of the control device 301.
[0077] The alternating current with DC bias is obtained by superimposing a DC current on the alternating current. Figure 4 Example a shows an alternating current without a DC bias being passed into the direct axis of the motor. Figure 4 Example b of FIG. 1 shows an alternating current with a DC bias being introduced into the direct axis of the motor. In example b, Id_1 is the superimposed DC bias.
[0078] It should be noted that Figure 4 In the example, a sine wave is used as an example for illustration of the alternating current. In actual applications, the alternating current described in the embodiments of the present application can be any one of a sine wave, a square wave, a triangle wave, a sawtooth wave and a trapezoidal wave, or can be other non-DC currents with periodic changes.
[0079] In particular, in the embodiment of the present application, the alternating current of the input direct axis or zero axis may have no negative value or only a small amount of negative value. No negative value means that at any time, the alternating current is positive. For example Figure 4 In example b, the alternating current of the input direct axis has no negative value; for another example, Figure 5 The alternating current shown in contains only a few negative values.
[0080] The alternating current has no negative value, and the magnetic field generated by the winding coil is a pulsating magnetic field with only amplitude changes but no direction changes, and no demagnetization magnetic field will be generated. Therefore, it is not difficult to understand that the alternating current has no negative value or contains only a small amount of negative value, so that the winding coil does not generate a demagnetization magnetic field or only generates a very small demagnetization magnetic field, thereby reducing the risk of demagnetization generated during the heating process of the motor and reducing the electromagnetic vibration and noise caused by the positive and negative changes of the magnetic field in the same direction.
[0081] The control device 301 controls the alternating current outputted by the inverter circuit 302 to the direct axis or zero axis of the motor. Since the quadrature axis of the motor does not pass current, the motor will not generate additional vibration and torque. Since the alternating current with DC bias is passed into the direct axis or zero axis, compared with the method of only using the end winding to generate heat in the prior art, since the current passed into the motor contains an alternating component, the iron loss and permanent magnet loss of the motor can be effectively stimulated, and the heating power of the motor can be increased, thereby improving the heating speed of the power battery. In addition, the heat generated by the resistance heating of the motor controller 300 can also be used to heat the power battery. At the same time, since the current on the DC bus is also an alternating current at this time, its effective value will be significantly greater than the effective value of the current when only DC is passed, so the internal resistance of the battery can be fully utilized to heat the battery.
[0082] In addition, compared with the solution of passing alternating current without DC bias into the direct axis or zero axis, when the current upper limit value of the DC bus is the same, passing alternating current with DC bias into the direct axis or zero axis can make the AC component flowing through the DC bus smaller, thereby reducing the fluctuation of the DC bus and improving the reliability of the system.
[0083] In practical applications, the inverter circuit 302 can use a three-phase three-wire system or a three-phase four-wire system. For the three-phase three-wire system and the three-phase four-wire system, the motor controller 300 can inject current into the motor in different ways. The following describes these two situations respectively.
[0084] 1. Three-phase three-wire system
[0085] The inverter circuit 302 adopts a three-phase three-wire system. The inverter circuit 302 is specifically used to: under the control of the control device 301, output a first alternating current with a DC bias to the direct axis of the motor.
[0086] For example, the structural diagram of the three-phase three-wire inverter circuit can be as follows: Figure 6 As mentioned above, when outputting current to the direct axis of the motor, the motor controller 300 needs to convert I_d into three-phase currents I_u, I_v, and I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, and I_w into the motor winding. The three-phase current output by the motor controller 300 to the motor winding is injected through the three phase lines of the three-phase three-wire inverter circuit.
[0087] by Figure 4 Example b shows an alternating current with a DC bias as an example. The current is converted into a three-phase current. The waveform of the three-phase current can be as follows Figure 7 As shown. Figure 7 It can be seen that when the first alternating current with a DC bias is passed through the direct axis of the motor, the phases of the three-phase currents are the same or opposite, and the amplitudes of the three-phase currents are not equal. Among them, the amplitudes and phases of the V phase and the W phase are the same, and the phase of the U phase is opposite to the phase of the V phase, and the amplitudes are also different.
[0088] The inverter circuit 302 outputs a first alternating current with a DC bias to the direct axis of the motor. Since the quadrature axis of the motor does not pass current, the motor does not generate additional vibration and torque. Since the first alternating current with a DC bias passed into the direct axis contains an alternating component, the iron loss and permanent magnet loss of the motor can be effectively stimulated, the heating power of the motor can be increased, and thus the heating speed of the power battery can be increased. In addition, the heat generated by the resistance heating of the motor controller 300 can also be used to heat the power battery.
[0089] It is worth noting that when the first alternating current with a DC bias is passed into the direct axis of the motor, the amplitudes of the three-phase currents are not equal. Figure 7 In the example, the amplitude of the U phase is larger, and the amplitudes of the V phase and the W phase are smaller. Therefore, the U phase winding coil in the motor generates more heat, and the U phase reaches the temperature limit first. At this time, the V phase and the W phase are still in a relatively low temperature state. Therefore, this method of heating the motor has the problem of insufficient utilization of the heating capacity of the winding.
[0090] 2. Three-phase four-wire system
[0091] The three-phase four-wire inverter circuit has one more power neutral wire drawn from the neutral point (star point) of the three phases than the three-phase three-wire inverter circuit.
[0092] The inverter circuit 302 adopts a three-phase four-wire system, and the motor controller 300 can output current to the motor in two ways.
[0093] Method 1
[0094] The inverter circuit 302 adopts a three-phase four-wire system. The inverter circuit 302 is specifically used for: under the control of the control device 301, outputting a second alternating current with a DC bias to the zero axis of the motor, that is, outputting a zero-sequence current to the motor.
[0095] For example, the structural diagram of the three-phase four-wire inverter circuit can be as follows: Figure 8 As mentioned above, when outputting current to the zero axis of the motor, the motor controller needs to convert I_d into three-phase currents I_u, I_v, and I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, and I_w into the motor winding. The three-phase current output to the motor winding is passed through the three phase lines of the three-phase four-wire inverter circuit.
[0096] Assume that the waveform of the second alternating current with a DC bias output by the inverter circuit 302 to the zero axis of the motor is the same as Figure 4 If the waveform in Example b is consistent with that in Example b, then the current of the above waveform is converted into a three-phase current, and the waveform of the three-phase current can be as follows Fig. 9 As shown. Fig. 9 It can be seen that when the second alternating current with a DC bias is introduced into the zero axis of the motor, the amplitudes and phases of the three-phase currents are the same.
[0097] The inverter circuit 302 outputs a second alternating current with a DC bias to the zero axis of the motor. Since the quadrature axis of the motor does not pass current, the motor does not generate additional vibration and torque. Since the second alternating current with a DC bias passed into the zero axis contains an alternating component, the iron loss and permanent magnet loss of the motor can be effectively stimulated, the heating power of the motor is increased, and thus the heating speed of the power battery is increased. In addition, the heat generated by the resistance heating of the motor controller 300 can also be used to heat the power battery.
[0098] In addition, when a second alternating current with a DC bias is passed through the zero axis of the motor, the amplitude and phase of the three-phase current are the same, so the three-phase windings in the motor heat up evenly and at similar temperatures. There will not be a phenomenon where one phase winding reaches the temperature limit while the other two phase windings have lower temperatures. Therefore, the heating capacity of the winding can be more fully utilized.
[0099] It should be noted that the three-phase four-wire system has an additional power neutral line drawn from the neutral point (star point) of the three phases compared to the three-phase three-wire system. In the embodiment of the present application, a second alternating current with a DC bias is output to the zero axis of the motor, and current will flow through the power neutral line. Therefore, the inverter circuit 302 provides a loop for the current on the power neutral line to flow. If the inverter circuit 302 itself is not configured with such a loop, it is necessary to connect the star point loop additionally.
[0100] Specifically, the inverter circuit 302 is connected to the DC bus. The inverter circuit 302 adopts a two-level topology. The star point loop can be connected in the following ways: 1. The neutral point of the inverter circuit 302 is connected to the positive electrode of the DC bus through the first switch unit and the first inductor. Fig.10 2. The neutral point of the inverter circuit 302 is connected to the negative electrode of the DC bus through the second switch unit and the second inductor, as shown in FIG. Fig.10 3. The neutral point of the inverter circuit 302 is connected to the positive electrode of the DC bus through the third switch unit and the third inductor, and the neutral point of the inverter circuit 302 is connected to the negative electrode of the DC bus through the fourth switch unit and the fourth inductor, wherein the third switch unit and the fourth switch unit are not closed at the same time, as shown in Example b. Fig.10 The c example is shown in the example.
[0101] In some cases, the topology of the inverter circuit 302 itself can provide a loop for the current flowing through the neutral line of the power source, so there is no need to connect an additional star point loop.
[0102] Case 1
[0103] If the inverter circuit 302 includes two sets of circuits with an inverter function, then the inverter circuit 302 already includes a star point loop, and there is no need to connect the star point loop additionally.
[0104] For example, the inverter circuit 302 for a dual three-phase motor or a six-phase motor can be as follows: Fig.11 As shown in example a, the inverter circuit 302 includes two sets of circuits with inverter functions, and there is no need to connect the star point loop additionally.
[0105] For another example, the inverter circuit 302 adopts an open winding structure, and the inverter circuit 302 does not need to be additionally connected to a star point loop. Fig.11 As shown in example b.
[0106] Case 2
[0107] If the inverter circuit 302 adopts a multi-level topology, since the multi-level topology itself contains a star point loop, there is no need to connect the star point loop additionally.
[0108] For example, the structure of the inverter circuit 302 using the three-level topology can be as follows: Fig.12 As shown. Fig.12 It can be seen that the inverter circuit 302 already includes a loop through which the neutral point (star point) flows.
[0109] It should be noted that, in the embodiments of the present application, only Fig.12 The three-level topology shown is used as an example for illustration. Other three-level topologies, five-level topologies or multi-level topologies in the prior art are also applicable to the embodiments of the present application.
[0110] Method 2
[0111] The inverter circuit 302 adopts a three-phase four-wire system, and the control device 301 is specifically used to control the inverter circuit 302 to output a third alternating current with a DC bias to the direct axis of the motor.
[0112] That is to say, if the inverter circuit 302 adopts a three-phase four-wire system, the control device 301 can also control the inverter circuit 302 to output a third alternating current with a DC bias to the direct axis of the motor, and no current flows through the neutral line of the power supply.
[0113] In the second method, the method of connecting the star point loop can refer to the relevant description in the first method, which will not be repeated here.
[0114] Compared with the first method, the amplitude and phase of the three-phase current in the second method are not exactly the same (refer to Figure 7 ), and thus there is the aforementioned problem of insufficient utilization of the heating capacity of the winding.
[0115] In summary, the motor controller 300 provided in the embodiment of the present application is used to pass current to the motor. Since the cross axis of the motor does not pass current, the motor will not generate additional vibration and torque. Since the alternating current with DC bias is passed into the direct axis or zero axis, compared with the method of only using the end winding to generate heat in the prior art, since the current passed into the motor contains an alternating component, the iron loss and permanent magnet loss of the motor can be effectively stimulated, the heating power of the motor is increased, and thus the heating speed of the power battery is increased. In addition, the heat generated by the resistance heating of the motor controller 300 can also be used to heat the power battery.
[0116] The present application also provides a heat exchange system. Fig.13 As shown, the heat exchange system 1300 includes a motor 1301, a heat exchanger 1302, a liquid pump 1303, a power battery 1304 and the aforementioned motor controller 300; the motor 1301, the heat exchanger 1302 and the liquid pump 1303 are connected through pipelines;
[0117] The motor controller 300 is used to output an alternating current to the direct axis or zero axis of the motor 1301 , the alternating current having a DC bias, and the alternating current is used to heat the motor 1301 ;
[0118] The liquid pump 1303 is used to drive the pipeline so that the heat generated by the motor 1301 is exchanged to the power battery 1304 through the heat exchanger 1302 .
[0119] The motor 1301 may be an oil-cooled motor. A possible structural diagram of the motor 1301 may be as follows: Figure 2 Of course, the structures of other oil-cooled motors in the prior art are also applicable to the embodiments of the present application.
[0120] It should be noted that the specific working principle and connection method of the heat exchange system 1300 can be found in Figure 1 The relevant description of the heat exchange system shown will not be repeated here.
[0121] Based on the same inventive concept, the present application also provides a current injection method. Fig.14 , the method comprising:
[0122] S1401: The motor controller determines parameters of the alternating current output to the motor.
[0123] The alternating current has a DC bias and is used to heat the motor.
[0124] Specifically, the parameters of the alternating current include waveform, phase, amplitude, frequency, and DC bias value. Since the alternating current with DC bias is output to the motor to heat the motor and then heat the power battery, the motor controller can determine the parameters of the alternating current based on factors such as the temperature of the motor, the temperature of the power battery, the current limit and temperature limit of the three-phase winding of the motor, etc.
[0125] S1402: The motor controller outputs the alternating current to the direct axis or zero axis of the motor.
[0126] The current injection method can be regarded as the method executed by the motor controller 300. By executing the method, the motor controller 300 can pass current into the motor, thereby heating the motor. The detailed implementation process of the method executed by the motor controller 300 can be found in Figure 3 The relevant description of the motor controller 300 shown is not repeated here.
[0127] Based on the same inventive concept, the present application also provides a powertrain. Fig.15 As shown, the powertrain 1500 includes a motor 1501 , a reducer 1502 , and the aforementioned motor controller 300 .
[0128] In addition, the present application also provides a vehicle. Fig.16 As shown, vehicle 1600 includes a power battery 1601 and a powertrain 1500 .
[0129] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present application without departing from the scope of the embodiments of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A powertrain with power battery heating function, It is characterized in that The powertrain includes a motor controller and a motor; wherein: The inverter circuit is used to connect the power battery through a DC bus and connect the motor through a three-phase line; The motor, the heat exchanger and the liquid pump are coupled via an oil cooling pipeline, and the motor controller, the heat exchanger and the power battery are coupled via a water cooling pipeline; The motor controller is used to output an alternating current to the direct axis or the zero axis of the motor and the current output to the quadrature axis of the motor is zero; The alternating current is used to: heating the motor, wherein the heat generated by the motor is conducted to the power battery through the oil cooling pipeline and the heat exchanger; The inverter circuit is heated, and the heat generated by the inverter circuit is transferred to the power battery through the water cooling pipeline and the heat exchanger.
2. The powertrain according to claim 1, It is characterized in that The alternating current is also used to generate heat on the internal resistance of the power battery to heat the power battery.
3. The powertrain according to claim 1, It is characterized in that The alternating current has a DC bias.
4. The powertrain according to claim 1, It is characterized in that The alternating current does not contain negative values.
5. The powertrain according to claim 1, It is characterized in that The inverter circuit adopts a three-phase three-wire system, the inverter circuit includes a three-phase bridge arm, the motor includes a three-phase winding, the two ends of each phase bridge arm of the three-phase bridge arm are respectively used to connect the two ends of the power battery, and the midpoints of the three-phase bridge arm are respectively used to connect the three-wire winding; The inverter circuit is specifically used for: Under the control of the control device, a first alternating current with a DC bias is output to the direct axis of the motor.
6. The powertrain according to claim 5, It is characterized in that The amplitudes of the three-phase currents generated by the first alternating current on the three-phase windings are not equal.
7. The powertrain according to claim 1, It is characterized in that The inverter circuit adopts a three-phase four-wire system, the inverter circuit includes a three-phase bridge arm, the motor includes a three-phase winding, the two ends of each phase bridge arm of the three-phase bridge arm are respectively used to connect the two ends of the power battery, the bridge arm midpoint of the three-phase bridge arm is respectively used to connect the three-wire winding, and the neutral point of the three-phase winding is used to connect one end of the power battery; The inverter circuit is specifically used for: Under the control of the control device, a second alternating current with a DC bias is output to the zero axis of the motor, or a third alternating current with a DC bias is output to the direct axis of the motor.
8. The powertrain according to claim 7, It is characterized in that The neutral point of the three-phase winding is used to connect one end of the power battery through an inductor.
9. The powertrain according to claim 7, It is characterized in that The three-phase currents generated by the second alternating current on the three-phase windings have the same amplitude and phase.
10. The powertrain according to any one of claims 1 to 9, It is characterized in that The motor comprises a rotor core, a stator and a rotating shaft. The rotating shaft and the rotor core are provided with oil passages. The liquid pump is used to drive the insulating coolant in the oil cooling pipeline to flow in the oil passages in the rotating shaft and the rotor core.
11. The powertrain according to claim 1, It is characterized in that The inverter circuit is connected to a DC bus, the inverter circuit adopts a two-level topology, and a neutral point of the inverter circuit is connected to a positive electrode of the DC bus through a first switch unit and a first inductor; or The inverter circuit adopts a two-level topology, and the neutral point of the inverter circuit is connected to the negative electrode of the DC bus through a second switch unit and a second inductor; or The inverter circuit adopts a two-level topology, the neutral point of the inverter circuit is connected to the positive electrode of the DC bus through a third switch unit and a third inductor, and the neutral point of the inverter circuit is connected to the negative electrode of the DC bus through a fourth switch unit and a fourth inductor.
12. The powertrain according to claim 11, It is characterized in that The inverter circuit adopts an open winding structure or a multi-level topology.
13. The power assembly according to any one of claims 1 to 12, It is characterized in that The alternating current is any one of a sine wave, a square wave, a triangle wave, a sawtooth wave and a trapezoidal wave.
14. A motor controller, It is characterized in that The motor controller includes a control device and an inverter circuit; The inverter circuit is used to connect the power battery through the DC bus and connect the motor through the three-phase line; The motor, the heat exchanger and the liquid pump are coupled via an oil cooling pipeline, and the motor controller, the heat exchanger and the power battery are coupled via a water cooling pipeline; The control device is used to control the inverter circuit to output an alternating current to the direct axis or zero axis of the motor and to control the current output by the inverter circuit to the quadrature axis of the motor to be zero; The alternating current is used to: heating the motor, wherein the heat generated by the motor is conducted to the power battery through the oil cooling pipeline and the heat exchanger; The inverter circuit is heated, and the heat generated by the inverter circuit is transferred to the power battery through the water cooling pipeline and the heat exchanger.
15. A vehicle, It is characterized in that It comprises a power battery and a power assembly as described in any one of claims 1 to 13 or a motor controller as described in claim 14, wherein the power assembly is used to heat the power battery.