Charging circuit and method for low-voltage electric motorcycle by high-voltage direct-current charging pile

Abstract

The invention discloses a charging circuit and method of a high-voltage direct-current charging pile for a low-voltage electric motorcycle. The low-voltage electric motorcycle comprises a low-voltage power battery, a motor driver and a motor. The charging circuit comprises a motor driver, a motor and a charging half-bridge circuit. The motor driver comprises a plurality of switch bridge arms, and the motor comprises a plurality of motor windings. Each motor winding can be regarded as a charging circuit inductor in the circuit, and a filter capacitor in the motor driver can be regarded as a charging circuit output filter capacitor, so that the motor windings and a motor driver capacitor can be used as a part of a charging voltage regulation circuit. The high-voltage direct-current charging pile can charge the low-voltage power battery without an additional external charger.

Description

Technical Field

[0001] The present application belongs to the technical field of charging circuits, and in particular, relates to a charging circuit and method for a high-voltage direct current charging pile to charge a low-voltage electric motorcycle. Background Art

[0002] At present, common electric motorcycles are usually charged with external chargers or OBCs (on-board chargers). However, due to the limitations of the charger's size, weight, cost and other factors, common external chargers and OBCs have problems such as low charging power and slow charging speed, which makes it difficult to meet the market demand for fast charging of long-range electric motorcycles with large-capacity batteries. In addition, a small number of electric motorcycles use additional high-power step-down DC / DCs to connect to automotive DC charging piles to achieve fast charging of low-voltage electric motorcycles. High-power DC / DCs have problems such as large size, heavy weight and high cost, which makes it difficult to match the real needs of the market. Summary of the invention

[0003] The purpose of this application is to provide a circuit and method for quickly charging low-voltage electric motorcycles using a public car resource DC charging pile without increasing too much cost, larger volume and heavier weight, so as to solve the problem of quickly replenishing energy for low-voltage electric motorcycles.

[0004] A first aspect of an embodiment of the present application provides a charging circuit, comprising: a motor driver, a motor and a charging half-bridge circuit; the motor driver comprises a plurality of switch bridge arms, and the motor comprises a plurality of motor windings; the two ends of each of the switch bridge arms of the motor driver are used to be connected to a low-voltage power battery, the midpoint of at least one of the switch bridge arms is connected to the midpoint of the bridge arm of the charging half-bridge circuit through at least one of the motor windings, and the two ends of the switch bridge arm of the charging half-bridge circuit are used to be connected to the positive and negative poles of a high-voltage DC charging pile.

[0005] In one embodiment, the motor windings correspond one-to-one to the switch bridge arms, the first ends of the motor windings are respectively connected to the midpoints of the corresponding switch bridge arms, the second ends of the motor windings are connected to each other, and the first end or the second end of at least one motor winding is connected to the midpoint of the bridge arm of the charging half-bridge circuit.

[0006] In one embodiment, the motor driver includes a mode switching switch, a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor includes a first motor winding, a second motor winding and a third motor winding; the two ends of the first switch bridge arm are connected to the low-voltage power battery, the midpoint of the first switch bridge arm is connected to the first end of the first motor winding, the two ends of the second switch bridge arm are connected to the low-voltage power battery, the midpoint of the second switch bridge arm is connected to the first end of the second motor winding through the mode switching switch, the two ends of the third switch bridge arm are connected to the low-voltage power battery, and the midpoint of the third switch bridge arm is connected to the first end of the third motor winding; the second end of the first motor winding, the second end of the second motor winding and the second end of the third motor winding are connected to each other, and the first end of the second motor winding is connected to the midpoint of the bridge arm of the charging half-bridge circuit.

[0007] In one embodiment, the charging half-bridge circuit includes a first voltage regulating switch, a second voltage regulating switch and a charging input capacitor, the first end of the first voltage regulating switch is used to connect to the positive electrode of the high-voltage DC charging pile, the second end of the first voltage regulating switch is connected to the first end of the second motor winding, the first end of the second voltage regulating switch is connected to the first end of the second motor winding, the second end of the second voltage regulating switch is used to connect to the negative electrode of the high-voltage DC charging pile, and the two ends of the charging input capacitor are connected to the first end of the first voltage regulating switch and the second end of the second voltage regulating switch.

[0008] In one embodiment, the motor driver includes a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor includes a first motor winding, a second motor winding and a third motor winding; the two ends of the first switch bridge arm are connected to the low-voltage power battery, the midpoint of the first switch bridge arm is connected to the first end of the first motor winding, the two ends of the second switch bridge arm are connected to the low-voltage power battery, the midpoint of the second switch bridge arm is connected to the first end of the second motor winding, the two ends of the third switch bridge arm are connected to the low-voltage power battery, and the midpoint of the third switch bridge arm is connected to the first end of the third motor winding; the second end of the first motor winding, the second end of the second motor winding and the second end of the third motor winding are connected to each other (motor center point), and are connected to the midpoint of the bridge arm of the charging half-bridge circuit.

[0009] In one embodiment, the charging half-bridge circuit includes a first voltage regulating switch, a second voltage regulating switch and a charging input capacitor, wherein the first end of the first voltage regulating switch is used to be connected to the positive electrode of the high-voltage DC charging pile, the second end of the first voltage regulating switch is connected to the center point of the motor, the first end of the second voltage regulating switch is connected to the center point of the motor, the second end of the second voltage regulating switch is used to be connected to the negative electrode of the high-voltage DC charging pile, and the two ends of the charging input capacitor are connected to the first end of the first voltage regulating switch and the second end of the second voltage regulating switch.

[0010] In one embodiment, the motor driver includes a filter capacitor, and two ends of the filter capacitor are used to be connected to the positive electrode and the negative electrode of the low-voltage power battery respectively.

[0011] In one embodiment, the charging circuit is configured as follows: in the discharge mode, the mode switching switch is turned on, and the motor driver drives the motor to work based on the electric energy provided by the low-voltage power battery; in the charging mode, the mode switching switch is turned off, the upper bridge arm of the first switch bridge arm and the upper bridge arm of the third switch bridge arm are turned on, and the other switches of the motor driver switch bridge arm are in the off state, and the first voltage regulating switch and the second voltage regulating switch are turned on and off at a set switching frequency and a set on time.

[0012] In one embodiment, the charging circuit is configured as follows: in a discharge mode, the first voltage regulating switch and the second voltage regulating switch are turned off, and the motor driver drives the motor to operate based on the electric energy provided by the low-voltage power battery; in a charging mode, the upper bridge arm of the first switch bridge arm, the upper bridge arm of the second switch bridge arm, and the upper bridge arm of the third switch bridge arm are turned on, and other switches of the motor driver switch bridge arms are in an off state, and the first voltage regulating switch and the second voltage regulating switch are turned on and off at a set switching frequency and a set on-time.

[0013] A second aspect of an embodiment of the present application provides a method for charging a low-voltage electric motorcycle with a high-voltage DC charging pile, comprising: a high-voltage DC charging converter, a low-voltage power battery and a charging circuit as described above, wherein the output end of the charging circuit is connected to the low-voltage power battery, and the input end of the charging circuit is connected to the high-voltage DC charging pile.

[0014] Compared with the prior art, the embodiments of the present application have the following beneficial effects: by connecting the motor winding of the motor in series between the motor driver and the charging half-bridge circuit, each motor winding can be regarded as an inductive device in the circuit, and the input capacitor in the motor driver can be regarded as an output filter capacitor of the charging circuit, so that the motor winding and the motor driver capacitor can be used as part of the charging voltage regulation circuit, and cooperate with the charging half-bridge circuit to form a BUCK circuit to achieve charging voltage regulation, so that the high-voltage DC charging pile can charge the low-voltage power battery without the need for an additional charger.

[0015] Since the motor winding of the motor can withstand a relatively high-power current, the charging circuit can quickly charge the low-voltage power battery with a relatively large charging power. At the same time, since only an additional charging half-bridge circuit is required to realize the charging of the low-voltage power battery by a high-voltage DC charging pile, the charging circuit of the present application can be integrated into the interior of the motor controller. Therefore, without increasing too much cost, larger volume and heavier weight, a car DC charging pile can be used to quickly charge the low-voltage electric motorcycle, thereby solving the problem of quickly replenishing energy for the low-voltage electric motorcycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a charging circuit according to an embodiment of the present application;

[0017] Figure 2 A circuit diagram of a charging circuit provided in an embodiment of the present application;

[0018] Figure 3 A waveform diagram of the voltage at the connection point between the motor and the charging half-bridge circuit provided in one embodiment of the present application;

[0019] Figure 4 A waveform diagram of the current flowing through the motor winding provided by an embodiment of the present application;

[0020] Figure 5 Another circuit diagram of a charging circuit provided by an embodiment of the present application;

[0021] Figure 6 A waveform diagram of a charging voltage provided in accordance with an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0024] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] Figure 1 The schematic diagram of the principle of the charging circuit of a high-voltage DC charging pile for a low-voltage electric motorcycle provided in an embodiment of the present application is shown. For the convenience of explanation, only the part related to the present embodiment is shown, which is described in detail as follows:

[0027] The low-voltage electric motorcycle includes a low-voltage power battery 20 , a motor driver 100 and a motor 200 .

[0028] The charging circuit 10 includes: a switch bridge arm of a motor driver 100 and a motor winding of a motor 200 , and also includes a charging half-bridge circuit 300 .

[0029] The two ends of each switch bridge arm are used to connect to the low-voltage power battery 20, the midpoint of at least one switch bridge arm is connected to the midpoint of the bridge arm of the charging half-bridge circuit 300 through at least one motor winding, and the two ends of the charging half-bridge circuit 300 are used to connect to the positive and negative poles of the high-voltage DC charging pile 30.

[0030] During charging, the inductor device is an important device for voltage regulation. In the present embodiment, by connecting the motor winding of the motor 200 in series between the motor driver 100 and the charging half-bridge circuit 300, each motor winding can be regarded as an inductor device in the circuit, and the filter capacitor in the motor driver 100 can be regarded as the output filter capacitor of the charging circuit 10. Therefore, the motor winding inductance and the filter capacitor in the motor driver 100 can be regarded as part of the charging circuit 10, and cooperate with the charging half-bridge circuit 300 to form a BUCK circuit to adjust the charging voltage. There is no need to add an additional high-power DC / DC to achieve high-power charging of the low-voltage power battery 20 by the high-voltage DC charging pile 30.

[0031] In one embodiment, the motor windings correspond one-to-one to the switch bridge arms of the motor driver, the first ends of each motor winding are respectively connected to the midpoint of the corresponding switch bridge arm, the second ends of each motor winding are connected to each other, and the first end or the second end of at least one motor winding is connected to the midpoint of the bridge arm of the charging half-bridge circuit 300.

[0032] When the low-voltage power battery 20 is discharging, the motor driver 100 can provide electric energy to each motor winding based on the voltage output by the low-voltage power battery 20 to drive the motor 200 to work. When the low-voltage power battery 20 is charging, by controlling the on and off of the corresponding switch device in the motor driver 100, at least one motor winding can be connected in series between the charging half-bridge circuit 300 and the low-voltage power battery 20, and participate in the voltage regulation as an inductor device.

[0033] In one embodiment, if Figure 2 As shown, the motor driver 100 includes a mode switching switch S1, a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor 200 includes a first motor winding L1, a second motor winding L2 and a third motor winding L3. The two ends of the first switch bridge arm are connected to the low-voltage power battery 20, the bridge arm midpoint of the first switch bridge arm is connected to the first end of the first motor winding L1, the two ends of the second switch bridge arm are connected to the low-voltage power battery 20, the bridge arm midpoint of the second switch bridge arm is connected to the first end of the second motor winding L2 through the mode switching switch S1, the two ends of the third switch bridge arm are connected to the low-voltage power battery 20, and the bridge arm midpoint of the third switch bridge arm is connected to the first end of the third motor winding L3. The second end of the first motor winding L1, the second end of the second motor winding L2 and the second end of the third motor winding L3 are connected to each other, and the first end of the second motor winding L2, the second end of the mode switching switch S1 and the bridge arm midpoint of the charging half-bridge circuit 300 are connected to each other.

[0034] It can be understood that when the mode switching switch S1 is turned on, by controlling the first switch bridge arm, the second switch bridge arm and the third switch bridge arm to be periodically turned on and off, the low-voltage power battery 20 can provide electrical energy to drive the motor 200 to work.

[0035] In some embodiments, the first switch bridge arm includes a first power supply switch Q1 and a second power supply switch Q2, the first end of the first power supply switch Q1 is connected to the positive electrode of the low-voltage power battery 20, the second end of the first power supply switch Q1 is connected to the first end of the first motor winding L1, the first end of the second power supply switch Q2 is connected to the second end of the first power supply switch Q1, and the second end of the second power supply switch Q2 is connected to the negative electrode of the low-voltage power battery 20.

[0036] The second switch bridge arm includes a third power supply switch Q3 and a fourth power supply switch Q4. The first end of the third power supply switch Q3 is connected to the positive electrode of the low-voltage power battery 20. The second end of the third power supply switch Q3 is connected to the first end of the second motor winding L2 through the mode switching switch S1. The first end of the fourth power supply switch Q4 is connected to the second end of the third power supply switch Q3. The second end of the fourth power supply switch Q4 is connected to the negative electrode of the low-voltage power battery 20.

[0037] The third switch bridge arm includes a fifth power supply switch Q5 and a sixth power supply switch Q6. The first end of the fifth power supply switch Q5 is connected to the positive electrode of the low-voltage power battery 20, the second end of the fifth power supply switch Q5 is connected to the first end of the third motor winding L3, the first end of the sixth power supply switch Q6 is connected to the second end of the fifth power supply switch Q5, and the second end of the sixth power supply switch Q6 is connected to the negative electrode of the low-voltage power battery 20.

[0038] The first power switch Q1 , the second power switch Q2 , the third power switch Q3 , the fourth power switch Q4 , the fifth power switch Q5 and the sixth power switch Q6 may all be N-type MOS transistors.

[0039] In one embodiment, the charging half-bridge circuit 300 includes a first voltage regulating switch S2, a second voltage regulating switch S3 and a charging input capacitor C2, the first end of the first voltage regulating switch S2 is used to connect to the positive electrode of the high-voltage DC charging pile 30, the second end of the first voltage regulating switch S2 is connected to the first end of the second motor winding L2, the first end of the second voltage regulating switch S3 is connected to the first end of the second motor winding L2, the second end of the second voltage regulating switch S3 is used to connect to the negative electrode of the high-voltage DC charging pile 30, and the two ends of the charging input capacitor C2 are respectively connected to the first end of the first voltage regulating switch S2 and the second end of the second voltage regulating switch S3.

[0040] Specifically, the charging circuit 10 is configured as follows: in the discharge mode, the mode switching switch S1 is turned on, and the motor driver 100 drives the motor 200 to work based on the electric energy provided by the low-voltage power battery 20. In the charging mode, the mode switching switch S1 is turned off, the upper bridge arm of the first switch bridge arm and the upper bridge arm of the third switch bridge arm are turned on, and the other bridge arm switches of the motor driver 100 are all in the off state (that is, the lower bridge arm of the first switch bridge arm, the upper bridge arm of the second switch bridge arm, the lower bridge arm of the second switch bridge arm, and the lower bridge arm of the third switch bridge arm are turned off), and the first voltage regulating switch S2 and the second voltage regulating switch S3 are periodically turned on and off at a set switching frequency and a set on time.

[0041] The set frequency of the first voltage regulating switch S2 is equal to the set frequency of the second voltage regulating switch S3, and the sum of the set on-time of the first voltage regulating switch S2 and the set on-time of the second voltage regulating switch S3 is equal to the duration of one cycle corresponding to the set frequency, that is, the control signal corresponding to the first voltage regulating switch S2 is complementary to the control signal corresponding to the second voltage regulating switch S3. In the charging mode, for example, the voltage waveform at the connection point between the motor 200 and the charging half-bridge circuit 300 and the current waveform flowing through the motor winding are as follows: Figure 3 , Figure 4 As shown, the switching frequency and the on-time of the first voltage regulating switch S2 and the second voltage regulating switch S3 can be adjusted by adjusting the duty cycle, frequency and other electrical parameters of the control signal used to control the first voltage regulating switch S2 and the second voltage regulating switch S3, so as to adjust the charging voltage and charging current transmitted to the low-voltage power battery. The set frequency and the set on-time can be set according to actual needs.

[0042] Specifically, in the charging mode, the motor driver 100 can turn on the first power switch Q1 and the fifth power switch Q5, and turn off the second power switch Q2 and the sixth power switch Q6. At this time, the second motor winding L2 and the first motor winding L1 are connected in series between the charging half-bridge circuit 300 and the first power switch Q1, and the second motor winding L2 and the third motor winding L3 are connected in series between the charging half-bridge circuit 300 and the fifth power switch Q5. It is also possible to only turn on one of the first power switch Q1 and the fifth power switch Q5 to achieve charging of the low-voltage power battery 20.

[0043] In some embodiments, Figure 2As shown, the charging circuit 10 further includes a charging interface 400, which is connected to the charging half-bridge circuit 300 and is used to connect to the high-voltage DC charging pile 30. Specifically, the first end of the first voltage regulating switch S2 can be connected to the positive electrode of the charging interface 400, thereby connecting to the positive electrode of the high-voltage DC charging pile 30 through the charging interface 400, and the second end of the second voltage regulating switch S3 can be connected to the negative electrode of the charging interface 400, thereby connecting to the negative electrode of the high-voltage DC charging pile 30 through the charging interface 400.

[0044] It should be noted that the low-voltage power battery 20 is provided with a positive electrode and a negative electrode, the upper bridge arm of the switch bridge arm of each motor driver is connected to the positive electrode of the low-voltage power battery 20, and the lower bridge arm of each switch bridge arm is connected to the negative electrode of the low-voltage power battery 20. At the same time, the negative electrode of the low-voltage power battery 20 can also be connected to the negative electrode of the charging interface 400.

[0045] In one embodiment, if Figure 5 As shown, different from the above embodiment, the motor driver 100 includes a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor 200 includes a first motor winding L1, a second motor winding L2 and a third motor winding L3. The two ends of the first switch bridge arm are connected to the low-voltage power battery 20, the bridge arm midpoint of the first switch bridge arm is connected to the first end of the first motor winding L1, the two ends of the second switch bridge arm are connected to the low-voltage power battery 20, the bridge arm midpoint of the second switch bridge arm is connected to the first end of the second motor winding L2, the two ends of the third switch bridge arm are connected to the low-voltage power battery 20, and the bridge arm midpoint of the third switch bridge arm is connected to the first end of the third motor winding L3. The second end of the first motor winding L1, the second end of the second motor winding L2 and the second end of the third motor winding L3 are all connected to the center point of the motor, and connected to the bridge arm midpoint of the charging half-bridge circuit 300.

[0046] It should be noted that, in the present embodiment, the second end of the first motor winding L1, the second end of the second motor winding L2 and the second end of the third motor winding L3 are all connected to the central terminal of the motor 200. By connecting the central terminal to the midpoint of the bridge arm of the charging half-bridge circuit 300, each motor winding can be directly connected in series between the charging half-bridge circuit 300 and the low-voltage power battery 20.

[0047] In some embodiments, the first switch bridge arm includes a first power supply switch Q1 and a second power supply switch Q2, the first end of the first power supply switch Q1 is connected to the positive electrode of the low-voltage power battery 20, the second end of the first power supply switch Q1 is connected to the first end of the first motor winding L1, the first end of the second power supply switch Q2 is connected to the second end of the first power supply switch Q1, and the second end of the second power supply switch Q2 is connected to the negative electrode of the low-voltage power battery 20.

[0048] The second switch bridge arm includes a third power supply switch Q3 and a fourth power supply switch Q4. The first end of the third power supply switch Q3 is connected to the positive electrode of the low-voltage power battery 20, the second end of the third power supply switch Q3 is connected to the first end of the second motor winding L2, the first end of the fourth power supply switch Q4 is connected to the second end of the third power supply switch Q3, and the second end of the fourth power supply switch Q4 is connected to the negative electrode of the low-voltage power battery 20.

[0049] The third switch bridge arm includes a fifth power supply switch Q5 and a sixth power supply switch Q6. The first end of the fifth power supply switch Q5 is connected to the positive electrode of the low-voltage power battery 20, the second end of the fifth power supply switch Q5 is connected to the first end of the third motor winding L3, the first end of the sixth power supply switch Q6 is connected to the second end of the fifth power supply switch Q5, and the second end of the sixth power supply switch Q6 is connected to the negative electrode of the low-voltage power battery 20.

[0050] In one embodiment, the charging half-bridge circuit 300 includes a first voltage regulating switch S2, a second voltage regulating switch S3 and a charging input capacitor C2, wherein the first end of the first voltage regulating switch S2 is used to be connected to the positive electrode of the high-voltage DC charging pile 30, the second end of the first voltage regulating switch S2 is connected to the central terminal of the motor 200, the first end of the second voltage regulating switch S3 is connected to the central terminal of the motor 200, the second end of the second voltage regulating switch S3 is used to be connected to the negative electrode of the high-voltage DC charging pile 30, and the two ends of the charging input capacitor C2 are connected to the first end of the first voltage regulating switch S2 and the second end of the second voltage regulating switch S3.

[0051] In one embodiment, the charging circuit 10 is configured as follows: in the discharge mode, the first voltage regulating switch S2 and the second voltage regulating switch S3 are turned off, and the motor driver 100 drives the motor 200 to work based on the electric energy provided by the low-voltage power battery 20. In the charging mode, the upper bridge arm of the first switch bridge arm, the upper bridge arm of the second switch bridge arm, and the upper bridge arm of the third switch bridge arm are turned on, and the other voltage regulating switches of the motor driver 100 are all in the off state (that is, the lower bridge arm of the first switch bridge arm, the lower bridge arm of the second switch bridge arm, and the lower bridge arm of the third switch bridge arm are turned off), and the first voltage regulating switch S2 and the second voltage regulating switch S3 are periodically turned on and off at a set frequency and a set conduction time.

[0052] In the charging mode, the motor driver 100 can turn on the first power switch Q1, the third power switch Q3 and the fifth power switch Q5, and turn off the second power switch Q2, the fourth power switch Q4 and the sixth power switch Q6. At this time, the first motor winding L1 is connected in series between the midpoint of the bridge arm of the charging half-bridge circuit 300 and the first power switch Q1, the second motor winding L2 is connected in series between the midpoint of the bridge arm of the charging half-bridge circuit 300 and the third power switch Q3, and the third motor winding L3 is connected in series between the midpoint of the bridge arm of the charging half-bridge circuit 300 and the fifth power switch Q5. It is also possible to turn on only one of the first power switch Q1, the third power switch Q3 and the fifth power switch Q5 to achieve charging of the low-voltage power battery 20.

[0053] The specific working principle of the charging half-bridge circuit 300 has been described in the above embodiment, and will not be described again in this embodiment.

[0054] In one embodiment, if Figure 5 As shown, the motor driver 100 includes a filter capacitor C1 , and two ends of the filter capacitor C1 are used to be connected to the positive electrode and the negative electrode of the low-voltage power battery 20 respectively.

[0055] Exemplarily, the charging voltage provided by the charging circuit 10 to the low-voltage power battery 20 is as follows: Figure 6 As shown, the filter capacitor C1 can filter and stabilize the voltage transmitted to the low-voltage power battery 20 to provide a stable voltage to the low-voltage power battery 20 .

[0056] An embodiment of the present application provides a charging method applied to any of the above embodiments, including steps S100 to S200.

[0057] Step S100: turning on the upper bridge arm of the switch bridge arm of at least one motor driver to connect at least one motor winding in series between the charging half-bridge circuit and the low-voltage power battery.

[0058] Step S200: Controlling the charging half-bridge circuit through pulse width modulation to cooperate with the motor winding of the motor and the charging half-bridge circuit C2 of the motor driver to step down the input high voltage provided by the high-voltage DC charging pile to output a charging voltage to the low-voltage power battery.

[0059] The motor winding inductance and the filter capacitor in the motor driver 100 are used as part of the charging circuit 10, and cooperate with the charging half-bridge circuit 300 to form a BUCK circuit to adjust the charging voltage. High-power charging of the low-voltage power battery 20 by the high-voltage DC charging pile 30 can be achieved without adding additional high-power DC / DC.

[0060] An embodiment of the present application provides a low-voltage electric motorcycle, which includes: a low-voltage power battery and a charging circuit as in any of the above embodiments, and the charging circuit is connected to the low-voltage power battery. The charging circuit can be used to connect to a high-voltage DC charging pile to charge the low-voltage power battery. Since the low-voltage electric motorcycle includes the charging circuit of any of the above embodiments, the low-voltage electric motorcycle has the beneficial effects of the charging circuit of any of the above embodiments, which will not be repeated here.

[0061] The low-voltage electric motorcycle can specifically be an electric motorcycle, an all-terrain vehicle, an electric car or other tools or equipment driven by an electric motor.

[0062] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0063] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0064] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A charging circuit for a high-voltage DC charging pile to a low-voltage electric motorcycle, wherein the low-voltage electric motorcycle comprises a low-voltage power battery, a motor driver and a motor, characterized in that: The charging circuit comprises: a charging half-bridge circuit, a switch bridge arm of the motor driver and a motor winding of the motor; The two ends of each of the switch bridge arms are used to connect to the low-voltage power battery, the midpoint of at least one of the switch bridge arms is connected to the midpoint of the bridge arm of the charging half-bridge circuit through at least one of the motor windings, and the two ends of the charging half-bridge circuit are used to connect to the positive and negative poles of the high-voltage DC charging pile.

2. The charging circuit according to claim 1, characterized in that: The motor windings correspond one-to-one to the switch bridge arms, the first ends of the respective motor windings are respectively connected to the midpoints of the corresponding switch bridge arms, the second ends of the respective motor windings are connected to each other, and the first end or the second end of at least one motor winding is connected to the midpoint of the bridge arm of the charging half-bridge circuit.

3. The charging circuit according to claim 1, characterized in that: The motor driver comprises a mode switching switch, a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor comprises a first motor winding, a second motor winding and a third motor winding; The two ends of the first switch bridge arm are connected to the low-voltage power battery, the bridge arm midpoint of the first switch bridge arm is connected to the first end of the first motor winding, the two ends of the second switch bridge arm are connected to the low-voltage power battery, the bridge arm midpoint of the second switch bridge arm is connected to the first end of the second motor winding through the mode switching switch, the two ends of the third switch bridge arm are connected to the low-voltage power battery, and the bridge arm midpoint of the third switch bridge arm is connected to the first end of the third motor winding; The second end of the first motor winding, the second end of the second motor winding and the second end of the third motor winding are connected to each other, and the first end of the second motor winding, the second end of the mode switching switch and the midpoint of the bridge arm of the charging half-bridge circuit are connected to each other.

4. The charging circuit according to claim 3, characterized in that: The charging half-bridge circuit includes a first voltage regulating switch, a second voltage regulating switch and a charging input capacitor, wherein the first end of the first voltage regulating switch is used to be connected to the positive electrode of the high-voltage DC charging pile, the second end of the first voltage regulating switch is connected to the first end of the second motor winding, the first end of the second voltage regulating switch is connected to the first end of the second motor winding, the second end of the second voltage regulating switch is used to be connected to the negative electrode of the high-voltage DC charging pile, and the two ends of the charging input capacitor are connected to the first end of the first voltage regulating switch and the second end of the second voltage regulating switch.

5. The charging circuit according to claim 1 or 2, characterized in that: The motor driver comprises a first switch bridge arm, a second switch bridge arm and a third switch bridge arm, and the motor comprises a first motor winding, a second motor winding and a third motor winding; The two ends of the first switch bridge arm are connected to the low-voltage power battery, the bridge arm midpoint of the first switch bridge arm is connected to the first end of the first motor winding, the two ends of the second switch bridge arm are connected to the low-voltage power battery, the bridge arm midpoint of the second switch bridge arm is connected to the first end of the second motor winding, the two ends of the third switch bridge arm are connected to the low-voltage power battery, and the bridge arm midpoint of the third switch bridge arm is connected to the first end of the third motor winding; The second end of the first motor winding, the second end of the second motor winding and the second end of the third motor winding are all connected to the center of the motor and to the midpoint of the bridge arm of the charging half-bridge circuit.

6. The charging circuit according to claim 5, characterized in that: The charging half-bridge circuit includes a first voltage regulating switch, a second voltage regulating switch and a charging input capacitor, wherein the first end of the first voltage regulating switch is used to be connected to the positive electrode of the high-voltage DC charging pile, the second end of the first voltage regulating switch is connected to the center point of the motor, the first end of the second voltage regulating switch is connected to the center point of the motor, the second end of the second voltage regulating switch is used to be connected to the negative electrode of the high-voltage DC charging pile, and the two ends of the charging input capacitor are connected to the first end of the first voltage regulating switch and the second end of the second voltage regulating switch.

7. The charging circuit according to claim 1, characterized in that: The motor driver comprises a filter capacitor, and two ends of the filter capacitor are used to be connected to the positive electrode and the negative electrode of the low-voltage power battery respectively.

8. The charging circuit according to claim 4, characterized in that: The charging circuit is configured such that: in a discharge mode, the mode switching switch is turned on, and the motor driver drives the motor to work based on the electric energy provided by the low-voltage power battery; In charging mode, the mode switching switch is turned off, the upper bridge arm of the first switch bridge arm and the upper bridge arm of the third switch bridge arm are turned on, the other bridge arm switches of the motor driver are in the off state, and the first voltage regulating switch and the second voltage regulating switch are periodically turned on and off at a set switching frequency and a set on time.

9. The charging circuit according to claim 6, characterized in that: The charging circuit is configured such that: in a discharge mode, the first voltage regulating switch and the second voltage regulating switch are turned off, and the motor driver drives the motor to work based on the electric energy provided by the low-voltage power battery; In the charging mode, the upper bridge arm of the first switch bridge arm, the upper bridge arm of the second switch bridge arm and the upper bridge arm of the third switch bridge arm are turned on, and the other bridge arm switches of the motor driver are in the off state. The first voltage regulating switch and the second voltage regulating switch are periodically turned on and off at a set switching frequency and a set on time.

10. A charging method, characterized in that: A charging circuit for a low-voltage electric motorcycle applied to a high-voltage DC charging pile, wherein the low-voltage electric motorcycle comprises a low-voltage power battery, a motor driver and a motor, and the charging circuit comprises: the motor driver, the motor and a charging half-bridge circuit; the motor driver comprises a plurality of switch bridge arms, and the motor comprises a plurality of motor windings; both ends of each of the switch bridge arms are used to be connected to the low-voltage power battery, the midpoint of at least one of the switch bridge arms is connected to the midpoint of the bridge arm of the charging half-bridge circuit through at least one of the motor windings, and the input end of the charging half-bridge circuit is used to be connected to the high-voltage DC charging pile; The charging method comprises: Turning on the upper bridge arm of the switch bridge arm of at least one motor driver to connect at least one motor winding in series between the charging half-bridge circuit and the low-voltage power battery; The charging half-bridge circuit is controlled by pulse width modulation to cooperate with the motor winding of the motor and the charging input capacitor of the charging half-bridge circuit to step down the input high voltage provided by the high-voltage DC charging pile, so as to output a charging voltage to the low-voltage power battery.

11. A low-voltage electric motorcycle, characterized in that: include: A low-voltage power battery, a motor driver motor and a charging circuit as claimed in any one of claims 1 to 9.

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