Power management circuit for electrically-assisted vehicle

Abstract

To provide a power management circuit for an electrically-assisted vehicle.SOLUTION: An electrically-assisted vehicle 10 includes a battery BT, a motor MT, and a power supply receiving terminal TC. A power management circuit 100 includes a transformer TR, a primary circuit 110, first and second power transmission circuits 120, 130, and a controller 140. The transformer TR includes primary and secondary windings LP, LS. The primary circuit 110 is connected to the primary winding LP and the power supply receiving terminal TC. The first power transmission circuit 120 is connected to the secondary winding LS and the battery BT. The second power transmission circuit 130 is connected to the secondary winding LS, the battery BT, and the motor MT. The controller 140 controls the primary circuit 110 and the first power transmission circuit 120 in a first operation mode to supply battery power from the battery BT to the power supply receiving terminal TC. In a second operation mode, the controller 140 controls the second power transmission circuit 130 to charge the battery BT using power from the motor MT.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power management circuit, and particularly to a power management circuit used in an electric assist vehicle.

Background Art

[0002] An electric assist vehicle (such as an electric assist wheelchair, an electric assist bicycle, an electric assist scooter, or an electric motorcycle) drives a motor using the power of a battery, and the motor provides power to assist the user. The electric assist vehicle receives an external power source wirelessly or by wire and charges the battery using the external power source.

[0003] In some designs, the electric assist vehicle can feed back the power of the battery to an external power source. However, the current charging mechanism and power feedback mechanism are implemented using different power converters. Therefore, the design cost of the electric assist vehicle will increase. Thus, how to provide a circuit having a plurality of power transmission functions is one of the research focuses of those skilled in the art.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention provides a power management circuit used in an electric assist vehicle. The power management circuit has a plurality of power transmission functions.

Means for Solving the Problems

[0005] The power management circuit of the present invention is used in an electric assist vehicle. The electric assist vehicle includes a battery, a motor, and a power reception terminal. The power management circuit includes a transformer, a primary circuit, a first power transmission circuit, a second power transmission circuit, and a controller. The transformer includes a primary winding and a secondary winding. The primary circuit is electrically connected to the primary winding and the power reception terminal. The first power transmission circuit is electrically connected to the secondary winding and the battery. The second power transmission circuit is electrically connected to the secondary winding, the battery, and the motor. The controller is electrically connected to the primary circuit, the first power transmission circuit, and the second power transmission circuit. In the first operation mode, the controller controls the primary circuit and the first power transmission circuit to provide the battery power of the battery to the power reception terminal. In the second operation mode, the controller controls the second power transmission circuit, and the second power transmission circuit charges the battery using the power of the motor.

Advantages of the Invention

[0006] Based on the above, in the first operation mode, the power management circuit feeds back the battery power of the battery to the power reception terminal. In the second operation mode, the power management circuit charges the battery using the power of the motor. Thus, the power management circuit has a plurality of power transmission functions.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Best Mode for Carrying Out the Invention

[0008] The following will describe in detail some embodiments of the present invention with reference to the drawings. In the following description, reference numerals cited are treated as the same or similar components when the same reference numerals are shown in different drawings. These embodiments are only a part of the present invention and do not disclose all possible implementations of the present invention. Rather, these embodiments are merely examples within the scope of the claims of the present invention.

[0009] Referring to FIG. 1, FIG. 1 is a schematic diagram of a power management circuit according to an embodiment of the present invention. In the present embodiment, the power management circuit 100 is used in an electric assist vehicle 10. The electric assist vehicle 10 includes a battery BT, a motor MT, and a power reception terminal TC. The electric assist vehicle 10 may be, for example, an electric assist wheelchair, an electric assist bicycle, an electric assist scooter, or an electric motorcycle, but the present invention is not limited thereto. In the present embodiment, the electric assist vehicle 10 receives DC power VWPT at the power reception terminal TC wirelessly or by wire and charges the battery BT using the DC power VWPT. The battery BT can be realized by an aluminum-ion battery, but the present embodiment is not limited thereto.

[0010] In the present embodiment, the power management circuit 100 includes a transformer TR, a primary circuit 110, a first power transmission circuit 120, a second power transmission circuit 130, and a controller 140. The transformer TR includes a primary winding LP and a secondary winding LS. The primary circuit 110 is electrically connected to the primary winding LP and the power reception terminal TC. The first power transmission circuit 120 is electrically connected to the secondary winding LS and the battery BT. The second power transmission circuit 130 is electrically connected to the secondary winding LS, the battery BT, and the motor MT.

[0011] In this embodiment, the controller 140 is electrically connected to the primary circuit 110, the first power transmission circuit 120, and the second power transmission circuit 130. The controller 140 controls the primary circuit 110, the first power transmission circuit 120, and the second power transmission circuit 130 to execute a plurality of operation modes corresponding to different power transmission methods.

[0012] In the first operation mode, the controller 140 controls the primary circuit 110 and the first power transmission circuit 120 to provide the battery power PB of the battery BT to the power reception terminal TC. That is, in the first operation mode, the power management circuit 100 can feedback the battery power PB from the battery BT to the power reception terminal TC.

[0013] In the second operation mode, the controller 140 controls the second power transmission circuit 130, and the second power transmission circuit 130 charges the battery BT using the power PM of the motor MT. For example, during the running period, when the electric assist vehicle 10 travels downhill, the electromotive force of the motor MT can supply a large amount of power. Therefore, when the voltage value VB of the battery BT is lower than the voltage value VM of the power PM of the motor MT, the power management circuit 100 can charge the battery BT using the power PM of the motor MT in the second operation mode. Therefore, the durability during the running period of the electric assist vehicle 10 can be improved.

[0014] Note that in the first operation mode, the power management circuit 100 feedbacks the battery power PB of the battery BT to the power reception terminal TC. In the second operation mode, the power management circuit 100 charges the battery BT using the power PM of the motor MT. Thus, the power management circuit 100 has a plurality of power transmission functions.

[0015] Also, in the third operation mode, the controller 140 can drive the motor MT using the battery power PB by controlling the first power transmission circuit 120 and the second power transmission circuit 130. In the fourth operation mode, the controller 140 controls the primary circuit 110. The primary circuit 110 provides the DC power VWPT located at the power reception terminal TC to the battery BT.

[0016] Referring to FIG. 2, FIG. 2 is a schematic circuit diagram of a power management circuit according to an embodiment of the present invention. In this embodiment, the power management circuit 200 includes a transformer TR, a primary circuit 210, a first power transmission circuit 220, a second power transmission circuit 230, and a controller 240. The transformer TR includes a primary winding LP and a secondary winding LS.

[0017] In this embodiment, the primary circuit 210 includes power switches Q1, Q2, and an input capacitor Cin. The first terminal of the power switch Q1 is electrically connected to the power reception terminal TC. The control terminal of the power switch Q1 is electrically connected to the controller 240. The first terminal of the power switch Q2 is electrically connected to the first terminal of the primary winding LP. The second terminal of the power switch Q2 is electrically connected to the second terminal of the power switch Q1. The control terminal of the power switch Q2 is electrically connected to the controller 240. The first terminal of the input capacitor Cin is electrically connected to the power reception terminal TC. The second terminal of the input capacitor Cin is electrically connected to the second terminal of the primary winding LP and the reference voltage terminal VSS (e.g., ground).

[0018] In this embodiment, the first power transmission circuit 220 includes a capacitor C1 and a power switch Q3. The first terminal of the capacitor C1 is electrically connected to the first terminal of the secondary winding LS and the positive electrode of the battery BT. The second terminal of the capacitor C1 is electrically connected to the negative electrode of the battery BT. The first terminal of the power switch Q3 is electrically connected to the second terminal of the capacitor C1 and the negative electrode of the battery BT. The second terminal of the power switch Q3 is electrically connected to the second terminal of the secondary winding LS. The control terminal of the power switch Q3 is electrically connected to the controller 240.

[0019] In this embodiment, the second power transmission circuit 230 includes a capacitor C2 and power switches Q4 and Q5. The capacitor C2 is electrically connected in parallel with the motor MT. The first terminal of the power switch Q4 is electrically connected to the first terminal of the secondary winding LS and the positive electrode of the battery BT. The second terminal of the power switch Q4 is electrically connected to one terminal of the capacitor C2. The control terminal of the power switch Q4 is electrically connected to the controller 240. The first terminal of the power switch Q5 is electrically connected to the other terminal of the capacitor C2. The second terminal of the power switch Q5 is electrically connected to the second terminal of the power switch Q3 and the second terminal of the secondary winding LS. The control terminal of the power switch Q5 is electrically connected to the controller 240.

[0020] In this embodiment, the controller 240 controls the power switches Q1 to Q5 to execute different power transmission functions. The controller 240 controls the power switch Q1 using the control signal SC1. The controller 240 controls the power switch Q2 using the control signal SC2. The controller 240 controls the power switch Q3 using the control signal SC3. The controller 240 controls the power switch Q4 using the control signal SC4. Also, the controller 240 controls the power switch Q5 using the control signal SC5.

[0021] Referring to FIGS. 2 and 3 simultaneously, FIG. 3 is a schematic diagram of the operation of the first operation mode according to an embodiment of the present invention. In this embodiment, the controller 240 provides a control signal SC1 having a high voltage level, control signals SC2, SC4, SC5 having a low voltage level, and a control signal SC3 having a duty cycle. The control signal SC3 may be a pulse-width modulation (PWM) signal. Accordingly, the controller 240 turns on the power switch Q1 and turns off the power switches Q2, Q4, Q5. The second power transmission circuit 230 does not operate. Also, the power switch Q3 performs a switching operation based on the duty cycle. The duty cycle is greater than 0% and less than 100%. Accordingly, the power management circuit 200 forms an equivalent circuit as shown in FIG. 3 in the first operation mode. The primary circuit 210 receives the battery power PB via the transformer TR and transmits the battery power PB to the power reception terminal TC via the diode element of the power switch Q2 and the power switch Q1.

[0022] Furthermore, in the first operation mode, the power switch Q3 performs a switching operation based on the duty cycle. Accordingly, an exciting inductor LM connected in parallel to the secondary winding LS is formed. While the power switch Q3 is on, the battery power PB first accumulates power in the capacitor C1 and accumulates power in the exciting inductor LM. Here, the input current value Iin1 provided by the battery BT and the current value IL1 flowing through the exciting inductor LM increase. Accordingly, while the power switch Q3 is on, the capacitor C1 and the exciting inductor LM can form an energy loop LC1.

[0023] While the power switch Q3 is turned off, the power accumulated by the excitation inductor LM enters the secondary winding LS through the dot terminal of the secondary winding LS and flows out from the non-dot terminal of the primary winding LP. Here, the current value IL1 flowing through the excitation inductor LM decreases. The battery power PB is transmitted to the input capacitor Cin and the power receiving terminal TC through the diode element and the power switch Q2 of the power switch Q2. Therefore, while the power switch Q3 is turned off, the excitation inductor LM, the secondary winding LS, the primary winding LP, and the primary circuit 210 can form an energy loop LC1.

[0024] In the first operation mode, the controller 240 can detect the voltage value VB of the battery power PB. When the voltage value VB is low, the controller 240 can increase the duty cycle of the control signal SC3. On the other hand, when the voltage value VB is high, the controller 240 can decrease the duty cycle of the control signal SC3. Therefore, the voltage value of the DC power VWPT can be stabilized. Therefore, the output current value Iout1 can also be stabilized.

[0025] Referring to FIGS. 2 and 4 simultaneously, FIG. 4 is an operation schematic diagram of a second operation mode according to an embodiment of the present invention. In the present embodiment, the controller 240 provides a control signal SC5 having a high voltage level, control signals SC1, SC2, SC3 having a low voltage level, and a control signal SC4 having a duty cycle. The control signal SC4 may be a PWM signal. Therefore, the controller 240 turns on the power switch Q5 and turns off the power switches Q1, Q2, Q3. The primary circuit 210 does not operate. Further, the power switch Q4 performs a switching operation based on the duty cycle. The duty cycle is greater than 0% and less than 100%. Therefore, the power management circuit 200 forms an equivalent circuit as shown in FIG. 4 in the second operation mode. The power PM generated by the motor MT is provided to the battery BT through the power switch Q5 and the excitation inductor LM of the transformer TR.

[0026] Furthermore, in the second operation mode, the power switch Q4 performs a switching operation based on a duty cycle. Accordingly, an exciting inductor LM connected in parallel to the secondary winding LS is formed. While the power switch Q4 is on, the power PM generated by the motor MT first accumulates power in the capacitor C2 and then accumulates power in the exciting inductor LM. Here, the input current value Iin2 provided by the motor MT and the current value IL2 flowing through the exciting inductor LM increase. While the power switch Q4 is on, the turned-on power switch Q5, the capacitor C2, and the exciting inductor LM can form an energy loop LC3.

[0027] While the power switch Q4 is off, the diode element of the power switch Q3 transmits the power accumulated by the exciting inductor LM to the capacitor C1 and the battery BT. Here, the current value IL2 flowing through the exciting inductor LM decreases. While the power switch Q4 is off, the exciting inductor LM, the diode element of the power switch Q3, the capacitor C1, and the battery BT can form an energy loop LC4.

[0028] In the second operation mode, the controller 240 can detect the voltage value VB of the battery power PB. When the voltage value VB is low, the controller 240 can increase the duty cycle of the control signal SC4. On the other hand, when the voltage value VB is high, the controller 240 can decrease the duty cycle of the control signal SC4. Accordingly, the voltage value VB of the battery power PB can be stabilized. Accordingly, the output current value Iout2 can also be stabilized. Also, when the power PM generated by the motor MT is insufficient, the controller 240 ends the second operation mode. For example, the controller 240 can detect the voltage value VM of the power PM. When the voltage value VM is lower than the voltage value VB, the controller 240 ends the second operation mode.

[0029] Referring to FIGS. 2 and 5 simultaneously, FIG. 5 is a schematic diagram of the operation of the third operation mode according to an embodiment of the present invention. In this embodiment, the controller 240 provides a control signal SC5 having a high voltage level, control signals SC1, SC2, SC4 having a low voltage level, and a control signal SC3 having a duty cycle. The control signal SC3 may be a PWM signal. Accordingly, the controller 240 turns on the power switch Q5 and turns off the power switches Q1, Q2, Q4. The primary circuit 210 does not operate. Also, the power switch Q3 performs a switching operation based on the duty cycle. The duty cycle is greater than 0% and less than 100%. Accordingly, the power management circuit 200 forms an equivalent circuit as shown in FIG. 5 in the third operation mode. The battery power PB drives the motor MT by being provided to the motor MT through the exciting inductor LM of the transformer TR, the power switch Q5, and the diode element of the power switch Q4.

[0030] Furthermore, in the third operation mode, the power switch Q3 performs a switching operation based on the duty cycle. Accordingly, an exciting inductor LM connected in parallel to the secondary winding LS is formed. While the power switch Q3 is on, the battery power PB first accumulates power in the capacitor C1 and then accumulates power in the exciting inductor LM. Here, the input current value Iin3 provided by the battery BT and the current value IL3 flowing through the exciting inductor LM increase. While the power switch Q3 is on, an energy loop LC5 is formed. The energy loop LC5 is similar to the energy loop LC1 in FIG. 3.

[0031] While the power switch Q3 is off, the power accumulated by the exciting inductor LM is provided to the motor MT through the power switch Q5 and the diode element of the power switch Q4. The current value IL3 flowing through the exciting inductor LM decreases. While the power switch Q3 is off, the exciting inductor LM, the power switch Q5, the diode element of the power switch Q4, and the motor MT can form an energy loop LC6.

[0032] In the third operation mode, the controller 240 can detect the voltage value VB of the battery power PB. When the voltage value VB is low, the controller 240 can increase the duty cycle of the control signal SC3. On the other hand, when the voltage value VB is high, the controller 240 can decrease the duty cycle of the control signal SC3. Therefore, the operation of the motor MT can be stabilized. Therefore, the voltage value VM and the output current value Iout3 can also be stabilized.

[0033] Referring to FIGS. 2 and 6 simultaneously, FIG. 6 is an operation schematic diagram of a fourth operation mode according to an embodiment of the present invention. In the present embodiment, the controller 240 provides a control signal SC1 having a high voltage level, control signals SC3, SC4, SC5 having a low voltage level, and a control signal SC2 having a duty cycle. The control signal SC2 may be a PWM signal. Therefore, the controller 240 turns on the power switch Q1 and turns off the power switches Q3, Q4, Q5. The second power transmission circuit 230 does not operate. Also, the power switch Q2 performs a switching operation based on the duty cycle. The duty cycle is greater than 0% and less than 100%. Therefore, the power management circuit 200 forms an equivalent circuit as shown in FIG. 6 in the fourth operation mode. The power located at the power reception terminal TC is provided to the battery BT via the power switches Q1, Q2, and the transformer TR to charge the battery BT.

[0034] Furthermore, in the fourth operation mode, the power switch Q2 performs a switching operation based on the duty cycle. Accordingly, an exciting inductor LM connected in parallel to the primary winding LP is formed. While the power switch Q2 is on, the primary circuit 210 receives DC power VWPT via the power receiving terminal TC. The primary circuit 210 accumulates the DC power VWPT using the input capacitor Cin and accumulates power in the exciting inductor LM via the power switches Q1 and Q2. Here, the input current value Iin4 provided by the primary circuit 210 and the current value IL4 flowing through the exciting inductor LM increase. While the power switch Q2 is on, the primary circuit 210 and the exciting inductor LM can form an energy loop LC7.

[0035] While the power switch Q2 is off, the power accumulated by the exciting inductor LM enters the primary winding LP from the dot terminal of the primary winding LP and flows out from the dot terminal of the secondary winding LS, thereby accumulating power in the battery BT and the capacitor C1. Next, the power accumulated by the exciting inductor LM enters the non-dot terminal of the secondary winding LS via the diode element of the power switch Q3. The current value IL4 flowing through the exciting inductor LM decreases. Accordingly, while the power switch Q2 is off, the transformer TR, the battery BT, and the first power transmission circuit 220 can form an energy loop LC8.

[0036] In the fourth operation mode, the controller 240 can detect the voltage value of the DC power VWPT. When the voltage value of the DC power VWPT is low, the controller 240 can increase the duty cycle of the control signal SC2. On the other hand, when the voltage value of the DC power VWPT is high, the controller 240 can decrease the duty cycle of the control signal SC2. Accordingly, the charging voltage value received by the battery BT can be stabilized. Accordingly, the output current value Iout4 can also be stabilized.

[0037] Summarizing the above, the power management circuit is used in an electric assist vehicle and provides a plurality of power transmission functions. In the first operation mode, the power management circuit feeds back the battery power of the battery to the power reception terminal. In the second operation mode, the power management circuit charges the battery using the power of the motor. Further, in the third operation mode, the power management circuit drives the motor using the battery power, and in the fourth operation mode, the power management circuit charges the battery using the power from the power reception terminal.

[0038] Although the present invention has been disclosed through the above embodiments, these are not intended to limit the present invention. Those having ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The protection scope of the present invention shall be determined by the scope of the attached patent application.

Industrial Applicability

[0039] The present invention provides a power management circuit used in an electric assist vehicle. The power management circuit of the present invention has power transmission functions in a plurality of operation modes.

Explanation of Reference Numerals

[0040] 10: Electric assist vehicle 100, 200: Power management circuit 110, 210: Primary circuit 120, 220: First power transmission circuit 130, 230: Second power transmission circuit 140, 240: Controller BT: Battery C1, C2: Capacitor Cin: Input capacitor Iin1~Iin4: Input current value IL1~IL4: Current value flowing through the exciting inductor Iout1~Iout4: Output current value LC1~LC8: Energy loop LM: Exciting inductor LP: Primary winding LS: Secondary winding MT: Motor PB: Battery power PM: Motor power Q1~Q5: Power switch SC1~SC5: Control signal TC: Power receiving terminal TR: Transformer VB, VM: Voltage value VWPT: DC power

Claims

1. A power management circuit for use in an electrically assisted vehicle, The electrically assisted vehicle includes a battery, a motor, and a power supply receiving terminal. The power management circuit includes: a transformer including a primary winding and a secondary winding; a primary circuit electrically connected to the primary winding and the power receiving terminal; a first power transfer circuit electrically connected to the secondary winding and the battery; a second power transfer circuit electrically connected to the secondary winding, the battery, and the motor; a controller electrically connected to the primary circuit, the first power transfer circuit, and the second power transfer circuit, In a first operating mode, providing battery power from the battery to the power receiving terminal by controlling the primary circuit and the first power transmission circuit; and In a second operating mode, the second power transmission circuit is controlled so that the second power transmission circuit charges the battery using power from the motor. The controller configured as described above; A power management circuit comprising:

2. the controller drives the motor using the battery power by controlling the first power transmission circuit and the second power transmission circuit in a third operating mode; 2. The power management circuit of claim 1.

3. and wherein the controller controls the primary circuit in a fourth mode of operation, the primary circuit providing DC power located at the power supply receiving terminals to the battery.

3. The power management circuit of claim 2.

4. The primary circuit includes: a first power switch, a first terminal of the first power switch electrically connected to the power receiving terminal and a control terminal of the first power switch electrically connected to the controller; a second power switch, a first terminal of the second power switch electrically connected to the first terminal of the primary winding, a second terminal of the second power switch electrically connected to the second terminal of the first power switch, and a control terminal of the second power switch electrically connected to the controller; an input capacitor, a first terminal of the input capacitor electrically connected to the power receiving terminal and a second terminal of the input capacitor electrically connected to the second terminal of the primary winding and a reference voltage terminal; 2. The power management circuit of claim 1, comprising:

5. The first power transmission circuit includes: a first capacitor, a first terminal of the first capacitor being electrically connected to a first terminal of the secondary winding and a positive terminal of the battery, and a second terminal of the first capacitor being electrically connected to a negative terminal of the battery; a third power switch, a first terminal of the third power switch being electrically connected to a second terminal of the first capacitor and a negative pole of the battery, a second terminal of the third power switch being electrically connected to a second terminal of the secondary winding, and a control terminal of the third power switch being electrically connected to the controller; The power management circuit of claim 4 comprising:

6. The second power transmission circuit includes: a second capacitor electrically connected in parallel with the motor; a fourth power switch, a first terminal of the fourth power switch being electrically connected to a first terminal of the secondary winding and a positive electrode of the battery, a second terminal of the fourth power switch being electrically connected to one terminal of the second capacitor, and a control terminal of the fourth power switch being electrically connected to the controller; a fifth power switch, a first terminal of the fifth power switch being electrically connected to the other terminal of the second capacitor, a second terminal of the fifth power switch being electrically connected to the second terminal of the third power switch and the second terminal of the secondary winding, and a control terminal of the fifth power switch being electrically connected to the controller; 6. The power management circuit of claim 5, comprising:

7. In the first mode of operation: the controller turns off the second power switch, the fourth power switch, and the fifth power switch, and turns on the first power switch; the third power switch performs a switching operation based on a duty cycle; the duty cycle is greater than 0% and less than 100%; the primary circuit receives the battery power via the transformer and transmits the battery power to the power receiving terminal via a diode element of the second power switch and the first power switch; 7. The power management circuit of claim 6.

8. In the second mode of operation, the controller turns off the first power switch, the second power switch, and the third power switch, and turns on the fifth power switch; the fourth power switch performs a switching operation based on a duty cycle; the duty cycle is greater than 0% and less than 100%; power for the motor is provided to the battery via the fifth power switch and an excitation inductor of the transformer; 7. The power management circuit of claim 6.

9. In a third mode of operation, the controller turns off the first power switch, the second power switch, and the fourth power switch, and turns on the fifth power switch; the third power switch performs a switching operation based on a duty cycle; the duty cycle is greater than 0% and less than 100%; the battery power is provided to the motor via an exciting inductor of the transformer, the fifth power switch, and a diode element of the fourth power switch; 7. The power management circuit of claim 6.

10. In a fourth mode of operation, the controller turns off the third power switch, the fourth power switch, and the fifth power switch, and turns on the first power switch; The second power switch performs a switching operation based on a duty cycle; the duty cycle is greater than 0% and less than 100%; power at the power receiving terminal is provided to the battery via the first power switch, the second power switch and the transformer; 7. The power management circuit of claim 6.

Images