Motor drive device

Abstract

To provide a motor driving device capable of reducing a voltage dropping loss of a conversion circuit in a charging mode.SOLUTION: A motor driving device 100 contains: a battery module; and a conversion circuit 120. The conversion circuit drives a motor in a driving mode, and charges the battery module in a charging mode. The conversion circuit contains: a determination circuit; a controller; and a first phase upper arm switch circuit SW1. In a power switch T1, a first terminal is coupled to a positive power supply terminal of the battery module, a second terminal is coupled to a first phase node NDU, and a control terminal is coupled to a controller. In a transistor M1, the first terminal is coupled to the positive power supply terminal, the second terminal is coupled to the first phase node, and the control terminal is coupled to the controller. The controller notifies a conduction of a first transistor when a first phase voltage value in the first phase node is larger than a battery voltage value in the positive power supply terminal in the charging mode.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a drive device, and particularly to a motor drive device for driving a motor.

Background Art

[0002] FIG. 1 is a schematic diagram of an existing motor drive device. The motor drive device 10 includes a battery module 11 and a conversion circuit 12. The conversion circuit 12 drives the motor MTR using the power stored in the battery module 11. The conversion circuit 12 can charge the battery module 11 using the power generated by the motor MTR. The conversion circuit 12 includes upper arm power switches T1, T3, T5, lower arm power switches T2, T4, T6, and diodes D1 to D6.

[0003] When charging the battery module 11, all of the upper arm power switches T1, T3, T5 and the lower arm power switches T2, T4, T6 of the conversion circuit 12 are turned off. The diodes D1 to D6 are used to perform a full-wave rectification operation on the power generated by the motor MTR. Taking the upper arm power switch T1 as an example, the upper arm power switch T1 is coupled between the first-phase node NDU and the positive power supply terminal of the battery module 11. When charging the battery module 11, the upper arm power switch T1 is turned off. When the voltage difference value obtained by subtracting the battery voltage value VP from the first-phase voltage value VU at the first-phase node NDU is greater than the forward bias value of the diode D1, the diode D1 is turned on. Therefore, the conversion circuit 12 charges the battery module 11 using the first-phase voltage value VU. Taking the lower arm power switch T2 as an example below, the lower arm power switch T2 is coupled between the first-phase node NDU and the negative power supply terminal of the battery module 11. When the voltage difference value obtained by subtracting the first-phase voltage value VU from the reference low voltage value VP is less than the forward bias value of the diode D2, the diode D2 is turned on.

[0004] When charging the battery module 11, in the process of performing full-wave rectification on the power generated by the motor MTR, the conversion circuit 12 may incur voltage drop losses. The voltage drop losses are caused by the forward bias values of the diodes D1 to D6. For example, the forward bias values of the diodes D1 to D6 are 0.7 to 1 volt. The voltage drop loss of each phase of the full-wave rectification operation is 1.4 to 2 volts. The voltage drop losses of the conversion circuit 12 may reduce the charging efficiency of the battery module 11. As can be seen from this, it is essential to reduce the voltage drop losses. Summary of the Invention Problems to be Solved by the Invention

[0005] The present invention provides a motor drive device used to drive a motor. The motor drive device has low voltage drop losses. Means for Solving the Problems

[0006] The motor drive device of the present invention is used to drive a motor. The motor drive device includes a battery module and a conversion circuit. The battery module stores battery power. The conversion circuit is coupled to the motor and the battery module. The conversion circuit drives the motor using the battery power in the drive mode and charges the battery module using the motor power generated by the motor in the charging mode. The conversion circuit includes a determination circuit, a controller, and a first-phase upper-arm switch circuit. The first-phase upper-arm switch circuit includes a first power switch and a first transistor. The first terminal of the first power switch is coupled to the positive power terminal of the battery module. The second terminal of the first power switch is coupled to the first-phase node. The control terminal of the first power switch is coupled to the controller. The first terminal of the first transistor is coupled to the positive power terminal. The second terminal of the first transistor is coupled to the first-phase node. The control terminal of the first transistor is coupled to the controller. In the charging mode, the controller turns off the first power switch and the first transistor. In the charging mode, the determination circuit determines the first-phase voltage value at the first-phase node. When the first-phase voltage value is greater than the battery voltage value at the positive power terminal, the determination circuit notifies the controller to turn on the first transistor.

Effect of the Invention

[0007] Based on the above, the first-phase upper-arm switch circuit includes a first power switch and a first transistor. The first terminal of the first transistor is coupled to the positive power terminal. The second terminal of the first transistor is coupled to the first-phase node. In the charging mode, when the first-phase voltage value is greater than the battery voltage value at the positive power terminal, the first transistor is turned on. When the first transistor is turned on, the voltage difference value between the first terminal and the second terminal of the first transistor is clearly lower than the forward bias value of the diode in the first power switch. In this way, in the charging mode, the voltage drop loss of the conversion circuit can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Embodiments for Carrying Out the Invention

[0009] Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings. Regarding the reference numerals cited in the following description, the same reference numerals appearing in different drawings are regarded as the same or similar members. These embodiments are only a part of the present invention and do not disclose all potential implementation modes of the present invention. More precisely, these embodiments are only examples within the patent scope of the present invention.

[0010] Referring to FIG. 2, FIG. 2 is a schematic diagram of a motor drive device illustrated based on one embodiment of the present invention. In the present embodiment, the motor drive device 100 is used to drive a motor MTR. The motor drive device 100 includes a battery module 110 and a conversion circuit 120. The battery module 110 stores battery power PB. The conversion circuit 120 is coupled to the motor MTR and the battery module 110. The conversion circuit 120 operates the motor MTR by driving the motor MTR using the battery power PB of the battery module 110 in the drive mode. The conversion circuit 120 charges the battery module 110 using the motor power PM generated by the motor MTR in the charging mode. The motor MTR may be a braking device used in a moving vehicle. The moving vehicle may be an electric assist walker, an electric bicycle, an electric vehicle, or an elevator.

[0011] In the present embodiment, the conversion circuit 120 includes a determination circuit 121, a controller 122, and switch circuits SW1 to SW6. The switch circuit SW1 may be a first-phase upper arm switch circuit. The switch circuit SW2 may be a first-phase lower arm switch circuit. The switch circuit SW3 may be a second-phase upper arm switch circuit. The switch circuit SW4 may be a second-phase lower arm switch circuit. The switch circuit SW5 may be a third-phase upper arm switch circuit. The switch circuit SW6 may be a third-phase lower arm switch circuit.

[0012] The switch circuit SW1 includes a power switch T1 and a transistor M1. The first terminal of the power switch T1 is coupled to the positive power terminal TP of the battery module 110. The second terminal of the power switch T1 is coupled to the first-phase node NDU. The control terminal of the power switch T1 is coupled to the controller 122. The first terminal of the transistor M1 is coupled to the positive power terminal TP. The second terminal of the transistor M1 is coupled to the first-phase node NDU. The control terminal of the transistor M1 is coupled to the controller 122. The controller 122 controls the power switch T1 using a control signal ST1. The controller 122 controls the transistor M1 using a control signal SM1.

[0013] In the charging mode, the controller 122 first shuts off the power switch T1 and the transistor M1. Also, in the charging mode, the determination circuit 121 determines the first-phase voltage value VU at the first-phase node NDU. When the first-phase voltage value VU is greater than the battery voltage value VP at the positive power supply terminal TP, the determination circuit 121 notifies the controller 121 to turn on the transistor M1.

[0014] Also, the switch circuit SW1 further includes a diode D1. The diode D1 is used to perform a rectifying operation in the charging mode.

[0015] Here, it should be noted that in the charging mode, when the first-phase voltage value VU is greater than the battery voltage value VP, the transistor M1 is turned on. When the transistor M1 is turned on, the voltage difference value between the first terminal and the second terminal of the transistor M1 is clearly lower than the forward bias value of the diode D1 in the switch circuit SW1. In this way, in the charging mode, the voltage drop loss of the conversion circuit 120 can be reduced. The charging efficiency of the battery module 110 can be improved.

[0016] In this embodiment, the determination circuit 121 is coupled to the first-phase node NDU and the positive power supply terminal TP to receive the first-phase voltage value VU and the battery voltage value VP in the charging mode. In a situation where both the power switch T1 and the transistor M1 are shut off, the determination circuit 121 compares the first-phase voltage value VU and the battery voltage value VP. When the first-phase voltage value VU is greater than the battery voltage value VP, the determination circuit 121 provides a notification signal SN. The controller 122 turns on the transistor M1 in response to the notification signal SN and charges the battery module 110 using the first-phase voltage value VU. In a situation where both the power switch T1 and the transistor M1 are shut off, when the first-phase voltage value VU is less than the battery voltage value VP, the transistor M1 is maintained in the off state.

[0017] The switch circuit SW2 includes a power switch T2 and a transistor M2. The first terminal of the power switch T2 is coupled to the first-phase node NDU. The second terminal of the power switch T2 is coupled to the negative power supply terminal TN of the battery module 110. The control terminal of the power switch T2 is coupled to the controller 122. The first terminal of the transistor M2 is coupled to the first-phase node NDU. The second terminal of the transistor M2 is coupled to the negative power supply terminal TN. The control terminal of the transistor M2 is coupled to the controller 122. The controller 122 controls the power switch T2 using a control signal ST2. The controller 122 controls the transistor M2 using a control signal SM2.

[0018] In the charging mode, the controller 122 shuts off the power switch T2 and the transistor M2. When the first-phase voltage value VU is less than the reference low voltage value VSS, the determination circuit 121 notifies the controller 122 to turn on the transistor M2.

[0019] In this embodiment, the determination circuit 121 is further coupled to the negative power supply terminal TN to receive the reference low voltage value VSS in the charging mode. In a situation where both the power switch T2 and the transistor M2 are shut off, the determination circuit 121 compares the first-phase voltage value VU with the reference low voltage value VSS. When the first-phase voltage value VU is less than the reference low voltage value VSS, the determination circuit 121 provides a notification signal SN. The controller 122 turns on the transistor M2 in response to the notification signal SN. On the other hand, in a situation where both the power switch T2 and the transistor M2 are shut off, when the first-phase voltage value VU is greater than the reference low voltage value VSS, the transistor M2 remains shut off.

[0020] The switch circuit SW3 includes a power switch T3 and a transistor M3. The first terminal of the power switch T3 is coupled to the positive power terminal TP of the battery module 110. The second terminal of the power switch T2 is coupled to the second-phase node NDV. The control terminal of the power switch T3 is coupled to the controller 122. The first terminal of the transistor M3 is coupled to the positive power terminal TP. The second terminal of the transistor M3 is coupled to the second-phase node NDV. The control terminal of the transistor M3 is coupled to the controller 122. The controller 122 controls the power switch T3 using the control signal ST3. The controller 122 controls the transistor M3 using the control signal SM3. The switch circuit SW4 includes a power switch T4 and a transistor M4. The first terminal of the power switch T4 is coupled to the second-phase node NDV. The second terminal of the power switch T4 is coupled to the negative power terminal TN of the battery module 110. The control terminal of the power switch T4 is coupled to the controller 122. The first terminal of the transistor M4 is coupled to the second-phase node NDV. The second terminal of the transistor M4 is coupled to the negative power terminal TN. The control terminal of the transistor M4 is coupled to the controller 122. The controller 122 controls the power switch T4 using the control signal ST2. The controller 122 controls the transistor M4 using the control signal SM4.

[0021] In the charging mode, the controller 122 first shuts off the power switches T3, T4 and the transistors M3, M4. The determination circuit 121 determines the second-phase voltage value VV at the second-phase node NDV. When the second-phase voltage value VV is greater than the battery voltage value VP, the determination circuit 121 notifies the controller 122 to turn on the transistor M3. When the second-phase voltage value VV is less than the battery voltage value VP, the determination circuit 121 notifies the controller 122 to turn on the transistor M4.

[0022] The switch circuit SW5 includes a power switch T5 and a transistor M5. The first terminal of the power switch T5 is coupled to the positive power terminal TP of the battery module 110. The second terminal of the power switch T5 is coupled to the third-phase node NDW. The control terminal of the power switch T5 is coupled to the controller 122. The first terminal of the transistor M5 is coupled to the positive power terminal TP. The second terminal of the transistor M5 is coupled to the third-phase node NDW. The control terminal of the transistor M5 is coupled to the controller 122. The controller 122 controls the power switch T5 using a control signal ST5. The controller 122 controls the transistor M5 using a control signal SM5. The switch circuit SW6 includes a power switch T6 and a transistor M6. The first terminal of the power switch T6 is coupled to the third-phase node NDW. The second terminal of the power switch T6 is coupled to the negative power terminal TN of the battery module 110. The control terminal of the power switch T6 is coupled to the controller 122. The first terminal of the transistor M6 is coupled to the third-phase node NDW. The second terminal of the transistor M6 is coupled to the negative power terminal TN. The control terminal of the transistor M6 is coupled to the controller 122. The controller 122 controls the power switch T6 using a control signal ST6. The controller 122 controls the transistor M4 using a control signal SM6.

[0023] In the charging mode, the controller 122 first shuts off the power switches T5, T6 and the transistors M5, M6. The determination circuit 121 determines the third-phase voltage value VW at the third-phase node NDW. When the third-phase voltage value VW is greater than the battery voltage value VP, the determination circuit 121 notifies the controller 122 to turn on the transistor M5. When the third-phase voltage value VW is less than the battery voltage value VP, the determination circuit 121 notifies the controller 122 to turn on the transistor M6.

[0024] In this embodiment, the switch circuit SW2 further includes a diode D2. The switch circuit SW3 further includes a diode D3. Similarly, it can be inferred that the switch circuit SW6 includes a diode D6. The diodes D2 to D6 are used to perform a rectifying operation in the charging mode.

[0025] Based on the above, in the charging mode, the determination circuit 121 determines whether to turn on the transistors M1 to M6 by detecting the first-phase voltage value VU, the second-phase voltage value VV, and the third-phase voltage value VW.

[0026] In this embodiment, the power switches T1 to T6 are each implemented by, for example, an insulated gate bipolar transistor (IGBT). The transistors M1 to M6 are each implemented by, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET). However, the present invention does not limit the forms of the power switches T1 to T6 and the transistors M1 to M6 in this embodiment. The power switches T1 to T6 and the transistors M1 to M6 may be implemented by any suitable form of transistor.

[0027] In the charging mode, the determination circuit 121 can further determine whether to turn on the transistors M1 to M6 by detecting the first-phase current IU flowing through the first-phase node NDU, the second-phase current IV flowing through the second-phase node NDV, and the third-phase current IW flowing through the third-phase node NDW.

[0028] Here, taking the first-phase current IU as an example, in the charging mode, the determination circuit 121 detects the direction of the first-phase current IU. When the first-phase current IU flows through the diode D1 of the first power switch T1 to the positive power supply terminal TP, the determination circuit 121 notifies the controller 122 to turn on the transistor M1. When the first-phase current IU flows through the diode D2 of the second power switch T2 to the first-phase node NDU, the determination circuit 121 notifies the controller 122 to turn on the transistor M2.

[0029] In this embodiment, the conversion circuit 120 may determine whether to turn on the transistors M3 to M6 using a similar operation as described above in the charging mode, and thus will not be repeatedly described here.

[0030] In the charging mode, the determination circuit 121 can further detect the first-phase current IU, the second-phase current IV, and the third-phase current IW to determine whether to cut off the transistors that have already been turned on among the transistors M1 to M6.

[0031] Here, taking the first-phase current IU as an example, in the charging mode, when the transistor M1 is turned on, the determination circuit 121 may determine the first-phase current IU. When the first-phase current IU flows from the positive power supply terminal TP to the first-phase node NDU, the determination circuit 121 determines to reflux the first-phase current IU to the motor MTR. Therefore, to prevent the motor MTR or the transistor M1 from burning out, the determination circuit 121 notifies the controller 122 to cut off the transistor M1. When the transistor M2 is turned on, the determination circuit 121 determines the first-phase current IU. When the first-phase current IU flows from the first-phase node NDU to the negative power supply terminal TN, the determination circuit 121 determines to flow the first-phase current IU to the reference low voltage value VSS. Therefore, to prevent the transistor M2 from burning out, the determination circuit 121 notifies the controller 122 to cut off the transistor M2.

[0032] In this embodiment, the conversion circuit 120 may determine whether to cut off any of the transistors M3 to M6 that are already conducting using an operation similar to the above in the charging mode, and thus will not be repeatedly described here.

[0033] In the charging mode, the determination circuit 121 can further determine whether to cut off any of the transistors M1 to M6 that are already conducting by detecting the first-phase voltage value VU, the second-phase voltage value VV, and the third-phase voltage value VW.

[0034] Taking the first-phase voltage value VU as an example here, in the charging mode, the determination circuit 121 determines the first-phase voltage value VU. When the first-phase voltage value VU is approximately equal to the battery voltage value VP, the determination circuit 121 notifies the controller 122 to cut off the transistor M1 based on the first conduction time length TL1. For this reason, the determination circuit 121 determines the first-phase voltage value VU in a situation where the transistor M1 is cut off.

[0035] To explain with an example, refer to FIGS. 2 and 3 simultaneously. FIG. 3 is an operation diagram illustrated based on one embodiment of the present invention. FIG. 3 shows a sequence diagram of a control signal SM1, a battery voltage value VP, and a first-phase voltage value VU in a charging mode. When the first-phase voltage value VU is less than the battery voltage value VP, the control signal SM1 has a low voltage value. Therefore, the transistor M1 is turned off. At time point tp1, when the first-phase voltage value VU is greater than the battery voltage value VP, the control signal SM1 is converted from a low voltage value to a high voltage value. Therefore, the transistor M1 is turned on. The first-phase voltage value VU is approximately equal to the battery voltage value VP. After the first conduction time length TL1, the control signal SM1 is converted from a high voltage value to a low voltage value at time point tp2. The transistor M1 is turned off. Therefore, the determination circuit 121 can compare the first-phase voltage value VU and the battery voltage value VP in a situation where the transistor M1 is turned off. When the first-phase voltage value VU is greater than the battery voltage value VP, the transistor M1 is turned on at time point tp3. Subsequently, the transistor M1 is turned off at time point tp4. The determination circuit 121 compares the first-phase voltage value VU and the battery voltage value VP, and the same applies hereinafter. In a situation where the transistor M1 is turned off, when the first-phase voltage value VU is less than the battery voltage value VP at time point tp5, the transistor M1 is turned off. In the present embodiment, the first conduction time length TL1 may be set.

[0036] Returning to the embodiment of FIG. 2, in the charging mode, when the transistor M2 is turned on, the determination circuit 121 determines the first-phase voltage value VU. When the first-phase voltage value VU is approximately equal to the reference low voltage value VSS, the determination circuit 121 notifies the controller 122 to turn off the transistor M1 based on the second conduction time length TL2. Therefore, the determination circuit 121 determines the first-phase voltage value VU in a situation where the transistor M2 is turned off.

[0037] To explain with an example, refer to FIGS. 2 and 4 simultaneously. FIG. 4 is an operation diagram illustrated based on one embodiment of the present invention. FIG. 4 shows a sequence diagram of the control signal SM2, the reference low voltage value VSS, and the first-phase voltage value VU in the charging mode. When the first-phase voltage value VU is greater than the reference low voltage value VSS, the control signal SM1 has a low voltage value. Therefore, the transistor M2 is cut off. At time point tp1, when the first-phase voltage value VU is lower than the reference low voltage value VSS, the control signal SM2 is converted from a low voltage value to a high voltage value. Therefore, the transistor M2 is turned on. The first-phase voltage value VU is approximately equal to the reference low voltage value VSS. After the second conduction time length TL2, the control signal SM2 is converted from a high voltage value to a low voltage value at time point tp2. The transistor M2 is cut off. Therefore, the determination circuit 121 can compare the first-phase voltage value VU and the reference low voltage value VSS in the situation where the transistor M2 is cut off. When the first-phase voltage value VU is less than the battery voltage value VP, the transistor M2 is turned on at time point tp3. Subsequently, at time point tp4, the transistor M2 is cut off. The determination circuit 121 compares the first-phase voltage value VU and the reference low voltage value VSS, and the same applies hereinafter. When the first-phase voltage value VU is greater than the reference low voltage value VSS at time point tp5 in the situation where the transistor M2 is cut off, the transistor M2 is cut off. In the present embodiment, the second conduction time length TL2 may be set.

[0038] In the present embodiment, the conversion circuit 120 may determine to cut off the transistors that have already been turned on among the transistors M3 to M6 using an operation similar to the above in the charging mode, and thus will not be repeatedly described here.

[0039] In the present embodiment, the battery module 110 is implemented by an aluminum ion battery. The aluminum ion battery has a high charge and discharge rate (C rate). Therefore, the battery module 110 can achieve the advantage of rapid charging.

[0040] Hereinafter, an implementation method of the determination circuit 121 will be described with an example.

[0041] Referring to FIG. 2 and FIG. 5 simultaneously, FIG. 5 is a schematic diagram of a determination circuit illustrated based on one embodiment of the present invention. In this embodiment, the determination circuit 121 includes a reference circuit 1211, a first-phase voltage detection circuit 1212_U, a second-phase voltage detection circuit 1212_V, a third-phase voltage detection circuit 1212_W, and a comparison circuit 1213.

[0042] In this embodiment, the reference circuit 1211 is coupled to the positive power supply terminal TP. The reference circuit 1211 receives a set voltage value VCC and a battery voltage value VP. The reference circuit 1211 converts the set voltage value VCC into a reference value VRN. Also, the reference circuit 1211 converts the battery voltage value VP into a reference value VRP.

[0043] In this embodiment, the first-phase voltage detection circuit 1212_U is coupled to the first-phase node NDU. The first-phase voltage detection circuit 1212_U receives a first-phase voltage value VU. The first-phase voltage detection circuit 1212_U generates a detection value VUN based on the first-phase voltage value VU and a reference low voltage value VSS. Also, the first-phase voltage detection circuit 1212_U generates a detection value VUP based on the first-phase voltage value VU and the set voltage value VCC.

[0044] In this embodiment, the comparison circuit 1213 is coupled to the first-phase voltage detection circuit 1212_U and the reference circuit 1211. When the first-phase voltage value VU is a negative voltage value, the comparison circuit 1213 notifies the controller 122 based on a first comparison result between the detection value VUN and the reference value VRN. Also, when the first-phase voltage value VU is a positive voltage value, it notifies the controller 122 based on a comparison result between the detection value VUP and the reference value VRP. Note that the first-phase voltage value VU is an AC electrical signal. The comparison circuit 1213 can provide a corresponding notification signal by providing one of a first comparison result and a second comparison result based on the first-phase voltage value VU. The determination circuit 121 does not determine that an error has occurred for positive and negative values of the first-phase voltage value VU.

[0045] In this embodiment, the second-phase voltage detection circuit 1212_V is coupled to the second-phase node NDV. The second-phase voltage detection circuit 1212_V receives the second-phase voltage value VV. The second-phase voltage detection circuit 1212_V generates a detection value VVN based on the second-phase voltage value VV and the reference low voltage value VSS. Also, the second-phase voltage detection circuit 1212_V generates a detection value VVP based on the second-phase voltage value VV and the set voltage value VCC. In this embodiment, the comparison circuit 1213 is further coupled to the second-phase voltage detection circuit 1212_V. When the second-phase voltage value VV is a negative voltage value, the comparison circuit 1213 notifies the controller 122 based on a first comparison result between the detection value VVN and the reference value VRN. Also, when the second-phase voltage value VV is a positive voltage value, it notifies the controller 122 based on a second comparison result between the detection value VVP and the reference value VRP.

[0046] In this embodiment, the third-phase voltage detection circuit 1212_W is coupled to the third-phase node NDW. The third-phase voltage detection circuit 1212_W receives the third-phase voltage value VW. The third-phase voltage detection circuit 1212_W generates a detection value VWN based on the third-phase voltage value VW and the reference low voltage value VSS. Also, the third-phase voltage detection circuit 1212_W generates a detection value VWP based on the third-phase voltage value VW and the set voltage value VCC. In this embodiment, the comparison circuit 1213 is further coupled to the third-phase voltage detection circuit 1212_W. When the third-phase voltage value VW is a negative voltage value, the comparison circuit 1213 notifies the controller 122 based on a first comparison result between the detection value VWN and the reference value VRN. Also, when the third-phase voltage value VW is a positive voltage value, it notifies the controller 122 based on a second comparison result between the detection value VWP and the reference value VRN.

[0047] Refer to FIGS. 2, 6, and 7 simultaneously. FIG. 6 is a circuit diagram of a reference circuit illustrated based on one embodiment of the present invention. FIG. 7 is a circuit diagram of a first-phase voltage detection circuit illustrated based on one embodiment of the present invention. The reference circuit 1211 includes reference resistors R1R, R2R, and a reference diode D1R. The first terminal of the reference resistor R1R receives the set voltage value VCC. The second terminal of the reference resistor R1R is used to output the reference value VRN. The first terminal of the reference resistor R2R is coupled to the second terminal of the reference resistor R1R. The anode of the reference diode D1R is coupled to the second terminal of the reference resistor R2R. The cathode of the reference diode D1R is coupled to the reference low voltage value VSS. In this embodiment, the reference circuit 1211 generates the reference value VRN based on the resistance value of the reference resistor R1R, the resistance value of the reference resistor R2R, and the forward bias value VD1R of the reference diode D1R. The reference value VRN is shown in Equation (1).

[0048]

Number

[0049] "RR1R" represents the resistance value of the reference resistor R1R. "RR2R" represents the resistance value of the reference resistor R2R.

[0050] In this embodiment, the first-phase voltage detection circuit 1212_U includes detection resistors R1U and R2U, and a detection diode D1U. The first terminal of the detection resistor R1U receives the set voltage value VCC. The second terminal of the detection resistor R1U is used to output the detection value VUN. The first terminal of the detection resistor R2U is coupled to the second terminal of the detection resistor R1U. The anode of the detection diode D1U is coupled to the second terminal of the detection resistor R2U. The cathode of the detection diode D1U receives the first-phase voltage value VU. When the voltage difference value obtained by subtracting the first-phase voltage value VU from the set voltage value VCC is greater than the forward bias value VD1U of the detection diode D1U, the detection diode D1U is in a conducting state. Therefore, the first-phase voltage detection circuit 1212_U generates the detection value VUN based on the resistance value of the detection resistor R1U, the resistance value of the detection resistor R2U, and the forward bias value VD1U of the detection diode D1U.

[0051] For example, when the voltage difference value obtained by subtracting the first-phase voltage value VU from the set voltage value VCC is greater than the forward bias value VD1U of the detection diode D1U, the detection diode D1U is in a conducting state. Therefore, the detection value VUN is represented by Equation (2).

[0052]

Equation

[0053] "RR1U" represents the resistance value of the reference resistor R1U. "RR1U" represents the resistance value of the reference resistor R1U.

[0054] In this embodiment, the comparison circuit 1213 generates a first comparison result based on the detected value VUN and the reference value VRN. The comparison circuit 1213 subtracts the reference value VRN from the detected value VUN to generate a voltage difference value. For example, the reference low voltage value VSS is 0 volts. The resistance value of the detection resistor R1U is equal to the resistance value of the reference resistor R1R. The resistance value of the detection resistor R2U is equal to the resistance value of the reference resistor R2U. The forward bias value VD1R of the reference diode D1R is equal to the forward bias value VD1U of the detection diode D1U. Therefore, the difference value is represented by Equation (3).

[0055] [Number]

[0056] In the charging mode, when the difference value is less than "0", it indicates that the detected value VUN is smaller than the reference value VRN. The comparison circuit 1213 determines that the first-phase voltage value VU is smaller than the reference low voltage value VSS (i.e., 0 volts). The comparison circuit 1213 generates a first comparison result corresponding to the first-phase voltage value VU being a negative voltage value, and provides a notification signal SN including the first comparison result. Therefore, in the charging mode, the transistor M2 is turned on. On the other hand, when the difference value is greater than "0", the transistor M2 is not turned on.

[0057] In this embodiment, the reference circuit 1211 further includes reference resistors R3R, R4R, and a reference diode D2R. The anode of the reference diode D2R receives the battery voltage value VP. The first terminal of the reference diode D3R is coupled to the cathode of the reference diode D2R. The second terminal of the reference resistor R3R is used to output the reference value VRP. The reference resistor R4R is coupled between the second terminal of the reference resistor R3R and the reference low voltage value VSS. The reference circuit 1211 generates the reference value VRP based on the resistance value of the reference resistor R3R, the resistance value of the reference resistor R4R, and the forward bias value VD2R of the reference diode D2R. For example, the reference low voltage value VSS is 0 volts. The reference value VRP is represented by Equation (4).

[0058]

Number

[0059] 「RR3R」 represents the resistance value of the reference resistor R3R. 「RR4R」 represents the resistance value of the reference resistor R4R.

[0060] In this embodiment, the first-phase voltage detection circuit 1212_U further includes detection resistors R3U, R4U, and a detection diode D2U. The anode of the detection diode D2U receives the first-phase voltage value VU. The first terminal of the detection resistor R3U is coupled to the cathode of the detection diode D2U. The second terminal of the detection resistor R3U is used to output a detection value VUP. The detection resistor R4U is coupled between the second terminal of the detection resistor R3U and the reference low voltage value VSS. When the voltage difference value obtained by subtracting the voltage value at the anode of the detection diode D2U from the first-phase voltage value VU is greater than the forward bias value VD2U of the detection diode D1U, the detection diode D2U is in a conducting state. Therefore, the first-phase voltage detection circuit 1212_U generates a detection value VUP based on the resistance value of the detection resistor R3U, the resistance value of the detection resistor R4U, and the forward bias value VD2U of the detection diode D2U.

[0061] For example, the reference low voltage value VSS is 0 volts. When the voltage difference value obtained by subtracting the reference low voltage value VSS from the first-phase voltage value VU is greater than the forward bias value VD2U of the detection diode D1U, the detection diode D2U is in a conducting state. Therefore, the detection value VUP is represented by Equation (5).

[0062]

Number

[0063] 「RR3U」 represents the resistance value of the detection resistor R3U. 「RR4U」 represents the resistance value of the detection resistor R4U.

[0064] In this embodiment, the comparison circuit 1213 generates a second comparison result based on the detected value VUP and the reference value VRP. The comparison circuit 1213 generates a difference value by subtracting the reference value VRP from the detected value VUP. The resistance value of the detection resistor R3U is equal to the resistance value of the reference resistor R3R. The resistance value of the detection resistor R4U is equal to the resistance value of the reference resistor R4R. The forward bias value VD2R of the reference diode D2R is equal to the forward bias value VD2U of the detection diode D2U. Therefore, the difference value is represented by Equation (6).

[0065] [Number]

[0066] In the charging mode, when the difference value is greater than "0", it indicates that the detected value VUP is smaller than the reference value VRP. The comparison circuit 1213 determines that the first-phase voltage value VU is greater than the battery voltage value VP. The comparison circuit 1213 generates a second comparison result corresponding to the fact that the first-phase voltage value VU is greater than the battery voltage value VP, and provides a notification signal SN including the second comparison result. Therefore, in the charging mode, the transistor M1 is turned on. On the other hand, when the difference value is less than "0", the transistor M1 is not turned on.

[0067] In this embodiment, the reference resistors R1R to R4R and the detection resistors R1U to R4U may be physical resistors or equivalent resistors formed by transistors, respectively.

[0068] FIG. 8 is a circuit diagram of a second-phase voltage detection circuit illustrated based on one embodiment of the present invention. In the present embodiment, the second-phase voltage detection circuit 1212_V includes detection resistors R1V and R2V, and a detection diode D1V. The first terminal of the detection diode D1V receives a set voltage value VCC. The second terminal of the detection resistor R1V is used to output a detected value VVN. The first terminal of the detection resistor R2V is coupled to the second terminal of the detection resistor R1V. The anode of the detection diode D1V is coupled to the second terminal of the detection resistor R2V. The cathode of the detection diode D1V receives a second-phase voltage value VV.

[0069] The second-phase voltage detection circuit 1212_V further includes detection resistors R3V and R4V, and a detection diode D2V. The anode of the detection diode D2V receives a second-phase voltage value VV. The first terminal of the detection resistor R3V is coupled to the cathode of the detection diode D2V. The second terminal of the detection resistor R3V is used to output a detected value VVP. The detection resistor R4V is coupled between the second terminal of the detection resistor R3V and a reference low voltage value VSS.

[0070] The operation of the second-phase voltage detection circuit 1212_V is similar to the operation of the first-phase voltage detection circuit 1212_U shown in FIG. 7, and thus will not be described repeatedly here.

[0071] In the present embodiment, the detection resistors R1V to R4V may each be a physical resistor or an equivalent resistor formed of a transistor.

[0072] FIG. 9 is a circuit diagram of a third-phase voltage detection circuit illustrated based on one embodiment of the present invention. In this embodiment, the third-phase voltage detection circuit 1212_W includes detection resistors R1W, R2W, and a detection diode D1W. The first terminal of the detection resistor R1W receives a set voltage value VCC. The second terminal of the detection resistor R1W is used to output a detected value VWN. The first terminal of the detection resistor R2W is coupled to the second terminal of the detection resistor R1W. The anode of the detection diode D1W is coupled to the second terminal of the detection resistor R2W. The cathode of the detection diode D1W receives a third-phase voltage value VW.

[0073] The third-phase voltage detection circuit 1212_W further includes detection resistors R3W, R4W, and a detection diode D2W. The anode of the detection diode D2W receives a third-phase voltage value VW. The first terminal of the detection resistor R3W is coupled to the cathode of the detection diode D2W. The second terminal of the detection resistor R3W is used to output a detected value VWP. The detection resistor R4W is coupled between the second terminal of the detection resistor R3W and a reference low voltage value VSS.

[0074] The operation of the third-phase voltage detection circuit 1212_W is similar to the operation of the first-phase voltage detection circuit 1212_U shown in FIG. 7, and thus will not be repeated here.

[0075] The detection resistors R1W to R4W may each be a physical resistor or an equivalent resistor formed by a transistor.

[0076] Summarizing the above, the motor drive device includes a battery module and a conversion circuit. The conversion circuit includes a determination circuit, a controller, and a plurality of switch circuits. Among the plurality of switch circuits, the first-phase upper-arm switch circuit includes a power switch and a transistor. In the charging mode, when the first-phase voltage value is greater than the battery voltage value, the transistor is turned on. When the transistor is turned on, the voltage difference value between the first terminal and the second terminal of the transistor is clearly lower than the forward bias value of the diode in the power switch. In this way, in the charging mode, the voltage drop loss of the conversion circuit can be reduced, and the charging efficiency of the battery module can be improved.

[0077] Although the present invention has been disclosed as above in the embodiments, it is not used to limit the present application. It is obvious that those skilled in the art can make some modifications and changes without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the appended patent claims.

Industrial Applicability

[0078] The present invention provides a motor drive device used to drive a motor. The motor drive device includes a battery module and a conversion circuit. In the charging mode, the voltage drop loss of the conversion circuit can be reduced, and the charging efficiency of the battery module can be improved.

Explanation of Reference Numerals

[0079] 10, 100: Motor drive device 11, 110: Battery module 12, 120: Conversion circuit 121: Determination circuit 1211: Reference circuit 1212_U: First-phase voltage detection circuit 1212_V: Second-phase voltage detection circuit 1212_W: Third-phase voltage detection circuit 1213: Comparison circuit 122: Controller D1~D6: Diode D1R, D2R: Reference Diode D1U, D2U, D1V, D2V, D1W, D2W: Detection Diode IU: Phase 1 Current IV: Phase 2 Current IW: Phase 3 Current M1~M6: Transistor MTR: Motor NDU: Phase 1 Node NDV: Phase 2 Node NDW: Phase 3 Node PB: Battery Power PM: Motor Power R1R, R2R, R3R, R4R: Reference Resistor R1U, R2U, R3U, R4U, R1V, R2V, R3V, R4V, R1W, R2W, R3W, R4W: Detection Resistor SM1~SM6, ST1~ST6: Control Signal SN: Notification Signal SW1~SW6: Switch Circuit T1~T6: Power Switch TL1: First Conduction Time Length TL2: Second Conduction Time Length TN: Negative Power Supply Terminal TP: Positive Power Supply Terminal tp1~tp5: Time Point VCC: Set Voltage Value VD1R, VD2R, VD1U, VD2U, VD1V, VD2V, VD1W, VD2W: Forward Bias Value VP: Battery Voltage Value VSS: Reference Low Voltage Value VRN, VRP: Reference Value VU: Phase 1 Voltage Value VUN, VUP, VVN, VVP, VWN, VWP: Detection Value VV: Phase 2 Voltage Value VW: Phase 3 Voltage Value

Claims

1. A motor drive device used to drive a motor, a battery module configured to store battery power, a conversion circuit coupled to the motor and the battery module, configured to drive the motor using the battery power in a drive mode and charge the battery module using the motor power generated by the motor in a charging mode and including, wherein the conversion circuit includes a determination circuit and a controller coupled to the determination circuit, a first power switch, and a first transistor and including, wherein a first terminal of the first power switch is coupled to a positive power terminal of the battery module, a second terminal of the first power switch is coupled to a first-phase node, and a control terminal of the first power switch is coupled to the controller, a first terminal of the first transistor is coupled to the positive power terminal, a second terminal of the first transistor is coupled to the first-phase node, and a control terminal of the first transistor is coupled to the controller, and a first-phase upper-arm switch circuit and including, wherein in the charging mode, the controller shuts off the first power switch and the first transistor, the determination circuit determines a first-phase voltage value at the first-phase node, and when the first-phase voltage value is greater than a battery voltage value at the positive power terminal, the determination circuit notifies the controller to turn on the first transistor. A motor drive device.

2. The conversion circuit further includes a second power switch, and a second transistor and including, wherein a first terminal of the second power switch is coupled to the first-phase node, a second terminal of the second power switch is coupled to a negative power terminal of the battery module, and a control terminal of the second power switch is coupled to the controller, a first terminal of the second transistor is coupled to the first-phase node, a second terminal of the second transistor is coupled to the negative power terminal, and a control terminal of the second transistor is coupled to the controller, and a first-phase lower-arm switch circuit and further including, The motor drive device according to claim 1.

3. In the charging mode, the controller shuts off the second power switch and the second transistor, and when the first-phase voltage value is less than a reference low voltage value, the determination circuit notifies the controller to turn on the second transistor. The motor drive device according to claim 2.

4. In the charging mode, the determination circuit determines a first-phase current flowing through the first-phase node, when the first-phase current is flowing through the diode of the first power switch to the positive power supply terminal, the determination circuit notifies the controller to turn on the first transistor, The motor drive device according to claim 3.

5. In the charging mode, when the first-phase current is flowing through the diode of the second power switch to the first-phase node, the determination circuit notifies the controller to turn on the second transistor, The motor drive device according to claim 4.

6. In the charging mode, when the first transistor is turned on, the determination circuit determines a first-phase current flowing through the first-phase node, when the first-phase current is flowing from the positive power supply terminal to the first-phase node, the determination circuit notifies the controller to turn off the first transistor, The motor drive device according to claim 3.

7. In the charging mode, when the second transistor is turned on, the determination circuit determines the first-phase current, when the first-phase current is flowing from the first-phase node to the negative power supply terminal, the determination circuit notifies the controller to turn off the second transistor, The motor drive device according to claim 6.

8. In the charging mode, when the first transistor is turned on, the determination circuit determines the first-phase voltage value, when the first-phase voltage value is equal to the battery voltage value, the determination circuit notifies the controller to turn off the first transistor based on a first conduction time length, and determines the first-phase voltage value in a situation where the first transistor is turned off, The motor drive device according to claim 3.

9. In the charging mode, when the second transistor is turned on, the determination circuit determines the first-phase voltage value, when the first-phase voltage value is equal to the reference low voltage value, the determination circuit notifies the controller to turn off the second transistor based on a second conduction time length, and determines the first-phase voltage value in a situation where the second transistor is turned off, The motor drive device according to claim 3.

10. The determination circuit Coupled to the first-phase node, configured to generate a first detection value based on the first-phase voltage value and a reference low voltage value, and generate a second detection value based on the first-phase voltage value and a set voltage value, a first-phase voltage detection circuit; Coupled to the positive power supply terminal, configured to convert the set voltage value into a first reference value and convert the battery voltage value into a second reference value, a reference circuit; Coupled to the first-phase voltage detection circuit and the reference circuit; When the first-phase voltage value is a negative voltage value, notify the controller based on a first comparison result between the first detection value and the first reference value; When the first-phase voltage value is a positive voltage value, notify the controller based on a second comparison result between the second detection value and the second reference value configured as; a comparison circuit further comprising; The motor drive device according to claim 1.

11. The first-phase voltage detection circuit includes: a first detection resistor; a second detection resistor; a first detection diode and includes; A first terminal of the first detection resistor receives the set voltage value, and a second terminal of the first detection resistor is used to output the first detection value; A first terminal of the second detection resistor is coupled to the second terminal of the first detection resistor; An anode of the first detection diode is coupled to a second terminal of the second detection resistor, and a cathode of the first detection diode receives the first-phase voltage value. The motor drive device according to claim 10.

12. The reference circuit includes: a first reference resistor; a second reference resistor; a first reference diode and includes; A first terminal of the first reference resistor receives the set voltage value, and a second terminal of the first reference resistor is used to output the first reference value; A first terminal of the second reference resistor is coupled to the second terminal of the first reference resistor; An anode of the first reference diode is coupled to a second terminal of the second reference resistor, and a cathode of the first reference diode is coupled to the reference low voltage value. The motor drive device according to claim 11.

13. The forward bias value of the first reference diode is equal to the forward bias value of the first detection diode. The motor drive device according to claim 12.

14. The first-phase voltage detection circuit further includes: a second detection diode; a third detection resistor; a fourth detection resistor and further includes; An anode of the second detection diode receives the first-phase voltage value. The first terminal of the third detection resistor is coupled to the cathode of the second detection diode, and the second terminal of the third detection resistor is used to output the second detection value. The fourth detection resistor is coupled between the second terminal of the third detection resistor and the reference low voltage value. The motor drive device according to claim 12.

15. The reference circuit further includes a second reference diode, a third reference resistor, and a fourth reference resistor . The anode of the second reference diode receives the battery voltage value. The first terminal of the third reference resistor is coupled to the cathode of the second reference diode, and the second terminal of the third reference resistor is used to output the second reference value. The fourth reference resistor is coupled between the second terminal of the third reference resistor and the reference low voltage value. The motor drive device according to claim 14.

16. The battery module is implemented by an aluminum ion battery. The motor drive device according to claim 1.

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