Wide-voltage bidirectional charging and discharging device for electric bicycle

Abstract

The utility model discloses a wide-voltage bidirectional charging and discharging device of an electric bicycle, which comprises a main control unit, a half-bridge driving circuit, a bidirectional half-bridge circuit, a filter circuit, a load switch unit and an input / output port, the output end of the half-bridge drive circuit is connected to the drive end of the bidirectional half-bridge circuit, the high potential end and the low potential end of the bidirectional half-bridge circuit are connected to a battery BAT and the ground respectively, and the input / output end of the bidirectional half-bridge circuit is connected to the first end of the filter circuit. The second end of the filter circuit is connected to the first switch end of the load switch unit, the second switch end of the load switch unit is connected to the input / output port, and the control end of the load switch unit is connected to the main control unit. The circuit structure is simpler, the application cost is lower, and the application requirements are better met.

Description

Technical Field

[0001] The utility model relates to a charging and discharging circuit for an electric bicycle, in particular to a wide-voltage bidirectional charging and discharging device for an electric bicycle. Background Art

[0002] With the advancement of charging technology, many e-bikes now use a Type-C connector as a charging port. This traditional Type-C connector only meets the output requirements of the PD (including QC) protocol and lacks input functionality. Furthermore, traditional bidirectional PD controllers, when used as inputs, are limited to voltages matching the PD protocol and are suitable for chargers using PD or QC protocols. These input voltages are fixed, such as 5V, 9V, 12V, 15V, or 20V. Furthermore, these controllers are not suitable for solar input, generators, or chargers that do not use PD (including QC) protocols. Furthermore, due to the low voltage resistance of mature PD (QC) integrated circuits, traditional e-bike PD (QC) outputs employ a unidirectional, two-stage architecture. A single DC-DC module steps down the 48V to 90V battery voltage to 24V, which is then sampled by the PD (QC) integrated IC for a two-stage conversion process until the voltage reaches the Type-C voltage level for the appliance. This results in a complex circuit architecture and high application costs. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an electric bicycle wide voltage bidirectional charging and discharging device with a simple circuit structure, low application cost and capable of realizing charging boost and discharging buck power conversion, in view of the shortcomings of the existing technology.

[0004] In order to solve the above technical problems, the present utility model adopts the following technical solutions.

[0005] A wide-voltage bidirectional charging and discharging device for an electric bicycle includes a main control unit, a half-bridge drive circuit, a bidirectional half-bridge circuit, a filter circuit, a load switch unit, and an input / output port. The input end of the half-bridge drive circuit is connected to the main control unit, the output end of the half-bridge drive circuit is connected to the drive end of the bidirectional half-bridge circuit, the high potential end and the low potential end of the bidirectional half-bridge circuit are respectively connected to a battery BAT and ground, the input / output end of the bidirectional half-bridge circuit is connected to a first end of the filter circuit, the second end of the filter circuit is connected to a first switch end of the load switch unit, the second switch end of the load switch unit is connected to the input / output port, and the control end of the load switch unit is connected to the main control unit.

[0006] Preferably, a sampling and power supply unit is included, which is used to collect the voltage of the battery BAT and transmit it to the main control unit, and to stabilize the output voltage of the battery BAT or the input voltage of the input / output port to power the main control unit.

[0007] Preferably, the bidirectional half-bridge circuit includes an NMOS transistor Q5 and an NMOS transistor Q6, the drain of the NMOS transistor Q5 is connected to the input / output terminal of the battery BAT, the source of the NMOS transistor Q5 is connected to the drain of the NMOS transistor Q6, the source of the NMOS transistor Q6 is grounded, the gate of the NMOS transistor Q5 and the gate of the NMOS transistor Q6 serve as the high control terminal and the low control terminal of the bidirectional half-bridge circuit respectively, and the drain of the NMOS transistor Q6 serves as the input / output terminal of the bidirectional half-bridge circuit.

[0008] Preferably, the half-bridge drive circuit includes a half-bridge drive chip U2, the input terminal HIN and the input terminal HIN of the half-bridge drive chip U2 are respectively used to receive two PWM drive signals issued by the main control unit, and the high output terminal HO and the low output terminal LO of the half-bridge drive chip U2 are respectively connected to the gate of the NMOS tube Q5 and the gate of the NMOS tube Q6.

[0009] Preferably, the filter circuit is an LC filter circuit including an inductor L1 and a capacitor C2.

[0010] Preferably, the load switch unit includes a PMOS tube Q10, a resistor R38 and a resistor R39, the resistor R38 and the resistor R39 are connected in series between the gate and the drain of the PMOS tube Q10, the connection point of the resistor R38 and the resistor R39 is connected to the main control unit, the source of the PMOS tube Q10 serves as the first switch end of the load switch unit, and the drain of the PMOS tube Q10 serves as the second switch end of the load switch unit and is connected to the input / output port.

[0011] Preferably, the sampling and power supply unit includes a PMOS transistor Q8, an NMOS transistor Q9, an OR gate D4, a voltage regulator U4, and a diode D3. The source of the PMOS transistor Q8 is connected to the input / output terminal of the battery BAT, the drain of the PMOS transistor Q8 is connected to the first input terminal of the OR gate D4, and the drain of the NMOS transistor Q9 is connected to the input / output terminal of the battery BAT via a resistor R30 and a resistor R28 connected in series. The connection point of the resistor R30 and the resistor R28 is connected to the gate of the PMOS transistor Q8. The source of the NMOS transistor Q9 is grounded, the gate of the NMOS transistor Q9 is connected to the input / output port through a resistor R35 and to ground through a resistor R36, the cathode of the diode D3 is connected to the gate of the NMOS transistor Q9, and the anode of the diode D3 is connected to the main control unit through a resistor R33. The voltage of the input / output port is transmitted to the second input end of the OR gate D4, and the output end of the OR gate D4 is connected to the input end of the voltage regulator U4. The output end voltage of the voltage regulator U4 is used to power the main control unit.

[0012] Preferably, the sampling and power supply unit includes a resistor R32 and a resistor R34, which are sequentially connected in series and connected between the input / output end of the battery BAT and the ground, and the voltage at the connection point between the resistor R32 and the resistor R34 is transmitted to the main control unit.

[0013] In the wide-voltage bidirectional charging and discharging device for an electric bicycle disclosed by the present utility model, the main control unit is used to realize the charging and discharging control function. It controls the half-bridge drive circuit through two PWM signals, and then uses the half-bridge drive circuit to drive the bidirectional half-bridge circuit to realize charging boost and discharging buck power conversion. At the same time, the main control unit controls the on-off state of the load switch unit to realize the input and output state control function of the input / output port. Compared with the existing technology, the present utility model adopts a one-stage bidirectional DC-CD conversion circuit, and realizes the charging boost and discharging buck power conversion functions with simple BOOST circuit and BUCK circuit. Compared with the traditional two-stage unidirectional DC-DC topology architecture, the circuit structure of the present utility model is simpler, the application cost is lower, and it better meets the application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a circuit diagram of the wide-voltage bidirectional charging and discharging device for electric bicycles of the utility model;

[0015] Figure 2 It is the schematic diagram of bidirectional half-bridge circuit;

[0016] Figure 3 This is the schematic diagram of the half-bridge drive circuit;

[0017] Figure 4 This is the circuit schematic diagram of the sampling and power supply unit;

[0018] Figure 5 This is the circuit schematic diagram of the main control unit;

[0019] Figure 6 This is a flow chart of the discharge control steps in the bidirectional charge and discharge control method;

[0020] Figure 7 This is a flow chart of the charging control steps in the bidirectional charging and discharging control method. DETAILED DESCRIPTION

[0021] The present invention will be described in more detail below with reference to the accompanying drawings and embodiments.

[0022] The utility model discloses a wide voltage bidirectional charging and discharging device for electric bicycles. Figure 1 It includes a main control unit 1, a half-bridge drive circuit 2, a bidirectional half-bridge circuit 3, a filter circuit 4, a load switch unit 5 and an input / output port 6, wherein the input end of the half-bridge drive circuit 2 is connected to the main control unit 1, the output end of the half-bridge drive circuit 2 is connected to the drive end of the bidirectional half-bridge circuit 3, the high potential end and the low potential end of the bidirectional half-bridge circuit 3 are respectively connected to the battery BAT and the ground, the input / output end of the bidirectional half-bridge circuit 3 is connected to the first end of the filter circuit 4, the second end of the filter circuit 4 is connected to the first switch end of the load switch unit 5, the second switch end of the load switch unit 5 is connected to the input / output port 6, and the control end of the load switch unit 5 is connected to the main control unit 1.

[0023] In the above circuit, the main control unit 1 is used to realize the charge and discharge control function. It controls the half-bridge drive circuit 2 through two PWM signals, and then uses the half-bridge drive circuit 2 to drive the bidirectional half-bridge circuit 3 to realize charging boost and discharging buck power conversion. At the same time, the main control unit 1 controls the on-off state of the load switch unit 5 to realize the input and output state control function of the input / output port 6. Compared with the existing technology, the utility model adopts a one-stage bidirectional DC-CD conversion circuit, and realizes the charging boost and discharging buck power conversion functions with simple BOOST circuit and BUCK circuit. Compared with the traditional two-stage unidirectional DC-DC topology architecture, the circuit structure of the utility model is simpler, the application cost is lower, and it better meets the application requirements.

[0024] On this basis, this embodiment includes a sampling and power supply unit 7, which is used to collect the voltage of the battery BAT and transmit it to the main control unit 1, and stabilize the output voltage of the battery BAT or the input voltage of the input / output port 6 to power the main control unit 1.

[0025] For the preferred circuit structure of the bidirectional half-bridge circuit 3, please refer to Figure 2 The bidirectional half-bridge circuit 3 includes an NMOS transistor Q5 and an NMOS transistor Q6. The drain of the NMOS transistor Q5 is connected to the input / output terminal of the battery BAT, the source of the NMOS transistor Q5 is connected to the drain of the NMOS transistor Q6, the source of the NMOS transistor Q6 is grounded, the gate of the NMOS transistor Q5 and the gate of the NMOS transistor Q6 serve as the high-order control terminal and the low-order control terminal of the bidirectional half-bridge circuit 3 respectively, and the drain of the NMOS transistor Q6 serves as the input / output terminal of the bidirectional half-bridge circuit 3.

[0026] In the above circuit, the bidirectional half-bridge circuit 3 is controlled by three signals, namely: a PDH signal loaded on the gate of the NMOS tube Q5, a PDL signal loaded on the gate of the NMOS tube Q6, and a PDS signal loaded on the connection point between the source of the NMOS tube Q5 and the drain of the NMOS tube Q6. The PDH signal, PDL signal and PDS signal are all output signals of the half-bridge drive circuit 2.

[0027] To output PDH, PDL, and PDS signals, see Figure 3 In this embodiment, the half-bridge drive circuit 2 includes a half-bridge drive chip U2. The input terminal HIN and the input terminal HIN of the half-bridge drive chip U2 are respectively used to receive two PWM drive signals emitted by the main control unit 1. The high-order output terminal HO and the low-order output terminal LO of the half-bridge drive chip U2 are respectively connected to the gate of the NMOS transistor Q5 and the gate of the NMOS transistor Q6.

[0028] In the above circuit, the model of the half-bridge driver chip U2 is preferably EG2132. The main control unit 1 controls the half-bridge driver chip U2 through two PWM drive signals, and then the half-bridge driver chip U2 drives it. The half-bridge driver chip U2 can meet the needs of high-power applications and can provide stable driving capabilities.

[0029] Furthermore, the filter circuit 4 is an LC filter circuit including an inductor L1 and a capacitor C2.

[0030] In this embodiment, the load switch unit 5 is provided at the front end of the input / output port 6. The function of the load switch unit 5 is to control the input and output on / off states of the input / output port 6. Figure 2 In this embodiment, the load switch unit 5 includes a PMOS transistor Q10, a resistor R38, and a resistor R39. The resistors R38 and R39 are connected in series between the gate and drain of the PMOS transistor Q10. The connection point between the resistors R38 and R39 is connected to the main control unit 1. The source of the PMOS transistor Q10 serves as the first switch end of the load switch unit 5. The drain of the PMOS transistor Q10 serves as the second switch end of the load switch unit 5 and is connected to the input / output port 6.

[0031] As a preferred method, see Figure 4 The sampling and power supply unit 7 includes a PMOS transistor Q8, an NMOS transistor Q9, an OR gate D4, a voltage regulator U4 and a diode D3. The source of the PMOS transistor Q8 is connected to the input / output terminal of the battery BAT, the drain of the PMOS transistor Q8 is connected to the first input terminal of the OR gate D4, and the drain of the NMOS transistor Q9 is connected to the input / output terminal of the battery BAT via a resistor R30 and a resistor R28 connected in series. The connection point of the resistor R30 and the resistor R28 is connected to the gate of the PMOS transistor Q8. The source of the MOS transistor Q9 is grounded, the gate of the NMOS transistor Q9 is connected to the input / output port 6 through a resistor R35 and to ground through a resistor R36, the cathode of the diode D3 is connected to the gate of the NMOS transistor Q9, and the anode of the diode D3 is connected to the main control unit 1 through a resistor R33. The voltage of the input / output port 6 is transmitted to the second input end of the OR gate D4, and the output end of the OR gate D4 is connected to the input end of the voltage regulator U4. The output end voltage of the voltage regulator U4 is used to power the main control unit 1.

[0032] In the above circuit, when the external voltage VIN is input, it is transmitted to the second input terminal of the OR gate D4 through the resistor R37. The OR gate D4 is turned on and transmits the input voltage to the input terminal of the voltage regulator U4. The voltage regulator U4 outputs a 5V voltage to power the main control unit 1. After the main control unit 1 is powered on, it outputs a high level through the AUX_LOCK line, so that the resistor R33, the diode D3 and the resistor R36 form a loop to the ground. The NMOS tube Q9 is turned on due to the high gate potential, and at the same time, the gate voltage of the PMOS tube Q8 is pulled down. The PMOS tube Q8 is turned on to power on the first input terminal of the OR gate D4. The OR gate D4 is continuously turned on so that the input terminal of the voltage regulator U4 continuously has voltage input. The voltage regulator U4 ensures the reliable operation of the main control unit 1 by stably outputting a 5V voltage. On this basis, the gate of the NMOS transistor Q9 is also connected to the input / output port 6 through the resistor R35. Therefore, as long as there is voltage input to the input / output port 6, the NMOS transistor Q9 and the PMOS transistor Q8 can be turned on in sequence, thereby ensuring that the voltage regulator U4 has a continuous and stable voltage input.

[0033] In order to realize the voltage acquisition of the battery BAT, in this embodiment, see Figure 4 The sampling and power supply unit 7 includes a resistor R32 and a resistor R34, which are connected in series between the input / output end of the battery BAT and the ground. The voltage at the connection point between the resistor R32 and the resistor R34 is transmitted to the main control unit 1.

[0034] See Figure 5 In this embodiment, the main control unit 1 preferably includes a CH32X035G8U6 controller.

[0035] Based on the above circuit, it can be seen that the utility model adopts a one-stage bidirectional DC-CD conversion to replace the traditional two-stage unidirectional DC-DC topology architecture. In practical applications, no bidirectional protocol IC is required to realize PD (or QC) bidirectional charging and discharging. At the same time, the utility model adopts simple BOOST and BUCK circuits to realize charging boost and discharging buck power conversion, which can be applied to various charging methods such as DC adapter input, solar energy, and generator.

[0036] Based on the above circuit structure, the utility model also discloses a wide voltage bidirectional charging and discharging control method for electric bicycles. The control method is implemented based on the above device and combined with Figures 1 to 7 As shown, the method includes:

[0037] In a discharge control step, when the input / output port 6 detects that an external load is connected, the main control unit 1 collects the voltage of the battery BAT. If the voltage of the battery BAT is not lower than a preset low-voltage alarm threshold, a preset PD (QC) protocol is triggered. The main control unit 1 controls the load switch unit 5 to turn on, and drives the bidirectional half-bridge circuit 3 to operate in a BUCK mode through the half-bridge drive circuit 2, and uses the battery BAT to output voltage to the input / output port 6.

[0038] Charging control step: when the input / output port 6 detects that an external voltage is connected, the main control unit 1 collects the access voltage of the input / output port 6. If the access voltage of the input / output port 6 is not greater than the voltage of the battery BAT, the preset PD (QC) protocol is triggered, and the main control unit 1 controls the load switch unit 5 to turn on and outputs a PWM signal to the half-bridge drive circuit 2. The half-bridge drive circuit 2 drives the bidirectional half-bridge circuit 3 to operate in BOOST mode, thereby charging the battery BAT.

[0039] Furthermore, in the charging control step, if the PD (QC) protocol is missing, the main control unit 1 determines:

[0040] Is the connection voltage of the input / output port 6 less than (the voltage of the battery BAT - 0.5V) established?

[0041] If yes, the main control unit 1 drives and controls the half-bridge drive circuit 2 according to the MPPT mode;

[0042] If not, the main control unit 1 drives and controls the half-bridge driving circuit 2 according to the DC mode.

[0043] In practical applications, when the bidirectional charge and discharge control method is used as a discharger, the main control unit 1 implements the negotiation of the PD protocol and the QC protocol through software control, and outputs the corresponding voltage and current according to the negotiation results; when used as a charger, the following situations are included:

[0044] a. If the charger is a charger with PD or QC protocol, the main control unit 1 first negotiates the PD protocol and QC protocol with the charger, and controls the DC-DC boost half-bridge according to the negotiation result, thereby inputting the corresponding voltage and current;

[0045] b. If the charger is not a charger with PD or QC protocol, the main control unit 1 detects the input voltage and controls the DC-DC boost half-bridge to stabilize the corresponding input voltage within the voltage regulation range and maximize the current;

[0046] c. If the input voltage characteristic is detected to be solar cell power generation input, the DC-DC boost half-bridge is controlled to stabilize the corresponding input voltage within the voltage regulation range, maximize the power, and realize the maximum power tracking MPPT function.

[0047] Based on the above principle, the utility model can be applied to various charging methods such as DC adapter input, solar energy, generator, etc.

[0048] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements or improvements made within the technical scope of the present invention should be included in the scope of protection of the present invention.

Claims

1. A wide voltage bidirectional charging and discharging device for electric bicycles, characterized in that: The invention comprises a main control unit (1), a half-bridge drive circuit (2), a bidirectional half-bridge circuit (3), a filter circuit (4), a load switch unit (5) and an input / output port (6), wherein the input end of the half-bridge drive circuit (2) is connected to the main control unit (1), the output end of the half-bridge drive circuit (2) is connected to the drive end of the bidirectional half-bridge circuit (3), the high potential end and the low potential end of the bidirectional half-bridge circuit (3) are respectively connected to the battery BAT and the ground, the input / output end of the bidirectional half-bridge circuit (3) is connected to the first end of the filter circuit (4), the second end of the filter circuit (4) is connected to the first switch end of the load switch unit (5), the second switch end of the load switch unit (5) is connected to the input / output port (6), and the control end of the load switch unit (5) is connected to the main control unit (1).

2. The wide-voltage bidirectional charging and discharging device for an electric bicycle according to claim 1, characterized in that: The system comprises a sampling and power supply unit (7), wherein the sampling and power supply unit (7) is used to collect the voltage of the battery BAT and transmit it to the main control unit (1), and to stabilize the output voltage of the battery BAT or the input voltage of the input / output port (6) to supply power to the main control unit (1).

3. The wide voltage bidirectional charging and discharging device for an electric bicycle according to claim 1, characterized in that: The bidirectional half-bridge circuit (3) comprises an NMOS transistor Q5 and an NMOS transistor Q6, the drain of the NMOS transistor Q5 being connected to the input / output terminal of the battery BAT, the source of the NMOS transistor Q5 being connected to the drain of the NMOS transistor Q6, the source of the NMOS transistor Q6 being grounded, the gate of the NMOS transistor Q5 and the gate of the NMOS transistor Q6 serving as the high-order control terminal and the low-order control terminal of the bidirectional half-bridge circuit (3) respectively, and the drain of the NMOS transistor Q6 serving as the input / output terminal of the bidirectional half-bridge circuit (3).

4. The wide-voltage bidirectional charging and discharging device for an electric bicycle as claimed in claim 3, characterized in that: The half-bridge drive circuit (2) comprises a half-bridge drive chip U2, wherein the input terminal HIN and the input terminal HIN of the half-bridge drive chip U2 are respectively used to receive two PWM drive signals sent by the main control unit (1), and the high-order output terminal HO and the low-order output terminal LO of the half-bridge drive chip U2 are respectively connected to the gate of the NMOS tube Q5 and the gate of the NMOS tube Q6.

5. The wide-voltage bidirectional charging and discharging device for an electric bicycle as claimed in claim 3, characterized in that: The filter circuit (4) is an LC filter circuit comprising an inductor L1 and a capacitor C2.

6. The wide-voltage bidirectional charging and discharging device for an electric bicycle as claimed in claim 3, characterized in that: The load switch unit (5) includes a PMOS tube Q10, a resistor R38, and a resistor R39. The resistor R38 and the resistor R39 are connected in series between the gate and the drain of the PMOS tube Q10. The connection point of the resistor R38 and the resistor R39 is connected to the main control unit (1). The source of the PMOS tube Q10 serves as the first switch end of the load switch unit (5). The drain of the PMOS tube Q10 serves as the second switch end of the load switch unit (5) and is connected to the input / output port (6).

7. The wide-voltage bidirectional charging and discharging device for an electric bicycle as claimed in claim 2, characterized in that: The sampling and power supply unit (7) includes a PMOS tube Q8, an NMOS tube Q9, an OR gate D4, a voltage regulator U4 and a diode D3, the source of the PMOS tube Q8 is connected to the input / output end of the battery BAT, the drain of the PMOS tube Q8 is connected to the first input end of the OR gate D4, the drain of the NMOS tube Q9 is connected to the input / output end of the battery BAT via a resistor R30 and a resistor R28 connected in series, the connection point of the resistor R30 and the resistor R28 is connected to the gate of the PMOS tube Q8, and the NMOS tube The source of Q9 is grounded, the gate of the NMOS tube Q9 is connected to the input / output port (6) through a resistor R35 and is grounded through a resistor R36, the cathode of the diode D3 is connected to the gate of the NMOS tube Q9, and the anode of the diode D3 is connected to the main control unit (1) through a resistor R33, the voltage of the input / output port (6) is transmitted to the second input end of the OR gate D4, the output end of the OR gate D4 is connected to the input end of the voltage regulator U4, and the output end voltage of the voltage regulator U4 is used to power the main control unit (1).

8. The wide-voltage bidirectional charging and discharging device for an electric bicycle according to claim 7, characterized in that: The sampling and power supply unit (7) comprises a resistor R32 and a resistor R34, wherein the resistor R32 and the resistor R34 are sequentially connected in series and connected between the input / output terminal of the battery BAT and the ground, and the voltage at the connection point between the resistor R32 and the resistor R34 is transmitted to the main control unit (1).

Images