Power generation system and method for motorcycle

Abstract

To provide a power generation system and method for motorcycle.SOLUTION: Provided is a power generation system for motorcycle including: a generator coupled to an engine and driven by the engine to generate three-phase power; a full-bridge rectifier circuit coupled to the generator to receive the three-phase power and generate a direct-current voltage signal according to the three-phase power and a switching signal output; a switching regulator circuit coupled to the full-bridge rectifier circuit to receive the direct-current voltage signal and buck the direct-current voltage signal according to a control signal so as to generate an output voltage to power a storage battery; and a controller coupled to the full-bridge rectifier circuit and the switching regulator circuit to generate the control signal and the switching signal output and output the control signal and the switching signal output respectively to the switching regulator circuit and the full-bridge rectifier circuit, the controller adjusting the switching signal output based on at least a voltage value of the direct-current voltage signal and a preset voltage value. In addition, there is provided a power generation method for motorcycle.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a power generation system and method, and more particularly to a power generation system and method for a motorcycle. [Background technology]

[0002] 1, the voltage regulation method in the existing motorcycle power generation system 1 is a short-circuit type voltage regulation method, and the power generation system 1 includes a rectifier circuit 11, a generator 12, a regulator controller 15, and three switches 16, 17, and 18 (predetermined to be in a non-conducting state). When the onboard engine 10 drives the generator 12, the three-phase power generated by the generator 12 is regulated to a DC output voltage by the rectifier circuit 11, and then supplied directly to the storage battery 13 and the vehicle load 14 for use.

[0003] As the rotation speed of the engine 10 increases, the voltage of the three-phase power generated by the generator 12 also increases, and accordingly, the DC output voltage generated by the rectifier circuit 11 increases. When the regulator controller 15 detects that the DC output voltage is higher than the voltage used by the storage battery 13 or the vehicle load 14, the regulator controller 15 controls at least one of the switches 16 to 18 to be conductive, thereby short-circuiting the coil of the generator 12 and preventing the DC output voltage from increasing (i.e., putting the power generation system 1 into a short-circuit type voltage regulation mode).

[0004] This controls the DC output voltage to a voltage that is appropriately used by the storage battery 13 and the vehicle load 14, thereby protecting the storage battery 13 or the vehicle load 14 from damage.

[0005] However, since the amount of electricity generated by the generator 12 is proportional to the rotational speed of the engine 10, the faster the rotational speed of the engine 10, the greater the amount of electricity generated by the generator 12. However, if the rotational speed of the engine 10 remains high for a long period of time and the amount of electricity generated by the generator 12 is large because the on-board electrical load has not increased, the power generation system 1 will be in short-circuit voltage regulation mode for a long period of time, and a large amount of excess energy will be dissipated in the form of heat energy, which may wear out the engine 10 or other elements of the motorcycle.

[0006] Furthermore, the rectifier circuit 11, regulator controller 15, and three switches 16 and 17 can be replaced with a three-phase bridge rectifier circuit (not shown, connected between the generator 12 and the storage battery 13). Existing generators 12 are often operated at a rotational speed of 9000 RPM (maximum rotational speed) and 1500 RPM (idling rotational speed). For a 12V motorcycle, when the idling rotational speed is 1500 RPM, in order to meet the voltage required to start charging, the voltage of the three-phase power generated when the generator 12 reaches a rotational speed of 1500 RPM must be at least 17V.

[0007] Furthermore, since the voltage of the three-phase power of the generator 12 is proportional to the rotational speed of the generator, when the rotational speed is operated at a maximum speed of 9000 RPM, the voltage of the three-phase power generated by the generator 12 can exceed 100 V. Therefore, it is necessary to use high-voltage (e.g., 150 V) resistant electrical elements for the transistors / electrical elements in the three-phase bridge rectifier circuit, which increases the manufacturing cost of the power generation system 1.

[0008] Therefore, the main point of the present invention is how to solve the above problems of the existing technology. Summary of the Invention [Problem to be solved by the invention]

[0009] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a power generation system for a motorcycle that can overcome the disadvantages of the prior art. [Means for solving the problem]

[0010] Thus, the power generating system for a motorcycle of the present invention is coupled between the engine and the storage battery, and includes a generator, a bridge rectifier circuit, a switching regulator circuit, and a controller.

[0011] The generator is coupled to the engine and driven by the engine to generate three-phase power, the bridge rectifier circuit is coupled to the generator to receive the three-phase power and generates a DC voltage signal based on the three-phase power and an output of a switching signal, and the switching regulator circuit is coupled to the bridge rectifier circuit to receive the DC voltage signal and step down the DC voltage signal based on a control signal to generate an output voltage to supply electricity to the storage battery.

[0012] The controller is coupled to the bridge rectifier circuit and the switching regulator circuit to generate the control signal and the switching signal, respectively, and adjusts the switching signal output based on at least the voltage value of the DC voltage signal and the predetermined voltage value.

[0013] In some embodiments, in the motorcycle power generating system of the present invention, when the generator is at idling speed, the peak voltage of the three-phase power is between 10 and 15V.

[0014] In some embodiments, in the power generating system for a motorcycle of the present invention, when the generator is at maximum rotation speed, the peak voltage of the three-phase power is between 80 and 100V.

[0015] In some embodiments, in the power generation system for a motorcycle of the present invention, the switching regulator circuit includes: an output capacitor coupled to the battery and having a first end providing the output voltage and a second end connected to GND; an inductor having a first end and a second end coupled to the first end of the output capacitor; a diode having a cathode coupled to the second end of the inductor and an anode connected to GND; and a switch coupled between the cathode of the diode and the bridge rectifier circuit.

[0016] In some embodiments, in the power generating system for a motorcycle of the present invention, the output of the switching signals includes a first switching signal, a second switching signal, a third switching signal, a fourth switching signal, a fifth switching signal, and a sixth switching signal.

[0017] The controller is further coupled to the generator to obtain the back EMF signal of the generator. The controller determines whether the voltage value of the DC voltage signal is less than or equal to the predetermined voltage value. If the determination result is "yes," the controller adjusts the start position of the high logic level in each switching period T of the first to sixth switching signals to be one predetermined electrical angle later than the zero position of the back EMF signal.

[0018] In some embodiments, in the power generating system for a motorcycle of the present invention, when the controller determines whether the voltage value of the DC voltage signal is less than or equal to the predetermined voltage value, if the result of the determination is "No", the controller adjusts or maintains the high logic level start position of each of the first to sixth switching signals in the switching period T to be the same as the zero position of the back EMF signal.

[0019] In some embodiments, in the power generating system for a motorcycle of the present invention, the bridge rectifier circuit is a three-phase bridge rectifier circuit including six transistors.

[0020] Another object of the present invention is to provide a method for generating electricity for motorcycles that can overcome the disadvantages of the prior art.

[0021] The power generation method for motorcycles of the present invention is performed by a power generation system for motorcycles and includes the following steps: (A) generating three-phase power driven by the engine; (B) generating a DC voltage signal from the three-phase power and outputting a switching signal; (C) generating an output voltage by stepping down the DC voltage signal based on a control signal to provide electricity to a storage battery; (D) determining whether the voltage value of the DC voltage signal is smaller than or equal to a predetermined voltage value; (E) when the determination result in step (D) is "yes," adjusting the start position of the high logic level of the output of the switching signal so that it is one predetermined electrical angle later than the zero position of the generator's back EMF signal; and (F) repeating steps (D) and (E) until the voltage value of the DC voltage signal becomes greater than the predetermined voltage value.

[0022] In some embodiments, in the power generating method for a motorcycle of the present invention, when the result of the determination in step (D) is "No", the controller adjusts or maintains the start position of the high logic level of the output of the switching signal to be the same as the zero position of the back EMF signal.

[0023] In some embodiments, in the method for generating electricity for a motorcycle of the present invention, when the generator is at idle speed, the peak voltage of the three-phase power is between 10 and 15 V. When the generator is at maximum speed, the peak voltage of the three-phase power is between 80 and 100 V. [Effects of the Invention]

[0024] The effects of the present invention are that by using the motorcycle power generation system and power generation method of the present invention, it is not necessary to convert large amounts of excess energy into thermal energy and dissipate it using a short-circuit voltage regulation system, thereby preventing wear on the engine or other elements of the motorcycle; by controlling the magnitude of the peak voltage, it is not necessary to use electrical elements with high voltage specifications in the power generation system, thereby reducing manufacturing costs; and by using the controller to delay the phase of the switching signal output and increase the voltage value of the DC voltage signal, it is possible to prevent situations from occurring in which the switching regulator circuit is unable to supply electricity to the storage battery or the vehicle load, thereby increasing the utilization efficiency of the power generation system. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a block diagram illustrating an existing power generation system for a motorcycle. [Figure 2] 1 is a block diagram illustrating an embodiment of a power generation system for a motorcycle according to the present invention; [Figure 3] 4 is a flowchart illustrating how to implement the power generation method for a motorcycle in the embodiment. [Figure 4] FIG. 10 is a schematic diagram illustrating how the start position of the high logic level of the output of the switching signal is adjusted to be one predetermined electrical angle later than the zero position of the back EMF signal in this embodiment. [Figure 5] FIG. 10 is a schematic diagram illustrating how the start position of the high logic level of the output of the switching signal is adjusted to be one predetermined electrical angle later than the zero position of the back EMF signal in this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] 2 illustrates an embodiment of a power generating system 2 for a motorcycle of the present invention. The power generating system 2 is coupled between an engine 20 and a battery 21, and includes a generator 22, a bridge rectifier circuit 23, a switching regulator circuit 24, and a controller 25. The power generating system 2 may be used for a motorcycle in a hybrid integrated starter generator (ISG) system.

[0027] The generator 22 is coupled to the engine 20 and is driven by the engine 20 to generate three-phase power. The generator 22 may be an ISG that, when starting the motorcycle, starts the engine 20 as an electric motor, and after the engine 20 has started, generates the three-phase power by driving the engine 20, and then enters a charging mode to supply electricity to the storage battery 21 or a vehicle load (not shown).

[0028] The peak voltage of the three-phase power of the generator 22 has a positive correlation with the rotational speed of the generator 22, so when the generator 22 reaches an idling rotational speed (i.e., a rotational speed of 1500 to 1800 RPM), the peak voltage of the three-phase power is controlled to be between 10 to 15 V. When the generator 22 reaches its maximum rotational speed (i.e., a rotational speed of 8000 to 10000 RPM), the peak voltage of the three-phase power is controlled to be between 80 to 100 V.

[0029] This prevents the peak voltage of the three-phase power from exceeding 100V when the generator 22 reaches its maximum rotation speed, and furthermore, it eliminates the need to use high-voltage resistant electrical elements for the transistors / electrical elements in the power generation system 2, which has the effect of reducing the manufacturing costs required to manufacture the power generation system 2.

[0030] The bridge rectifier circuit 23 is coupled to the generator 22 to receive the three-phase power and generates a DC voltage signal according to the three-phase power and outputs switching signals. In this embodiment, the output switching signals include a first switching signal S1, a second switching signal S2, a third switching signal S3, a fourth switching signal S4, a fifth switching signal S5, and a sixth switching signal S6. The bridge rectifier circuit 23 is a three-phase bridge rectifier circuit and includes a first transistor 231, a second transistor 232, a third transistor 233, a fourth transistor 234, a fifth transistor 235, and a sixth transistor 236.

[0031] The first transistor 231 has a first end coupled to the switching regulator circuit 24, a second end coupled to the U-phase coil 22u of the generator 22, and a control end S1 receiving the first switching signal. The first transistor 231 is turned on or off under the control of the first switching signal S1. The second transistor 232 has a first end coupled to the W-phase coil 22w of the generator 22, a second end connected to GND, and a control end receiving the second switching signal S2.

[0032] The second transistor 232 is turned on or off under the control of the second switching signal S2. The third transistor 233 has a first end coupled to the first end of the first transistor 231, a second end coupled to the V-phase coil 22V of the generator 22, and a control end receiving the third switching signal S3. The third transistor 233 is turned on or off under the control of the third switching signal S3.

[0033] The fourth transistor 234 has a first end coupled to the second end of the first transistor 231, a second end connected to GND, and a control end receiving the fourth switching signal S4, and is controlled by the fourth switching signal S4 to be turned on or off.

[0034] The fifth transistor 235 has a first end coupled to the first end of the third transistor 233, a second end coupled to the W-phase coil 22w of the generator 22, and a control end receiving the fifth switching signal S5. The fifth transistor 235 is turned on or off under the control of the fifth switching signal S5. The sixth transistor 236 has a first end coupled to the V-phase coil 22v of the generator 22, a second end connected to GND, and a control end receiving the sixth switching signal S6. The sixth transistor 236 is turned on or off under the control of the sixth switching signal S6.

[0035] The switching regulator circuit 24 is coupled to the bridge rectifier circuit 23 to receive the DC voltage signal, and generates an output voltage by stepping down the DC voltage signal based on a control signal C1 to supply electricity to the storage battery 21 or the vehicle load. In this embodiment, the switching regulator circuit 24 includes an output capacitor 241, an inductor 242, a diode 243, and a switch 244.

[0036] The output capacitor 241 has a first end coupled to the storage battery 21 and providing the output voltage, and a second end connected to GND. The inductor 242 has a first end coupled to the first end of the output capacitor 241, and a second end connected to GND. The diode 243 has a cathode coupled to the second end of the inductor 242 and an anode connected to GND. The switch 244 is coupled between the cathode of the diode 243 and the first end of the first transistor 231.

[0037] In another embodiment, the diode 243 may be replaced by a switch (not shown), and when this switch is turned on (off), the switch 244 is turned off (on).

[0038] This reduces conduction loss and improves efficiency. In addition, by replacing the diode 243 with the switch, the switching regulator circuit 24 is configured as a boost circuit, so that the storage battery 21, such as a 12V battery, can perform the function of inverting boost and provide work to the generator 22.

[0039] The switch 244, and the switches in other embodiments, may be semiconductor switches such as a metal-oxide-semiconductor field-effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a gallium nitride (GaN), or a silicon carbide (SiC).

[0040] The controller 25 is coupled to the bridge rectifier circuit 23 and the switching regulator circuit 24 to generate the control signal C1 and the switching signal outputs (i.e., the first to sixth switching signals S1 to S6) and outputs them to the switching regulator circuit 24 and the bridge rectifier circuit 23, respectively. The controller 25 is further coupled to the generator 22 to obtain the back EMF signal Bs (see FIG. 4) of the generator 22.

[0041] The controller 25 adjusts the output of the switching signal based on at least the voltage value of the DC voltage signal and a predetermined voltage value. The controller 25 is a hybrid ISG controller. The predetermined voltage value is, for example, the minimum voltage value at which the storage battery 21 can be charged even after regulation by the switching regulator circuit 24. The specific operation of the controller 25 will be described below with reference to FIG. 3.

[0042] Furthermore, a flowchart for carrying out the power generation method for a motorcycle according to the present invention in the power generation system 2 for a motorcycle according to the present invention will be described with reference to Figures 3 to 5. The power generation method for a motorcycle according to the present invention includes the following steps 31 to 36.

[0043] In step 31, after the bike is started, the generator 22 is driven by the engine 20 to generate the three-phase power.

[0044] In step 32, the bridge rectifier circuit 23 generates the DC voltage signal according to the three-phase power and the output of the switching signals (i.e., the first to sixth switching signals S1 to S6), where the high logic level start position of each of the first to sixth switching signals S1 to S6 in a switching period T is the same as the zero position of the back EMF signal Bs (see FIG. 4 . Since the first to sixth switching signals S1 to S6 are well known to those skilled in the art, for the sake of simplicity, only the first switching signal S1 is depicted in FIG. 4 as a simple schematic illustration).

[0045] In step 33, the switching regulator circuit 24 generates the output voltage by stepping down the DC voltage signal in accordance with the control signal C1, and supplies electricity to the storage battery 21.

[0046] In step 34, the controller 25 determines whether the voltage value of the DC voltage signal is less than or equal to the predetermined voltage value. If the result of the determination is "yes" (i.e., the voltage of the DC voltage signal is insufficient to allow the switching regulator circuit 24 to perform regulation), proceed to step 35. If the result of the determination is "no," proceed to step 36.

[0047] In step 35, the controller 25 adjusts the start position of the high logic level in the switching period T of each of the switching signal outputs to be delayed by one predetermined electrical angle De (see FIG. 5; since the first to sixth switching signals S1 to S6 are well known to those skilled in the art, for simplicity, only the first switching signal S1 is depicted in FIG. 5 as a simple schematic illustration).

[0048] Subsequently, steps 34 and 35 are repeated until the voltage value of the DC voltage signal becomes higher than the predetermined voltage value. In this way, the present invention continuously increases the voltage value of the DC voltage signal by delaying the output phase of the switching signal from the zero position of the back EMF signal Bs, so that when the generator 22 reaches the idling rotation speed, the peak voltage of the three-phase power is too low, and the voltage value of the DC voltage signal is also too low, preventing the switching regulator circuit 24 from performing regulation and therefore preventing the switching regulator circuit 24 from supplying electricity to the storage battery 21 or the vehicle load, thereby improving the utilization efficiency of the power generation system 2.

[0049] In step 36, the controller 25 adjusts or maintains the starting position of the high logic level in the switching period T of each of the switching signal outputs to be the same as the zero position of the back EMF signal Bs, and then enters step 34 to continue the determination and perform the subsequent corresponding steps until the motorcycle stalls, but this is not limited to this.

[0050] In detail, when step 34 is entered from initial step 33 and the result of the determination is "No", the controller 25 maintains the start position of the high logic level in the switching period T of each of the switching signal outputs to be the same as the zero position of the back EMF signal Bs. When step 34 is entered from initial step 33 and the result of the determination is "Yes", steps 35 and 34 are repeated in order until the voltage value of the DC voltage signal becomes higher than the predetermined voltage value (i.e., until the result of the determination in step 34 changes from "Yes" to "No").

[0051] The controller 25 then adjusts the starting position of the high logic level in the switching period T of each of the switching signal outputs to be the same as the zero position of the back EMF signal Bs.

[0052] In this embodiment, the controller 25 adjusts the start position of the high logic level in the switching period T of each of the output switching signals to be the same as the zero position of the back EMF signal Bs, in a manner that is not limited to the following: The controller 25 sequentially restores the start position of the high logic level in the switching period T of each of the output switching signals to one predetermined restoration angle (i.e., after each restoration of the predetermined restoration angle, it re-enters step 34 and makes a judgment again to perform restoration at the next predetermined restoration angle) until the start position of the high logic level in the switching period T of each of the output switching signals becomes the same as the zero position of the back EMF signal Bs (i.e., as shown in FIG. 4 ).

[0053] The predetermined recovery angle is the same as the predetermined electrical angle De, and the total number of times the controller 25 recovers the start position of the logic high level in the switching period T of each of the outputs of the switching signals at the predetermined recovery angle corresponds to the total delay number of times the controller 25 adjusts the start position of the logic high level in the switching period T of each of the outputs of the switching signals to be later than the zero position of the back EMF signal Bs.

[0054] In another embodiment, the predetermined recovery angle may be the predetermined electrical angle De multiplied by the total number of delays. Thus, the total number of recovery times of the controller 25 is one. If the total number of delays is one, the total number of recovery times corresponds to the total number of delays. If the total number of delays is greater than one, the total number of recovery times is less than the total number of delays.

[0055] In summary, the motorcycle power generation system 2 of the present invention uses the switching regulator circuit 24 to regulate the DC voltage signal, thereby generating the output voltage which is supplied to the storage battery 21 or the vehicle load. As a result, the DC voltage signal is proportional to the rotational speed of the engine 20. Because the DC voltage signal is not directly related to the output voltage generated by the switching regulator circuit 24, the power generation system 2 does not need to short-circuit the coil of the generator 12 as is conventionally known. In other words, the power generation system 2 does not need to operate in a short-circuit voltage regulation state. Therefore, the power generation system 2 does not need to convert the large amount of excess energy generated by the generator 22 into heat energy and dissipate it using a short-circuit voltage regulation method, thereby achieving higher efficiency.

[0056] Furthermore, the heat generation is significantly reduced, which prevents wear on the engine 20 or other components of the motorcycle, thereby extending the useful life of the motorcycle components.

[0057] Furthermore, when the generator 22 reaches the idling rotation speed (or the maximum rotation speed), the peak voltage of the three-phase power is controlled to be between 10 and 15 V (or 80 and 100 V), which prevents the peak voltage of the three-phase power from exceeding 100 V when the generator 22 reaches the maximum rotation speed. This eliminates the need to use high-voltage resistant electrical elements as transistors / electrical elements in the power generation system 2, resulting in reduced manufacturing costs for the power generation system 2.

[0058] In addition, by delaying the output phase of the switching signal by the controller 25, the voltage value of the DC voltage signal can be increased, so that when the generator 22 reaches the idling rotation speed, the voltage value of the DC voltage signal is prevented from being too low to allow the switching regulator circuit 24 to perform regulation. This prevents the switching regulator circuit 24 from being unable to supply electricity to the storage battery or the vehicle load, and improves the usage efficiency of the power generation system 2.

[0059] Although the present invention has been described in the above preferred embodiments, those skilled in the art will understand that these embodiments are merely for illustrating the present invention and should not be construed as limiting the scope of the present invention. It should be noted that any modifications or replacements that have the same effect as the embodiments should be considered to be within the scope of the present invention. Therefore, the scope of protection sought for the present invention is based on that defined by the claims. [Explanation of symbols]

[0060] 1, 2 Power generation system 10 Engine 11 Rectifier circuit 12. Generator 13 Storage battery 14 Vehicle Load 15 Regulator Controller 16~18 Switch 20 Engine 21 Storage battery 22 Generator 22u U-phase coil 22v V phase coil 22w W phase coil 23 Bridge rectifier circuit 24 Switching regulator circuit 25 Controller 31~36 steps 231 First Transistor 232 Second transistor 233 Third Transistor 234 4th transistor 235 5th transistor 236 6th Transistor 241 Output Capacitor 242 Inductor 243 Diode 244 Switch Bs back EMF signal Cl control signal Deprecated electrical angle S1 First switching signal S2 Second switching signal S3 Third switching signal S4 Fourth switching signal S5 Fifth switching signal S6 6th switching signal T switching period

Claims

1. It is connected between the engine and the battery. a generator coupled to the engine and driven by the engine to generate three-phase electrical power; a bridge rectifier circuit coupled to the generator to receive the three-phase power and generate a DC voltage signal according to the three-phase power and an output of a switching signal; a switching regulator circuit coupled to the bridge rectifier circuit, which receives the DC voltage signal and steps down the DC voltage signal based on a control signal to generate an output voltage and supply electricity to the storage battery; a controller coupled to the bridge rectifier circuit and the switching regulator circuit to generate the control signal and the switching signal outputs, and to output the control signal and the switching signal to the switching regulator circuit and the bridge rectifier circuit, respectively; The controller adjusts the output of the switching signal based on at least the voltage value of the DC voltage signal and a predetermined voltage value.

2. 2. The power generating system for a motorcycle according to claim 1, wherein the peak voltage of the three-phase power is between 10 and 15 V when the generator is at an idling rotation speed.

3. 2. The power generating system for a motorcycle according to claim 1, wherein the peak voltage of the three-phase power is between 80 and 100 V when the generator reaches its maximum rotation speed.

4. The switching regulator circuit comprises: an output capacitor coupled to the battery and having a first end providing the output voltage and a second end at GND; an inductor having a first end coupled to the first end of the output capacitor and a second end; a diode having a cathode coupled to the second end of the inductor and an anode at GND; 2. The power generating system for a motorcycle according to claim 1, further comprising: a switch coupled between the cathode of the diode and the bridge rectifier circuit.

5. the switching signal outputs include a first switching signal, a second switching signal, a third switching signal, a fourth switching signal, a fifth switching signal, and a sixth switching signal; the controller is further coupled to the generator to obtain a back EMF signal of the generator; 2. The power generating system for a motorcycle as claimed in claim 1, wherein the controller determines whether the voltage value of the DC voltage signal is less than or equal to the predetermined voltage value, and if the result of the determination is "yes", adjusts the start position of a high logic level in the switching period T of each of the first to sixth switching signals to be one predetermined electrical angle later than the zero position of the back EMF signal.

6. 6. The power generating system for a motorcycle as claimed in claim 5, wherein the controller determines whether the voltage value of the DC voltage signal is less than or equal to the predetermined voltage value, and when the result of the determination is "No", adjusts or maintains the high start position of the logic level in the switching period T of each of the first to sixth switching signals to be the same as the zero position of the back EMF signal.

7. 2. The power generating system for a motorcycle according to claim 1, wherein the bridge rectifier circuit is a three-phase bridge rectifier circuit including six transistors.

8. This is done by a motorcycle power generation system, (A) generating three-phase electrical power driven by an engine; (B) generating a DC voltage signal by outputting the three-phase power and switching signals; (C) generating an output voltage by stepping down the DC voltage signal based on a control signal to provide electricity to a storage battery; (D) determining whether the voltage value of the DC voltage signal is less than or equal to a predetermined voltage value; (E) when the determination result of step (D) is "yes", adjusting the high logic level start position of the output of the switching signal to be one predetermined electrical angle later than the zero position of the back EMF signal of the generator; (F) repeating steps (D) and (E) until the voltage value of the DC voltage signal becomes greater than the predetermined voltage value.

9. 9. The method for generating electricity for a motorcycle according to claim 8, wherein when the result of the determination in step (D) is "No", the start position of the high logic level of the output of the switching signal is adjusted or maintained to be the same as the zero position of the back EMF signal.

10. 9. The method of generating electricity for a motorcycle according to claim 8, wherein the peak voltage of the three-phase power is between 10 and 15 V when the generator is at idling rotation speed, and the peak voltage of the three-phase power is between 80 and 100 V when the generator is at maximum rotation speed.

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