High-reliability electro-tricycle power system

Abstract

The utility model discloses a high-reliability electro-tricycle power system, which relates to the technical field of electro-tricycle power systems and comprises a motor controller and a motor. A rotary transformer and a temperature sensor are arranged in the motor; the motor controller comprises an MCU, a rotary transformer excitation circuit, a rotary transformer receiving circuit and a temperature detection circuit. The MCU comprises a PWM module and an ADC module. The PWM module generates a PWM signal, the PWM signal is converted into a sine wave signal through the rotary transformer excitation circuit, the sine wave signal enters the rotary transformer to induce differential sine and cosine signals, the rotary transformer receiving circuit converts the differential sine and cosine signals into single-end sine and cosine signals, and the MCU obtains the real-time position of a motor rotor and controls the motor; the temperature sensor reads the temperature of the motor winding and sends the temperature to the ADC module through the temperature detection circuit. The temperature of the motor winding can be monitored, and the motor winding or the encoder is prevented from being damaged due to overheating, so that the reliability of a power system is greatly improved, and the failure rate is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric tricycle power systems, and particularly relates to a high-reliability electric tricycle power system. Background Art

[0002] An electric tricycle is a means of transportation that uses electricity as a power source. Its principle is to store electricity through batteries, and then convert the electricity into power through a controller to drive the vehicle. Compared with traditional fuel vehicles, electric tricycles have the advantages of environmental protection, energy saving, and low noise, so they have been widely used in short-distance travel in cities.

[0003] In the power system of existing electric tricycles, due to the use of some position detection units such as magnetic encoders or photoelectric encoders of semiconductor devices that are sensitive to temperature or vibration, the encoder has low reliability, resulting in the inability to control the motor of the electric tricycle well. In addition, during the operation of the motor, the motor temperature cannot be monitored in real time, and the motor cannot be protected in real time, which can easily cause the winding to burn out due to overheating. Utility Model Content

[0004] The purpose of the utility model is to provide a highly reliable electric tricycle power system, thereby overcoming the defect that the encoder has low reliability and cannot control the motor. The specific technical solution is as follows:

[0005] A highly reliable electric tricycle power system comprises a motor controller and a motor; a rotary transformer and a temperature sensor are arranged in the motor;

[0006] The motor controller includes an MCU, a resolver excitation circuit, a resolver receiving circuit and a temperature detection circuit;

[0007] The MCU includes a PWM module and an ADC module;

[0008] The PWM module generates a PWM signal which is converted into a sine wave signal after passing through a resolver excitation circuit. The sine wave signal enters the resolver transformer to induce differential sine and cosine signals, and the sine and cosine signals are sent to a resolver receiving circuit and converted into single-ended sine and cosine signals recognized by an ADC module in the MCU. The MCU obtains the real-time position of the motor rotor and controls the motor.

[0009] The temperature sensor is used to read the temperature of the motor winding and send it to the ADC module through the temperature detection circuit to monitor the motor temperature in real time.

[0010] Preferably, the resolver excitation circuit includes a second-order RC low-pass filter circuit and a single-ended to differential operational amplifier circuit;

[0011] One end of the first resistor of the second-order RC low-pass filter circuit is connected to the PWM module, and the other end is connected to the second resistor and the first capacitor respectively, the other end of the second resistor is connected to the second capacitor, and the first resistor, the first capacitor and the second capacitor are grounded;

[0012] The single-ended to differential operational amplifier circuit comprises a first chip and a second chip, one end of the second resistor R2 is connected to the positive input end of the first amplifier in the first chip, the negative input end of the first amplifier is respectively connected to the third capacitor and the fourth resistor, one end of the third resistor in the first chip is connected to the second capacitor, and the other end is connected to the fourth resistor, and the output end of the first amplifier is connected to the fourth resistor and outputs a REF+ signal;

[0013] The negative input terminal of the second amplifier in the second chip is connected to one end of a fifth resistor and one end of a sixth resistor respectively, the other end of the fifth resistor is connected to the output terminal of the first amplifier, the sixth resistor is connected in parallel with a fourth capacitor, the output terminal of the second amplifier is connected to the fifth capacitor and the sixth resistor, the other end of the fifth capacitor is connected to one end of a seventh resistor and outputs a REF- signal, and the other end of the seventh resistor is connected to one end of the fourth resistor;

[0014] The second amplifier is also connected to a sixth capacitor, and the other end of the sixth capacitor is grounded.

[0015] Preferably, the resolver receiving circuit includes a TVS tube, a common mode inductor, a low-pass filter circuit and a differential to single-ended circuit;

[0016] One end of a group of TVS tubes receives a sine or cosine signal, and the other end is connected to a common-mode inductor. One end of the low-pass filter circuit is connected to the common-mode inductor, and the other end is connected to a differential-to-single-ended circuit and outputs a single-ended signal SIN_A or COS_A and then sends it to the ADC module of the MCU.

[0017] Preferably, the temperature detection circuit includes a signal Mtr_T_IN after the motor thermistor NTC / PTC thermistor is connected in series with a 3K resistor for voltage division, which is sent to the subsequent RC low-pass filter circuit to filter out interference, and is converted into an Mtr_T signal after passing through a clamping diode and sent to the ADC module of the MCU.

[0018] Preferably, the resolver transformer comprises a resolver excitation coil, a sine winding and a cosine winding;

[0019] The resolver excitation coil is used to receive a sine wave signal sent by an excitation circuit. The sine wave signal is sent to a resolver receiving circuit after the sine winding and the cosine winding generate a sine signal and a cosine signal.

[0020] Preferably, the phase difference between the sine signal and the cosine signal is 90°.

[0021] Compared with the existing technology, the utility model has the following beneficial effects:

[0022] The utility model introduces a highly reliable rotary transformer and a thermistor for monitoring the winding temperature into the electric tricycle system, which can improve the reliability of the encoder while monitoring the motor winding temperature to prevent the motor winding or encoder from being damaged due to overheating, thereby greatly improving the reliability of the power system and reducing the failure rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. In all drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0024] Figure 1 It is a system structure diagram of the utility model.

[0025] Figure 2 This is a rotary transformer excitation circuit diagram of the utility model.

[0026] Figure 3 The utility model is a cosine receiving circuit diagram in a rotary transformer receiving circuit.

[0027] Figure 4 The utility model is a sinusoidal receiving circuit diagram in a rotary transformer receiving circuit.

[0028] Figure 5 This is a temperature detection circuit diagram of the utility model.

[0029] Figure 6 This is a working principle diagram of the rotary transformer of the utility model. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "top", "bottom", "top surface", "bottom surface", "inside", "outside", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0032] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If the terms "first", "second", "third" are described, they are only used for the purpose of description and distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0033] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The following is a description of the embodiments of the present invention based on its overall structure.

[0034] Example

[0035] See also Figure 1 The present embodiment discloses a highly reliable electric tricycle power system, including a motor controller and a motor; a rotary transformer and a temperature sensor are arranged in the motor; the motor controller includes an MCU, a rotary transformer excitation circuit, a rotary transformer receiving circuit and a temperature detection circuit; the MCU includes a PWM module and an ADC module; the PWM module generates a PWM signal which is converted into a sine wave signal after passing through the rotary transformer excitation circuit, and the sine wave signal enters the rotary transformer to induce a differential sine and cosine signal, and the sine and cosine signals are sent to the rotary transformer receiving circuit and converted into single-ended sine and cosine signals recognized by the ADC module in the MCU, and the MCU obtains the real-time position of the motor rotor, and then controls the motor; the temperature sensor is used to read the temperature of the motor winding and send it to the ADC module through the temperature detection circuit, so as to monitor the motor temperature in real time.

[0036] like Figure 2 As shown, as a preferred embodiment, the resolver excitation circuit includes a second-order RC low-pass filter circuit and a single-ended to differential operational amplifier circuit;

[0037] One end of the first resistor R1 of the second-order RC low-pass filter circuit is connected to the PWM module, and the other end is connected to the second resistor R2 and the first capacitor C1 respectively, the other end of the second resistor R2 is connected to the second capacitor C2, and the first resistor R1, the first capacitor C1, and the second capacitor C2 are grounded;

[0038] The single-ended to differential operational amplifier circuit includes a first chip and a second chip, one end of the second resistor R2 is connected to the positive input end of the first amplifier AMP1 in the first chip, the negative input end of the first amplifier AMP1 is respectively connected to the third capacitor C3 and the fourth resistor R4, one end of the third resistor R3 in the first chip is connected to the second capacitor C2, and the other end is connected to the fourth resistor R4, the output end of the first amplifier AMP1 is connected to the fourth resistor R4 and outputs a REF+ signal;

[0039] The negative input terminal of the second amplifier AMP2 in the second chip is connected to one end of the fifth resistor R5 and one end of the sixth resistor R6 respectively, the other end of the fifth resistor R5 is connected to the output terminal of the first amplifier AMP1, the sixth resistor R6 is connected in parallel with the fourth capacitor C4, the output terminal of the second amplifier AMP2 is connected to the fifth capacitor R5 and the sixth resistor R6, the other end of the fifth capacitor R5 is connected to one end of the seventh resistor R7 and outputs the REF- signal, and the other end of the seventh resistor R7 is connected to one end of the fourth resistor R4;

[0040] The second amplifier AMP2 is also connected to a sixth capacitor C6, the other end of which is grounded. The sixth capacitor C6 has a voltage stabilizing function.

[0041] It can be understood that the PWM signal REF_C of the microcontroller MCU is converted into a sine wave of 4 to 10KHz (the specific frequency depends on different applications) through a second-order RC low-pass filter, and then passes through a single-ended to differential op amp to become the differential excitation signals REF+ and REF-, which are sent to the resolver excitation winding for excitation.

[0042] As a preferred embodiment, the resolver receiving circuit includes a TVS tube, a common mode inductor, a low-pass filter circuit and a differential to single-ended circuit;

[0043] One end of a set of TVS tubes receives sine or cosine signals, and the other end is connected to the common-mode inductor. One end of the low-pass filter circuit is connected to the common-mode inductor, and the other end is connected to the differential-to-single-ended circuit and outputs the single-ended signal SIN_A or COS_A and then sends it to the ADC module of the MCU.

[0044] Specifically, the resolver receiving circuit includes a sine signal receiving circuit and a cosine receiving circuit, wherein the cosine receiving circuit is as follows: Figure 3 As shown, the cosine receiving circuit includes a group of TVS tubes for receiving cosine signals COS+ and COS-, and entering the common mode inductor, the COS- output end of the common mode inductor is connected to the tenth resistor R10 and the eighth capacitor C8 of the low-pass filter circuit, the other end of the tenth resistor R10 is respectively connected to the eleventh resistor R11, the twelfth resistor R12 and one end of the ninth capacitor C9, the other end of the twelfth resistor R12 is respectively connected to the tenth capacitor C10 and the positive input end of the third amplifier AMP3 of the differential to single-ended circuit, the tenth capacitor C10 is connected to a 1.65V power supply and one end of the twelfth resistor R12 is connected to the 1.65V power supply The COS+ output end of the common-mode inductor is connected to the fourteenth resistor R14 of the low-pass filter circuit and one end of the eighth capacitor C8, the other end of the fourteenth resistor R14 is respectively connected to the fifteenth resistor R15 and one end of the sixteenth resistor R16, the other end of the fifteenth resistor R15 is respectively connected to the negative input end of the third amplifier AMP3 and one end of the eleventh capacitor C11, the other end of the eleventh capacitor C11 is connected to the sixteenth resistor R16 and the output end of the third amplifier AMP3, the output end of the third amplifier AMP3 is connected to the seventeenth resistor R17, the seventeenth resistor R17 is connected to the twelfth capacitor C12 and outputs the signal COS_A.

[0045] Similarly, if Figure 4 As shown, the sine receiving circuit has a similar structure to the cosine receiving circuit. After receiving the sine signals SIN+ and SIN_, a 3.3V power supply is provided to the third amplifier to change the phase to generate the output signal SIN_A.

[0046] In summary, the differential sine and cosine signals SIN+, SIN-, COS+, and COS- fed back by the resolver pass through the TVS tube and common-mode inductor in front, enter the low-pass filter and differential-to-single-ended circuit at the back, and are converted into single-ended signals SIN_A and COS_A and then sent to the ADC module of the microcontroller for resolver position calculation.

[0047] like Figure 5 As shown, as a preferred embodiment, the temperature detection circuit includes a motor thermistor NTC / PTC thermistor, which is connected in series with a 3K resistor to generate a voltage-divided signal Mtr_T_IN, which is sent to the subsequent RC low-pass filter circuit to filter out interference, and is converted into an Mtr_T signal after passing through a clamping diode and sent to the ADC module of the MCU.

[0048] like Figure 6 As shown, as a preferred embodiment, the resolver transformer includes a resolver excitation coil, a sine winding and a cosine winding;

[0049] The resolver excitation coil is used to receive the sinusoidal wave signal sent by the excitation circuit. The sinusoidal wave signal is sent to the resolver receiving circuit after the sine winding and the cosine winding generate a sine signal and a cosine signal.

[0050] It can be understood that after receiving the sinusoidal excitation signal from the excitation circuit, the excitation coil of the resolver will generate a sine signal and a cosine signal in the sine winding and the cosine winding. The two signals have a phase difference of 90°, and the amplitude varies with the rotor position. It is only necessary to send the sine and cosine signals to the resolver receiving circuit, convert them into single-ended signals, and then send them to the MCU ADC module. The MCU can calculate the current actual position of the rotor based on the detected amplitude, thereby completing the FOC control of the motor. Since the materials that make up the resolver only contain copper and iron, and there are no semiconductor devices that are sensitive to temperature or vibration, the resolver itself has excellent reliability compared to other types of position detection units such as magnetic encoders or photoelectric encoders. It is particularly suitable for scenarios such as electric vehicles that have high reliability requirements and harsh operating environments.

[0051] In addition, in this embodiment, the phase difference between the sine signal and the cosine signal is 90°.

[0052] Next, the working principle of the embodiment is described in detail to enable those skilled in the art to better understand the present invention:

[0053] After the PWM signal of the MCU passes through the resolver excitation circuit, it becomes a sine wave signal, which is used to drive the resolver excitation coil, and then sense the differential sine and cosine signals on the resolver's sine and cosine windings. The differential sine and cosine signals are sent to the resolver receiving circuit and converted into single-ended sine and cosine signals that can be recognized by the MCU ADC. After the MCU solves, the real-time position of the motor rotor can be obtained, and then the motor is controlled by FOC. The winding temperature of the motor during operation is sent to the ADC module of the MCU after the NTC / PTC thermistor, the pull-up resistor voltage division and low-pass filtering, and the motor temperature is monitored in real time to provide real-time temperature protection for the motor to prevent the winding from burning due to overheating.

[0054] In summary, this embodiment introduces a highly reliable rotary transformer and a thermistor for monitoring the winding temperature into the electric tricycle system, which can improve the reliability of the encoder while monitoring the motor winding temperature to prevent the motor winding or encoder from being damaged due to overheating, thereby greatly improving the reliability of the power system and reducing the failure rate.

[0055] The foregoing descriptions of specific exemplary embodiments of the present invention are for the purpose of explanation and illustration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is obvious that many changes and variations can be made based on the above teachings. Although an embodiment of the present invention has been shown and described, this specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. The specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can make modifications, substitutions, variations and various selections and changes to the embodiments without creative contribution as needed after reading this specification without departing from the principles and purpose of the present invention, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A highly reliable electric tricycle power system, characterized in that: It includes a motor controller and a motor; the motor is provided with a rotary transformer and a temperature sensor; The motor controller includes an MCU, a resolver excitation circuit, a resolver receiving circuit and a temperature detection circuit; The MCU includes a PWM module and an ADC module; The PWM module generates a PWM signal which is converted into a sine wave signal after passing through a resolver excitation circuit. The sine wave signal enters the resolver transformer to induce differential sine and cosine signals, and the sine and cosine signals are sent to a resolver receiving circuit and converted into single-ended sine and cosine signals recognized by an ADC module in the MCU. The MCU obtains the real-time position of the motor rotor and controls the motor. The temperature sensor is used to read the temperature of the motor winding and send it to the ADC module through the temperature detection circuit to monitor the motor temperature in real time.

2. A highly reliable electric tricycle power system according to claim 1, characterized in that: The resolver excitation circuit includes a second-order RC low-pass filter circuit and a single-ended to differential operational amplifier circuit; One end of the first resistor of the second-order RC low-pass filter circuit is connected to the PWM module, and the other end is connected to the second resistor and the first capacitor respectively, and the first resistor, the first capacitor and the second capacitor are grounded; The single-ended to differential operational amplifier circuit comprises a first chip and a second chip, one end of the second resistor R2 is connected to the positive input end of the first amplifier in the first chip, the negative input end of the first amplifier is respectively connected to the third capacitor and the fourth resistor, one end of the third resistor in the first chip is connected to the second capacitor, and the other end is connected to the fourth resistor, and the output end of the first amplifier is connected to the fourth resistor and outputs a REF+ signal; The negative input terminal of the second amplifier in the second chip is connected to one end of a fifth resistor and one end of a sixth resistor respectively, the other end of the fifth resistor is connected to the output terminal of the first amplifier, the sixth resistor is connected in parallel with a fourth capacitor, the output terminal of the second amplifier is connected to the fifth capacitor and the sixth resistor, the other end of the fifth capacitor is connected to one end of a seventh resistor and outputs a REF- signal, and the other end of the seventh resistor is connected to one end of the fourth resistor; The second amplifier is also connected to a sixth capacitor, and the other end of the sixth capacitor is grounded.

3. A highly reliable electric tricycle power system according to claim 1, characterized in that: The resolver receiving circuit includes a TVS tube, a common mode inductor, a low-pass filter circuit and a differential to single-ended circuit; One end of a group of TVS tubes receives a sine or cosine signal, and the other end is connected to a common-mode inductor. One end of the low-pass filter circuit is connected to the common-mode inductor, and the other end is connected to a differential-to-single-ended circuit and outputs a single-ended signal SIN_A or COS_A and then sends it to the ADC module of the MCU.

4. A highly reliable electric tricycle power system according to claim 1, characterized in that: The temperature detection circuit includes a signal Mtr_T_IN from the motor thermistor NTC / PTC thermistor which is connected in series with a 3K resistor to divide the voltage, which is sent to the RC low-pass filter circuit behind to filter out interference, and is converted into an Mtr_T signal after passing through a clamping diode and sent to the ADC module of the MCU.

5. A highly reliable electric tricycle power system according to claim 1, characterized in that: The resolver transformer comprises a resolver excitation coil, a sine winding and a cosine winding; The resolver excitation coil is used to receive a sine wave signal sent by an excitation circuit. The sine wave signal is sent to a resolver receiving circuit after the sine winding and the cosine winding generate a sine signal and a cosine signal.

6. A highly reliable electric tricycle power system according to claim 1, characterized in that: The phase difference between the sine signal and the cosine signal is 90°.

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