A wireless power supply and information communication system and method

Abstract

The present invention proposes a wireless power supply and information communication system and method. The method uses wireless power supply to power a rotating temperature measurement circuit, and at the same time encodes temperature sampling information by changing the power of the temperature measurement circuit at the power receiving end. The stationary power transmitting end decodes the encoded information by detecting the change in transmission power, ultimately realizing the dual functions of energy transmission and information communication.

Description

Technical Field

[0001] The present invention belongs to the technical field of permanent magnet synchronous motor rotor temperature signal transmission, and in particular relates to a wireless power supply and information communication system and method. Background Art

[0002] Permanent magnet synchronous motors are widely used in new energy vehicles, rail transit, wind power and other fields due to their simple structure, small size and high efficiency. While converting electrical energy into mechanical energy, the motor itself consumes a part of the energy, which can be divided into iron loss, copper loss and mechanical loss, causing the motor to heat up. The permanent magnet material used in the motor rotor is very sensitive to temperature. Excessive temperature will reduce its performance and even cause irreversible demagnetization, affecting the motor performance. Therefore, in order to ensure the safety and reliability of the motor, it is very important to monitor the temperature of the motor permanent magnet.

[0003] The rotor of a permanent magnet synchronous motor rotates continuously during operation, which makes the signal transmission between the rotor temperature measurement system (rotating with the rotor) and the signal receiving end (stationary) a challenge. In order to achieve real-time communication between the rotor signal transmitter and the signal receiving end to ensure real-time monitoring of the rotor temperature by the host computer, there are two main traditional methods:

[0004] 1. Turn off the working motor, quickly measure the rotor resistance, and calculate the rotor temperature through relevant empirical formulas;

[0005] 2. Realize signal transmission between the rotating part and the stationary part through brushes;

[0006] Of these two methods, the former cannot meet the requirements of real-time monitoring of the motor rotor temperature, and the latter has many problems such as indoor pollution and low reliability.

[0007] The widely used method at present is to use wireless communication to achieve signal transmission, such as Bluetooth module and WIFI module. This strategy has some disadvantages. During data transmission, strong magnetic fields can cause data packets to be lost. In order to overcome electromagnetic interference, the power of wireless transmission can be increased, but this will inevitably lead to increased power consumption. At the same time, the circuit structure of the wireless communication module is complex, which not only increases the system cost, but also reduces the system reliability.

[0008] Since the rotor of a permanent magnet synchronous motor rotates at high speed during operation, the power supply of the rotor temperature measurement system becomes a problem. The usual practice is to fix a DC power supply on the rotor and keep it relatively still to power the temperature measurement system. However, this design is not suitable for high-speed operation of the motor, which greatly reduces the reliability of the motor. Compared with directly fixing the power supply on the rotor, wireless power supply technology directly powers the temperature measurement system through air, which is safer and more flexible.

[0009] There are four main ways to achieve wireless power supply technology:

[0010] 1. Electromagnetic induction

[0011] The electromagnetic induction type is to pass an alternating current of a certain frequency through the primary coil. According to the principle of electromagnetic induction, the secondary coil will also generate a current of this frequency, thereby realizing the transfer of energy from the transmission end to the receiving end. Its advantages are that it is suitable for short-distance power supply and has high conversion efficiency. Its disadvantages are that it requires a specific placement and metal induction contact will generate heat.

[0012] 2. Magnetic field resonance

[0013] The magnetic field resonance type consists of an energy transmitter and an energy receiver. When the frequencies of the two are the same, they will resonate at this specific frequency, thereby exchanging energy. Its advantages are that it is suitable for long-distance high-power power supply and has moderate conversion efficiency. Its disadvantages are low efficiency and safety and health issues.

[0014] 3. Radio wave type

[0015] The radio wave type is mainly composed of a microwave transmitting device and a microwave receiving device, which can capture the rebounded radio wave energy and keep the DC voltage constant while adjusting with the load. Its advantages are that it is suitable for long-distance low-power power supply and can automatically supply power anytime and anywhere. Its disadvantages are low conversion efficiency and low transmission power.

[0016] 4. Electric field coupling

[0017] The electric field coupling type transmits energy through the induced electric field generated by two sets of asymmetric dipoles coupled in the vertical direction. The general charging module is composed of two asymmetric dipoles arranged in the vertical direction. Each of the dipoles consists of an activated carbon electrode and a ground electrode for the power supply part and the receiving part. The wireless power supply module is powered by the induced electric field generated by the electric field coupling of these two asymmetric dipoles. Its advantages are that it is suitable for short-distance power supply, high conversion efficiency, low heat generation, and the position cannot be fixed. The disadvantages are that it is large in size and low in power. Summary of the invention

[0018] The purpose of the present invention is to solve the problem of power supply and communication with the outside world of a rotor temperature measurement system, and to provide a wireless power supply and information communication system and method.

[0019] The present invention is implemented by the following technical scheme. The present invention proposes a wireless power supply and information communication system, the system comprising a wireless power supply part, a rotor temperature measurement part, a signal encoding part, a signal transmission part and a signal decoding part;

[0020] The wireless power supply part adopts the magnetic field resonance mode, and its power receiving end and power transmitting end are both composed of inductance and capacitance. By using LC resonance, when the power transmitting end generates high-frequency oscillation after being powered on, the power receiving end will also oscillate at the same frequency, thereby realizing the transmission of electric energy across the air. The power transmitting end wirelessly powers the power receiving end, and the power of the two is equal.

[0021] The rotor temperature measurement part uses a contact temperature sensor PT100 to measure the rotor temperature. Since the resistance value of PT100 is linearly related to the temperature, the rotor temperature can be obtained by measuring the resistance value of PT100;

[0022] The signal encoding part performs binary encoding on the temperature signal, specifically: the PT100 signal is passed through the temperature measurement circuit to obtain the real-time temperature T0 of the rotor, and T0 is binary encoded and output by MCU1 to obtain a PWM waveform containing the rotor temperature information; for the convenience of signal recognition, when MCU1 encodes T0, the data is processed, and the data format processed by MCU1 is: 1 start bit, i.e., low level, 8 data bits, and 1 stop bit, i.e., high level. When there is no data communication, a high level is output; the data T0 is represented by 8 binary data bits, and the PWM wave is applied to the switch tube S, which is MOSFET;

[0023] The signal transmission part uses an LC resonant circuit. When the signal transmitting end and the signal receiving end oscillate at the same frequency, electrical energy is transmitted between the two ends. Since the power of the transmitting end and the receiving end is equal, as the switch tube of the signal transmitting end is continuously turned on and off, the output power of the signal receiving end changes accordingly, and the transmitting end continuously transmits data to the receiving end.

[0024] The signal decoding part uses a power sensor to measure the power of the power transmitting end, and collects and decodes the signal measured by the power sensor through MCU2. When a low level is detected, it means that data transmission begins. The last eight bits of the start bit are the rotor temperature data. When the stop bit is high, the transmission data is considered valid.

[0025] Furthermore, let the output of MCU1 be D1. When D1=1, the switch tube S is closed and the output power of the signal transmitting end is:

[0026]

[0027] Where P m is the power of the temperature measurement circuit; P o is the output power of the signal transmitting end; U is the effective value of the AC voltage at the signal receiving end; R is the resistance value;

[0028] When D1=0, the switch tube S is disconnected and the output power of the signal transmitter is:

[0029] Po =P m

[0030] From this, we can establish the relationship between the MCU1 output and the signal transmitter output power:

[0031]

[0032] Furthermore, let the rotor temperature data be D2, then

[0033]

[0034] The corresponding rotor temperature signal T0 can be obtained by performing digital-to-analog conversion on D2.

[0035] The present invention proposes a communication method based on the wireless power supply and information communication system. The method uses wireless power supply to power a rotating temperature measurement circuit, and at the same time encodes temperature sampling information by changing the power of the temperature measurement circuit at the power receiving end. The stationary power transmitting end decodes the encoded information by detecting the change in transmission power, ultimately realizing the dual functions of energy transmission and information communication.

[0036] The present invention has the following beneficial effects:

[0037] The present invention proposes a wireless power supply and information communication system and method. The system has low cost and high system reliability. The method can ensure real-time monitoring of the rotor temperature by the host computer and realize the dual functions of energy transmission and information communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the basic structure diagram of wireless power supply and communication method.

[0039] Figure 2 This is a diagram showing the arrangement of PT100 in the motor.

[0040] Figure 3 This is the overall layout diagram of the motor.

[0041] Figure 4 It is a schematic diagram of the data transmission format at the signal transmitter. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] The present invention proposes a wireless power supply and information communication system, the system comprising a wireless power supply part, a rotor temperature measurement part, a signal encoding part, a signal transmission part and a signal decoding part;

[0044] The wireless power supply part adopts the magnetic field resonance mode, and its power receiving end and power transmitting end are both composed of inductance and capacitance. By using LC resonance, when the power transmitting end generates high-frequency oscillation after being powered on, the power receiving end will also oscillate at the same frequency, thereby realizing the transmission of electric energy across the air. The power transmitting end wirelessly powers the power receiving end, and the power of the two is equal.

[0045] Considering that non-contact temperature sensors (such as infrared sensors) are only applicable to low-speed operation of the motor and have limited measurement accuracy, the rotor temperature measurement part uses a contact temperature sensor PT100 to measure the rotor temperature. Since the resistance value of PT100 is linearly related to the temperature, the rotor temperature can be obtained by measuring the resistance value of PT100; the PT100 arrangement is as follows Figure 2 The PT100 is fixed to the surface of the permanent magnet through thermal conductive glue, and the lead wire is connected to the temperature measurement circuit (fixed on the motor end cover) through the hollow shaft of the motor. The overall layout of the motor is as follows: Figure 3 shown.

[0046] The signal encoding part performs binary encoding on the temperature signal, specifically: the PT100 signal is passed through the temperature measurement circuit to obtain the real-time rotor temperature T0, and T0 is binary encoded and output by MCU1 to obtain a PWM waveform containing rotor temperature information; for the convenience of signal recognition, when MCU1 encodes T0, it processes the data, and the data format after processing by MCU1 is: 1 start bit, i.e., low level, 8 data bits, and 1 stop bit, i.e., high level, such as Figure 4 As shown, when there is no data communication, the output is high level; data T0 is represented by 8 binary data bits, and the PWM wave is applied to the switch tube S. The switch tube S is MOSFET. Compared with the common triode and IGBT, MOSFET has a faster switching speed and is convenient for signal transmission;

[0047] Note that the output of MCU1 is D1. When D1=1, the switch tube S is closed and the output power of the signal transmitter is:

[0048]

[0049] Where P m is the power of the temperature measurement circuit; P o is the output power of the signal transmitting end; U is the effective value of the AC voltage at the signal receiving end; R is the resistance value;

[0050] When D1=0, the switch tube S is disconnected and the output power of the signal transmitter is:

[0051] P o =P m

[0052] From this, we can establish the relationship between the MCU1 output and the signal transmitter output power:

[0053]

[0054] The signal transmission part utilizes an LC resonant circuit. When the signal transmitting end and the signal receiving end oscillate at the same frequency, electrical energy is transmitted across space between the two. Since the power of the transmitting end and the receiving end is equal, as the switch tube of the signal transmitting end is continuously opened and closed, the output power of the signal receiving end changes accordingly, and the transmitting end continuously transmits data to the receiving end. Therefore, the LC resonant circuit can solve the signal transmission problem between the rotating part and the stationary part of the motor.

[0055] The signal decoding part uses a power sensor to measure the power of the power transmitter. The signal measured by the power sensor is collected and decoded by MCU2. When a low level is detected, it means that data transmission begins. The last eight bits of the start bit are the rotor temperature data. When the stop bit is high, the transmission data is considered valid. The rotor temperature data is D2, then

[0056]

[0057] The corresponding rotor temperature signal T0 can be obtained by performing digital-to-analog conversion on D2.

[0058] The present invention proposes a communication method based on the wireless power supply and information communication system. The method uses wireless power supply to power a rotating temperature measurement circuit, and at the same time encodes temperature sampling information by changing the power of the temperature measurement circuit at the power receiving end. The stationary power transmitting end decodes the encoded information by detecting the change in transmission power, ultimately realizing the dual functions of energy transmission and information communication.

[0059] The above is a detailed introduction to a wireless power supply and information communication system and method proposed in the present invention, and the invention content, claims, invention effects and specific implementation methods of the present invention are explained. At the same time, for those skilled in the art, based on the idea of ​​the present invention, the specific form of the network structure adopted, the optimization algorithm and hyperparameter selection of model training, the specific form of the loss function, the specific value of the weight coefficient, etc. can be changed and adjusted according to the actual scenario and condition restrictions. Therefore, the relevant statements should not be understood as limitations on the present invention.

Claims

1. A wireless power supply and information communication system, characterized in that: The system includes a wireless power supply part, a rotor temperature measurement part, a signal encoding part, a signal transmission part and a signal decoding part; The wireless power supply part adopts the magnetic field resonance mode, and its power receiving end and power transmitting end are both composed of inductance and capacitance, and utilize LC resonance; The rotor temperature measurement part uses a contact temperature sensor PT100 to measure the rotor temperature; The signal encoding part performs binary encoding on the temperature signal, specifically: the PT100 signal is passed through the temperature measurement circuit to obtain the real-time temperature T0 of the rotor, and T0 is binary encoded and output by MCU1 to obtain a PWM waveform containing the rotor temperature information; for the convenience of signal recognition, when MCU1 encodes T0, the data is processed, and the data format processed by MCU1 is: 1 start bit is low level, 8 data bits, 1 stop bit is high level, and when there is no data communication, a high level is output; the data T0 is represented by 8 binary data bits, and the PWM wave is applied to the switch tube S, and the switch tube S is MOSFET; The signal transmission part utilizes an LC resonant circuit; The signal decoding part uses a power sensor to measure the power of the power transmitting end, and collects and decodes the signal measured by the power sensor through MCU2. When a low level is detected, it means that data transmission begins. The last eight bits of the start bit are the rotor temperature data. When the stop bit is high, the transmission data is considered valid.

2. The system according to claim 1, characterized in that: Note that the output of MCU1 is D1. When D1=1, the switch tube S is closed and the output power of the signal transmitter is: Where P m is the power of the temperature measurement circuit; P o is the output power of the signal transmitting end; U is the effective value of the AC voltage at the signal receiving end; R is the resistance value; When D1=0, the switch tube S is disconnected and the output power of the signal transmitter is: P o =P m This establishes the relationship between the MCU1 output and the signal transmitter output power:

3. The system according to claim 2, characterized in that: Let the rotor temperature data be D2, then The corresponding rotor temperature signal T0 can be obtained by performing digital-to-analog conversion on D2.

4. The communication method of the wireless power supply and information communication system according to any one of claims 1 to 3, characterized in that: The method uses wireless power supply to power the rotating temperature measurement circuit, and at the same time encodes the temperature sampling information by changing the power of the temperature measurement circuit at the power receiving end. The stationary power transmitting end decodes the encoded information by detecting the change of transmission power, and finally realizes the dual functions of energy transmission and information communication.

Images