Electric vehicle AC charging pile control and guidance CP circuit

Abstract

The present invention relates to a control and guidance CP circuit for an AC charging pile of an electric vehicle, which is characterized by comprising a level switching unit and a level amplifying unit, wherein: when the input CP oscillation wave signal output by the MCU is at a high level, the level switching unit outputs a high-level voltage signal; when the input CP oscillation wave signal output by the MCU is at a low level, the level switching unit outputs a low-level voltage signal; the level amplifying unit amplifies the signal output by the level switching unit by N times and then outputs the final CP oscillation wave signal. Due to the use of an operational amplifier to amplify the output, after the implementation of the control and guidance CP circuit for an AC power supply device of an electric vehicle according to the present invention, the CP oscillation wave +V cc ,‑V cc The accuracy error is within 2%, demonstrating very high precision. The CP oscillator waveform has relatively steep rising and falling edges, meeting standard specifications and demonstrating good consistency. Real-world charging pile testing has demonstrated high interoperability and excellent charging pile performance.

Description

Technical Field

[0001] The present invention relates to a CP oscillator waveform control steering circuit for an AC power supply device for electric vehicles (hereinafter referred to as an "AC charging pile"). Background Art

[0002] With the national promotion of new energy electric vehicles, AC charging piles are experiencing enormous demand. With continuous technological advancements, installations have skyrocketed, meeting the growing charging needs of electric vehicle owners. However, the quality of AC charging piles varies greatly, with some manufacturers experiencing issues such as interoperability issues with electric vehicles, unstable performance, and unsafe charging. To address interface compatibility and interoperability issues between electric vehicles and AC charging piles from different manufacturers, the Ministry of Energy and the National Standards Administration have developed a series of specifications and national standards, the most fundamental of which is GBT18487.1-2015 Electric Vehicle Conductive Charging Systems Part 1 - General Requirements.

[0003] CP Control pilot function is the full name of the control pilot function, which is used to monitor the interaction between electric vehicles and AC charging piles. GB / T 18487.1-2015 has detailed specifications for the CP signal. The CP oscillator waveform can be found in Figure 1 , Figure 1 Where f represents the output frequency of the CP oscillator. The voltage and waveform parameters are shown in Table 1.

[0004]

[0005] Table 1

[0006] The existing CP oscillator waveform control steering circuit still has some deficiencies, which do not meet or barely meet the parameters required by GBT18487. The following are the main problems:

[0007] 1) The output PWM waveform has insufficient accuracy in terms of maximum and minimum voltages.

[0008] 2) The PWM output duty cycle and frequency accuracy do not meet the requirements.

[0009] 3) The PWM waveform signal is severely distorted, and the rising and falling edge times are too long.

[0010] Some CP oscillator waveform control and steering circuits also have the problem of high cost. For example, the control and steering circuit of the charging pile and the charging pile disclosed in invention patent CN106347153 B use two optical couplers and one inverter, which are relatively expensive. Summary of the Invention

[0011] The technical problem to be solved by the present invention is that the CP signal quality of the existing AC charging pile is poor.

[0012] In order to solve the above technical problems, the technical solution of the present invention is to provide an electric vehicle AC charging pile control and guidance CP circuit, which is characterized by including a level switching unit and a level amplification unit, wherein:

[0013] The level switching unit is connected to the CP oscillation wave signal output terminal of the MCU. At the same time, the level switching unit is connected to the precision high-level reference voltage signal V H and a precision low-level reference voltage signal V L When the input CP oscillation wave signal output by the MCU is high, the level switching unit outputs a high-level voltage signal V H When the input CP oscillation wave signal output by the MCU is at a low level, the level switching unit outputs a low level voltage signal V L ;

[0014] The level amplifying unit receives the high level voltage signal V output by the level switching unit. H And the low level voltage signal V L And after amplifying it N times, the final CP oscillation wave signal is output, N ≥ 2, and the CP oscillation wave signal output by the level amplification unit is made

[0015] Preferably, the level switching unit includes an integrated circuit of model BL1551, the first pin of the integrated circuit is connected to the precision high-level reference voltage signal, the third pin is connected to the precision low-level reference voltage signal, the fourth pin is connected to the level amplification unit, and the sixth pin is connected to the CP oscillation wave signal output end of the MCU.

[0016] Preferably, the level amplification unit includes an amplifier and an external interface terminal having a CP terminal and a PE terminal, wherein:

[0017] The non-inverting input terminal of the amplifier is connected to the 4th pin of the integrated circuit via a resistor R63, and the non-inverting input terminal of the amplifier is also grounded via a resistor R64; the inverting input terminal of the amplifier is connected to the reference signal voltage source via a resistor; a resistor R65 is connected between the inverting input terminal and the output terminal of the amplifier; the output terminal of the amplifier is connected to the CP terminal of the external interface terminal via a resistor R68; and the PE terminal of the external interface terminal is grounded via a resistor R69.

[0018] Since the operational amplifier is used to amplify the output, after the electric vehicle AC power supply equipment control guide CP circuit is implemented, the CP oscillation wave +V cc 、-V ccThe accuracy error is within 2%, demonstrating very high precision. The CP oscillator waveform has relatively steep rising and falling edges, meeting standard specifications and demonstrating good consistency. Real-world charging pile testing has demonstrated high interoperability and excellent charging pile performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the CP oscillator waveform;

[0020] Figure 2 Schematic diagram of the circuit of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalents fall within the scope limited by the appended claims of the application equally.

[0022] like Figure 2 As shown, this embodiment discloses an electric vehicle AC charging pile control and guidance CP circuit, which includes a level switching unit and a level amplification unit.

[0023] The CP oscillation signal CP_PWM output by the MCU is input to the level-shifting unit. This unit also receives a precision 3V reference voltage signal and a precision 0V reference voltage signal. When the CP oscillation signal CP_PWM is high, the level-shifting unit outputs a 3V voltage signal; when the CP oscillation signal CP_PWM is low, the level-shifting unit outputs a 0V voltage signal.

[0024] In this embodiment, the level switching unit is implemented based on integrated circuit U1, which uses a BL1551 integrated circuit chip. Based on the pin definitions in the chip's specification sheet, the connection relationship is as follows: Pin 1 of integrated circuit U1 is connected to a precision 3V reference voltage signal, and pin 3 is grounded, thereby connecting to a precision 0V reference voltage signal. Pin 4 of integrated circuit U1 provides an output voltage signal V01 to the level amplification unit. This output voltage signal V01 can be either a 3V or 0V voltage signal. Pin 6 of integrated circuit U1 is connected to the CP oscillation wave signal CP_PWM output terminal of the MCU. Pin 2 of integrated circuit U1 is grounded, and pin 5 is connected to a 5V voltage source. Pin 2 is grounded, and pin 5 serves as the power supply pin for integrated circuit U1.

[0025] The level amplification unit receives the 3V voltage signal and the 0V voltage signal output by the level switching unit and amplifies the 3V voltage signal and the 0V voltage signal. In this embodiment, the amplification factor of the level amplification unit is 8 times. When the output voltage signal V01 provided by the level switching unit is a 3V voltage signal, the output voltage signal V02 output by the level amplification unit via the external interface terminal J1 is a 12V voltage signal, that is, the V of the output CP oscillation wave signal finally obtained in this embodiment. cc =12V. When the output voltage signal V01 provided by the level switching unit is a 0V voltage signal, the output voltage signal V02 output by the level amplifying unit via the external interface terminal J1 is a -12V voltage signal, i.e., the -V of the output CP oscillation wave signal finally obtained in this embodiment. cc =-12V. It can be seen that due to the use of the level amplification unit, the electric vehicle AC power supply device control guide CP circuit output disclosed by the present invention can quickly respond to the input CP oscillation wave signal CP_PWM, and the waveform of the output CP oscillation wave signal is V cc =12V, -V cc =-12V, with extremely steep rising or falling edges and high voltage accuracy.

[0026] In this embodiment, the level amplification unit includes amplifier U1B (in this embodiment, amplifier U1B uses an LM2904), resistors R62, R63, R64, R65, R68, and R69, and an external interface terminal J1. In this embodiment, resistors R62 and R63 are 15kΩ resistors, resistors R64 and R65 are 120kΩ resistors, resistor R68 is 1kΩ, and resistor R69 is a jumper resistor. External interface terminal J1 has a CP terminal and a PE terminal.

[0027] One end of resistor R63 is connected to pin 4 of integrated circuit U1 in the level shift unit, and the other end is connected to the non-inverting input of amplifier U1B and one end of resistor R64. The other end of resistor R64 is grounded. The inverting input of amplifier U1B is connected to a 1.5V precision voltage source via resistor R62. Resistor R65 is connected between the inverting input and output of amplifier U1B. The output of amplifier U1B outputs the aforementioned output voltage signal V02. The output of amplifier U1B is connected to the CP terminal of external interface terminal J1 via resistor R68. The PE terminal of external interface terminal J1 is grounded via resistor R69.

Claims

1. A control and guidance CP circuit for an electric vehicle AC charging pile, characterized in that: It includes a level switching unit and a level amplification unit, wherein: The level switching unit is connected to the CP oscillation wave signal output terminal of the MCU. At the same time, the level switching unit is connected to the precision high-level reference voltage signal V H and a precision low-level reference voltage signal V L When the input CP oscillation wave signal output by the MCU is high, the level switching unit outputs a high-level voltage signal V H When the input CP oscillation wave signal output by the MCU is at a low level, the level switching unit outputs a low level voltage signal V L The level switching unit includes an integrated circuit model BL1551, the first pin of the integrated circuit is connected to the precision high-level reference voltage signal, the third pin is connected to the precision low-level reference voltage signal, the fourth pin is connected to the level amplification unit, and the sixth pin is connected to the CP oscillation wave signal output terminal of the MCU; The level amplifying unit receives the high level voltage signal V output by the level switching unit. H And the low level voltage signal V L And after amplifying it N times, the final CP oscillation wave signal is output, N ≥ 2, and the CP oscillation wave signal output by the level amplification unit is made The level amplification unit includes an amplifier U1B of model LM2904, resistors R62, R63, R64, R65, R68, and R69, and an external interface terminal J1. Resistors R62 and R63 are 15kΩ resistors, resistors R64 and R65 are 120kΩ resistors, and resistor R68 is 1kΩ. Resistor R69 is a jumper resistor. The external interface terminal J1 has a CP terminal and a PE terminal. One end of resistor R63 is connected to pin 4 of the integrated circuit in the level shift unit, and the other end is connected to the non-inverting input of amplifier U1B and one end of resistor R64; the other end of resistor R64 is grounded; the inverting input of amplifier U1B is connected to a 1.5V precision voltage source via resistor R62; a resistor R65 is connected between the inverting input and output of amplifier U1B; the output of amplifier U1B outputs the aforementioned output voltage signal V02, and the output of amplifier U1B is connected to the CP terminal of external interface terminal J1 via resistor R68; the PE terminal of external interface terminal J1 is grounded via resistor R69; The level amplification unit receives the 3V voltage signal and the 0V voltage signal output by the level switching unit, and amplifies the 3V voltage signal and the 0V voltage signal. The amplification factor of the level amplification unit is 8 times. When the output voltage signal V01 given by the level switching unit is a 3V voltage signal, the output voltage signal V02 output by the level amplification unit through the external interface terminal J1 is a 12V voltage signal, that is, the +V of the output CP oscillation wave signal finally obtained. cc =12V, when the output voltage signal V01 given by the level switching unit is a 0V voltage signal, the output voltage signal V02 output by the level amplifying unit through the external interface terminal J1 is a -12V voltage signal, that is, the -V of the output CP oscillation wave signal finally obtained. cc =-12V.

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