Diode detection circuit

Abstract

The diode detection circuit of the present application comprises: a voltage follower circuit which inputs a control pilot signal formed as a PWM signal from the alternating current charging post and outputs a voltage follower signal obtained after voltage following the control pilot signal; a reverse amplification circuit which only inputs a negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit and performs reverse operation to output a positive voltage PWM signal having the same voltage value as the negative voltage PWM signal but opposite direction as a reverse amplification signal; and a voltage division sampling circuit which divides the voltage of the reverse amplification signal output from the reverse amplification circuit and clamps the voltage value of the voltage sampling signal obtained after voltage division while outputting the voltage sampling signal for voltage collection by a controller of the alternating current charging post.

Description

Technical Field

[0001] This invention relates to electric vehicle charging and discharging technology, and more particularly to a diode detection circuit for detecting the presence of a diode on the control guide circuit when an AC charging pile is connected to an electric vehicle through the control guide circuit. Background Technology

[0002] In AC power supply equipment, the CP signal stands for Control Pilot Function signal, which is mainly used to monitor the interaction between electric vehicles and electric vehicle power supply equipment (i.e., charging piles).

[0003] The CP control guide typically uses a CP signal modulated onto a power supply sine wave. This modulation method is sometimes called frequency modulation, where a 1kHz signal is modulated onto the power supply frequency. Because the CP control guide signal is a sine wave, if a D1 diode is not placed on the CP control guide, it is impossible to distinguish whether the charging device is connected to an electric vehicle or a load device. Therefore, the detection diode becomes particularly important when the charging device is connected to an electric vehicle. Furthermore, the presence of a detection diode is also required in the latest "General Requirements for Charging Systems GB / T18487.1-2023" A.2.6. Summary of the Invention

[0004] The technical problem that the invention aims to solve

[0005] In conventional detection schemes, a diode detection circuit architecture typically consists of resistors, capacitors, and operational amplifiers. The PWM signal is input to the operational amplifier through the capacitor, forms a feedback network through the resistors on the operational amplifier, and is finally output to the controller of the AC charging pile for ADC sampling. When the 3.3V input signal provided by the auxiliary power supply is boosted, because the operational amplifier's supply voltage is 0-12V and the operational amplifier has a headroom voltage (also known as voltage margin), the minimum value of the output signal (AC plus DC) is greater than 0V, resulting in bottom distortion.

[0006] The purpose of this invention is to provide a diode detection circuit that can detect the presence of diodes on the CP control guide circuit while avoiding bottom distortion. Furthermore, without affecting the interaction between the PWM waveform output by the AC charging pile and the vehicle, the circuit performs waveform conversion so that the output signal can be acquired by the microcontroller of the AC charging pile without auxiliary power supply processing.

[0007] Technical solutions to solve technical problems

[0008] According to an embodiment of the present invention, a diode detection circuit is provided for detecting the presence of a diode located at the electric vehicle end on the control guide circuit when an AC charging pile is connected to an electric vehicle through a control guide circuit, characterized in that it includes:

[0009] A voltage follower circuit is provided, which takes a control guidance signal formed as a PWM signal from the AC charging pile as input and outputs a voltage follower signal obtained by voltage following the control guidance signal.

[0010] An inverting amplifier circuit that takes only a negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit as input, performs an inversion operation, and outputs a positive voltage PWM signal with the same voltage value but opposite direction as the negative voltage PWM signal as the inverting amplifier signal; and

[0011] The voltage divider sampling circuit divides the inverted amplified signal output from the inverted amplification circuit, clamps the voltage value of the voltage sampling signal obtained after voltage division, and outputs the voltage sampling signal for the controller of the AC charging pile to collect voltage.

[0012] Furthermore, according to the diode detection circuit described above, the characteristic is that when the controller of the AC charging pile can acquire the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is within a specified range, thereby determining that the diode located at the electric vehicle end on the control guidance circuit exists.

[0013] Furthermore, according to the diode detection circuit described above, when the controller of the AC charging pile cannot acquire the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is not within the specified range, thereby determining that the diode located at the electric vehicle end on the control guidance circuit is not present.

[0014] Furthermore, according to the aforementioned diode detection circuit, the voltage follower circuit includes a follower operational amplifier, a first capacitor, and a second capacitor. The positive input terminal of the follower operational amplifier is connected to the AC charging pile, and the negative input terminal and output terminal of the follower operational amplifier are short-circuited. One end of the first capacitor is connected to the positive power supply of the follower operational amplifier, and the other end is grounded. One end of the second capacitor is connected to the negative power supply of the follower operational amplifier, and the other end is grounded.

[0015] Furthermore, according to the diode detection circuit described above, the inverting amplifier circuit includes a first diode, an inverting operational amplifier, a first resistor, a second resistor, a third resistor, a third capacitor, and a fourth capacitor. The cathode of the first diode is connected to the output terminal of the voltage follower circuit to allow the PWM signal of the negative voltage of the voltage follower signal received from the voltage follower circuit to pass through. The negative input terminal of the inverting operational amplifier is connected to the anode of the first diode via the first resistor and to the output terminal of the inverting operational amplifier via the second resistor. The positive input terminal of the inverting operational amplifier is grounded via the third resistor. One end of the third capacitor is connected to the negative power supply of the inverting operational amplifier, and the other end is grounded. One end of the fourth capacitor is connected to the positive power supply of the inverting operational amplifier, and the other end is grounded.

[0016] Furthermore, according to the diode detection circuit described above, the first resistor and the second resistor have the same resistance value.

[0017] Furthermore, according to the aforementioned diode detection circuit, the voltage divider sampling circuit comprises a fourth resistor, a fifth resistor, a second diode, a third diode, and a fifth capacitor. One end of the fourth resistor is connected to the output terminal of the inverting operational amplifier circuit. One end of the fifth resistor is connected to the other end of the fourth resistor, and the other end of the fifth resistor is grounded. The cathode of the second diode is connected to one end of the fifth resistor, and the anode of the second diode is grounded. The anode of the third diode is connected to one end of the fifth resistor, and the cathode of the third diode is connected to a 3.3V voltage. One end of the fifth capacitor is connected to one end of the fifth resistor and is also connected to the controller of the AC charging pile. The other end of the fifth capacitor is grounded. The fourth and fifth resistors divide the inverted amplified signal output from the inverting operational amplifier. The second and third diodes constitute clamping diodes, clamping the voltage-divided sampling signal obtained after the voltage division within the range of 0 to 3.3V.

[0018] Furthermore, according to an embodiment of the present invention, a diode detection method is provided, which is based on a diode detection circuit for detecting the presence of a diode located at the electric vehicle end on the CP control guidance circuit when an AC charging pile is connected to an electric vehicle through a control guidance circuit. The method is characterized by using a voltage follower circuit to input a control guidance signal formed as a PWM signal from the AC charging pile, and outputting a voltage follower signal obtained by voltage following the control guidance signal. An inverting amplifier circuit is used to input only the negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit, and performs an inverse operation to output a positive voltage PWM signal with the same voltage value but opposite direction as the negative voltage PWM signal as an inverting amplifier signal. A voltage divider sampling circuit is used to divide the inverting amplifier signal output from the inverting amplifier circuit, and clamps the voltage value of the voltage sample signal obtained after voltage division. Simultaneously, the voltage sample signal is output for voltage acquisition by the controller of the charging pile.

[0019] Furthermore, according to the diode detection method described above, the characteristic is that when the controller of the AC charging pile can acquire the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is within a specified range, thereby determining that the diode located at the electric vehicle end on the control guidance circuit exists.

[0020] Furthermore, according to the diode detection method described above, the characteristic is that when the controller of the AC charging pile cannot collect the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is not within the specified range, thereby determining that the diode located at the electric vehicle end on the control guidance circuit does not exist.

[0021] Invention Effects

[0022] According to the diode detection circuit of the present invention, the presence of the diode set on the CP control guide circuit can be detected while avoiding bottom distortion. Furthermore, without affecting the interaction between the PWM waveform output by the AC charging pile and the vehicle, the waveform is converted by the circuit so that the output signal can be acquired by the microcontroller of the AC charging pile without auxiliary power supply processing. Attached Figure Description

[0023] This disclosure can be better understood by describing exemplary embodiments of the present disclosure in conjunction with the accompanying drawings, in which:

[0024] Figure 1 This is a schematic diagram representing the guiding principle in the latest general requirements for charging systems, GB / T 18487.1-2023.

[0025] Figure 2 This is a schematic diagram of the diode detection circuit according to an embodiment of the present invention.

[0026] Figure 3 This is a flowchart of a diode detection method according to an embodiment of the present invention.

[0027] Figure 4 This is a flowchart of a diode detection method according to an embodiment of the present invention.

[0028] Label Explanation:

[0029] 100 Diode detection circuit; 1 Voltage follower circuit; 2 Transient amplifier circuit; 3 Voltage divider sampling circuit; U1 Follower operational amplifier; U2 Inverting operational amplifier; C11 First capacitor; C22 Second capacitor; C33 Third capacitor; C44 Fourth capacitor; C55 Fifth capacitor; D1 Diode; D11 First diode; D22 Second diode; D33 Third diode; R11 First resistor; R22 Second resistor; R33 Third resistor; R44 Fourth resistor; R55 Fifth resistor; GND Ground; VCC AC power supply; CP_IN Diode detection circuit input terminal; CP_ADC_D Diode detection circuit output terminal (sampling terminal); C1, C2 Contactors; S1, S2, S3 Switches; R1, R2, R3, RC resistors. Detailed Implementation

[0030] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0031] In the description of this disclosure, it should be noted that, unless otherwise stated, "a plurality of" means two or more. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that, unless otherwise expressly specified and limited, the terms "connected," "linked," "relative," "interlocking," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0032] In this document, the term "implementation" means that a particular feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same implementation, nor is it a separate or alternative implementation mutually exclusive with other implementations. It will be explicitly and implicitly understood by those skilled in the art that the implementations described herein can be combined with other implementations.

[0033] Diode Presence Test Standard

[0034] Figure 1 This represents the guiding schematic diagram from the latest general requirements for charging systems, GB / T 18487.1-2023. For example... Figure 1 As shown, the charging system consists of electric vehicle power supply equipment, a vehicle interface, and an electric vehicle. Figure 1 The diode D1 located on the electric vehicle side of the CP control guide circuit is required to undergo diode presence detection in A.2.6 of GB / T18487.1-2023. That is, before energy transmission, the power supply equipment should be able to verify that the connected device is an electric vehicle and not a load device by detecting the presence of diode D1 on the control conductor. This detection should be performed at least once before the power supply equipment turns on the AC power supply circuit, from state X (X = 1, 2, 3, defined in Table A.5 (partial excerpt below)) to state X' or during state X'.

[0035] Specifically, as shown in Table A.5 below, state X / state X' refers to the charging process state. When state X = 1 (state 1), it means that switch S1 is connected to the +12V of the power supply equipment, and switch S2 is in the open state. At this time, the power supply equipment and the electric vehicle are not connected, so the voltage value detected at detection point 1 is +12V. When state X' = 1' (state 1'), it means that switch S1 in the power supply equipment switches to PWM and generates a ±12V square wave, and switch S2 is in the open state. At this time, the power supply equipment and the electric vehicle are still not connected, and a PWM waveform signal with a voltage value of ±12V will be detected at detection point 1.

[0036] When state X = 2 (state 2), it indicates that switch S1 is connected to the +12V of the power supply equipment, and switch S2 is in the open state. At this time, the power supply equipment is connected to the electric vehicle, meaning the power supply equipment is ready to charge, but the electric vehicle is not yet ready to charge. Due to the voltage division effect of R3, the voltage detected at detection point 1 is +9V. When state X' = 2' (state 2'), it indicates that switch S1 in the power supply equipment switches to PWM and generates a ±12V square wave, and switch S2 is in the open state. Due to the voltage division effect of R3 and the fact that diode D1 placed on the CP control guide circuit can only allow positive voltage to pass, PWM waveform signals with voltage values ​​of +9V and -12V will be detected at detection point 1.

[0037] When state X = 3 (state 3), it indicates that switch S1 is connected to the +12V of the power supply equipment, and switch S2 is closed. At this time, the power supply equipment is connected to the electric vehicle, but the power supply equipment is not yet ready to charge while the electric vehicle is ready to charge. Due to the voltage division effect of R2, the voltage detected at detection point 1 is +6V. When state X' = 3' (state 3'), it indicates that switch S1 in the power supply equipment switches to PWM and generates a ±12V square wave, and switch S2 is closed. At this time, the power supply equipment and the electric vehicle are in a charging state. Due to the voltage division effect of R2 and the fact that diode D1 placed on the CP control guide circuit can only allow positive voltage to pass, PWM waveform signals with voltage values ​​of +6V and -12V will be detected at detection point 1.

[0038] The detection of the presence of diode D1 in the control conductor must be performed at least once during the following periods: from state 1 to state 1', from state 2 to state 2', from state 3 to state 3', during state 1', during state 2', and during state 3'. This control conductor is also called the CP control pilot circuit or control pilot circuit.

[0039] Table A.5 Voltage status and corresponding charging process status at detection point 1

[0040]

[0041] Embodiments of the Invention

[0042] According to the requirements for diode presence detection, when the charging process is in state 1', state 2', or state 3', the voltage at detection point 1 is always -12V. This is because diode D1 in the CP control guide circuit can only allow positive voltage to pass through and cannot allow negative voltage to pass through. Therefore, when the power supply outputs a ±12V PWM waveform, the positive PWM waveform will be detected at detection point 1 with a voltage value of +12V, +9V, or +6V due to the voltage division effect of R2 and R3 on the electric vehicle side. However, the PWM waveform with a voltage value of -12V will not change due to the voltage division effect of R2 and R3 and will always remain at -12V. Here, only the nominal value is used as an example for explanation. The voltage detected at detection point 1 should be within the range of the maximum and minimum values ​​shown in Table A.5 above.

[0043] Therefore, this embodiment provides a diode detection circuit that determines whether diode D1 exists in the CP control guide circuit and whether it is connected to an electric vehicle by detecting the negative voltage at detection point 1. In this invention, the power supply equipment is sometimes also referred to as an AC charging pile.

[0044] The specific structure of the diode detection circuit of the present invention will be described below. Figure 2 This is a schematic diagram of the diode detection circuit according to an embodiment of the present invention. Furthermore, for ease of explanation, the detection of the presence of diode D1 on the CP control guide circuit during the transition from state 3 to state 3' is used as an example. When the charging state transitions from state 3 to state 3', a PWM waveform signal with a frequency of 1kHz and a voltage value of ±12V is output from the power supply device. This PWM waveform signal is output to the positive terminal of D1 in the CP control guide circuit via detection point 1, forming a voltage divider through D1, R2, and R3. Simultaneously, the input terminal CP_IN of the diode detection circuit of the present invention is connected to detection point 1 to detect the voltage waveform at detection point 1.

[0045] The diode detection circuit of this invention includes a voltage follower circuit 1, an inverting amplifier circuit 2, and a voltage divider sampling circuit 3. The input terminal of the diode detection circuit is set as CP_IN, and the output terminal is set as CP_ADC_D.

[0046] Voltage Follower Circuit 1

[0047] The voltage follower circuit 1 takes a CP control pilot signal from the power supply device as a PWM signal as input and outputs a voltage follower signal obtained by voltage following the control pilot signal.

[0048] Specifically, the voltage follower circuit 1 includes a follower operational amplifier U1, a first capacitor C11, and a second capacitor C22. The positive input terminal (pin 1) of the follower operational amplifier U1 is connected to the input terminal CP_IN of the diode detection circuit, and the negative input terminal (pin 3) of the follower operational amplifier U1 is short-circuited to the output terminal (pin 4). One end of the first capacitor C11 is connected to the positive power supply VCC+12V of the follower operational amplifier U1, and the other end is grounded. One end of the second capacitor C22 is connected to the negative power supply VCC-12V of the follower operational amplifier U1, and the other end is grounded.

[0049] Therefore, the PWM waveform signal input from the input terminal CP_IN of the diode detection circuit is voltage followed by the voltage follower circuit 1 to obtain a signal with the same magnitude as the input PWM waveform signal. Simultaneously, it removes some noise signals accompanying the PWM waveform signal caused by wiring, etc., so that the inverting amplifier circuit 2 described later is unaffected by these noise signals. Furthermore, the first capacitor C11 and the second capacitor C22 are mainly used for filtering noise from the power supply.

[0050] For example, in this embodiment, when the charging state of the power supply equipment and the electric vehicle changes from state 3 to state 3', the diode detection circuit is connected to the detection point 1 of the power supply equipment. The ±12V PWM waveform signal input at the input terminal CP_IN of the diode detection circuit is output as a voltage follower signal with the same ±12V PWM waveform signal after noise removal via the voltage follower circuit 1.

[0051] Inverting amplifier circuit 2

[0052] The input terminal of the inverting amplifier circuit 2 is connected to the output terminal of the voltage follower circuit 1 (pin 4 of the follower operational amplifier U1). It only inputs the negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit 1 and performs inversion operation to output a positive voltage PWM signal with the same voltage value but opposite direction as the inverting amplifier signal.

[0053] Specifically, the inverting amplifier circuit 2 includes a first diode D11, an inverting operational amplifier U2, a first resistor R11, a second resistor R22, a third resistor R33, a third capacitor C33, and a fourth capacitor C44. The negative terminal (pin 2) of the first diode D11 is connected to the output terminal (pin 4) of the voltage follower circuit 1, i.e., the output terminal of the voltage follower amplifier U1. This connection allows the negative voltage PWM signal received from the voltage follower circuit 1 to pass through, while blocking the positive voltage PWM signal received from the voltage follower circuit 1. For example, when the ±12V PWM waveform signal, which serves as the voltage follower signal, passes through the first diode D11, because the first diode D11 is in reverse configuration, only the -12V PWM waveform signal can pass through, while the +12V PWM waveform signal is filtered out. Therefore, a negative voltage PWM waveform signal is output from the positive terminal (pin 1) of the inverted first diode D11.

[0054] The negative input terminal (pin 3) of the inverting operational amplifier U2 is connected to the positive terminal of the first diode D11 (pin 1) via the first resistor R11, and is connected to the output terminal (pin 4) of the inverting operational amplifier U2 via the second resistor R22. The positive input terminal (pin 1) of the inverting operational amplifier U2 is grounded via the third resistor R33. One end of the third capacitor C33 is connected to the negative power supply VCC-12V of the inverting operational amplifier U2, and the other end is grounded. One end of the fourth capacitor C44 is connected to the positive power supply VCC+12V of the inverting operational amplifier U2, and the other end is grounded.

[0055] The principle of the inverting operational amplifier U2 is explained. According to Ohm's law: current = voltage / resistance, we know that (Vin - (v-)) / R22 = ((v-) - Vout) / R11. Therefore, Vin / R22 = -Vout / R11, Vout = -Vi * R11 / R22. Since the output from pin 1 of the first diode D11 is a -12V PWM waveform signal, and R22 and R11 both use the same resistance value of 10K, Vout = -(-12V) * 10k / 10k = 12V. Thus, the inverting amplifier circuit 2 outputs a +12V PWM waveform signal with the same magnitude but opposite direction to the input -12V PWM waveform signal as the inverting amplification signal.

[0056] Voltage divider sampling circuit 3

[0057] The voltage divider sampling circuit 3 divides the inverted amplified signal output from the inverting amplifier circuit 2, clamps the voltage value of the voltage sampling signal obtained after voltage division, and outputs the voltage sampling signal for the microcontroller of the power supply equipment to collect voltage.

[0058] Specifically, the voltage divider sampling circuit 3 includes a fourth resistor R44, a fifth resistor R55, a second diode D2, a third diode D3, and a fifth capacitor C55. One end of the fourth resistor R44 is connected to the output terminal (pin 4) of the inverting operational amplifier circuit 2, i.e., the output terminal of the inverting operational amplifier U3. One end of the fifth resistor R55 is connected to the other end of the fourth resistor R44, and the other end of the fifth resistor R55 is grounded. The cathode of the second diode D22 is connected to one end of the fifth resistor R55, and the anode of the second diode D22 is grounded. The anode of the third diode D33 is connected to one end of the fifth resistor R55, and the cathode of the third diode D33 is connected to VCC + 3.3V. One end of the fifth capacitor C55 is connected to one end of the fifth resistor R55 and the output terminal CP_ADC_D of the diode detection circuit, and the other end of the fifth capacitor C55 is grounded to filter out noise coupled into the circuit. In addition, the output terminal CP_ADC_D of the diode detection circuit is connected to the sampling port ADC (not shown) of the microcontroller of the power supply device. For example, the +12V PWM waveform signal output from the inverting operational amplifier circuit 2 is divided by the fourth resistor R44 and the fifth resistor R55 to obtain a voltage-divided sampling signal. The second diode D22 and the third diode D33 form a clamping diode, ensuring that the voltage-divided sampling signal is always clamped within the range of 0 to 3.3V, thereby protecting the microcontroller of the downstream power supply equipment.

[0059] The circuit structure of the diode detection circuit of the present invention has been described above.

[0060] When the microcontroller of the power supply equipment can acquire a voltage sampling signal within the range of 0 to 3.3V, it indicates that the negative voltage PWM signal of the CP control guidance signal input to the voltage follower circuit 1 is within the specified voltage range (i.e., the voltage detected at detection point 1 is within the range of -13V to -11V as specified in Table A). Therefore, it can be determined that the diode located at the electric vehicle terminal on the control guidance circuit exists and is connected to the electric vehicle. Conversely, when the microcontroller of the power supply equipment can acquire a voltage sampling signal within the range of 0 to 3.3V, it indicates that the negative voltage PWM signal detected by the diode detection circuit 100 at detection point 1 is -12V. Therefore, it can be determined that a diode exists on the control guidance circuit and is connected to the electric vehicle.

[0061] The above explanation addresses the case where diode D1 is present in the CP control guide circuit. On the other hand, when diode D1 is absent in the CP control guide circuit, since the negative voltage signal of the PWM waveform output from the power supply also passes through R2 and R3, after voltage division by R2 and R3, the voltage detectable at detection point 1 could be not only -12V, but also -9V or -6V. Therefore, after detection by the diode detection circuit 100 of this invention, the voltage output at the output terminal CP_ADC_D may be a voltage that the microcontroller of the power supply cannot acquire. That is, when the microcontroller of the power supply cannot acquire the voltage sampling signal, it indicates that the voltage value of the negative voltage PWM signal input to the voltage follower circuit is outside the specified range. Therefore, it can be determined that the diode located at the electric vehicle terminal in the control guide circuit is absent, and the connected component is not an electric vehicle but a load.

[0062] The above explanation uses the example of detecting diode D1 on the CP control guide circuit when the charging state of the power supply equipment and the electric vehicle changes from state 3 to state 3'. This also applies to other situations. Additionally, the same detection can be performed each time the charging state changes from state 1 to state 1', from state 2 to state 2', during state 1', during state 2', and during state 3', but it must be performed at least once.

[0063] This allows for the detection of the diodes on the CP control guide circuit while avoiding bottom distortion. Furthermore, without affecting the interaction between the power supply equipment's output PWM waveform and the vehicle, waveform conversion is performed via the diode detection circuit, enabling the output signal to be acquired by the power supply equipment's microcontroller without auxiliary power supply processing. By determining whether the connected device is a load or an electric vehicle and feeding back the status to the microcontroller, diverse charging application scenarios can be provided.

[0064] Below, please refer to the appendix. Figure 3 and 4 The diode detection method of the present invention will be described. Figure 3 This is a flowchart of a diode detection method according to an embodiment of the present invention. Figure 4 This is a flowchart of a diode detection method according to an embodiment of the present invention.

[0065] For ease of explanation, we will take the detection of the presence of diode D1 on the CP control circuit when the charging state changes from state 3 to state 3' as an example.

[0066] The diode detection method of the present invention is based on a diode detection circuit used to detect the presence of a diode located at the electric vehicle end of the CP control guidance circuit when an AC charging pile is connected to an electric vehicle via a control guidance circuit. Figure 3 As shown, in step S1, it is first confirmed whether diode detection is required, i.e., whether the charging state is from state X to state X' or during state X'. If the answer in step S1 is "yes", in step S2, the input terminal of the diode detection circuit of the present invention is connected to the detection point 1 of the power supply device. Then, in step S3, the control guidance signal formed as a PWM signal (±12V) for the power supply device is input using the voltage follower circuit 1, and the voltage follower signal obtained after voltage following the control guidance signal is output. In step S4, the negative voltage (-12V) PWM signal from the voltage follower signal output from the voltage follower circuit is input only using the inverting amplifier circuit 2, and the inversion operation is performed to output a positive voltage PWM signal (+12V) with the same voltage value but opposite direction as the negative voltage PWM signal as the inverting amplifier signal. In step S5, the voltage divider sampling circuit 3 is used to divide the inverted amplified signal output from the inverting amplifier circuit 2, and the voltage value of the voltage sampling signal obtained after voltage division is clamped to clamp the voltage value of the voltage sampling signal between 0 and 3.3V. At the same time, the voltage sampling signal is output for the controller of the power supply equipment to collect voltage.

[0067] In addition, such as Figure 4 As shown, in step S6, it is confirmed whether the microcontroller of the power supply equipment can acquire the voltage sampling signal. When the microcontroller of the power supply equipment can acquire the voltage sampling signal, in step S7, the voltage value of the negative voltage PWM signal of the control guidance signal input to the voltage follower circuit 1 is within the specified range (-13V to -11V, for example -12V). Therefore, in step S8, it can be determined that the diode located at the electric vehicle end on the control guidance circuit exists and is connected to the electric vehicle.

[0068] Furthermore, when the controller of the power supply equipment cannot acquire the aforementioned voltage sampling signal, the voltage value of the negative voltage PWM signal of the control guidance signal input to the voltage follower circuit 1 in step S9 is not within the specified range. Therefore, in step S10, it can be determined that the diode located at the electric vehicle end on the control guidance circuit is not present.

[0069] The diode detection circuit method of this invention can detect the presence of diodes on the CP control guide circuit while avoiding bottom distortion. Furthermore, without affecting the interaction between the PWM waveform output by the power supply equipment and the vehicle, the diode detection circuit performs waveform conversion, allowing the output signal to be acquired by the microcontroller of the power supply equipment without auxiliary power supply processing. By determining whether the connected device is a load or an electric vehicle and feeding back the status to the microcontroller, it can provide diversity for charging application scenarios.

[0070] It should be understood that the above description is illustrative and not restrictive. For example, the above embodiments (and / or aspects thereof) can be used in combination with each other. Furthermore, many modifications can be made to adapt particular conditions or materials to the teachings of the various embodiments of the invention without departing from the scope of the invention. Many other embodiments will become apparent to those skilled in the art upon reading the above description. Therefore, the scope of the various embodiments of the invention should be determined by reference to the appended claims and the full scope of their equivalents.

Claims

1. A diode detection circuit for detecting the presence of a diode located at the electric vehicle end of the control guidance circuit when an AC charging pile is connected to an electric vehicle via a control guidance circuit, characterized in that, include: A voltage follower circuit is provided, which takes a control guidance signal formed as a PWM signal from the AC charging pile as input and outputs a voltage follower signal obtained by voltage following the control guidance signal. An inverting amplifier circuit that takes only a negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit as input, performs an inversion operation, and outputs a positive voltage PWM signal with the same voltage value but opposite direction as the negative voltage PWM signal as the inverting amplifier signal; and A voltage divider sampling circuit divides the inverted amplified signal output from the inverting amplifier circuit, clamps the voltage value of the resulting voltage sampling signal, and outputs the voltage sampling signal for voltage acquisition by the controller of the AC charging pile. When the controller of the AC charging pile can acquire the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is within the specified range. Therefore, it can be determined that the diode located at the electric vehicle end on the control guidance circuit is present. When the controller of the AC charging pile cannot collect the voltage sampling signal, the voltage value of the negative voltage PWM signal of the control guidance signal input to the voltage follower circuit is not within the specified range, which can be used to determine that the diode located at the electric vehicle end on the control guidance circuit is not present.

2. The diode detection circuit as described in claim 1, characterized in that, The voltage follower circuit includes a follower operational amplifier, a first capacitor, and a second capacitor, wherein... The positive input terminal of the follower operational amplifier is connected to the AC charging pile, and the negative input terminal of the follower operational amplifier is short-circuited to its output terminal. One end of the first capacitor is connected to the positive power supply of the follower operational amplifier, and the other end is grounded. One end of the second capacitor is connected to the negative power supply of the follower operational amplifier, and the other end is grounded.

3. The diode detection circuit as described in claim 1, characterized in that, The inverting amplifier circuit includes a first diode, an inverting operational amplifier, a first resistor, a second resistor, a third resistor, a third capacitor, and a fourth capacitor, wherein... The cathode of the first diode is connected to the output terminal of the voltage follower circuit, allowing the negative voltage PWM signal of the voltage follower signal received from the voltage follower circuit to pass through. The negative input terminal of the inverting operational amplifier is connected to the positive terminal of the first diode via the first resistor, and to the output terminal of the inverting operational amplifier via the second resistor. The positive input terminal of the inverting operational amplifier is grounded via the third resistor. One end of the third capacitor is connected to the negative power supply of the inverting operational amplifier, and the other end is grounded. One end of the fourth capacitor is connected to the positive power supply of the inverting operational amplifier, and the other end is grounded.

4. The diode detection circuit as described in claim 3, characterized in that, The first resistor and the second resistor have the same resistance value.

5. The diode detection circuit as described in claim 1, characterized in that, The voltage divider sampling circuit includes a fourth resistor, a fifth resistor, a second diode, a third diode, and a fifth capacitor. One end of the fourth resistor is connected to the output terminal of the inverting operational amplifier circuit. One end of the fifth resistor is connected to the other end of the fourth resistor, and the other end of the fifth resistor is grounded. The cathode of the second diode is connected to one end of the fifth resistor, and the anode of the second diode is grounded. The positive terminal of the third diode is connected to one end of the fifth resistor, and the negative terminal of the third diode is connected to a 3.3V voltage. One end of the fifth capacitor is connected to one end of the fifth resistor and to the controller of the AC charging pile; the other end of the fifth capacitor is grounded. The inverted amplified signal output from the inverting operational amplifier is divided by the fourth resistor and the fifth resistor. The second diode and the third diode constitute a clamping diode, clamping the voltage-divided sampling signal obtained after voltage division within the range of 0 to 3.3V.

6. A diode detection method, based on a diode detection circuit for detecting the presence of a diode located at the electric vehicle end on the control guidance circuit when an AC charging pile is connected to an electric vehicle via a control guidance circuit, characterized in that... A control guidance signal, formed as a PWM signal, is input from the AC charging pile using a voltage follower circuit, and a voltage follower signal is output after voltage following the control guidance signal. By using an inverting amplifier circuit to input only the negative voltage PWM signal from the voltage follower signal output from the voltage follower circuit, and performing an inversion operation, a positive voltage PWM signal with the same voltage value but opposite direction as the negative voltage PWM signal is output as the inverting amplifier signal. The inverted amplified signal output from the inverting amplifier circuit is divided using a voltage divider sampling circuit, and the voltage value of the resulting voltage sampling signal is clamped. Simultaneously, the voltage sampling signal is output for voltage acquisition by the charging pile's controller. When the controller of the AC charging pile can acquire the voltage sampling signal, the voltage value of the PWM signal of the negative voltage of the control guidance signal input to the voltage follower circuit is within the specified range. Therefore, it can be determined that the diode located at the electric vehicle end on the control guidance circuit is present. When the controller of the AC charging pile cannot collect the voltage sampling signal, the voltage value of the negative voltage PWM signal of the control guidance signal input to the voltage follower circuit is not within the specified range, which can be used to determine that the diode located at the electric vehicle end on the control guidance circuit is not present.

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