Control circuit and method suitable for electric vehicle charging equipment
By introducing reference voltage and signal comparison technology, the problem of switching error of the control pilot signal voltage level in the electric vehicle charging system is solved, error compensation and closed-loop detection are achieved, and the stability of the electric vehicle charging process is ensured.
Patent Information
- Application Number
- CN202410269959.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-11
- Publication Date
- 2025-09-12
AI Technical Summary
Existing electric vehicle charging systems lack compatible control over the timing of connecting the charging gun and coupler and switching voltages, resulting in errors when switching the control guidance signal voltage level. These systems are unable to adapt to different types of charging guns and couplers, potentially leading to charging anomalies.
By introducing a reference voltage, the actual voltage is compared with the sensed signal under the reference voltage through a signal generator, a PWM unit, a relay, and a sensing circuit to obtain the error value and compensate for it, thus realizing the closed-loop detection and control guidance signal capability.
Effectively eliminate sensing errors, avoid interruptions or abnormalities in the electric vehicle charging process, and ensure the stability and reliability of the charging process.
Smart Images
Figure CN120621132A_ABST
Abstract
Description
Technical Field
[0001] This case involves a control circuit and method, and in particular, a control circuit and method suitable for electric vehicle charging equipment. Background Art
[0002] Current EV charging systems lack optimized compatibility control during the connection and voltage switching between the charging gun and the EV's coupler. This can lead to errors in the detection of the pilot signal voltage level during coupler connection and control due to differences in the charging gun and coupler configurations. Because the coupler operates in an open circuit and lacks the adaptability to adapt to compatibility, it cannot adjust for these errors. Consequently, when these errors occur, the charging system may malfunction and fail to charge the EV.
[0003] Therefore, it is an urgent need to invent a control circuit and method for electric vehicle charging equipment that can improve the above-mentioned prior art. Summary of the Invention
[0004] The purpose of this application is to provide a control circuit and method for electric vehicle charging equipment. This circuit introduces a reference voltage and compares the reference voltage with the actual voltage sensed control pilot signal to determine the error. The control pilot signal at the actual voltage is then compensated based on the error. This enables the electric vehicle charging equipment to detect the control pilot signal in a closed-loop manner and compensate for errors, thereby preventing interruptions or abnormalities in the electric vehicle charging process caused by these errors.
[0005] To achieve the above-mentioned purpose, the present invention provides a control circuit suitable for an electric vehicle charging device, comprising a signal generator, a PWM unit, a relay and a sensing circuit. The signal generator is configured to generate a voltage signal. The PWM unit is configured to perform pulse width modulation and is electrically connected to a control pilot signal between the electric vehicle charging device and the electric vehicle. The relay can selectively switch the PWM unit to be electrically connected to a voltage signal or a reference voltage. The sensing circuit is configured to sense the control pilot signal and generate a sensing signal. The control circuit can selectively execute a first mode or a second mode. In the first mode, the relay switches the PWM unit to be electrically connected to the voltage signal, and in the second mode, the relay switches the PWM unit to be electrically connected to the reference voltage. The control circuit obtains an error value by comparing the sensing signal in the first mode with the sensing signal in the second mode, and compensates the control pilot signal according to the error value when executing the first mode.
[0006] To achieve the above-mentioned objectives, the present invention further provides a control method for an electric vehicle charging device, comprising the following steps: (a) providing a signal generator, a PWM unit, a relay, and a sensing circuit, wherein the signal generator is configured to generate a voltage signal, the PWM unit is configured to perform pulse width modulation, and is electrically connected to a control pilot signal between the electric vehicle charging device and the electric vehicle, the relay can selectively switch the PWM unit to be electrically connected to a voltage signal or a reference voltage, and the sensing circuit is configured to sense the control pilot signal; (b) selectively executing a first mode or a second mode, wherein in the first mode, the relay is controlled to switch the PWM unit to be electrically connected to the voltage signal, and in the second mode, the relay is controlled to switch the PWM unit to be electrically connected to the reference voltage; and comparing the sensing signal in the first mode with the sensing signal in the second mode to obtain an error value, and compensating the control pilot signal according to the error value when executing the first mode. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 The waveforms of the control guidance signal in different states are illustrated;
[0008] Figure 2 and Figure 3 The waveforms of the control pilot signal and the output of the electric vehicle charging device during the charging process are illustrated;
[0009] Figure 4 This is a schematic diagram of the structure of a control circuit applicable to an electric vehicle charging device in one embodiment of the present case;
[0010] Figure 5 This is a control method applicable to electric vehicle charging equipment in one embodiment of this case.
[0011] Description of Figure Numbers:
[0012] 1: Control circuit
[0013] 11: Signal generator
[0014] 12: PWM unit
[0015] 13: Relay
[0016] 14: Sensing circuit
[0017] CP: Control Pilot Signal
[0018] P1: moving contact
[0019] P2: First static contact
[0020] P3: Second static contact
[0021] Vref: reference voltage
[0022] 15: Control unit
[0023] S1, S2, S3: Steps
[0024] A, B1, B2, C, D, E: Status
[0025] t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12: time DETAILED DESCRIPTION
[0026] Some typical embodiments that embody the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different embodiments without departing from the scope of this invention.
[0027] In electric vehicle charging applications, the electric vehicle charger and the electric vehicle communicate by handshaking via control pilot signals. Depending on the waveform and voltage level of the control pilot signals, the electric vehicle charger and the electric vehicle enter different states and perform corresponding actions.
[0028] Figure 1 The waveforms of the control guidance signal in different states are shown as examples. Figure 1 As shown, in state A, the EV charger is not yet connected to the EV. At this time, the control pilot signal CP is at a first voltage level (e.g., 12V). In state B1, the EV charger is connected to the EV, but the EV is not yet ready to receive power. Due to the voltage offset at the EV end, the control pilot signal CP drops to a second voltage level (e.g., 9V). In state B2, similar to state B1, the EV charger is connected to the EV, but the EV is not yet ready to receive power. At this time, the control pilot signal CP is a PWM (pulse width modulation) signal, where the high level of the PWM signal is at a second voltage level and the low level of the PWM signal is at a third voltage level (e.g., -12V). In state C, the EV charger is connected to the EV, and the EV is ready to receive power. At this time, the control pilot signal CP is a PWM signal, where the high level of the PWM signal drops to a fourth voltage level (e.g., 6V) due to the voltage offset at the EV end, while the low level of the PWM signal remains at the third voltage level (e.g., -12V). In state D, the electric vehicle charging device may be disconnected, unable to provide stable power, or in other abnormal operating conditions, and the control pilot signal CP is zero. In state E, the electric vehicle charging device may be unable to provide power, or in other abnormal operating conditions, and the control pilot signal CP is at a third voltage level (e.g., -12V).
[0029] To understand the waveform changes and corresponding states of the control guidance signal during the charging process of electric vehicles, Figure 2 and Figure 3 The waveforms of the control pilot signal and the output of the electric vehicle charging device during the charging process are shown in the following example. The difference between the two examples is that Figure 2 In the example, charging is stopped according to the command from the electric vehicle, and Figure 3 In the example, charging is stopped by disconnecting the electric vehicle (for example, pulling out the charging gun).
[0030] like Figure 2 As shown, at time t1, the EV charger is connected to the EV, and the corresponding state of the control pilot signal CP changes from state A to state B1. At time t2, high-frequency communication begins between the EV charger and the EV, and the corresponding state of the control pilot signal CP changes from state B1 to state B2. At time t3, the EV is ready to receive power, and the corresponding state of the control pilot signal CP changes from state B2 to state C. After a period of time, at time t4, the EV charger begins supplying power to the EV to charge it. At time t5, the EV issues a command to stop charging, and the corresponding state of the control pilot signal CP changes from state C to state B2. After a period of time, at time t6, the EV charger stops supplying power. At time t7, the EV is disconnected.
[0031] exist Figure 3 In the example, the process of entering the state of charging the electric vehicle is the same as Figure 2 The example is similar to Figure 3 The actions performed at times t8, t9, t10 and t11 and the changes in the control pilot signal CP correspond to Figure 2 The actions performed at time t1, t2, t3 and t4 and the changes in the control pilot signal CP are not described here. Figure 3 In the example, after charging the electric vehicle for a period of time, at time t12, the electric vehicle is disconnected, and the electric vehicle charging device stops supplying power after a short period of time.
[0032] As can be seen from the above examples, the waveform changes of the control pilot signal closely correspond to the changes in the operation of the electric vehicle charging equipment and the electric vehicle. Therefore, the accuracy of the sensing of the control pilot signal is very important in electric vehicle charging applications. If there is a deviation in the sensing of the control pilot signal, it may cause the electric vehicle charging equipment to stop supplying power to the electric vehicle, resulting in charging interruption. In actual applications, there are many possible factors that may cause deviations in the sensing of the control pilot signal. For example, in the sensing circuit that senses the control pilot signal, its input impedance may cause deviations. When the electric vehicle charging equipment is connected to the electric vehicle, different types of charging guns or different types of vehicles (with different couplers) may also cause different degrees of deviation in the sensing of the control pilot signal.
[0033] In order to eliminate the deviation and avoid affecting the charging process, this case provides a control circuit suitable for electric vehicle charging equipment. Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the control circuit structure of an electric vehicle charging device in an embodiment of the present invention. Figure 4 As shown, the control circuit 1 includes a signal generator 11, a PWM unit 12, a relay 13, and a sensing circuit 14. The signal generator 11 is configured to generate a voltage signal. The PWM unit 12 is configured to perform pulse width modulation on the received signal, and the PWM unit 12 is electrically connected to the control pilot signal CP between the electric vehicle charging device and the electric vehicle. The relay 13 can selectively switch the PWM unit 12 to be electrically connected to the voltage signal generated by the signal generator 11 or a reference voltage Vref. For example, the relay 13 includes a moving contact P1, a first stationary contact P2, and a second stationary contact P3, which are respectively connected to the PWM unit 12, the signal generator 11, and the reference voltage Vref. When the relay 13 switches the moving contact P1 to connect to the first stationary contact P2, the PWM unit 12 is electrically connected to the signal generator 11 via the relay 13; when the relay 13 switches the moving contact P1 to connect to the second stationary contact P3, the PWM unit 12 is electrically connected to the reference voltage Vref via the relay 13. The sensing circuit 14 is electrically connected to the control pilot signal CP, and is configured to sense the control pilot signal CP and generate a sensing signal accordingly.
[0034] The control circuit 1 can selectively operate in a first mode or a second mode. In the first mode, the relay 13 switches the PWM unit 12 electrically connected to the voltage signal generated by the signal generator 11. In the second mode, the relay 13 switches the PWM unit 12 electrically connected to the reference voltage Vref. The control circuit 1 compares the sensed signal in the first mode with the sensed signal in the second mode to obtain an error value. When operating in the first mode, the control circuit 1 compensates the control pilot signal CP based on the error value. In some embodiments, the signal generator 11 adjusts the generated voltage signal based on the error value to compensate for the control pilot signal CP, thereby eliminating the error in the sensed control pilot signal CP.
[0035] Thus, the electric vehicle charging device can have the ability to detect the control pilot signal CP in a closed loop and compensate for the sensing error of the control pilot signal CP to avoid interruption or abnormality in the charging process of the electric vehicle caused by the sensing error.
[0036] Furthermore, as can be seen from the foregoing, when the EV charger is connected to an EV, the EV charger and the EV each perform different actions when the control pilot signal CP is at different voltage levels. For example, these actions may include the EV charger and the EV performing high-frequency communication, the EV charger charging the EV, and the EV charger ceasing charging the EV. Accordingly, the reference voltage Vref encompasses all possible voltage levels of the control pilot signal CP (e.g., 12V, 9V, and 6V). Thus, when the control circuit 1 operates in the first mode, regardless of the voltage level of the control pilot signal CP, the sensed signal can be compared with the sensed signal obtained in the second mode at the corresponding reference voltage Vref level to obtain an error value.
[0037] In some embodiments, the control circuit 1 further includes a control unit 15 configured to control the switching of the relay 13 to cause the control circuit 1 to operate in the first mode or the second mode. In some embodiments, when the EV charger is not connected to the EV, or when the EV charger is connected to the EV but not charging the EV, the control unit 15 controls the relay 13 to electrically connect the PWM unit 12 to the reference voltage Vref, causing the control circuit 1 to operate in the second mode. It should be noted that the control circuit 1 may not operate in the second mode at all times. For example, when the EV charger is charging the EV, the control circuit 1 should avoid operating in the second mode to prevent the reference voltage Vref from affecting the waveform of the control pilot signal CP and causing charging interruption.
[0038] Figure 5 This is a control method applicable to an electric vehicle charging device in one embodiment of the present invention. This control method is applicable to the control circuit 1 in the above embodiment. Figure 5 As shown, the control method includes steps S1, S2, and S3. In step S1, a signal generator 11, a PWM unit 12, a relay 13, and a sensing circuit 14 are provided. The signal generator 11 is configured to generate a voltage signal, the PWM unit 12 is configured to perform pulse width modulation and is electrically connected to a control pilot signal CP between the electric vehicle charger and the electric vehicle. The relay 13 can selectively switch the PWM unit 12 to be electrically connected to the voltage signal or a reference voltage Vref, and the sensing circuit 14 is configured to sense the control pilot signal CP. In step S2, a first mode or a second mode is selectively executed. In the first mode, the relay 13 is controlled to switch the PWM unit 12 to be electrically connected to the voltage signal, while in the second mode, the relay 13 is controlled to switch the PWM unit 12 to be electrically connected to the reference voltage Vref. In step S3, the sensing signal in the first mode and the sensing signal in the second mode are compared to obtain an error value. When executing the first mode, the control pilot signal CP is compensated based on the error value.
[0039] In summary, this application provides a control circuit and method for electric vehicle charging equipment. This circuit introduces a reference voltage and compares the reference voltage with the actual voltage sensed signal of the control pilot signal to determine the sensing error. The control pilot signal at the actual voltage is then compensated based on the sensing error. This enables the electric vehicle charging equipment to detect the control pilot signal in a closed-loop manner and compensate for the sensing error, thereby preventing interruptions or abnormalities in the electric vehicle charging process caused by the sensing error.
[0040] It should be noted that the above description is merely a preferred embodiment for the purpose of illustrating the present invention. The present invention is not limited to the described embodiment. The scope of the present invention is determined by the appended patent claims. Furthermore, the present invention is subject to various modifications conceived by those skilled in the art without departing from the intended protection of the appended patent claims.
Claims
1. A control circuit, suitable for electric vehicle charging equipment, comprising: A signal generator configured to generate a voltage signal; A PWM unit configured to perform pulse width modulation and electrically connected to a control pilot signal between the electric vehicle charging device and the electric vehicle; a relay, selectively switching the PWM unit to be electrically connected to the voltage signal or the reference voltage; as well as The sensing circuit is configured to sense the control pilot signal and generate a sensing signal. The control circuit can selectively execute a first mode or a second mode. In the first mode, the relay switches the PWM unit to be electrically connected to the voltage signal. In the second mode, the relay switches the PWM unit to be electrically connected to the reference voltage. The control circuit obtains an error value by comparing the sensing signal in the first mode with the sensing signal in the second mode, and compensates the control pilot signal according to the error value when executing the first mode.
2. The control circuit according to claim 1 further comprises a control unit, wherein the control unit is configured to control the switching of the relay so that the control circuit executes the first mode or the second mode; when the electric vehicle charging device is not connected to the electric vehicle, or when the electric vehicle charging device is connected to the electric vehicle but is not charging the electric vehicle, the control unit controls the relay to switch the PWM unit to be electrically connected to the reference voltage so that the control circuit executes the second mode.
3. The control circuit according to claim 1, wherein the relay includes a moving contact, a first stationary contact, and a second stationary contact, which are respectively connected to the PWM unit, the signal generator, and the reference voltage; when the relay switches the moving contact to connect to the first stationary contact, the PWM unit is electrically connected to the signal generator; when the relay switches the moving contact to connect to the second stationary contact, the PWM unit is electrically connected to the reference voltage. 4 . The control circuit according to claim 1 , wherein the signal generator adjusts the generated voltage signal according to the error value to compensate for the control pilot signal.
5. The control circuit according to claim 1, wherein when the electric vehicle charging device is connected to the electric vehicle, the electric vehicle charging device and the electric vehicle respectively perform multiple actions when the control pilot signal is at multiple voltage levels, the multiple actions including the electric vehicle charging device performing high-frequency communication with the electric vehicle, the electric vehicle charging device charging the electric vehicle, and the electric vehicle charging device stopping charging the electric vehicle; the reference voltage includes the multiple voltage levels.
6. A control method, applicable to electric vehicle charging equipment, comprising the steps of: (a) providing a signal generator, a PWM unit, a relay, and a sensing circuit, wherein the signal generator is configured to generate a voltage signal, the PWM unit is configured to perform pulse width modulation and is electrically connected to a control pilot signal between the electric vehicle charging device and the electric vehicle, the relay can selectively switch the PWM unit to be electrically connected to the voltage signal or a reference voltage, and the sensing circuit is configured to sense the control pilot signal; (b) selectively executing a first mode or a second mode, wherein in the first mode, the relay is controlled to switch the PWM unit electrically connected to the voltage signal, and in the second mode, the relay is controlled to switch the PWM unit electrically connected to the reference voltage; as well as (c) comparing the sensing signal in the first mode with the sensing signal in the second mode to obtain an error value, and compensating the control guidance signal according to the error value when executing the first mode.
7. The control method according to claim 6, further comprising: using a control unit to control the switching of the relay to execute the first mode or the second mode; wherein, When the electric vehicle charging device is not connected to the electric vehicle, or when the electric vehicle charging device is connected to the electric vehicle but not charging the electric vehicle, the control unit controls the relay to switch the PWM unit to be electrically connected to the reference voltage to execute the second mode.
8. The control method according to claim 6, wherein the relay comprises a moving contact, a first stationary contact, and a second stationary contact, which are respectively connected to the PWM unit, the signal generator, and the reference voltage; when controlling the relay to switch the moving contact to connect to the first stationary contact, the PWM unit is electrically connected to the signal generator; when controlling the relay to switch the moving contact to connect to the second stationary contact, the PWM unit is electrically connected to the reference voltage.
9. The control method according to claim 6, wherein in the step (c), the signal generator is controlled to adjust the generated voltage signal according to the error value to achieve compensation for the control pilot signal.
10. The control method according to claim 6, wherein when the electric vehicle charging device is connected to the electric vehicle, the electric vehicle charging device and the electric vehicle respectively perform multiple actions when the control guidance signal is at multiple voltage levels, the multiple actions including the electric vehicle charging device performing high-frequency communication with the electric vehicle, the electric vehicle charging device charging the electric vehicle, and the electric vehicle charging device stopping charging the electric vehicle; the reference voltage includes the multiple voltage levels.