Control circuit and method for power supply device for electric vehicle

Abstract

To provide a control circuit and a method applicable to charging equipment for electric vehicles.SOLUTION: In electric vehicle charging equipment, a control circuit includes a signal generator, a PWM unit, a relay, and a sensing circuit. The signal generator generates a voltage signal. The PWM unit performs pulse width modulation and is electrically connected to a control induction signal between the charging equipment and the electric vehicle. The relay switches the PWM unit to connect to the voltage signal generated by the signal generator or a reference voltage. The sensing circuit senses the control induction signal and generates a sensing signal. The control method selectively executes a first mode or a second mode, and the relay switches the PWM unit to connect to the voltage signal in the first mode and to electrically connect to the reference voltage in the second mode. The control circuit compares the sensing signals in the first mode and the second mode to obtain an error value, and compensates the control induction signal on the basis of the error value in the first mode.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a control circuit and method, and more particularly to a control circuit and method applied to charging equipment for electric vehicles. [Background technology]

[0002] In current electric vehicle charging system applications, compatibility control is not optimized for the connection and voltage change points between the charging gun and electric vehicle coupler. Therefore, when the coupler connects and the voltage level of the control induction signal changes, errors can occur in detecting the voltage level change of the control induction signal due to differences in the types of charging gun and coupler. Because the coupler operates in an open loop and lacks the adaptability to adapt to compatibility, it cannot adjust to the error. Therefore, when an error occurs, the charging system may malfunction, preventing the electric vehicle from charging.

[0003] Therefore, there is an urgent need to invent a control circuit and method applicable to charging equipment for electric vehicles that can improve upon the above-mentioned conventional technology. Summary of the Invention Problem to be solved

[0004] An object of the present invention is to provide a control circuit and method applicable to electric vehicle charging equipment, which introduces a reference voltage, compares the sensed signal of a control induction signal at the reference voltage and an actual voltage to determine an error, and compensates for the control induction signal at the actual voltage based on the error, thereby enabling the electric vehicle charging equipment to detect the control induction signal in a closed loop and compensate for the error, thereby avoiding interruptions or abnormalities in the electric vehicle charging process due to the error. [Means for solving the problem]

[0005] To achieve the above object, the present invention provides a control circuit and method applicable to charging equipment for electric vehicles. The control circuit includes a signal generator, a PWM unit, a relay, and a sensing circuit. The signal generator generates a voltage signal. The PWM unit performs pulse width modulation and is electrically connected to a control induction signal. The relay selectively switches the PWM unit to be electrically connected to the voltage signal or a reference voltage. The sensing circuit senses the control induction signal and generates a sensing signal. The control circuit selectively executes a first mode or a second mode, where 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 signals in the first mode and the second mode, and compensates the control induction signal based on the error value when executing the first mode.

[0006] In order to achieve the above object, the present invention further provides a control method applied to charging equipment for electric vehicles, comprising: The present invention provides a control method including: step (a) of 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 performs pulse width modulation, and is configured to be electrically connected to a control induction signal between an electric vehicle charging device and the electric vehicle, the relay selectively switches 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 induction signal; step (b) of selectively performing a first mode or a second mode, in the first mode, controlling the relay to switch the PWM unit to be electrically connected to the voltage signal, and in the second mode, controlling the relay to switch the PWM unit to be electrically connected to the reference voltage; and step (c) of 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 induction signal based on the error value when performing the first mode. [Brief explanation of the drawings]

[0007] [Figure 1] 4 shows waveforms of control induction signals in different states. [Figure 2] 4 shows the control induction signals during the charging process and the waveforms output by the electric vehicle charging equipment. [Figure 3] 4 shows the control induction signals during the charging process and the waveforms output by the electric vehicle charging equipment. [Figure 4] 1 is a structural conceptual diagram of a control circuit applied to an electric vehicle charging facility according to an embodiment of the present invention; [Figure 5] 1 shows a control method applied to an electric vehicle charging facility in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] Some illustrative examples of the features and advantages of the present invention are described in detail below. It should be understood that the present invention is susceptible to various modifications in different situations, all of which do not depart from the scope of the present invention.

[0009] In electric vehicle charging applications, the electric vehicle charging equipment and the electric vehicle communicate by handshake using control and induction signals between them. According to changes in the waveform and voltage level of the control and induction signals, the electric vehicle charging equipment and the electric vehicle enter different states and perform corresponding operations.

[0010] FIG. 1 shows waveforms of the control induction signal in different states. As shown in FIG. 1, in state A, the electric vehicle charging device is not connected to the electric vehicle. At this time, the control induction signal CP is at a first voltage level (e.g., 12V). In state B1, the electric vehicle charging device is connected to the electric vehicle, but the electric vehicle is not ready to receive electrical energy. At this time, the control induction signal CP drops to a second voltage level (e.g., 9V) due to a voltage offset on the electric vehicle side. In state B2, similar to state B1, the electric vehicle charging device is connected to the electric vehicle, but the electric vehicle is not ready to receive electrical energy. At this time, the control induction signal CP is a PWM (pulse width modulation) signal, with the high level of the PWM signal at a second voltage level and the low level of the PWM signal at a third voltage level (e.g., -12V). In state C, the electric vehicle charging device is connected to the electric vehicle, and the electric vehicle is ready to receive electrical energy. At this time, the control induction signal CP is a PWM signal, and the high level of the PWM signal drops to a fourth voltage level (e.g., 6V) due to a voltage offset on the electric vehicle side, and the low level of the PWM signal remains at the third voltage level (e.g., −12V). In state D, the electric vehicle charging equipment may be disconnected, resulting in an instability in the supply of power or other abnormal operating conditions, and the control induction signal CP is 0. In state E, the electric vehicle charging equipment may be unable to stably supply power or other abnormal operating conditions, and the control induction signal CP is at the third voltage level (e.g., −12V).

[0011] To facilitate understanding of the waveform changes and corresponding states of the control induction signals during the electric vehicle charging process, Figures 2 and 3 show the control induction signals during the charging process and the waveforms output by the electric vehicle charging equipment. The difference between the two examples is that in the example of Figure 2, charging is stopped based on a command from the electric vehicle, while in the example of Figure 3, charging is stopped when the electric vehicle is disconnected (for example, by removing the charging gun).

[0012] As shown in FIG. 2 , at time t1, the electric vehicle charging equipment is connected to the electric vehicle, and the corresponding state of the control induction signal CP changes from state A to state B1. At time t2, high-frequency communication is initiated between the electric vehicle charging equipment and the electric vehicle, and the corresponding state of the control induction signal CP changes from state B1 to state B2. At time t3, the electric vehicle is ready to receive electric energy, and the corresponding state of the control induction signal CP changes from state B2 to state C. After a certain time has passed, at time t4, the electric vehicle charging equipment starts providing electric energy to the electric vehicle and charging the electric vehicle. At time t5, the electric vehicle issues a command to stop charging, and the corresponding state of the control induction signal CP changes from state C to state B2. After a certain time has passed, at time t6, the electric vehicle charging equipment stops providing electric energy. At time t7, the electric vehicle is disconnected.

[0013] In the example of Figure 3, the process of entering the state of charging the electric vehicle is the same as in the example of Figure 2. That is, the operations performed and changes in the control induction signal CP at times t8, t9, t10, and t11 in Figure 3 correspond to the operations performed and changes in the control induction signal CP at times t1, t2, t3, and t4 in Figure 2, respectively, and therefore will not be described here. In the example of Figure 3, after the electric vehicle has been charged for a certain period of time, the electric vehicle is disconnected at time t12, and the electric vehicle charging equipment stops supplying power after a short time.

[0014] As can be seen from the above example, waveform changes in the control induction signal closely correspond to operational changes in the electric vehicle charging equipment and the electric vehicle, making the accuracy of the control induction signal detection extremely important in electric vehicle charging applications. Deviations in the detection of the control induction signal may cause the electric vehicle charging equipment to stop supplying power to the electric vehicle, interrupting charging. In practical applications, many factors may cause deviations in the detection of the control induction signal. For example, deviations may occur due to input impedance in the sensing circuit that detects the control induction signal. 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 varying degrees of deviation in the detection of the control induction signal.

[0015] To resolve the deviation and avoid its impact on the charging process, the present invention provides a control circuit for use in an electric vehicle charging equipment. Referring to FIG. 4, a structural conceptual diagram of a control circuit for use in an electric vehicle charging equipment in one embodiment of the present invention is shown. As shown in FIG. 4, 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 is electrically connected to a control induction signal CP between the electric vehicle charging equipment and the electric vehicle. The relay 13 selectively switches 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 movable contact P1, a first fixed contact P2, and a second fixed 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 movable contact P1 to connect to the first fixed contact P2, the PWM unit 12 is electrically connected to the signal generator 11 through the relay 13. When the relay 13 switches the movable contact P1 to connect to the second fixed contact P3, the PWM unit 12 is electrically connected to the reference voltage Vref through the relay 13. The sensing circuit 14 is electrically connected to the control induction signal CP and is configured to sense the control induction signal CP and generate a corresponding sensing signal.

[0016] The control circuit 1 selectively executes a first mode or a second mode. In the first mode, the relay 13 switches the PWM unit 12 to be electrically connected to the voltage signal generated by the signal generator 11. In the second mode, the relay 13 switches the PWM unit 12 to be electrically connected to a reference voltage Vref. The control circuit 1 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 induction signal CP based on the error value when executing the first mode. In some embodiments, the signal generator 11 compensates the control induction signal CP by adjusting the generated voltage signal based on the error value, thereby eliminating an error in sensing the control induction signal CP.

[0017] As a result, the electric vehicle charging equipment has the ability to detect the control induction signal CP in a closed loop, and can compensate for the sensing error of the control induction signal CP, thereby avoiding interruptions or abnormalities in the electric vehicle charging process caused by the sensing error.

[0018] Furthermore, as can be seen from the above, when an electric vehicle charging device is connected to an electric vehicle, the electric vehicle charging device and the electric vehicle perform different operations when the control induction signal CP is at different voltage levels. For example, the operations may include high-frequency communication between the electric vehicle charging device and the electric vehicle, charging the electric vehicle with the electric vehicle charging device, and stopping charging of the electric vehicle with the electric vehicle charging device. Since the reference voltage Vref includes all possible voltage levels of the control induction signal CP (e.g., 12V, 9V, 6V), when the control circuit 1 operates in the first mode, it can obtain an error value by comparing the sensing signal with the sensing signal obtained at the corresponding level of the reference voltage Vref in the second mode, regardless of the voltage level of the control induction signal CP.

[0019] In some embodiments, the control circuit 1 further includes a control unit 15, which is configured to control the switching of the relay 13 so that the control circuit 1 executes the first mode or the second mode. In some embodiments, when the electric vehicle charging equipment is not connected to the electric vehicle, or when the electric vehicle charging equipment is connected to the electric vehicle but not charging the electric vehicle, the control unit 15 controls the relay 13 to switch the PWM unit 12 to be electrically connected to the reference voltage Vref, causing the control circuit 1 to execute the second mode. Note that the control circuit 1 does not necessarily execute the second mode at all times; for example, when the electric vehicle charging equipment is charging the electric vehicle, the control circuit 1 should avoid executing the second mode to avoid the reference voltage Vref affecting the waveform of the control induction signal CP and interrupting charging.

[0020] FIG. 5 illustrates a control method applied to an electric vehicle charging equipment in one embodiment of the present invention. This control method is applied to the control circuit 1 of the embodiment. As shown in FIG. 5, 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 performs pulse width modulation and is configured to be electrically connected to a control induction signal CP between the electric vehicle charging equipment and the electric vehicle. The relay 13 selectively switches the PWM unit 12 to be electrically connected to the voltage signal generated by the signal generator 11 or a reference voltage Vref. The sensing circuit 14 is configured to sense the control induction signal CP. In step S2, a first mode or a second mode is selectively performed. In the first mode, the relay 13 is controlled to switch the PWM unit 12 to be electrically connected to the voltage signal, and 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, and the control induction signal CP is compensated according to the error value when the first mode is performed.

[0021] In view of the above, the present invention provides a control circuit and method applicable to electric vehicle charging equipment, which introduces a reference voltage, compares the sensed signal of the control induction signal at the reference voltage and the actual voltage to determine an error, and compensates for the control induction signal at the actual voltage based on the error, thereby enabling the electric vehicle charging equipment to detect the control induction signal in a closed loop and compensate for the error, thereby avoiding interruptions or abnormalities in the electric vehicle charging process caused by the error.

[0022] It should be noted that the above are merely preferred embodiments for explaining the present invention, and the present invention is not limited to the above embodiments. The scope of the present invention is determined by the appended claims. Those skilled in the art can make various modifications to the present invention, but they will not deviate from the scope defined by the claims. [Explanation of symbols]

[0023] 1: Control circuit 11: Signal generator 12: PWM unit 13: Relay 14: Sensing circuit CP: Control guidance signal P1: Movable contact P2: 1st fixed contact P3: 2nd fixed contact Vref: Reference voltage 15: Control unit S1, S2, S3: Steps A, B1, B2, C, D, E: Status t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12: time points

Claims

1. A control circuit applied to a charging facility for an electric vehicle, the control circuit comprising: a signal generator configured to generate a voltage signal; a PWM (pulse width modulation) unit configured to perform pulse width modulation and to be electrically connected to a control induction signal between the electric vehicle charging equipment and the electric vehicle; a relay that selectively switches the PWM unit to be electrically connected to the voltage signal or a reference voltage; a sensing circuit configured to sense the control induction signal to generate a sensing signal; the control circuit selectively executes 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 and the sensing signal in the second mode, and compensates the control induction signal based on the error value when performing the first mode.

2. Further comprising a control unit, the control unit is configured to control switching of the relay so that the control circuit executes the first mode or the second mode; 2. The control circuit of claim 1, wherein when the electric vehicle charging equipment is not connected to the electric vehicle, or when the electric vehicle charging equipment 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, causing the control circuit to execute the second mode.

3. the relay includes a movable contact, a first fixed contact, and a second fixed contact, which are respectively connected to the PWM unit, the signal generator, and the reference voltage; When the relay switches the movable contact to connect to the first fixed contact, the PWM unit is electrically connected to the signal generator; The control circuit of claim 1 , wherein the PWM unit is electrically connected to the reference voltage when the relay switches the movable contact to connect to the second fixed contact.

4. The control circuit of claim 1 , wherein the signal generator compensates the control induction signal by adjusting the generated voltage signal based on the error value.

5. When the electric vehicle charging device is connected to the electric vehicle, the electric vehicle charging device and the electric vehicle respectively perform a plurality of operations when the control induction signal is at a plurality of voltage levels; the plurality of operations include high-frequency communication between the electric vehicle charging equipment and the electric vehicle, charging the electric vehicle by the electric vehicle charging equipment, and stopping charging of the electric vehicle by the electric vehicle charging equipment; The control circuit of claim 1 , wherein the reference voltage comprises the plurality of voltage levels.

6. A control method applied to an electric vehicle charging facility, Step (a) of 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 to be electrically connected to a control induction signal between the electric vehicle charging equipment and the electric vehicle, the relay selectively switches 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 induction signal; (b) selectively executing a first mode or a second mode, in which, 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 (c) comparing the sensing signal in the first mode and the sensing signal in the second mode to obtain an error value, and compensating the control induction signal based on the error value when performing the first mode.

7. further comprising using a control unit to control switching of the relay to implement the first mode or the second mode; 7. The control method of claim 6, wherein when the electric vehicle charging equipment is not connected to the electric vehicle, or when the electric vehicle charging equipment is connected to the electric vehicle but not charging the electric vehicle, the control unit is used to control the relay to switch the PWM unit to be electrically connected to the reference voltage, thereby executing the second mode.

8. the relay includes a movable contact, a first fixed contact, and a second fixed contact, which are respectively connected to the PWM unit, the signal generator, and the reference voltage; the PWM unit is electrically connected to the signal generator when controlling the relay to switch the movable contact to connect to the first fixed contact; The control method of claim 6 , wherein when the relay is controlled to switch the movable contact to connect to the second fixed contact, the PWM unit is electrically connected to the reference voltage.

9. 7. The control method according to claim 6, wherein in step (c), the control induction signal is compensated by controlling the signal generator based on the error value to adjust the generated voltage signal.

10. When the electric vehicle charging device is connected to the electric vehicle, the electric vehicle charging device and the electric vehicle respectively perform a plurality of operations when the control induction signal is at a plurality of voltage levels; the plurality of operations include high-frequency communication between the electric vehicle charging equipment and the electric vehicle, charging the electric vehicle by the electric vehicle charging equipment, and stopping charging of the electric vehicle by the electric vehicle charging equipment; The control method of claim 6 , wherein the reference voltage comprises the plurality of voltage levels.

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