Relay control system, electrical equipment and vehicle

Abstract

The utility model relates to a relay control system, electrical equipment and a vehicle, and relates to the technical field of relay driving. The relay control system comprises a high-side driving circuit, a conversion circuit and a control circuit. Wherein the high-side driving circuit is connected with a coil of the relay, provides driving current for the coil and generates a recovery current signal according to the driving current. The conversion circuit is connected with the high-side driving circuit and converts the recovery current signal into a recovery voltage signal. The control circuit is connected with the conversion circuit, samples the recovery voltage signal to obtain a recovery voltage value, and generates a pulse width modulation signal for controlling the relay according to the recovery voltage value. Therefore, as the on-off control of the relay is directly related to the current flowing through the coil, the overcurrent on the coil can be mastered in a mode of collecting the current flowing through the coil as the feedback quantity, so that the relay can be more accurately controlled, the control flow is closed, and the safety of relay control is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of relay driving, and in particular to a relay control system, an electrical appliance and a vehicle. BACKGROUND

[0002] A relay is a commonly used electrical control device, which realizes on-off control of a circuit through electromagnetic effect, and has functions of isolation, conversion and automatic control. When the coil of the relay is powered, a magnetic field is generated to attract the armature, so that the contacts are closed or opened, thereby realizing on-off control of the controlled circuit.

[0003] At present, in the related technology, a microcontroller unit (MCU) is usually used to generate a pulse width modulation (PWM) signal with a certain duty cycle according to the supply voltage of the relay, and the voltage flowing through the coil of the relay is controlled by using the pulse width modulation signal, so as to control the attraction, holding and release of the relay.

[0004] However, the way of generating a pulse width modulation signal by the supply voltage of the relay can control the relay according to the actual supply voltage, but the overcurrent condition and the attraction state of the coil in the relay cannot be obtained. In particular, in the high-voltage attraction state, the relay may bear strong electrical stress and be easily damaged. Therefore, how to more accurately control the relay to improve the safety of the relay is a problem to be solved at present. Invention content

[0005] The embodiment of the present application provides a relay control system, which more accurately controls the relay to improve the safety of the relay, so as to at least partially solve the above technical problems.

[0006] In order to achieve the above purpose, according to the first aspect of the present application, a relay control system is provided, comprising:

[0007] A high-side drive circuit connected with the coil of the relay, providing a drive current to the coil and generating a back-borrowing current signal according to the drive current;

[0008] A conversion circuit connected with the high-side drive circuit, converting the back-borrowing current signal into a back-borrowing voltage signal;

[0009] A control circuit connected with the conversion circuit, sampling the back-borrowing voltage signal to obtain a back-borrowing voltage value, and generating a pulse width modulation signal for controlling the relay according to the back-borrowing voltage value.

[0010] Optionally, the high-side drive circuit comprises a first switch tube and a sampling sub-circuit.

[0011] The first switch tube comprises a first electrode connected with the power supply, a second electrode connected with the sampling sub-circuit and the first end of the coil, and a control electrode connected with the control circuit;

[0012] The sampling sub-circuit samples the driving current flowing through the first switch tube through the second electrode to obtain the back sampling current signal.

[0013] Optionally, the conversion circuit comprises a first resistor;

[0014] The first resistor comprises a first end connected with the high-side drive circuit and the control circuit, and a second end grounded.

[0015] Optionally, the low-side drive circuit is further connected with the control circuit and the second end of the coil, and is configured to control the on-off between the coil and the ground according to the pulse width modulation signal to control the current flowing through the coil.

[0016] Optionally, the low-side drive circuit comprises a second switch tube;

[0017] The second switch tube comprises a control electrode connected with the control circuit, a first electrode connected with the second end of the coil, and a second electrode grounded.

[0018] Optionally, the control circuit comprises a first controller and a second controller;

[0019] The first controller is configured to sample the output of the power supply to obtain an output voltage value, and generate a duty cycle adjustment instruction according to the back sampling voltage value and the output voltage value;

[0020] The second controller is connected with the first controller and the low-side drive circuit, generates the pulse width modulation signal according to the duty cycle adjustment instruction, and outputs the pulse width modulation signal to the low-side drive circuit to control the current flowing through the coil by controlling the on-off of the low-side drive circuit.

[0021] Optionally, the first controller sends a start instruction to the second controller after power-on, and the second controller controls the high-side drive circuit to be turned on according to the start instruction to provide driving current to the coil, and controls the low-side drive circuit to be turned on at a preset duty cycle.

[0022] Optionally, an RC filter for filtering the back sampling voltage signal is further arranged between the conversion circuit and the control circuit

[0023] The control circuit samples the ripple voltage of the RC filter processed back mining voltage signal, and generates the duty cycle adjustment instruction according to the ripple voltage, the output voltage value and the back mining voltage value.

[0024] According to a second aspect of the present application, an electric appliance is provided, comprising the above-mentioned relay control system according to the second aspect of the present application,

[0025] According to a third aspect of the present application, a vehicle is provided, comprising the above-mentioned electric appliance.

[0026] In summary, in the relay control system of the embodiments of the present application, first, the high-side drive circuit provides a drive current to the relay coil, and the high-side drive circuit also generates a back mining current signal according to the drive current, and the back mining current signal reflects the current flowing through the coil. Second, the conversion circuit converts the back mining current signal into a back mining voltage signal. Voltage sampling is more stable and simple than current sampling, so that the control circuit can more accurately sample the back mining voltage signal and obtain the back mining voltage value according to the back mining voltage signal. Finally, according to the size of the current flowing through the coil represented by the back mining voltage value, a pulse width modulation signal for adjusting the working state of the relay is generated. In this way, since the on-off control of the relay is directly related to the current flowing through the coil, by collecting the current flowing through the coil as a feedback quantity, not only can the overcurrent flowing through the coil be grasped to realize more accurate control of the relay, but also the control process is closed loop, thereby improving the safety of the relay control.

[0027] Other features and advantages of the present application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0029] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings, wherein the same reference numerals in the following description represent the same parts.

[0030] Figure 1 is a block diagram of the relay control system provided in the exemplary embodiment of the present disclosure;

[0031] Figure 2 is a connection relationship diagram of the relay control system provided in the exemplary embodiment of the present disclosure;

[0032] Figure 3 is a circuit schematic diagram of a relay control system provided in an exemplary embodiment of the present disclosure;

[0033] Figure 4 is a schematic diagram of the relationship between the average value of the recovery voltage value, the output voltage and the duty cycle of the pulse width modulation signal provided in an exemplary embodiment of the present disclosure;

[0034] Figure 5 is a schematic diagram of the relationship between the current value flowing through the coil, the output voltage and the duty cycle of the pulse width modulation signal provided in an exemplary embodiment of the present disclosure;

[0035] Figure 6 is a schematic diagram of the relationship between the current value flowing through the coil, the output voltage and the ripple voltage provided in an exemplary embodiment of the present disclosure.

[0036] BRIEF DESCRIPTION OF DRAWINGS 1, high-side drive circuit; 11, sampling sub-circuit; 2, conversion circuit; 3, control circuit; 31, first controller; 32, second controller; 4, low-side drive circuit; 5, RC filter. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0038] According to a first aspect of the present application, with reference to Figures 1 to 4 The present disclosure provides a relay control system, comprising a high-side drive circuit 1, a conversion circuit 2 and a control circuit 3. The high-side drive circuit 1 is connected with the coil of the relay, provides driving current to the coil, and generates a recovery current signal according to the driving current. The conversion circuit 2 is connected with the high-side drive circuit 1, and converts the recovery current signal into a recovery voltage signal. The control circuit 3 is connected with the conversion circuit 2, samples the recovery voltage signal to obtain a recovery voltage value, and generates a pulse width modulation signal for controlling the relay according to the recovery voltage value.

[0039] The high-side drive circuit 1 is further connected with the power supply U, and has a switch control function to transmit the drive current output by the power supply U to the coil. The backhaul current signal has a multiple relationship with the drive current flowing through the high-side drive circuit 1. For example, if the current flowing through the high-side drive circuit 1 is IY, the backhaul current signal can be represented as IF = IY / K; wherein K is a preset multiple. It should be noted that when the high-side drive circuit 1 is continuously turned on, the current flowing through the high-side drive circuit 1 is equal to the drive current IY; when the high-side drive circuit 1 is turned on with a duty cycle a%, the current flowing through the high-side drive circuit 1 is IY = IX * a%; wherein IX is the drive current.

[0040] As an example, the backhaul voltage value is used to represent the size of the backhaul current signal, the backhaul voltage value can have a positive correlation with the backhaul current signal, and the backhaul voltage value corresponds to the amplitude of the backhaul current signal one by one, so as to obtain the size of the backhaul current signal through the backhaul voltage value. For example, when the backhaul voltage value is too small, the duty cycle of the pulse width modulation signal can be increased to increase the current flowing through the coil, so as to maintain the stable attraction of the coil. If the backhaul voltage value is too large, the duty cycle of the pulse width modulation signal can be reduced to reduce the current flowing through the coil, so as to avoid the overcurrent phenomenon of the coil.

[0041] In the above embodiment, first, the high-side drive circuit 1 provides the drive current to the relay coil, and the high-side drive circuit 1 also generates the backhaul current signal according to the drive current, and the backhaul current signal reflects the size of the current flowing through the coil. Second, the conversion circuit 2 converts the backhaul current signal into the backhaul voltage signal. Voltage sampling is more stable and easier to implement than current sampling, so that the control circuit 3 can more accurately sample the backhaul voltage signal, and obtain the backhaul voltage value according to the backhaul voltage signal. Finally, according to the size of the current flowing through the coil represented by the backhaul voltage value, the pulse width modulation signal for adjusting the working state of the relay is generated. Since the on-off control of the relay is directly related to the current flowing through the coil, by collecting the current flowing through the coil as the feedback, not only can the overcurrent of the coil be grasped to realize more accurate control of the relay, but also the control process is closed loop, thereby improving the safety of the relay control.

[0042] Referring to Figure 2 and Figure 3 In some embodiments, the high-side drive circuit 1 includes a first switch tube M1 and a sampling sub-circuit 11. The first switch tube M1 includes a first electrode connected with the power supply U, a second electrode connected with the sampling sub-circuit 11 and the first end of the coil, and a control electrode connected with the control circuit 3. In this way, the sampling sub-circuit 11 can sample the drive current flowing through the first switch tube M1 through the second electrode to obtain the backhaul current signal.

[0043] As an example, the first electrode of the first switch tube M1 can be an input terminal, and the second electrode can be an output terminal. By arranging the sampling sub-circuit 11 at the second electrode of the first switch tube M1, the sampling sub-circuit 11 only samples the current flowing through the first switch tube M1, so as to obtain a more accurate back sampling current signal.

[0044] In the above embodiment, the first switch tube M1 is turned on or turned off according to the signal accessed by the control electrode, so as to control the on-off between the power supply U and the coil, and the sampling sub-circuit 11 connected in parallel with the first switch tube M1 samples the current flowing through the first switch tube M1, so as to obtain a back sampling current signal capable of reflecting the current flowing through the coil.

[0045] With reference to Figure 2 and Figure 3 In some embodiments, the conversion circuit 2 includes a first resistor R. The first resistor R includes a first terminal connected with the high-side drive circuit 1 and the control circuit 3, and a second terminal grounded.

[0046] As an example, the resistance of the first resistor R is known, and the back sampling voltage signal generated by the conversion circuit 2 can be represented as UR = IF * R; wherein IF represents the back sampling current signal, and R represents the resistance of the first resistor R.

[0047] In the above embodiment, since the second terminal of the first resistor R is grounded, the potential of the first terminal of the first resistor R is equal to the voltage division on the first resistor R, and then according to the volt-ampere characteristic, the relationship between the back sampling voltage signal of the first terminal of the first resistor R and the back sampling current signal can be obtained. By connecting the control circuit 3 with the first terminal of the first resistor R, the back sampling voltage value capable of representing the amplitude of the back sampling current signal can be obtained by directly sampling the back sampling voltage signal of the first terminal of the first resistor R, so as to achieve the effect of converting the back sampling current signal into the back sampling voltage signal.

[0048] With reference to Figure 2 and Figure 3 In some embodiments, the relay control system further includes a low-side drive circuit 4 connected with the control circuit 3 and the second terminal of the coil, for controlling the on-off between the coil and the ground according to the pulse width modulation signal, so as to control the current flowing through the coil.

[0049] As an example, the high-side drive circuit 1 is connected between the positive pole of the power supply U and the coil of the relay, since the positive pole of the power supply U usually has a high potential, if the pulse width modulation control is realized by using the high-side drive circuit 1, electromagnetic interference is easily generated, which causes misoperation when the switch action is performed, therefore, during the operation of the relay, the high-side drive circuit 1 can be kept in the always-on state to transmit the drive current to the coil of the relay. The low-side drive circuit 4 is arranged between the coil of the relay and the ground, that is, the low-side drive circuit 4 bears a low potential, which is more suitable for realizing accurate control and performing fast switch action under the control of the pulse width modulation signal, and prevents the high voltage in the relay from interfering with the switch action while realizing the control of the current flowing through the coil.

[0050] In some embodiments, the low-side drive circuit 4 includes a second switch tube M2. The second switch tube M2 includes a control pole connected with the control circuit 3, a first pole connected with the second end of the coil, and a second pole grounded.

[0051] In the above implementation, by connecting the second switch tube M2 in series between the second end of the coil and the ground, the on-off control between the second end of the coil and the ground is realized, when the coil is disconnected with the ground, there is no voltage difference between the first end and the second end of the coil, so no current flows through the coil; when the coil is grounded, there is a voltage difference between the first end and the second end of the coil, so the drive current flows from the first end to the second end of the coil, thereby realizing the control of the current flowing through the coil through the second switch tube M2.

[0052] In some embodiments, as shown in Figure 3 , the control circuit 3 includes a first controller 31 and a second controller 32. The first controller 31 is used to sample the output of the power supply U to obtain an output voltage value, and generate a duty cycle adjustment instruction according to the sampled voltage value and the output voltage value. The second controller 32 is connected with the first controller 31 and the low-side drive circuit 4, generates a pulse width modulation signal according to the duty cycle adjustment instruction, and outputs the pulse width modulation signal to the low-side drive circuit 4, so as to control the current flowing through the coil by controlling the on-off of the low-side drive circuit 4.

[0053] As an example, with reference to Figure 4 and Figure 5 , Figure 4 , the relationship between the average value of the sampled voltage value, the output voltage and the duty cycle of the pulse width modulation signal is illustrated, that is, the higher the sampled voltage value and the output voltage, the lower the duty cycle of the pulse width modulation signal required; on the contrary, the lower the sampled voltage value and the output voltage, the higher the duty cycle of the pulse width modulation signal required. Figure 5The example illustrates the relationship between the current flowing through the coil, the output voltage, and the duty cycle of the pulse width modulation signal. That is, the higher the current flowing through the coil and the higher the output voltage, the lower the required duty cycle of the pulse width modulation signal; the lower the current flowing through the coil and the lower the output voltage, the higher the required duty cycle of the pulse width modulation signal.

[0054] As an example, a duty cycle adjustment command is generated based on the preset pull-in current threshold of the relay, combined with the sampled voltage value and the output voltage value. The pull-in current threshold is the minimum current value flowing through the coil when the relay can maintain a stable pull-in state. The pull-in current threshold can be set according to the relay model. For example, the pull-in current threshold can be set to 2A.

[0055] As an example, it can be based on Figure 4 and Figure 5 A mapping table is established using the average value of the sampled voltage, the output voltage, the current flowing through the coil, and the duty cycle of the pulse width modulation signal. The duty cycle can be 0.1, 0.2, 0.3…0.9, and the output voltage can be set within a range according to actual conditions. For example, the output voltage can be an integer between 9V and 16V. In this way, the average value of the sampled voltage and the current flowing through the coil corresponding to each output voltage at each duty cycle can be obtained. Then, when the sampled voltage and output voltage are obtained, the duty cycle adjustment command is generated by looking up the duty cycle corresponding to the current flowing through the coil that is greater than the pull-in current threshold in the mapping table.

[0056] For example, when the duty cycle is 50%, if the output voltage of power supply U drops from 16V to 9V, and the sampled current value is 2.415550603V, the corresponding current flowing through the coil is 1.665681174A. Since this current is less than the pull-in current threshold, the system looks up the duty cycle with a current value greater than the pull-in current threshold in the mapping table based on the current output voltage. A duty cycle adjustment command is then generated based on this duty cycle, such as increasing the duty cycle by 10%, causing the second controller 32 to generate a pulse width modulation signal with a 60% duty cycle. Conversely, if the output voltage of power supply U drops from 16V to 9V, and the sampled current value is 2.431688193V, the corresponding current flowing through the coil is 2.08A. This current is greater than the pull-in current threshold, ensuring the relay remains stably engaged. In this case, maintaining the same duty cycle is sufficient. In this way, the effect of generating duty cycle adjustment commands based on the sampled voltage value and the output voltage value is achieved.

[0057] In the above embodiment, the first controller 31 needs to work in a high-voltage environment to sample the output voltage value and the back sampling voltage value, and generate the duty cycle adjustment instruction according to the back sampling voltage value and the output voltage value, and output the duty cycle adjustment instruction to the second controller 32, so that the second controller 32 can generate the pulse width modulation signal according to the duty cycle adjustment instruction without working in a high-voltage environment, thereby achieving electrical isolation to prevent the low-side drive circuit 4 connected to the second controller 32 from being affected by the high-voltage environment.

[0058] With reference to Figure 2 and Figure 3 In some embodiments, the first controller 31 sends a start instruction to the second controller 32 after power-on, and the second controller 32 controls the high-side drive circuit 1 to be turned on to provide a drive current to the coil and controls the low-side drive circuit 4 to be turned on at a preset duty cycle according to the start instruction.

[0059] In the above embodiment, when the relay needs to start working, the first controller 31 can be powered on first, and then the first controller 31 sends a start instruction to the second controller 32 after power-on, so that the second controller 32 controls the high-side drive circuit 1 to be turned on according to the start instruction. In this way, the circuit breaker is completely isolated from the power supply U when it does not need to work, and is turned on with the power supply U when it starts to work, further improving safety.

[0060] In some embodiments, the relay control system further comprises an RC filter 5 arranged between the conversion circuit 2 and the control circuit 3 for filtering the back sampling voltage signal; the control circuit 3 samples the ripple voltage of the back sampling voltage signal filtered by the RC filter 5, and generates the duty cycle adjustment instruction according to the ripple voltage, the output voltage value and the back sampling voltage value.

[0061] As an example, the RC filter 5 can be a first-order filter, and by controlling the resistance value and the capacitance value of the RC filter 5, the cutoff frequency of the RC filter 5 can be adjusted to match the frequency of the pulse width modulation signal. For example, when the frequency of the pulse width modulation signal is 20KHz, the resistance value and the capacitance value of the RC filter 5 can be set to 10kΩ and 1uF respectively, so that the cutoff frequency of the RC filter 5 is close to 16Hz, so as to effectively filter the back sampling voltage signal and obtain the ripple voltage of the filtered back sampling voltage signal.

[0062] As an example, with reference to Figure 6 , Figure 6The correspondence between the ripple voltage, the output voltage and the duty cycle of the pulse width modulation signal is shown. It can be seen that when the output voltage is constant, the ripple voltage is smaller as the duty cycle increases; when the duty cycle is constant, the ripple voltage is larger as the output voltage is larger. The smaller the ripple voltage is, the more stable the current flowing to the coil is. Considering the ripple voltage when generating the duty cycle adjustment instruction can realize the relay pull-in control and make the current on the coil more stable.

[0063] As an example, the ripple voltage can be added in the mapping relationship table. Taking the duty cycle of 0.1 as an example, part of the content of the mapping relationship table is shown in Table 1.

[0064] Table 1

[0065]

[0066] Based on the mapping relationship table, when the ripple voltage, the output voltage value and the back sampling voltage value are sampled, the corresponding duty cycle can be queried from the mapping relationship table to generate the duty cycle adjustment instruction.

[0067] According to a second aspect of the present disclosure, an electric appliance is provided, which comprises the relay control system described above. The electric appliance has all the beneficial effects of the relay control system described above, and the present disclosure will not be repeated here.

[0068] According to a third aspect of the present disclosure, a vehicle is provided, which comprises the electric appliance described above.

[0069] The vehicle can be a fuel automobile, a plug-in hybrid electric vehicle or a new energy vehicle, and the present disclosure does not make specific limitations thereon.

[0070] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first" and "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0071] In the above embodiments, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0072] The embodiments, implementation manners and related technical features of the present application can be combined or replaced with each other without conflict.

[0073] The above are only the preferred embodiments of the present application, and do not limit the present application in any form, but any simple modification, equivalent change and modification made to the above embodiments without departing from the technical solution of the present application and according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A relay control system characterized by comprising: The relay control system comprises: a high-side drive circuit connected with a coil of a relay, providing a drive current to the coil, and generating a back-biased current signal according to the drive current; a conversion circuit connected with the high-side drive circuit, converting the back-biased current signal into a back-biased voltage signal; a control circuit connected with the conversion circuit, sampling the back-biased voltage signal to obtain a back-biased voltage value, and generating a pulse width modulation signal for controlling the relay according to the back-biased voltage value.

2. The relay control system according to claim 1, characterized by, The high-side drive circuit comprises a first switch tube and a sampling sub-circuit. The first switch tube comprises a first electrode connected with a power supply, a second electrode connected with the sampling sub-circuit and a first end of the coil, and a control electrode connected with the control circuit. The sampling sub-circuit samples the drive current flowing through the first switch tube through the second electrode to obtain the back-biased current signal.

3. The relay control system of claim 1, wherein The conversion circuit comprises a first resistor. The first resistor comprises a first end connected with the high-side drive circuit and the control circuit, and a second end grounded.

4. The relay control system of claim 1, wherein The relay control system further comprises a low-side drive circuit connected with the control circuit and a second end of the coil, for controlling the on-off of the coil and the ground according to the pulse width modulation signal, so as to control the current flowing through the coil.

5. The relay control system of claim 4, wherein The low-side drive circuit comprises a second switch tube. The second switch tube comprises a control electrode connected with the control circuit, a first electrode connected with the second end of the coil, and a second electrode grounded.

6. The relay control system of claim 4, wherein The control circuit comprises a first controller and a second controller. The first controller is configured to sample an output of the power supply to obtain an output voltage value, and generate a duty cycle adjustment instruction according to the back-biased voltage value and the output voltage value. The second controller is connected with the first controller and the low-side drive circuit, and is configured to generate the pulse width modulation signal according to the duty cycle adjustment instruction, and output the pulse width modulation signal to the low-side drive circuit, so as to control the current flowing through the coil by controlling the on-off of the low-side drive circuit.

7. The relay control system according to claim 6, wherein: the first controller sends a start instruction to the second controller after power-on, and the second controller controls the high-side drive circuit to be turned on according to the start instruction, so as to provide the drive current to the coil, and controls the low-side drive circuit to be turned on at a preset duty cycle.

8. The relay control system of claim 6, wherein, The relay control system further comprises an RC filter circuit arranged between the conversion circuit and the control circuit, for filtering the back-biased voltage signal. The control circuit samples a ripple voltage of the back-biased voltage signal filtered by the RC filter, and generates the duty cycle adjustment instruction according to the ripple voltage, the output voltage value, and the back-biased voltage value.

9. An electrical appliance, characterized in that The relay control system comprises the relay control system according to any one of claims 1 to 8, and a relay connected with the relay control system.

10. A vehicle characterized by comprising: The electric appliance comprises the relay control system according to claim 9.

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