KR20240128278A - Relay Power Saving Circuit - Google Patents

Abstract

The relay control circuit includes a first relay having one end connected to a first node, a first switch connected between the other end of the first relay and a second node, a second switch having one end connected to the first node, a second relay connected between the other end of the second switch and the second node, and a diode connected between a third node to which the first relay and the first switch are connected and a fourth node to which the second switch and the second relay are connected. With this configuration, the power and heat consumed by a control coil when using the relay can be reduced with only the switch and diode configuration, while also miniaturizing the relay and reducing electrical noise generated from the control coil.

Description

Relay Power Saving Circuit {Relay Power Saving Circuit}

The present invention relates to a relay control circuit, and more specifically, to a power reduction circuit of a relay.

In order to close the contacts of a relay used in an electric vehicle charger, a large amount of power must be supplied to the relay coil, but the required power to be supplied to the coil to maintain the contacts closed after closing the contacts is greatly reduced. Accordingly, if the power supplied to the relay coil after closing the contacts is not reduced, more power will be supplied to the relay coil than necessary.

Fig. 1 is a drawing showing an example of a conventional relay circuit, and Fig. 2 is a table showing the operating states of each control section of Fig. 1. The circuit shown in Fig. 1 is a circuit that uses an individual control method among circuits according to a basic relay control method, and since Vdc is applied to the relay coil at full power, power consumption is high and heat generation is severe. The power consumption of this circuit is 2*Vdc ² /Rcoil.

To solve such conventional problems, power reduction devices are used to reduce the driving power and heat generation of relays. However, conventional power reduction technologies have problems such as complex circuits, dual power supplies, and a lot of noise.

Fig. 3 is a diagram illustrating an example of a conventional relay power reduction circuit, and Fig. 4 is a table illustrating the operating states of each control section of Fig. 3. Fig. 3 is a circuit that uses an individual control method among circuits for reducing power consumption by giving PWM Duty to a relay control circuit, but has a problem in that switching noise according to PWM control adversely affects system performance and EMC characteristics. The power consumption of this circuit is Vdc ² /Rcoil.

Fig. 5 is a diagram illustrating another example of a conventional relay power reduction circuit, and Fig. 6 is a table illustrating the operating states of each control section of Fig. 5. Fig. 5 is a circuit using a simultaneous control method among circuits for varying the relay voltage by adjusting the feedback of the DC-DC, but has a problem in that an additional DC-DC must be used, and the switching noise of the DC-DC has a bad effect on the system performance and EMC characteristics. The power consumption of this circuit is ½*Vdc ² /Rcoil.

Fig. 7 is a diagram illustrating another example of a conventional relay power reduction circuit, and Fig. 8 is a table illustrating the operating states of each control section of Fig. 7. Fig. 7 is a circuit using a simultaneous control method among circuits for supplying two DC power sources, Vdc and 1/2Vdc, from the outside, and has a problem in that it causes an increase in cost because an additional ½Vdc power source must be provided. The power consumption of this circuit is ½*Vdc ² /Rcoil.

KR 102142459 B1

The present invention has been made to solve the above-described conventional problems, and aims to provide a relay control circuit capable of reducing power and heat consumed by a control coil when using a relay, while also miniaturizing the relay and reducing electrical noise generated from the control coil.

To achieve the above object, a relay control circuit according to the present invention includes a first relay having one end connected to a first node, a first switch connected between the other end of the first relay and a second node, a second switch having one end connected to the first node, a second relay connected between the other end of the second switch and the second node, and a diode connected between a third node to which the first relay and the first switch are connected and a fourth node to which the second switch and the second relay are connected.

With this configuration, the power and heat consumed by the control coil when using the relay can be reduced using only the switch and diode configuration, while also miniaturizing the relay and reducing the electrical noise generated from the control coil.

At this time, a third switch connected to the first node or the second node may be further included, and with this configuration, two relays can be controlled simultaneously.

In addition, it may further include a fourth switch connected between the first relay and the first node or the third node, and a fifth switch connected between the second relay and the second node or the fourth node. With this configuration, the two relays can be individually controlled.

The present invention provides the effect of reducing power consumption by ¼ by reducing the voltage applied to the control coil by half using a diode bridge after the relay contact is closed. In addition, by reducing the power consumed by the control coil, it provides the effect of reducing the heat generated in the relay.

In addition, it provides the effect of enabling relay miniaturization and system miniaturization by lowering heat. In addition, it provides the effect of not generating electrical noise generated by the conventional PWM control method by using the DC method control. In addition, it provides the effect of lowering cost compared to the simple DC control method or the two DC power supply method by using the DC control method using the diode bridge.

Figure 1 is a diagram illustrating an example of a conventional relay circuit.
Figure 2 is a table showing the operating status by control section of Figure 1.
Figure 3 is a diagram illustrating an example of a conventional relay power reduction circuit.
Figure 4 is a table showing the operating status by control section of Figure 3.
Fig. 5 is a diagram illustrating another example of a conventional relay power reduction circuit.
Figure 6 is a table showing the operating status by control section of Figure 5.
Fig. 7 is a diagram illustrating another example of a conventional relay power reduction circuit.
Table 8 shows the operating status by control section of Fig. 7.
FIG. 9 is a circuit diagram of a relay power reduction circuit (1-Vdc Diode Bridge power reduction individual control) according to one embodiment of the present invention.
Fig. 10 is a table for explaining the operation in each control section of the relay power reduction circuit of Fig. 9.
FIG. 11 is a circuit diagram of a relay power reduction circuit (simultaneous control of 1-Vdc Diode Bridge power reduction) according to another embodiment of the present invention.
Fig. 12 is a table for explaining the operation in each control section of the relay power reduction circuit of Fig. 11.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings.

Fig. 9 is a circuit diagram of a relay power reduction circuit (1-Vdc Diode Bridge power reduction individual control) according to one embodiment of the present invention. In Fig. 9, the relay power reduction circuit includes RY1 and Q1 for controlling RY1, RY2 and Q2 for controlling RY2, and D1 for connecting RY1 and RY2 in series.

Fig. 10 is a table for explaining the operation in each control section of the relay power reduction circuit of Fig. 9. Referring to Fig. 10, in section 1, RY1 and RY2 are in the OFF state. In section 2, Q3 and Q4 are turned ON. RY1 and RY2 remain in the OFF state. In section 3, Q1 is turned ON to apply a Vdc voltage higher than the Pickup Voltage to the RY1 Coil, thereby turning RY1 ON. In section 4, Q2 is turned ON to apply a Vdc voltage higher than the Pickup Voltage to the RY2 Coil, thereby turning RY2 ON.

In section 5, if Q3 and Q4 are turned off simultaneously, a current path is created from Vdc through RY1 to D1 to RY2. At this time, ½Vdc voltage is applied to each of RY1 and RY2. (Assuming that D1 is ideal) This is the section where RY1 and RY2 maintain contact, and this is the section where a lot of heat is generated due to the resistance component of the RY1 and RY2 coils. Compared to when Vdc is applied to each, power consumption is reduced by ¼, and heat generation is reduced by that much.

Power consumption is a value calculated according to P= ^V2 /R. When Vdc is applied to each of the two Relays, ^Vdc2 /Rcoil is consumed by each Relay, and the sum of the power consumption of the two Relays becomes 2* ^Vdc2 /Rcoil. In the circuit proposed in the present invention, when 1/2Vdc is applied to each of the two Relays, (1/2*Vdc) ² /Rcoil is consumed by each Relay, and the sum of the power consumption of the two Relays becomes ½*Vdc/Rcoil. That is, when ½Vdc is applied, the power consumption is reduced by ¼ compared to when Vdc is applied.

Finally, in section 6, if either Q1 or Q2 is turned OFF first or simultaneously, RY1 and RY2 will also be turned OFF simultaneously.

Fig. 11 is a circuit diagram of a relay power reduction circuit (simultaneous control of 1-Vdc Diode Bridge power reduction) according to another embodiment of the present invention. In Fig. 11, it can be seen that the relay power reduction circuit includes two relay parts forming contacts, a switch part for relay contact control, and a diode bridge part for achieving power reduction.

Fig. 12 is a table for explaining the operation in each control section of the relay power reduction circuit of Fig. 11. As in Fig. 12, the relay control switch section is made conductive to enable initial short-circuiting of the relay, and after the short-circuiting is formed, the control switch section is cut off and instead, the supply voltage is distributed half and half to the two relay coils through a diode, thereby reducing power consumption to ¼ and maintaining the contact point.

In summary, the present invention relates to a power reduction circuit during relay control, and is characterized by including a relay section for directly opening and closing an electric circuit, a switch section for controlling the relay, and a diode bridge section for reducing DC power. In addition, considering that the relay holding voltage is lower than 1/2 of the relay rated voltage, the present invention is characterized by connecting a switch for each relay control when controlling two relays in conjunction, and connecting a diode between the two relays.

Accordingly, when each relay control switch is blocked in the relay operating state, the diode located between the two relays becomes conductive, so that about 1/2 of the rated voltage is applied to each relay, and the power consumption is reduced to about ¼. In addition, according to the reduced power consumption, the heat generated from the relay is also reduced to ¼, and the reduced heat enables the miniaturization of relay components and the miniaturization of the system. In addition, since this method does not cause noise as a DC voltage control method, it provides the effect of suppressing additional cost increases for noise removal.

Although the present invention has been described by some preferred embodiments, the scope of the present invention should not be limited thereby, but should extend to modifications and improvements of the above embodiments as supported by the scope of the claims.

Claims (3)

A first relay connected at one end to the first node;
A first switch connected between the other end of the first relay and the second node;
A second switch having one end connected to the first node;
a second relay connected between the other end of said second switch and said second node; and
A relay power reduction circuit characterized by including a diode connected between a third node to which the first relay and the first switch are connected and a fourth node to which the second switch and the second relay are connected.
In claim 1,
A relay power reduction circuit, characterized in that it further comprises a third switch connected to the first node or the second node.
In claim 1,
a fourth switch connected between the first relay and the first node or the third node; and
A relay power reduction circuit further comprising a fifth switch connected between the second relay and the second node or the fourth node.

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