WO2021194395A1

WO2021194395A1 - Wireless device for switching an electrical load

Info

Publication number: WO2021194395A1
Application number: PCT/RU2021/050079
Authority: WO
Inventors: Алексей Юрьевич УСКОВ; Евгений Анатольевич СИРОТКИН; Андрей Игоревич ЦИМБОЛ; Надежда Викторовна УСКОВА
Original assignee: Общество С Ограниченной Ответственностью "Инсмартавтоматика"
Priority date: 2020-03-27
Filing date: 2021-03-24
Publication date: 2021-09-30
Also published as: RU2733487C1

Abstract

The invention relates to electrical engineering and can be used for controlling the power supply to different electrical appliances, inter alia for remotely turning electrical appliances on to/off from a mains supply, and also for turning electrical appliances on/off according to different programmed scenarios. A device for switching an electrical load comprises the following arranged in a single housing: an electric power unit, a contact relay with changeover contacts, a semiconductor triac connected in parallel to the changeover contacts of the contact relay, and connectors for connection to communication lines, wherein the device comprises from 1 to 8 contact relays with parallel-connected semiconductor triacs controlled by an optical driver with a zero-crossing detector, and further comprises a mesh module capable of controlling the switching device, transmitting data to a remote server and supporting ad hoc wireless mesh networks. The invention makes it possible to increase the operating life of a power switching device, to improve connection reliability and increase the range and, thus, improve the quality of connection over a network (e.g. a Wi-Fi network or a mesh network based on ZigBee or Thread standards), and to reduce the overall dimensions of the device.

Description

Wireless electrical load switching device

The technical field to which the invention relates

The invention relates to electrical engineering and can be used to control power supply of various electrical appliances, including for remote switching on / off electrical appliances from the power supply, as well as for switching on / off electrical appliances according to various programmable scenarios.

State of the art

At the moment, the use of wireless switches of electrical energy is becoming relevant. This is due to the rapid development of smart home and Internet of Things technologies, the development of mobile applications for controlling electronic devices, etc. A wireless electrical switching device can perform one of the key functions in these areas, namely, power management of various electrical appliances.

A housing for a smart socket is known from the prior art (see [1] RF patent for a useful model N ° 183511, IPC H01 R13 / 00, publ. 09/25/2018) with a load control module located at the base of the socket; connecting the load to the electrical contact elements, and the power supply network to the contact pins of the plug; indication of the power level consumed by the load using a light guide and a light diffuser; compliance with electrical safety requirements by connecting the grounding pins on the cover with the grounding contact of the plug housing. The disadvantage of this socket is a small resource and low reliability due to the use of contact elements (relays) in it.

There are a lot of similar devices made in the form of a socket module for one plug (see, for example, [2] RF patent for a useful model N ° 145549, IPC G08B13 / 00, publ. 09/20/2014; [3] RF patent for a useful model N ° 126221, IPC H02J3 / 00, publ. 03/20/2013; [4] utility model patent of China N ° 204028223, IPC G01 R21 / 00, publ. 17.12.2014; [5] US patent for inventions Ns 9378530, IPC G06Q50 / 06, publ. 06/28/2018; [6] application for a US patent for invention N ° 20170155526, IPC H01 R13 / 66, publ. 06/01/2017). The main structural element of such devices is a contact relay, which has mechanical elements and a corresponding inertia coefficient, and the inertia coefficient changes both during the operation of the relay and differs in different relay models, which does not allow the contacts to be closed at the right time (at the moment of the phase transition through zero). In addition, when the relay contacts are closed / opened, an electric arc occurs, which shortens the life of the product and, ultimately, can lead to "sticking" of the contacts.

The disadvantage associated with "sticking contacts" was solved by replacing the relay with a bidirectional triode thyristor (triac) (see [7] RF patent for invention N ° 2638182, IPC N01 N43 / 00, publ. 12.12.2017). The use of a triac allows for almost instantaneous closure of the circuit without the formation of an electric arc, however, this solution has a significant drawback - during prolonged operation, the triac will heat up significantly, which will require additional heat dissipation, which in turn will increase the size of the product, etc. overheating will simply fail, which ultimately reduces the overall reliability of the device.

A contact protection circuit for a relay is known from the prior art (see [8] US patent N ° 3639808, MPKN01 N9 / 54, publ. 02/01/1972), to the coil of which a constant voltage is applied and the contact switches alternating current. The triac is connected in parallel with the relay contact and can be controlled by a coil that is magnetically connected to the relay coil. The disadvantage of such a scheme is the complexity of manufacturing the relay, due to the need for an additional magnetically coupled coil. Also, the circuit under consideration serves to protect the relay contacts only at the moment of opening the contacts.

From the prior art, a method for controlling the voltage of a transformer under load is known (see [9] RF patent for invention N ° 2711587, IPC N02R13 / 06, publ. 17.01.2020). In the method of controlling the voltage of the transformer under load, including setting the level of the output voltage of the transformer, monitoring the voltage of the supply network, monitoring the current, supplying control pulses to the bidirectional thyristor switches included in the branch circuits of the primary winding of the transformer, the control of each bidirectional thyristor switch is carried out in conjunction with the control of the controlled relay connected in parallel with the bidirectional thyristor switch, so that in the steady-state operation of the transformer, the state of the controlled relay is set similarly to the state of the bidirectional thyristor switch, and in the process of controlling the voltage of the transformer, when the state of the bidirectional switch changes from off to on, the change in the state of the controlled relay from off to on is carried out with a time delay after turning on the bidirectional thyristor switch, and before changing the state of the bidirectional switch from on to off beforehand the controlled relay is transferred from the on state to the off state, and in the voltage control device of the transformer under load, containing at least two bidirectional thyristor switches, a controlled relay connected to the control unit is connected in parallel to each bidirectional thyristor switch.

The disadvantage of this analogue is the lack of galvanic isolation, while the triac is an anti-parallel connection of thyristors, therefore, the specified switching method is analogous.

From the prior art, a load switching device for electricity meters is known (see [10] RF patent for utility model N ° 21307, IPC G01 R11 / 63, publ. 10.01.2002), containing an electricity meter and a switching circuit connected between the power grid and the consumer bus , while the switching circuit contains an electromechanical relay connected between the power grid and the consumer bus and a solid-state relay parallel to it, while the electricity meter is connected to the interface bus, the control inputs of the electromechanical and solid-state relay are connected to the electricity meter, and the solid-state relay is made on discrete elements, for example, optocoupler and triac.

The described device is analogous, since it uses parallel connection of relay contacts and a solid-state relay (triac controlled by an optical driver). However, this analogue does not allow remote control of the load, but uses this switching scheme only for emergency shutdown of consumers in case of overload.

The closest analogue of the claimed invention, adopted for the prototype, is a system for remote control of devices and control of devices (see [11] RF patent for invention N ° 2648564, MI1KG08C17 / 00, publ. 03/26/2018). In a particular embodiment of the invention, the prevention of "sticking" of the relay (in particular, the electromagnetic relay, which is part of the implementation of the final device / module, for example, the module 110A ... 110N) when switching on (capacitive) loads such as reactive loads. So, when the loads are switched on, in particular (significant) reactive loads, for example, capacitive loads through the relay, in the latter, a short-term breakdown of the gap between the contacts can occur. To prevent burning of contacts and the need for mechanical human intervention, the following method of eliminating such incidents is carried out: at the first moment of switching on the load, it is switched through a triac, then after a certain / given (insignificant, for example, from 400 to 700 milliseconds) a period of time is carried out (in particular , by means of the controller) relay switching. The load is switched off in the reverse order, which avoids switching currents on the relay, and the short operating time of the triac allows it to completely absorb the dissipated power without harming the component design (in particular, the triac) even at the maximum allowable currents. Moreover, the maximum permissible current value, in a particular case, depends on the configuration of the final device 110A ... 110N and can be limited by the used pair of relays - triac.

The disadvantage of the prototype is the lack of a driver with a zero detector and galvanic isolation, which in turn reduces the reliability and safety of operation (galvanic isolation) of the product.

The disadvantages of the listed technical solutions are:

- limited service life of products when only a contact relay is used in their composition, the contacts of which melt and erode over time due to the arising electric arc when it is closed and opened;

- when using Wi-Fi modules as part of products, the working area is limited by the coverage area of the Wi-Fi signal;

- lack of modularity of products - if it is necessary to place products next to each other, then for each product a separate Wi-Fi module is required, which in turn increases the total cost of the product group, as well as its dimensions.

The essence of the invention

The objective of the claimed invention is to create a reliable device for switching electrical energy with an increased service life.

The technical result is to increase the resource of the electrical energy switching device, increase the reliability of communication and increase range and, as a result, improve the quality of communication over the network (Wi-Fi networks, Mesh networks based on ZigBee standards, Thread), reduce the overall dimensions of the device.

The problem is solved, and the technical result is achieved due to a device for switching electrical loads containing a power supply unit, a contact relay with switching contacts, a semiconductor triac: a conventional anode and a conventional cathode are connected parallel to the switching contacts of a contact relay, connectors for connecting to communications, located in one housing, the device contains from 1 to 8 contact relays with parallel-connected semiconductor triacs, controlled by an optical driver with a zero detector, while the device contains a Mesh module responsible for controlling the switching device, transmitting data to a remote server and supporting self-organizing wireless Mesh networks.

Brief Description of Drawings

FIG. 1 - Block diagram of the switch.

FIG. 2 - Electrical diagram of the switch.

FIG. 3 - Diagram of a mesh network formed by wireless electrical switches.

FIG. 4 - Diagram of a group of switching devices in a modular design.

Implementation of the invention

The device for switching electrical loads contains, placed in one housing and connected to each other: a power supply unit; contact relay with changeover contacts; semiconductor triac: the conventional anode and the conventional cathode of which are connected in parallel with the switching contacts of the contact relay; connectors for connection to communications. The power supply unit (power supply) has a well-known standard layout and includes a fuse to protect the device and communications from short circuits, a varistor to protect the device from voltage surges, a diode bridge to rectify the mains voltage, an electric capacitor to store energy for a switching regulator, a switching voltage regulator, ceramic and tantalum capacitors for smoothing voltage ripples, linear stabilizer (if the device has a Mesh module). The device contains from 1 to 8 contact relays with semiconductor triacs connected in parallel, controlled by an optical driver with a zero detector. The device also contains a Mesh module capable of controlling a switching device, transmitting data to a remote server, and supporting self-organizing wireless Mesh networks.

The increase in resource is achieved by the presence of a triac in the switch (Fig. 1). This is one of the main distinguishing features of the device being patented. Contact closure is carried out using a relay. In our case, the triac closes first (when the phase passes through the zero mark) and only then the relay closes to prevent overheating of the triac, see Fig. 2. This principle allows you to avoid the appearance of an electric arc when the contacts are closed / opened (because at the moment of the phase transition through the zero mark, the voltage is equal to zero), that is, there will be no erosion of the contacts. As a result, the resource of the electrical load switching device is significantly increased.

An increase in the resource of the electrical energy switching device is achieved through the use of a parallel circuit for a contact relay (electromechanical) and a semiconductor triac. To increase the operating life of the triac, as well as reduce the power dissipated on it at the time of switching and reduce the level of noise in the network, a driver with a zero detector (for example, based on optocouplers) is used to control the triac. Due to the use of an optical driver with a zero detector, galvanic isolation between the control and high-voltage circuits is also provided, which is simply necessary. The triac is controlled by an optical driver with zero crossing detection. At the initial moment of time, the triac will switch the electrical load. This is due to the fact that the contact relay has mechanical elements and a corresponding inertia coefficient, and the inertia coefficient changes both during the operation of the relay and differs in different relay models, which does not allow the contacts to be closed at the right time (at the moment of the phase transition through zero) ... In addition, when the relay contacts are closed / opened, an electric arc occurs, which shortens the life of the product and, ultimately, can lead to "sticking" of the contacts. Driver controlled triac with detection crossing zero, allows for almost instantaneous closure of the circuit without the formation of an electric arc. However, during long-term operation, the triac will heat up to a significant extent, which will require additional heat dissipation. The use of a triac as a load switch entails the problem of heat dissipation, when currents of more than 0.5 A flow through it, which will subsequently lead to its destruction. That is why the developers are forced to additionally place a radiator on the PCB of the switching device, which ultimately leads to an increase in the size of the product and its cost, which, in turn, is not always available. Thus, a contact relay will be used to keep the circuit closed for a long time. The contact relay will close after the triac is closed in the parallel circuit, as a result of which, an electric arc will not occur between the relay contacts. As a result, on the one hand, a guaranteed connection of the load is ensured at the moment of the phase transition through zero, on the other hand, there is no overheating and overload of electronic components. This option will significantly increase the resource of the device. At the moment of disconnection of the electrical load, the relay contacts will first open, then the circuit will finally open the triac. The main advantage of a triac is its ability to switch loads without sparking and the absence of mechanically moving parts, which guarantees, with the necessary heat removal and compliance with recommendations for its protection, an almost unlimited resource of the element.

Improved communication reliability and increased range are achieved by integrating a Mesh module (eg, but not limited to Wi-Fi technology) into the device to build a Mesh network. This is the main distinguishing feature from analogues. The presence of a Mesh module in the switch allows you to build a wireless network between the same devices (Fig. 3), thereby the coverage area of Wi-Fi signal devices (from a router) increases to the area of the formed wireless network using switches with Mesh modules. Mesh networking allows multiple devices located over a large area (both indoor and outdoor) to be connected within a single wireless LAN. Such a network is self-organizing and self-healing. This means that the network can be built and maintained autonomously. Traditional Wi-Fi infrastructure is a point-to-multipoint network in which one central node (access point), directly connected to other devices. An access point is responsible for arbitrating and transferring data between it and connected devices. Some access points are repeaters from an external IP network or to an external IP network via a router. Traditional Wi-Fi network infrastructures differ in that they have limited coverage. In addition, traditional Wi-Fi networks are prone to congestion because the maximum number of connected devices is limited by the capabilities of the access point. Thanks to the use of Mesh technology, connected devices do not need to connect to a central site. Instead, they are allowed to connect with neighboring devices. The devices are mutually responsible for relaying information to each other. This allows the Mesh network to have a large coverage area as devices can communicate with each other without having to be in the coverage area of a central site. Likewise, the Mesh network is also less susceptible to congestion, as the number of nodes allowed on the network is no longer limited to a single central node.

The reduction in size is achieved by cascading switching devices without individual wireless Mesh modules, while only one wireless Mesh network module is connected to the entire group, with which it is possible to control each switch separately (Fig. 4). The absence of individual modules makes it possible to reduce the size of a group of devices. When using a group of similar switching devices (cascade connection), only one wireless Mesh network module is added to them, which is connected to them using a wired communication line. At the same time, wireless electrical load switching devices no longer contain built-in wireless Mesh network modules, which allows them to reduce their cost and overall dimensions.

Claims

CLAIM

An electrical load switching device containing a power supply unit located in one housing, a contact relay with changeover contacts, a semiconductor triac connected in parallel with the switching contacts of a contact relay, connectors for connecting to communications, characterized in that the device contains from 1 to 8 contact relays with semiconductor connected in parallel triacs controlled by an optical driver with a zero detector, while the device contains a Mesh module capable of controlling a switching device, transmitting data to a remote server, and supporting self-organizing wireless Mesh networks.