Geneva, November 5, 2018 — STMicroelectronics’ PWD5F60 high-density power driver is the second in a new series of power-driver systems-in-package addressing high-voltage brushed DC and single-phase brushless motor applications. It integrates a 600V/3.5A single-phase MOSFET bridge with gate drivers, bootstrap diodes, protection features, and two comparators in a 15mm x 7mm outline. The HIP4083 is a three phase high side N-channel MOSFET driver, specifically targeted for PWM motor control. Two HIP4083 may be used together for 3 phase full bridge. 3 Phase Full Bridge DriverThe brushless DC (BLDC) motor’s increasing popularity is due to the use of electronic commutation. This replaces the conventional mechanics comprised of brushes rubbing on the commutator to energize the windings in the armature of a DC motor. Electronic commutation provides greater efficiency over conventional DC motors with improvements of 20 to 30% for motors running at the same speed and load. As the International Energy Agency reports that 40% of all global electricity is used to power electric motors, such efficiency gains become compelling. Further, the BLDC motor is more durable. It retains its high performance while the efficiency and power of an equivalent conventional motor declines due to wear, causing poor brush contact, arcing between the brushes and the commutator dissipating energy, and dirt compromising electrical conductivity. Greater efficiency allows BLDC motors to be made smaller, lighter and quieter for a given power output, further increasing their popularity in sectors such as automotive; white goods; and heating, ventilation and air conditioning (HVAC). Other advantages of BLDC motors include superior speed versus torque characteristics (with the exception of torque at start-up), a more dynamic response, noiseless operation, and higher speed ranges. The downside of BLDC motors is their complexity and the associated increase in cost. Electronic commutation demands supervisory circuits to ensure precise timing of coil energization for accurate speed and torque control, as well as ensuring the motor runs at peak efficiency. Fortunately, this sector is rapidly maturing and silicon vendors now offer a wide range of highly-integrated BLDC motor driver power MOSFET chips with either external or embedded microcontrollers to simplify the design process, while also lowering component costs. This article will explain how the designer can take advantage of these latest chips to ease the design process BLDC motor basics All electric motors, whether mechanically or electronically commutated, adhere to the same basic method of converting electrical energy into mechanical energy. Current through a winding generates a magnetic field, which in the presence of a second magnetic field (typically initiated by permanent magnets) generates a force on that winding that reaches a maximum when its conductors are at 90° to the second field. Increasing the number of coils raises the motor output and smooths power delivery. ( (MPS) has produced an application note (see Reference 1) which nicely summarizes motor fundamental concepts.) A BLDC motor overcomes the requirement for a mechanical commutator by reversing the motor set-up; the windings become the stator and the permanent magnets become part of the rotor. The stator is typically comprised of steel laminations, slotted axially to accommodate an even number of windings along its inner periphery. The rotor consists of a shaft and a hub with permanent magnets arranged to form between two to eight pole pairs that alternate between ‘N’ and ‘S’. Figure 1 shows one example of a common magnet arrangement, in this case two magnet pairs bonded directly to the rotor hub. Rosetta stone 3 rapidshare. Figure 1: In a BLDC motor the permanent magnets are attached to the rotor. Typical configurations comprise between two and eight pairs alternating between ‘N’ and ‘S’ poles. (Courtesy: MPS) Because the windings are stationary, permanent connections can be established to energize them. In order for the stationary windings to move the permanent magnet, the windings need to be energized (or commutated) in a controlled sequence to produce a rotating magnetic field. Because the rotating magnetic field generated by the stator causes the rotor to revolve at the same frequency, a BLDC motor is known as a “synchronous” type. BLDC motors can come in one-, two-, or three-phase. Three-phase BLDC motors are the most common and will be the subject of the rest of this article. Anydvd download slysoft. Are able to copy CSS protected movies. Copy with the help of AnyDVD tools like CloneDVD, Pinnacle Instant Copy, InterVideo DVD-Copy, etc. BLDC motor control By far the most common configuration for sequentially applying current to a three-phase BLDC motor is to use three pairs of power MOSFETs arranged in a bridge structure, as shown in Figure 2. Each pair governs the switching of one phase of the motor. In a typical arrangement, the high-side MOSFETs are controlled using pulse-width modulation (PWM) which converts the input DC voltage into a modulated driving voltage. The use of PWM allows the start-up current to be limited and offers precise control over speed and torque. The PWM frequency is a trade-off between the switching losses that occur at high frequencies and the ripple currents that occur at low frequencies, and which in extreme cases, can damage the motor. Typically, designers use a PWM frequency of at least an order of magnitude higher than the maximum motor rotation speed. Figure 2: A three-phase BLDC motor is typically powered by three pairs of MOSFETs arranged in a bridge structure and controlled by PWM. PWM offers precise control over the motor’s speed and torque. (Diagram drawn using ) There are three control schemes for electronic commutation: trapezoidal, sinusoidal and field-oriented control. The trapezoidal technique (described in the example below) is the simplest. At each step, two windings are energized (one “high” and one “low”) while the other winding floats. The downside of the trapezoidal method is that this ‘stepped’ commutation causes the torque to ‘ripple’, especially at low speeds. Sinusoidal control is more complex, but it reduces torque ripple. During this control regime, all three coils remain energized with the driving current in each of them varying sinusoidally at 120° from each other. The result is a much smoother power delivery compared with the trapezoidal technique. 3 Phase H-bridge Motor DriverField-oriented control relies on measuring and adjusting stator currents so that the angle between the rotor and stator flux is always 90°. This technique is more efficient at high speeds than the sinusoidal method and gives better performance during dynamic load changes compared to all other techniques. Un barrage contre le pacifique duras pdf de. There is virtually no torque ripple, and smoother, accurate motor control can be achieved at both low and high speeds. This article will limit the rest of the technical discussion to the trapezoidal technique. In a motor employing a trapezoidal control scheme, the MOSFET bridge switching must occur in a precisely defined sequence for the BLDC motor to operate efficiently. The switching sequence is determined by the relative positions of the rotor’s magnet pairs and the stator’s windings. A three-phase BLDC motor requires a six step commutation sequence to complete one electrical cycle. The number of mechanical revolutions per electrical cycle is determined by the number of pairs of magnets on the rotor. 3 Phase Full Bridge DriversFor example, two electrical cycles will be required to mechanically spin a rotor comprised of two pairs of magnets one revolution. Sensorless Two technologies offer a solution for positional feedback. The first and most common uses three Hall-effect sensors embedded in the stator and arranged at equal intervals, typically 60° or 120°. A second, ‘sensorless’ control technology comes into its own for BLDC motors that require minimal electrical connections. In a sensor-equipped BLDC motor, each Hall-effect sensor is combined with a switch which generates a logic “high” (for one magnetic pole) or “low” (for the opposite pole) signal. The commutation sequence is determined by combining the logic signals from the Hall-effect sensors and associated switches.
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